MO251HIGHLY SENSITIVE FLOW CYTOMETRIC DETECTION OF RESIDUAL B-CELLS AFTER RITUXIMAB IN ANTI-NEUTROPHIL CYTOPLASMIC ANTIBODY-ASSOCIATED VASCULITIS PATIENTS*

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Y K O Teng ◽  
L Van Dam ◽  
Jelle Oskam ◽  
S W A Kamerling ◽  
E J Arends ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
B Cells ◽  
B Cell ◽  
Mononuclear Cells ◽  
Plasma Cells ◽  
Memory B Cells ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Peripheral Blood Mononuclear

Abstract Background and Aims B-cell depletion with rituximab (RTX) is an effective treatment for anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) patients. Nevertheless, relapses are frequent after RTX, often preceded by B-cell repopulation suggesting that residual autoreactive B-cells persist despite therapy. Therefore, this study aimed to identify minimal residual autoimmunity (MRA) in the B-cell compartment of AAV patients treated with RTX. Method EuroFlow-based highly-sensitive flow cytometry (HSFC) was employed to study B-cell and plasma cell (PC) subsets in-depth in AAV patients before and after RTX treatment. Additionally, peripheral blood mononuclear cells (PBMCs) of these RTX-treated AAV patients were cultured and in vitro stimulated with CpG, IL-2, and IL-21 to induce antibody-secreting cells (ASC). (ANCA)-IgG was measured in these supernatants by ELISA. Results By employing EuroFlow-based HSFC, we detected circulating CD19+ B-cells at all timepoints after RTX treatment, in contrast to conventional low-sensitive flow cytometry. Pre-germinal center (Pre-GC) B-cells, memory B-cells and CD20+CD138− plasmablasts (PBs) were rapidly and strongly reduced, while CD20−CD138− PrePC and CD20-CD138+ mature (m)PCs were reduced slower and remained detectable. Both memory B-cells and CD20− PCs remained detectable after RTX. Serum ANCA-IgG decreased significantly upon RTX. Changes in ANCA levels strongly correlated with changes in naive, switched CD27+ and CD27− (double-negative) memory B-cells, but not with plasma cells. Lastly, we demonstrated in vitro ANCA production by AAV PBMCs, 24 and 48 weeks after RTX treatment reflecting MRA in the memory compartment of AAV patients. Conclusion We demonstrated that RTX induced strong reductions in circulating B-cells, but never resulted in complete B-cell depletion. Despite strongly reduced B-cell numbers after RTX, ANCA-specific memory B-cells were still detectable in AAV patients. Thus, MRA is identifiable in AAV and can provide a potential novel approach in personalizing RTX treatment in AAV patients.

scholarly journals Highly Sensitive Flow Cytometric Detection of Residual B-Cells After Rituximab in Anti-Neutrophil Cytoplasmic Antibodies-Associated Vasculitis Patients

2020 ◽  
Vol 11 ◽  
Author(s):  
Laura S. van Dam ◽  
Jelle M. Oskam ◽  
Sylvia W. A. Kamerling ◽  
Eline J. Arends ◽  
O. W. Bredewold ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
B Cells ◽  
B Cell ◽  
Mononuclear Cells ◽  
Memory B Cells ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Peripheral Blood Mononuclear ◽  
Highly Sensitive

