B cell numbers predict humoral and cellular response upon SARS-CoV-2 vaccination among patients treated with rituximab

Objectives: Patients with autoimmune inflammatory rheumatic diseases receiving rituximab (RTX) therapy show substantially impaired anti-SARS-CoV-2 vaccine humoral but partly inducible cellular immune responses. However, the complex relationship between antigen-specific B and T cells and the level of B cell repopulation necessary to achieve anti-vaccine responses remain largely unknown. Methods: Antibody responses to SARS-CoV-2 vaccines and induction of antigen-specific B and CD4/CD8 T cell subsets were studied in 19 rheumatoid arthritis (RA) and ANCA-associated vasculitis (AAV) patients receiving RTX, 12 RA patients on other therapies and 30 healthy controls after SARS-CoV-2 vaccination with either mRNA or vector based vaccines. Results: A minimum of 10 B cells/uL in the peripheral circulation was necessary in RTX patients to mount seroconversion to anti-S1 IgG upon SARS-CoV-2 vaccination. RTX patients lacking IgG seroconversion showed reduced antigen-specific B cells, lower frequency of TfH-like cells as well as less activated CD4 and CD8 T cells compared to IgG seroconverted RTX patients. Functionally relevant B cell depletion resulted in impaired IFNgamma secretion by spike-specific CD4 T cells. In contrast, antigen-specific CD8 T cells were reduced in patients independently of IgG formation. Conclusions: Patients receiving rituximab with B cell numbers above 10 B cells/ul were able to mount humoral and more robust cellular responses after SARS-CoV-2 vaccination that may permit optimization of vaccination in these patients. Mechanistically, the data emphasize the crucial role of co-stimulatory B cell functions for the proper induction of CD4 responses propagating vaccine-specific B and plasma cell differentiation.

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CXCR5+PD-1+ follicular helper CD8 T cells control B cell tolerance

Nature Communications ◽

10.1038/s41467-019-12446-5 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 11

Author(s):

Yuhong Chen ◽

Mei Yu ◽

Yongwei Zheng ◽

Guoping Fu ◽

Gang Xin ◽

...

Keyword(s):

T Cells ◽

B Cells ◽

B Cell ◽

Cd8 T Cells ◽

T Cell Subsets ◽

Cell Tolerance ◽

B Cell Tolerance ◽

Autoantibody Production ◽

Tfh Cells ◽

Follicular Helper

Abstract Many autoimmune diseases are characterized by the production of autoantibodies. The current view is that CD4+ T follicular helper (Tfh) cells are the main subset regulating autoreactive B cells. Here we report a CXCR5+PD1+ Tfh subset of CD8+ T cells whose development and function are negatively modulated by Stat5. These CD8+ Tfh cells regulate the germinal center B cell response and control autoantibody production, as deficiency of Stat5 in CD8 T cells leads to an increase of CD8+ Tfh cells, resulting in the breakdown of B cell tolerance and concomitant autoantibody production. CD8+ Tfh cells share similar gene signatures with CD4+ Tfh, and require CD40L/CD40 and TCR/MHCI interactions to deliver help to B cells. Our study thus highlights the diversity of follicular T cell subsets that contribute to the breakdown of B-cell tolerance.

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B-cell and T-cell values in peripheral blood in Polish mixed-breed rabbits with addition of blood of meet breeds

Polish Journal of Veterinary Sciences ◽

10.2478/pjvs-2014-0060 ◽

2014 ◽

Vol 17 (3) ◽

pp. 421-426 ◽

Cited By ~ 1

Author(s):

B. Tokarz-Deptuła ◽

P. Niedźwiedzka-Rystwej ◽

B. Hukowska-Szematowicz ◽

M. Adamiak ◽

A. Trzeciak-Ryczek ◽

...