BackgroundB-cell depletion with rituximab (RTX) is an effective treatment for anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) patients. Nevertheless, relapses are frequent after RTX, often preceded by B-cell repopulation suggesting that residual autoreactive B-cells persist despite therapy. Therefore, this study aimed to identify minimal residual autoimmunity (MRA) in the B-cell compartment of AAV patients treated with RTX.MethodsEuroFlow-based highly-sensitive flow cytometry (HSFC) was employed to study B-cell and plasma cell (PC) subsets in-depth in AAV patients before and after RTX treatment. Additionally, peripheral blood mononuclear cells (PBMCs) of these RTX-treated AAV patients were cultured and in vitro stimulated with CpG, IL-2, and IL-21 to induce antibody-secreting cells (ASC). (ANCA)-IgG was measured in these supernatants by ELISA.ResultsBy employing EuroFlow-based HSFC, we detected circulating CD19+ B-cells at all timepoints after RTX treatment, in contrast to conventional low-sensitive flow cytometry. Pre-germinal center (Pre-GC) B-cells, memory B-cells and CD20+CD138− plasmablasts (PBs) were rapidly and strongly reduced, while CD20−CD138− PrePC and CD20-CD138+ mature (m)PCs were reduced slower and remained detectable. Both memory B-cells and CD20− PCs remained detectable after RTX. Serum ANCA-IgG decreased significantly upon RTX. Changes in ANCA levels strongly correlated with changes in naive, switched CD27+ and CD27− (double-negative) memory B-cells, but not with plasma cells. Lastly, we demonstrated in vitro ANCA production by AAV PBMCs, 24 and 48 weeks after RTX treatment reflecting MRA in the memory compartment of AAV patients.ConclusionWe demonstrated that RTX induced strong reductions in circulating B-cells, but never resulted in complete B-cell depletion. Despite strongly reduced B-cell numbers after RTX, ANCA-specific memory B-cells were still detectable in AAV patients. Thus, MRA is identifiable in AAV and can provide a potential novel approach in personalizing RTX treatment in AAV patients.

Steady-state generation of mucosal IgA+ plasmablasts is not abrogated by B-cell depletion therapy with rituximab

Blood ◽  
2010 ◽  
Vol 116 (24) ◽  
pp. 5181-5190 ◽  
Author(s):  
Henrik E. Mei ◽  
Daniela Frölich ◽  
Claudia Giesecke ◽  
Christoph Loddenkemper ◽  
Karin Reiter ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Steady State ◽  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Plasma Cells ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Ki 67

AbstractThe anti-CD20 antibody rituximab depletes human B cells from peripheral blood, but it remains controversial to what extent tissue-resident B cells are affected. In representative patients with rheumatoid arthritis, we here demonstrate that recently activated presumably short-lived plasmablasts expressing HLA-DRhigh and Ki-67 continuously circulate in peripheral blood after B-cell depletion by rituximab at 26%-119% of their initial numbers. They circulate independent of splenectomy, express immunoglobulin A (IgA), β7 integrin, and C-C motif receptor 10 (CCR10) and migrate along CCL28 gradients in vitro, suggesting their mucosal origin. These plasmablasts express somatically hypermutated VH gene rearrangements and spontaneously secrete IgA, exhibiting binding to microbial antigens. Notably, IgA+ plasmablasts and plasma cells were identified in the lamina propria of patients treated with rituximab during peripheral B-cell depletion. Although a relation of these “steady state”–like plasmablasts with rheumatoid arthritis activity could not be found, their persistence during B-cell depletion indicates that their precursors, that is, B cells resident in the mucosa are not deleted by this treatment. These data suggest that a population of mucosal B cells is self-sufficient in adult humans and not replenished by CD20+ B cells immigrating from blood, lymphoid tissue, or bone marrow, that is, B cells depleted by rituximab.

Emergence of Long-Lived Autoreactive Plasma Cells in the Spleen of Primary Warm Auto-Immune Hemolytic Anemia Patients Treated with Rituximab

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 569-569
Author(s):  
Matthieu Mahevas ◽  
Marc Michel ◽  
Benoit Vingert ◽  
Julien Moroch ◽  
David Boutboul ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Blood Cells ◽  
Plasma Cells ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
Bone Marrow Plasma ◽  
Previously Treated

Abstract Introduction: We recently proposed that B-cell depletion in immune thrombocytopenia (ITP) promotes the generation of long-lived plasma cells in the spleen, some of them being auto-reactive; but it remained possible that this observation was related to ITP itself rather than to B-cell depletion. Primary warm autoimmune hemolytic anemia (wAIHA) is a rare disease characterized by IgG auto-antibodies directed against antigens at the surface of red blood cells (RBCs) antigens, leading to their accelerated destruction. The use of B-cell depletion in wAIHA leads to 60 % to 70% of overall response at one-year and beyond. Nevertheless, 30-40 % of patients may resist to rituximab and then require a splenectomy. Nothing is known about antibody secreting cells (ASC) in the spleen of wAIHA patients, who have previously been treated or not with rituximab. In this study, we analyzed at the single cell level the splenic ASC from patients with chronic and active wAIHA, previously treated or not with rituximab (RTX), and we compared them with splenic ASC from ITP patients, and with splenic and bone marrow plasma cells from healthy donors (HD). Methods: We took advantage of the different therapeutic outcomes to analyze the splenic B-cell compartment of wAIHA patients, not previously treated with RTX (n=6), or after failure RTX treatment (n=3).Splenic tissues from organ donors and bone marrow from cardiovascular thoracotomy were used as controls. Blood samples from wAIHA (n=19), and (HD) (n=8) enrolled in this study were obtained after giving written informed consent in accordance with the Declaration of Helsinki. Results: We observed by flow cytometry and microscopy that the spleen from wAIHA patients who received less than 3 months of steroid therapy was the site of a B-cell response characterized by the presence of Bcl6+ germinal-center (GC) B-cells. Furthemore, splenic ASC secreted anti-red blood cell IgG in vitro. In line with this observation, we observed in the peripheral blood from patients with a newly diagnosed wAIHA (n=11), that short-lived IgG plasmablasts were increased compared with HD (n=8) (Mean 4.2 ± 0.84 % vs 0.99 ± 0.19% of CD19+ cells, p< 0.01). Moreover, for patients receiving long term steroid therapy (> 6 months) the plasmablast response was suppressed in the peripheral blood (Mean: 0.68 ± 0.2 % of CD19+ cells, n=8) and the splenic GC B-cell reaction was impaired (n=3). We conclude that short-lived IgG ASC result from an over-activity of GC reactions in wAIHA. We then analyzed the spleen of 3 patients who failed to respond to RTX, and observed a residual population of CD19+B-cells (median: 0.9% of lymphoid cells), including non-proliferative memory B-cells and plasma cells (PC). A fraction of these residual PC secreted anti-red blood cells IgG in vitro, thus accounting for the faillure of the B-cell depletion therapy. By using a single cell multiplex quantitative RT-PCR (Fluidigm dynamic arrays), we showed that such RTX-resistant plasma cells display a long-lived transcriptional program, which differs from PC from untreated wAIHA patients or HD, as well as from plasmablasts. Interestingly, the gene expression profile of wAIHA long-lived plasma cells segregated with long-lived PC previously observed in the spleen of ITP patients treated with rituximab. By a principal component analysis, we observed a gradient of maturation from plasmablasts to bone marrow plasma cells in which PC from RTX-treated spleens segregated close to bone marrow PC. We also observed that the cytokine BAFF was increased in the supernatants of spleen cell cultures from wAIHA patients treated with rituximab compared with controls (p< 0.05), suggesting, in keeping with our previous report in ITP, a role for BAFF in the differentiation of short-lived plasma cells into long-lived plasma cells. Conclusion: The presence of splenic long-lived autoreactive PC in wAIHA may explain why some patients cannot achieve a response after RTX. Our results show that, the B-cell depletion induced by rituximab itself, as opposed to the underlying auto-immune condition, promotes a suitable environment for the maturation of auto-immune long-lived plasma cells in the spleen. Targeting specifically some factors such as BAFF right after rituximab injection could be an interesting therapeutic option in the future. Disclosures No relevant conflicts of interest to declare.

scholarly journals OP0186 CHANGES IN CIRCULATING B CELL LEVELS AND IMMUNOPHENOTYPE ARE ASSOCIATED WITH DEVELOPMENT OF ARTHRITIS FOLLOWING TREATMENT WITH CHECKPOINT INHIBITORS

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 112.2-113
Author(s):  
M. Gatto ◽  
S. Bjursten ◽  
C. Jonell ◽  
C. Jonsson ◽  
S. Mcgrath ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
B Cells ◽  
Adverse Events ◽  
B Cell ◽  
Mononuclear Cells ◽  
Checkpoint Inhibitors ◽  
Therapy Monitoring ◽  
Cell Subset ◽  
Peripheral Blood Mononuclear ◽  
Transitional B Cells