Keyword(s):

T Cells ◽

B Cells ◽

B Cell ◽

Cd8 T Cells ◽

Peripheral Blood ◽

Laboratory Animals ◽

Immunological Parameters ◽

Four Seasons ◽

Mixed Breed ◽

The Impact

Abstract In Poland, rabbit is a highly valued animal, due to dietetic and flavour values of its meat, but above all, rabbits tend to be commonly used laboratory animals. The aim of the study was developing standards for counts of B-cells with CD19+ receptor, T-cells with CD5+ receptor, and their subpopulations, namely T-cells with CD4+, CD8+ and CD25+ receptor in the peripheral blood of mixed-breed Polish rabbits with addition of blood of meet breeds, including the assessment of the impact of four seasons of the year and animal sex on the values of the immunological parameters determined. The results showed that the counts of B- and T-cells and their subpopulations in peripheral blood remain within the following ranges: for CD19+ B-cells: 1.05 - 3.05%, for CD5+ T-cells: 34.00 - 43.07%, CD4+ T-cells: 23.52 - 33.23%, CD8+ T-cells: 12.55 - 17.30%, whereas for CD25+ T-cells: 0.72 - 2.81%. As it comes to the season of the year, it was observed that it principally affects the values of CD25+ T-cells, while in the case of rabbit sex, more changes were found in females.

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Immunostimulation During and After R-CHOP Therapy for B-Cell Lymphoma

Journal of Clinical & Experimental Immunology ◽

10.33140/jcei.01.01.07 ◽

2016 ◽

Vol 01 (01) ◽

Keyword(s):

T Cells ◽

B Cell ◽

Tumor Immunity ◽

Cd8 T Cells ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Treg Cells ◽

T Cell Subsets ◽

T Helper ◽

Chop Therapy

Backgrounds: Many studies show an immune imbalance in the tumor environment; some reports show that the T helper 1 (Th1)/ T helper 2 (Th2) ratio, the number of regulatory T-cells (Treg cells) or CD8+T-cells, and the CD8+Tcell/Treg cell ratio are associated with tumor suppression and expansion. Additionally, chemotherapy was reported to affect the immunity of patients with malignancy. Patients and Methods: Using flow cytometry we measured peripheral blood lymphocytes including non T-cells, as well as T-cell subsets such as CD3+T-cells, CD4+T-cells, CD8+T-cells, Treg cells, Th1 cells and Th2 cells before treatment, at the fourth cycle, and at 1, 3, 6 and 12 months after treatment in 21 patients with B-cell lymphoma receiving R-CHOP therapy. We also analyzed the changes in three immune indexes that reflect anti-tumor immunity (the CD4/CD8 ratio, the CD8/Treg ratio and the Th1/Th2 ratio). Results: Compared to pre-treatment there were significant decreases in the CD4/CD8 ratio between 1 month and 12 months after treatment (p<0.001, for all time points). The CD8/Treg ratio gradually increased with treatment with significant increases observed at 6 months (p=0.009) and 12 months after treatment (p=0.002). The Th1/ Th2 ratio showed a significant increase only before 4 cycles of therapy (p=0.007). Conclusion: Based on the changes in these three immune indexes, we propose that anti-tumor immunity improved after R-CHOP therapy, which enhanced the efficacy of R-CHOP therapy for lymphoma as well as its direct cytotoxic activity

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Lymphocyte interleukin 2 production and responsiveness are altered in patients with primary myelodysplastic syndrome

Blood ◽

10.1182/blood.v70.2.494.bloodjournal702494 ◽

1987 ◽

Vol 70 (2) ◽

pp. 494-500

Author(s):

O Ayanlar-Batuman ◽

J Shevitz ◽

UC Traub ◽

S Murphy ◽

D Sajewski

Keyword(s):