Background:Inflammatory arthritis (IA) is frequent among rheumatic side effects induced by checkpoint inhibitor (CPI) therapy for metastatic malignancies1. While T cells are likely to sustain the inflammatory process2, fewer data are available concerning the role of B cells3.Objectives:To investigate the phenotype of circulating B cells in patients who develop CPI-induced IA (CPI-IA) and to compare it with features of B cells in patients not developing immune-related adverse events (irAE) upon CPI treatment.Methods:B cell subsets at baseline (before CPI initiation) and during CPI treatment were analyzed in CPI-IA patients and in patients receiving CPI but who did not develop irAE (non-irAE). Peripheral blood mononuclear cells (PBMC) were analyzed by flow cytometry and B cells were identified as CD19+ and divided into naïve (CD27-IgD+), memory (CD27+IgD+/-), double negative (CD27-IgD-) and transitional (CD10+CD24+CD38+/hi) B cells. Levels of CD21, an activation marker on transitional B cells, were also analyzed. Non-parametric tests were used for analysis of differences between groups.Results:Six CPI-IA and 7 non-irAE patients matched for age, gender and CPI treatment were included, who had received CPI treatment due to metastatic melanoma. Flow cytometry revealed a significant increase of circulating B cells (p=0.002) (Figure 1A) and especially of transitional B cells in CPI-IA patients vs. non-irAE (median %, range: 7.8 (4.5-11.4) vs. 3.2 (1.6-4.3),p=0.007) (Figure 1B), while no remarkable changes were seen across other subsets. Transitional B cell levels significantly decreased from active to quiescent CPI-IA in all patients (p=0.008). In two CPI-IA patients for whom baseline sampling was available, the increase of transitional levels occurred early after CPI treatment and before CPI-IA onset. Levels of expression of CD21 on transitional B cells were increased in CPI-IA vs. non-irAE (p=0.01).Conclusion:Transitional B cells are expanded in CPI-IA patients and seem to increase early after start of CPI therapy. Monitoring this B cell subset might lead to closer follow-up and earlier diagnosis of CPI-IA.References:[1]Ramos-Casals M, Brahmer JR, Callahan MK, et al. Immune-related adverse events of checkpoint inhibitors. Nat Rev Dis Primers 2020;6:38[2]Murray-Brown W, Wilsdon TD, Weedon H, et al. Nivolumab-induced synovitis is characterized by florid T cell infiltration and rapid resolution with synovial biopsy-guided therapy. J Immunother Cancer 2020;8:e000281[3]Das R, Bar N, Ferreira M, et al. Early B cell changes predict autoimmunity following combination immune checkpoint blockade. J Clin Invest. 2018;128:715-2Disclosure of Interests:None declared

Potent B-Cell Depletion by IMGN529, a CD37-Targeting Antibody-Maytansinoid Conjugate for the Treatment of B-Cell Malignancies,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3726-3726
Author(s):  
Jutta Deckert ◽  
Sharon Chicklas ◽  
Yong Yi ◽  
Min Li ◽  
Jan Pinkas ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Whole Blood ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
B Cell Malignancies