T Cells ◽

B Cells ◽

Myelodysplastic Syndrome ◽

B Cell ◽

Interleukin 2 ◽

T Cell Proliferation ◽

Cell Functions ◽

Normal Limits ◽

Stimulatory Capacity

Immunoregulatory T and B cell functions in 15 patients with primary myelodysplastic syndrome (MDS) were studied by measuring the proliferative and the stimulatory capacity of T and B cells, respectively, in autologous (auto) and allogeneic (allo) mixed lymphocyte reaction (MLR). T cell proliferation in the auto MLR was 25% of the control (P less than .02), whereas proliferation in the allo MLR was normal. When control T cells were stimulated by MDS B cells, their proliferative response was only 57% of the control (P less than .01). The mechanism responsible for these abnormalities was studied by determining the capacity of MDS and normal T cells to produce interleukin 2 (IL 2) and to generate IL 2 receptors (IL 2R) following stimulation with control and MDS B cells. In the auto MLR of MDS patients, only 3% +/- 2% of T cells developed IL 2R positivity, whereas in control cultures 12% +/- 2% of T cells were positive, as determined by immunofluorescence, using a monoclonal antibody (MoAb) directed against the IL 2R, and FACS analysis. When MDS T cells were stimulated by control B cells, IL 2R generation and the production of IL 2 were within normal limits. In contrast, when control T cells were stimulated by MDS B cells or control B cells, the MDS B cells induced production of only 26% of IL 2 as compared with control B cells. In parallel experiments, IL 2R generation in control T cells stimulated by either MDS or control B cells was similar. We conclude that in the primary MDS, T and B cell interactions are impaired. Although MDS T cells develop normal quantities of IL 2R and produce normal amounts of IL 2 when stimulated by control B cells, they are markedly impaired when stimulated by self B cells. Similarly, MDS B cells can induce IL 2R generation in control T cells but not in MDS T cells. Myelodysplastic B cells are also defective in inducing IL 2 production by normal T cells in an allo MLR. These in vitro abnormalities strongly suggest that generation of lymphocytes with immunoregulatory functions is impaired in patients with MDS.

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Short-Term Immunopathological Changes Associated with Pulse Steroids/IVIG/Rituximab Therapy in Late Kidney Allograft Antibody Mediated Rejection

Kidney360 ◽

10.34067/kid.0001082019 ◽

2020 ◽

Vol 1 (5) ◽

pp. 389-398

Author(s):

Kenna R. Degner ◽

Nancy A. Wilson ◽

Shannon R. Reese ◽

Sandesh Parajuli ◽

Fahad Aziz ◽

...

Keyword(s):

T Cells ◽

B Cells ◽

Regulatory T Cells ◽

B Cell ◽

Cd8 T Cells ◽

Hla Class I ◽

B Cell Depletion ◽

Short Term ◽

Antibody Mediated Rejection ◽

Pulse Steroids

BackgroundB cell depletion is a common treatment of antibody-mediated rejection (ABMR). We sought to determine the specific immunopathologic effects of this therapeutic approach in kidney transplantation.MethodsThis was a prospective observational study of recipients of kidney transplants diagnosed with late ABMR (>3 months after transplant). Patients received treatment with pulse steroids, IVIG, and rituximab. Donor-specific HLA antibodies (DSA), kidney allograft pathology, renal function, immune cell phenotypes, and 47 circulating cytokines were assessed at baseline and at 3 months.ResultsWe enrolled 23 patients in this study between April 2015 and March 2019. The majority of patients were male (74%) and white (78%) with an average age of 45.6±13.8 years. ABMR was diagnosed at 6.8±5.9 years (4 months to 25 years) post-transplant. Treatment was associated with a significant decline in circulating HLA class I (P=0.003) and class II DSA (P=0.002) and peritubular capillaritis (ptc; P=0.04) compared to baseline. Serum creatinine, BUN, eGFR, and proteinuria (UPC) remained stable. Circulating B cells were depleted to barely detectable levels (P≤0.001), whereas BAFF (P=0.0001), APRIL (P<0.001), and IL-10 (P=0.02) levels increased significantly post-treatment. Notably, there was a significant rise in circulating CD4+ (P=0.02) and CD8+ T cells (P=0.003). We also noted a significant correlation between circulating cytotoxic CD8+ T cells and BAFF (P=0.05), regulatory T cells and IL-10 (P=0.002), and regulatory T cells and HLA class I DSA (P=0.005).ConclusionsShort-term pulse steroids/IVIG/rituximab therapy was associated with inhibition of ABMR (DSA and ptc), stabilization of kidney function, and increased regulatory B cell and T cell survival cytokines. Additional studies are needed to understand the implications of B cell depletion on the crosstalk between T cells and B cells, and humoral components that regulate ABMR.