Abstract Abstract 3726 CD37 is a B-cell surface antigen which is widely expressed on malignant B cells in non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL). In normal tissues CD37 expression is limited to blood cells and lymphoid tissues. This restricted expression profile makes CD37 an attractive therapeutic target for antibodies and antibody-drug conjugates. We developed a novel anti-CD37 antibody, K7153A, which provides a unique combination of functional properties: it demonstrated strong pro-apoptotic and direct cell killing activity against NHL cell lines and could mediate effector activity such as CDC and ADCC. The antibody-maytansinoid conjugate, IMGN529, was produced by conjugation of K7153A with the potent maytansinoid, DM1, via the non-cleavable linker, SMCC. The direct cytotoxic potency of the K7153A antibody was superior to that of the CD20-directed rituximab and was further enhanced with maytansinoid conjugation in IMGN529. In vivo, IMGN529 demonstrated better anti-tumor activity than the K7153A antibody in established subcutaneous follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and CLL xenograft models in SCID mice. A single administration of IMGN529 showed similar or improved efficacy compared to anti-CD20 antibodies or standard chemotherapy where tested. Immunohistochemical (IHC) staining of formalin fixed paraffin-embedded (FFPE) NHL tissue sections was performed to evaluate CD37 expression. CD37 exhibited a similar prevalence to CD20 in subtypes of NHL such as FL, DLBCL, Burkitt's lymphoma (BL) and mantle cell lymphoma (MCL). B-cell depletion is an important measure of efficacy for targeted therapies, such as CD20-directed antibodies, in B-cell malignancies. CD37 expression in blood cells from healthy human donors was measured by quantitative flow cytometry in comparison to CD20. The greatest CD37 expression was found in B cells at approximately 77,000 antibodies bound per cell (ABC), which was similar to CD20 expression in B cells at 95,000 ABC. In other blood cell types CD37 staining was seen at low levels, about 2,000 – 5,000 ABC, in monocytes, NK cells and T cells. In vitro depletion experiments were performed with purified peripheral blood mononuclear cells (PBMCs) and with whole blood, both derived from several healthy donors. Cells were incubated for 1 hr with 10 μg/mL of either K7153A, IMGN529, CD37-targeting TRU-016, rituximab or the anti-CD52 antibody alemtuzumab, with cell depletion determined relative to counting beads by flow cytometry. The K7153A antibody and the IMGN529 conjugate efficiently and specifically depleted B-cells in a dose-dependent manner in the context of purified PBMCs and whole blood. With purified PBMCs, both K7153A and IMGN529 caused 50–60% depletion of B cells, with little to no depletion of T cells or monocytes. IMGN529 was more potent than rituximab, which led to 30–40% B-cell depletion, or TRU-016, which caused 20–30% B-cell depletion. IMGN529 also was more specific than alemtuzumab, which depleted T-cells and monocytes as well as B cells. With whole blood samples, both K7153A and IMGN529 resulted in 30–40% B-cell depletion with no effect on T cells, NK cells or monocytes. IMGN529 was again more potent than rituximab or TRU-016, which caused approximately 10% B-cell depletion, and was more specific than alemtuzumab, which depleted the majority of T cells in addition to 40% of B cells. IMGN529 embodies a unique B-cell targeted agent as it combines the intrinsic pro-apoptotic, CDC and ADCC activities of its anti-CD37 antibody component with the potent cytotoxic mechanism provided by the targeted delivery of its maytansinoid payload. It is highly active in vitro and in vivo against B-cell lymphoma and CLL cell lines. In addition, it mediates specific B-cell depletion in vitro that is greater than B-cell depletion by CD20-directed rituximab. Together, these findings indicate that IMGN529 is a promising therapeutic candidate for the treatment of B-cell malignancies. Disclosures: Deckert: ImmunoGen, Inc.: Employment. Chicklas:ImmunoGen, Inc.: Employment. Yi:ImmunoGen, Inc.: Employment. Li:ImmunoGen, Inc.: Employment. Pinkas:ImmunoGen, Inc.: Employment. Chittenden:ImmunoGen, Inc.: Employment. Lutz:ImmunoGen, Inc.: Employment. Park:ImmunoGen, Inc.: Employment.

Gastrointestinal defects and immunodeficiency syndrome with normal in vitro IgG production

2018 ◽  
Vol 5 (3) ◽  
pp. 91-99
Author(s):  
Alexandra Langlois ◽  
Bahar Torabi ◽  
Marieme Dembele ◽  
Marylin Desjardins ◽  
Reza Alizadehfar ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Mononuclear Cells ◽  
Cell Function ◽  
Current Knowledge ◽  
Genetic Defect ◽  
Peripheral Blood Mononuclear ◽  
Cardiac Malformations ◽  
Immunodeficiency Syndrome