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Rituximab Administration before Allogeneic HSCT Is Associated with Accelerated T Cell Reconstitution after Transplantation: Kinetic Evidence for a Graft-Versus-Leukemia Effect

Blood ◽

10.1182/blood.v124.21.3905.3905 ◽

2014 ◽

Vol 124 (21) ◽

pp. 3905-3905

Author(s):

Sakura Hosoba ◽

Christopher R. Flowers ◽

Catherine J Wu ◽

Jens R. Wrammert ◽

Edmund K. Waller

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

B Cell ◽

Cd8 T Cells ◽

Cell Subset ◽

Post Transplant ◽

T Cell Reconstitution ◽

Relative Value ◽

History Of

Abstract Introduction: Rituximab (R) administration results in depletion of blood B cells and suppression of B cell reconstitution for several months after, with suggestions that T cell reconstitution may also be impaired. We hypothesized that pre-transplant R would be associated with delayed B and T cell reconstitution after allo-HSCT compared with non-R-treated allo-HSCT recipients. Methods: We conducted a retrospective analysis of 360 patients who underwent allo-HSCT using BM or G-CSF mobilized PB. Recipients of cord blood, T cell depleted grafts and 2nd allo-HSCT were excluded. Analysis of lymphocyte subsets in at least one blood at 1, 3, 6, 12, and 24 months post-allo-HSCT was available for 255 eligible patients. Data on lymphocyte recovery was censored after DLI or post-transplant R therapy. Post-HSCT lymphocyte recovery in 217 patients who never received R (no-R) was compared to 38 patients who had received R before allo-HSCT (+R) including 12 CLL, 19 NHL, and 7 B-cell ALL patients. +R patients received a median of 9 doses of R with the last dose of R at a median of 45 days pre-transplant. Results: Mean lymphocyte numbers in the blood at 1, 3, 6, 12, and 24 months were B-cells: 55 ± 465/µL, 82 ± 159/µL, 150 ± 243/µL, 255 ± 345/µL, and 384 ± 369/µL (normal range 79-835); and T-cells: 65 ± 987/µL, 831 ± 667/µL, 1058 ± 788/µL, 1291 ± 985/µL, and 1477 ± 1222/µL (normal range 675-3085). Lymphocyte reconstitution kinetics did not vary significantly based upon the intensity of the conditioning regimen or related vs. unrelated donors allowing aggregation of patients in the +R and no-R groups (Figure). B cell reconstitution in the +R patients was higher at 1 month post-allo-HSCT (relative value of 143% p=0.008) and lower at 3 months post-transplant (19.2%, p=0.069) compared to no-R patients. Blood B cells in the +R group rebounded by the 6th month post-allo-HSCT and remained higher than the no-R group through the 24th month post-HSCT (197% at the 6th month, p=0.037). Higher levels of B-cells at 1 month in the +R group was due to higher blood B-cells at 1 month post-HSCT among 12 CLL patients compared with no-R patients (423%, p<0.001; Figure), while B-cell counts in the remaining +R patients (B-cell NHL and B-cell ALL) were lower than the no-R patients at both 1 and 3 months. Reconstitution of CD4+ and CD8+ T cells among +R patients were similar to no-R patients in the first month post-allo-HSCT and then rebounded to higher levels than the no-R group of patients (relative value 194%, p=0.077 at the 24th month for CD4+ T cell subset, and 224%, p=0.020 for CD8+ T cell subset; Figure). CLL patients had a striking increase in blood levels of donor-derived CD4+ and CD8+ T cells at 3 months post-transplant concomitant with the disappearance of blood B cells compared with no-R patients (relative value of 178% and 372%, p=0.018 and p=0.003, respectively; Figure). Long term T cell reconstitution remained higher for +R patients compared with no-R patients, even when CLL patients were excluded (relative value of 203%, p=0.005 at 24 months post-HSCT; Figure). Conclusions: We observed higher levels of blood B cells and T cells ³ 6 months post-allo-HSCT in +R patients compared with no-R patients. B cell recovery at 6 months post-transplant is consistent with clearance of residual plasma R given the 1-2 months half-life of R, and the median of 1.5 months between the last dose of R and allo-HSCT. The increased blood CD8+ T cells in the blood of CLL patients at 3 months post-allo-HSCT associated with clearance of the B-cells seen 1 month post-HSCT is consistent with a donor T cell-mediated GVL effect. Pre-transplant R therapy does not appear to have any long-term deleterious effect on immune reconstitution, indicating that post-allo-HSCT vaccination at ≥6 months may be efficacious. Figure: Kinetics of lymphocyte reconstitution after allo-HSCT varied by history of pre-transplant R administration and primary disease. Panels show mean counts of each lymphocyte subset at 1, 3, 6, 12 and 24 months post-allo-HSCT for: (1) B cell, (2) T cell, (3) CD4+ and (4) CD8+ T cells. Solid lines with triangle show no-R group; dashed lines with circles shows subgroups of CLL and NHL/ALL +R patients. Asterisks show p values from t-test of the comparison between CLL +R or the NHL/ALL +R patients with no-R patients. *p<0.05; ** p<0.01; *** p<0.001. Figure:. Kinetics of lymphocyte reconstitution after allo-HSCT varied by history of pre-transplant R administration and primary disease. Panels show mean counts of each lymphocyte subset at 1, 3, 6, 12 and 24 months post-allo-HSCT for: (1) B cell, (2) T cell, (3) CD4+ and (4) CD8+ T cells. Solid lines with triangle show no-R group; dashed lines with circles shows subgroups of CLL and NHL/ALL +R patients. Asterisks show p values from t-test of the comparison between CLL +R or the NHL/ALL +R patients with no-R patients. *p<0.05; ** p<0.01; *** p<0.001. Disclosures No relevant conflicts of interest to declare.

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Leukemia-associated monoclonal and oligoclonal TCR-BV use in patients with B-cell chronic lymphocytic leukemia

Blood ◽

10.1182/blood-2002-03-0746 ◽

2003 ◽

Vol 101 (3) ◽

pp. 1063-1070 ◽

Cited By ~ 50

Author(s):

Mohammad-Reza Rezvany ◽

Mahmood Jeddi-Tehrani ◽

Hans Wigzell ◽

Anders Österborg ◽

Håkan Mellstedt

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

Chronic Lymphocytic Leukemia ◽

B Cell ◽

Cd8 T Cells ◽

Leukemia Cell ◽

Lymphocytic Leukemia ◽

Cell Chronic Lymphocytic Leukemia

Abstract T-cell receptor–B-variable (TCR-BV) gene usage and the CDR3 size distribution pattern were analyzed by reverse transcription–polymerase chain reaction (RT-PCR) in patients with B-cell chronic lymphocytic leukemia (B-CLL) to assess the T-cell repertoire. The use of TCR-BV families in CD4 and CD8 T cells stimulated with autologous activated leukemic cells was compared with that of freshly obtained blood T cells. Overexpression of individual TCR-BV families was found in freshly isolated CD4 and CD8 T cells. Polyclonal, oligoclonal, and monoclonal TCR-CDR3 patterns were seen within such overexpressed native CD4 and CD8 TCR-BV families. In nonoverexpressed TCR-BV families, monoclonal and oligoclonal populations were noted only within the CD8 subset. After in vitro stimulation of T cells with autologous leukemic B cells, analyses of the CDR3 length patterns showed that in expanded TCR-BV populations, polyclonal patterns frequently shifted toward a monoclonal/oligoclonal profile, whereas largely monoclonal patterns in native overexpressed TCR-BV subsets remained monoclonal. Seventy-five percent of CD8 expansions found in freshly obtained CD8 T cells further expanded on in vitro stimulation with autologous leukemic B cells. This suggests a memory status of such cells. In contrast, the unusually high frequency of CD4 T-cell expansions found in freshly isolated peripheral blood cells did not correlate positively to in vitro stimulation as only 1 of 9 expansions continued to expand. Our data suggest that leukemia cell–specific memory CD4 and CD8 T cells are present in vivo of patients with CLL and that several leukemia cell–associated antigens/epitopes are recognized by the patients' immune system, indicating that whole leukemia cells might be of preference for vaccine development.

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Posttransplant Cyclophosphamide Promote Naïve-Subset Dominant B Cell Recovery Coordinated with Early Treg Expansion; Implication of Reduced Risk of Pathogenesis into Chronic Gvhd

Blood ◽

10.1182/blood-2018-99-120081 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4566-4566

Author(s):

Miki Iwamoto ◽

Yusuke Meguri ◽

Takumi Kondo ◽

Hiroyuki Sugiura ◽

Shuntaro Ikegawa ◽

...