Background: Gastrointestinal defects and immunodeficiency syndrome (GIDID) is a severe neonatal disorder usually fatal within the first months of life. We report a case presenting with intestinal atresia, combined immunodeficiency, and a novel association with hypothyroidism and cardiac malformations. The immune phenotype was remarkable for agammaglobulinemia, lymphopenia, and mildly decreased lymphocyte proliferation. We present here the unique phenotype as well as studies to determine if the agammaglobulinemia was due to an intrinsic B lymphocyte defect. Methods: Peripheral blood mononuclear cells from the patient and a healthy control were isolated by Ficoll-Hypaque centrifugation and stimulated with anti-CD40, IL-4 and IL-21 for 7 days. Total IgG production was measured by ELISA in the supernatant of the stimulated sample on day 7. Cells were stained for CD19, CD27, IgM, CD11b, CD11c, and CD14. Results: At day 7, supernatant from the patient stimulated cells contained levels of total IgG comparable to the control (755 ng/mL vs. 658 ng/mL, respectively). B cell maturation appeared impaired, as morphologically the patient sample demonstrated fewer B cell clones and cells with dendritic projections. Conclusions: Despite this typical severe clinical picture of GIDID with agammaglobulinemia, IgG production was detected under optimal stimulation for induction of plasma cells. This suggests that there may not be an inherent defect in class switching and antibody production in B cells in this disorder. It is possible that the in vivo physical or cytokine milieu may be defective for optimal B cell function. Further studies assessing the function of the immune cells as well as possible gastrointestinal loss of immunoglobulins are needed in this disease. Statement of novelty: Despite much improvement in understanding the effects of TTC7A mutations in GIDID, the root cause of hypogammaglobulinemia in these patients is still unclear. The work portrayed in this study furthers the current knowledge. It suggests that when appropriately stimulated in vitro, this patient’s B cells were capable of adequate immunoglobulin production. Moreover, to the best of our knowledge, this patient is the first with this genetic defect to be reported with hypothyroidism and cardiac malformations.

B-cell-activating factor receptor expression on naive and memory B cells: relationship with relapse in patients with rheumatoid arthritis following B-cell depletion therapy

2010 ◽  
Vol 69 (12) ◽  
pp. 2181-2188 ◽  
Author(s):  
Inmaculada de la Torre ◽  
Rita A Moura ◽  
Maria J Leandro ◽  
Jonathan Edwards ◽  
Geraldine Cambridge
Keyword(s):  
Rheumatoid Arthritis ◽  
B Cells ◽  
B Cell ◽  
Memory B Cells ◽  
Receptor Expression ◽  
Cell Depletion ◽  
B Cell Depletion ◽  
B Cell Activating Factor ◽  
Significant Difference ◽  
Cell Repopulation

ObjectivesTo examine the expression of B-cell-activating factor receptor (BAFF-R) on naive CD27− and memory CD27+ B cells in normal individuals and patients with rheumatoid arthritis (RA) undergoing B-cell depletion therapy with rituximab.Patients and MethodsBAFF-R expression on B-cell subsets was determined in normal controls (NC; n=11), active patients with RA pre-rituximab (pre-RX; n=15), relapsing patients either concordant for B-cell repopulation (C-R, n=13) or discordant, with relapse more than 3 months after repopulation (D-R, n=11) and patients in remission over 3 months postrepopulation (discordant non-relapsing (D-NR), n=5). Serum BAFF was measured by ELISA and analysed using Mann–Whitney.ResultsThere was no significant difference between NC, pre-RX and D-NR patients in %BAFF-R-positive B cells or mean fluorescence intensity (MFI) in naive and memory B cells. Relapsing patients had significantly lower MFI and %BAFF-R-positive cells in both naive and memory compartments from NC and pre-RX (C-R and D-R; p<0.01). BAFF levels in pre-RX patients were within the normal range and did not correlate with BAFF-R expression in any patient group. D-NR patients had relatively lower proportions of pre and postswitch CD27+ B cells than pre-RX patients (D-NR vs pre-RX; p<0.05 for both) and also lower numbers of postswitch B cells than D-R patients (D-NR vs D-R, p<0.05).ConclusionBAFF-R expression was significantly reduced on both naive and memory B cells in patients at relapse, regardless of the relationship with B-cell repopulation or serum BAFF levels. Re-establishment of active disease was also associated with an increase in class-switch recombination. Factors responsible for lower levels of BAFF-R may relate to altered thresholds for autoreactive B-cell generation at relapse in patients with RA.