Keyword(s):

T Cells ◽

B Cells ◽

B Cell ◽

Cell Population ◽

Cd8 T Cells ◽

Peripheral Blood ◽

Chronic Gvhd ◽

Lymphocyte Subset ◽

Cell Recovery ◽

Haplo Group

Abstract Posttransplant cyclophosphamide (PTCy) is an effective prophylaxis for both acute and chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT). We recently studied the immune reconstitution dynamics of each lymphocyte subset after PTCy-based transplant using murine haploidentical BMT model and reported that PTCy strongly promoted Treg-dominant T-cell reconstitution and stem cell-derived mature B-cell generation with broad BCR-diversity. We also found that the early reconstitution of Treg could contribute to promote naïve B cell emergence from bone marrow, indicating the T and B cell recovery might be mutually coordinated after PTCy-based transplant (Iwamoto et al, ASH2017). However, the detailed process of immune reconstitution in patients after haploidentical HSCT with PTCy has not been well studied. To address this issue, we here investigated the early dynamics of donor-lymphocyte subset chimerisms in patient after clinical PTCy-based haploidentical HSCT with comparing those in patients after low-dose ATG-based haploidentical HSCT and patients after cord blood transplantation. Laboratory studies were undertaken in 13 adult patients who received HLA-mismatched allogeneic graft; unrelated cord blood (n=5), and haploidentical related peripheral blood after ATG-based conditioning (n=5) and haploidentical related peripheral blood after PTCy-based conditioning (n=5). Blood samples were obtained before and at 1, 2, 4, 6 and 8 weeks after HSCT. Peripheral blood mononuclear cells (PBMCs) were isolated from blood samples by density gradient centrifugation and cryopreserved before being analyzed. After thawing, to analyze the subset-specific chimerism, PBMCs were stained with anti-HLA monoclonal antibodies and other subset-specific antibodies as follows: Pacific Blue conjugated anti-CD4, eFluor450 conjugated anti-CD3, PE-Cy7 conjugated anti-CD25, anti-CD14, APC conjugated anti-CD127, anti-CD56, and APC-eFluor780 conjugated anti-CD8a, anti-CD19. Gated lymphotes (CD4+Tcons, CD4+Tregs, CD8+T cells, B cells, NK cells, Monocytes) were analyzed their chimerism by flowcytometry. To examine the detailed phenotype of B cells, the expression of CD27, CD24, CD38 and IgD were tested. Flowcytometry-based method enables us to analyze the lymphocyte subset chemerism in the very early phase after HSCT. At 2 weeks after HSCT, our analysis revealed that CD4+Tcons, CD4+Tregs and CD8+T cells had already achieved complete donor chimerisms (>95% in all subsets) in patients after ATG-based SCT and had been approaching complete donor chimerisms (85.8%, 75.4% and 87.2%, respectively) in patients after CBT. In contrast, percentage of donor chimerisms of CD4+Tcons, CD4+Tregs and CD8+T cells after PTCy-based haplo-SCT was 73.5%, 59.6% and 59.2%, respectively, and those remained to be in the lower levels than other 2 groups. However, at 4 weeks after HSCT, all examined patients achieved complete donor chimerism of T cells, NK cells and Monocytes (>90%). At 8 weeks after HSCT, the number of B cells in PTCy-based haplo-group was higher than in ATG-based haplo-group (3494 vs 1901/mm3). Of note, B cell population in PTCy-based haplo-group at 8 weeks contained the significantly higher percentage of CD24+CD27-IgD+CD38+ transitional/naïve subset and the significantly lower percentage of CD24+CD27+IgD-CD38neg/dim activated/switched-memory subset when compared to B cell population in ATG-based haplo-group (59.9% vs 10.2%, 2.6% vs 21.5%, P<0.02 respectively), suggesting PTCy treatment might be associated with the favorable B cell reconstitution with naïve-subset dominant composition. Moreover, in patients after PTCy-based haplo-group, the percentage of activated/switched-memory subsets in B cell population at 8 weeks was inversely correlated with percentage of Treg in CD4 T cells at 4 weeks (P<0.05, r2=0.77). Taken together, consistently with our murine study, the current data from clinical samples again suggest that PTCy-based immune-modulation lead to coordinated T and B cell recovery, especially promoting naïve-subset dominant B cell recovery with help of the early expansion of Treg, which might reduce the risk of subsequent chronic GVHD. These data provide the important information for understanding the immunological reconstitution after PTCy-based haploidentical HSCT. Disclosures No relevant conflicts of interest to declare.