Delayed Redistribution of CD27, CD40 and CD80 Positive B Cells and the Impaired In Vitro Immunoglobulin G Production in Patients with Non-Hodgkin Lymphoma Treated with Rituximab.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 938-938
Author(s):  
Mitsufumi Nishio ◽  
Katsuya Fujimoto ◽  
Satoshi Yamamoto ◽  
Toshiya Sakai ◽  
Kohki Kumano ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Plasma Cells ◽  
Memory B Cells ◽  
Healthy Controls ◽  
Immunoglobulin Production ◽  
Significant Difference ◽  
Healthy Control ◽  
Delayed Recovery

Abstract Rituximab (RT) has been proven to be very effective in depleting normal and malignant B lymphocytes in vivo and it is widely used for the treatment of B cell malignancies, particularly B cell non-Hodgkin’s lymphoma (NHL). RT alone does not appear to cause severe hypogammaglobulinemia according to initial clinical trials. However, recent studies revealed that patients who received RT as an adjuvant to stem cell transplantation (SCT) demonstrated an increased risk of developing severe hypogammaglobulinemia. We have found such hypogammaglobulinemia to be due to the delayed recovery of CD27 positive memory B cells and an impaired isotype expression. (Nishio et al. Eur J Haematol, 2006). This finding suggests that RT can influence not only the quantity, but also the quality of B-cell redistribution. Nevertheless, to our knowledge, precisely how the B-cell repertoire regenerates after anti-CD20-mediated transient B-cell depletion in patients with NHL remains to be elucidated. To clarify this, we performed a phenotypical analysis of B cells. A total of 22 patients with NHL who received RT combined with autologous SCT (n=17) or CHOP (n=5) were evaluated to identify their immunophenotype. The median period after the last administration of RT was 33.5 months (range from 12 to 56 months). We investigated the expression of various markers, including CD27, CD38, CD40, CD80, CD86 and CD95 on B cells by immunofluorescence staining with a flowcytometry analysis. A statistically significant difference was noted in three of the six surface antigens when the expressions of those antigens were compared with those in the healthy control populations (N=14). The most striking differences we found was the expression levels of CD27. The healthy control group had a much higher expression of CD27 in comparison to those of the patients treated with RT (28.1±14.1% vs 8.2±6.1%, p&lt;0.001). In addition, significant differences in the expression of CD40 and CD80 were also noted. While the positive rates of CD80 and CD40 on B cells from healthy controls were 21.5±10.8% and 80.5±16.7%, those of patients treated with RT were 9.9±6.9% and 49.7±33.5%, respectively (p&lt;0.01 and p&lt;0.05). Since CD40-CD40L and CD80-CD28 pathways between B and T cells are necessary for the development of CD27 positive polyclonal B-cell activation and immunoglobulin production, we hypothesized that the B cells from patients treated with RT thus had a reduced ability to differentiate into plasma cells and immunoglobulin production in vitro. To test this hypothesis, we purified the B cells from ten patients with NHL treated with RT and then cultured them upon the engagement of immunoglobulin receptor and CD40 in the presence of IL-2 and IL-10. After eight days of stimulation, the supernatants of the culture were harvested and the concentrations of immunoglobulin were measured by ELISA. As a result, the IgG production was found to be significantly impaired in patients with NHL in comparison to those from the healthy controls. The observation of a delayed recovery of the memory B cells with an abnormal cell marker expression and function demonstrates that naive B cells may therefore be responsible for their failure to differentiate into plasma cells after RT therapy.

Evaluation of Immune Profile in Patients with Multiple Myeloma Using Cytof Technology

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3404-3404
Author(s):  
Jana Jakubikova ◽  
Efstathios Kastritis ◽  
Danka Cholujova ◽  
Teru Hideshima ◽  
Ludmila M Flores ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Flow Cytometry ◽  
B Cells ◽  
B Cell ◽  
Natural Killer ◽  
Plasma Cells ◽  
Memory B Cells ◽  
High Dimensional ◽  
Newly Diagnosed ◽  
D Cells

Abstract Introduction: CyTOF (time-of-flight mass cytometry) is a novel high-dimensional technology which permits immunophenotyping and analysis of signaling in single cells. This approach enables simultaneous evaluation of up to 40 parameters using antibodies tagged with distinct elemental isotopes, by combining flow cytometry with atomic mass spectrometry. Since multiple myeloma (MM) is characterized by immune dysfunction, we used CyTOF technology to define the complex immune profile in MM patient bone marrow (BM) samples. Methods: We used 40 different markers to define various B, T, natural killer (NK) subsets, as well as cells of monocytic, granulocytic, erythroid and platelet lineages. Our preliminary data are results from 10 patients with MGUS/ smoldering MM (SMM); 10 newly diagnosed MM; 20 relapsed/refractory MM; and 15 WM patients (5 newly diagnosed and 10 receiving treatment) in comparison with age-matched healthy donors’ BM (HD). A significantly larger cohort of MM (N=150) and WM (N=50) patients is being similarly analyzed and will be presented. To evaluate phenotypic abnormalities in various B cell subsets, we used B lineage markers CD10, CD19, CD20, CD22, CD27, CD34, CD38, CD45, IgA, IgD, IgG and IgM to define B cells maturation stages from hematopoietic stem cells (HSC) to naïve to mature B lymphocytes (pro-B; pre-B-I; pre-B-II; immature B; and mature (naïve) B cells), as well as memory non-switched and memory switched B cells, plasmablasts, normal (CD138+CD38+CD19+CD45+) and clonal plasma cells (CD138+CD38+CD19-CD45-/low), which reside in the specific BM niche. Furthermore, natural killer (NK) subsets (such as NK and NKT cells) and T cells (such as memory CD4T, naive CD4T, memory CD8T, naive CD8T, T regulatory cells and Tg/d cells) were examined. High-dimensional data was obtained using CyTOF technology and analyzed by SPADE and viSNE software. Results: Our data showed significantly decreased HSC in patients with newly diagnosed and relapsed/refractory MM compared to HD (P<0.025). A significant increase in pre-B-I cells was detected in relapsed/refractory MM vs. MGUS/SMM (P<0.028), but the opposite trend was observed in the pre-B-II subpopulation (P<0.005). No differences in immature B cell populations were observed in different stages of MM. However, a significantly higher percentage of immature B cells was present in relapsed/refractory MM compared to HD (P=0.008), and transitional B cells were significantly decreased in newly diagnosed MM compared to HD (P<0.001). Moreover, memory B cells were significant decreased in all MM stages compared to HD (P<0.003). Non-switched memory B cells were significantly increased in MGUS and SMM compared to newly diagnosed MM, while a significant increase of switched memory B cells was present in newly diagnosed MM compared to relapsed/refractory MM. A significant increase in plasmablasts was seen in relapsed/refractory MM in comparison with other MM stages (P<0.011) by CyTOF analyses. Malignant plasma cells (PC) were defined as CD19-, CD38++, CD45-/dim, CD138+ and either cyk or cyl positive. Importantly, a significant increase in clonal PC was found in all MM stages vs. HD, as well as in newly diagnosed MM compared to relapsed/refractory MM (P<0.01). The percentage of PC from CyTOF analyses correlated with % of PC obtained using flow cytometry by Bland-Altman method comparison. We also observed significant differences in T cell subsets including naïve, central memory, effector, and effector memory CD4+ and CD8+T populations between MGUS and newly diagnosed MM, but no significant changes in T regulatory and Tg/d cells. Furthermore, plasmacytoid dendritic (pDC) cells were significantly increased in newly diagnosed MM, and PD-1 expressed on pDC was significantly decreased in newly diagnosed MM compared to MGUS (P=0.007). Interestingly, PD-1 and its ligand PD-L1 were variably expressed on B cells (2-9% and 3-27%) and PC (0.5-46% and 3-41%) from MM BM samples. Other surface molecules including CD269 (4-32%), CD289 (1-8%), CD362 (0.5-1%) and CD329 (1-4%), were variably expressed in PC. Conclusion: A better understanding of the neoplastic BM milieu will provide the framework for identifying and validating novel targeted therapies directed against MM. CyTOF technology represents a novel diagnostic tool to assess the status not only of MM, but also of host immunity, and may allow for the development of rational personalized therapies. Disclosures No relevant conflicts of interest to declare.

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