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Deficit of Circulating CD19+CD24hiCD38hi Regulatory B Cells in Severe Aplastic Anemia

Blood ◽

10.1182/blood-2019-127053 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1219-1219

Author(s):

Yoshitaka Zaimoku ◽

Bhavisha A Patel ◽

Sachiko Kajigaya ◽

Xingmin Feng ◽

Lemlem Alemu ◽

...

Keyword(s):

T Cells ◽

B Cells ◽

B Cell ◽

Aplastic Anemia ◽

Nk Cells ◽

Cd8 T Cells ◽

Healthy Individuals ◽

Regulatory B Cells ◽

Significant Difference ◽

Cell Phenotypes

Background: Immune aplastic anemia (AA) is caused by cytotoxic T cells (CTLs) that destroy hematopoietic stem and progenitor cells. Regulatory T cells (Tregs) are reduced in AA and increase in response to immunosuppressive therapy (IST; Solomou E et al, Blood 2007). Recent studies suggested an immune regulatory role of regulatory B cells (Bregs). Human CD19+CD24hiCD38hi Bregs suppress Th1 response of CD4+ T cells as well as IFN-γ production by CD8+ CTLs (Mauri C, Menon M, J Clin Invest 2017). The quantity and/or function of Bregs are impaired in autoimmune diseases, malignancies, chronic graft-versus-host disease, and during rejection of transplanted organs. Methods: We investigated B cell phenotypes including CD24hiCD38hi Bregs in previously untreated severe AA (SAA) and very severe AA (VSAA) patients, and healthy individuals aged 18 years and older, and tested their correlation with severity and response to IST. Absolute numbers of lymphocyte subsets, including CD19+ B cells, CD8+ T cells, CD4+ T cells, and NK cell (TBNK), were quantified in fresh blood. Percentages of B cell subsets among total CD19+ B cells, including CD24hiCD38hi Bregs, CD24loCD38lo mature naïve B cells, CD24hiCD38lo memory B cells and CD24loCD38hi plasma cells/plasmablasts, were analyzed using cryopreserved peripheral blood mononuclear cells (PBMCs). Blood samples were obtained from patients close to time of diagnosis and before institution of definitive therapy. All patients were treated with horse anti-thymocyte globulin, cyclosporine, and eltrombopag between 2012 and 2018 at the Hematology Branch, NHLBI (clinicaltrials.gov NCT01623167). Results: TBNK analysis revealed no significant difference in total B cell counts in 104 AA patients compared to 40 healthy individuals (median, 137/μl [IQR, 73-212] vs 163/μl [106-242], P=.11); NK cells were significantly decreased in patients with AA, as previously reported (Gascon P et al, Blood 1986). Total B cell count did not correlate with severity of AA (P=.89) nor with overall response at six months (P=.93). CD8+ T cells and NK cells were lower in VSAA patients compared to SAA patients. None of the TBNK subsets was predictive of overall response in six months after IST. When we assessed the phenotype of B cells among 60 AA patients whose cryopreserved PBMCs were available, CD24hiCD38hi Bregs were markedly decreased as compared to 29 healthy individuals (0.31% [0.14-0.85%] vs 1.9% [1.3-3.6%], P=3×10-7; Figure, Table), while there was no significant difference in other B cell phenotypes. Among these 60 patients, the percentage of CD24hiCD38hi Bregs was especially decreased in VSAA patients compared to SAA (0.18% [0.11-0.34%] vs 0.50% [0.17-1.4%], P=.017). In contrast, CD24loCD38lo mature naïve B cells were higher in VSAA than in SAA (69% [58-86%] vs 60% [42-70%], P=.024). CD24hiCD38hi Breg frequency was positively associated with neutrophil and reticulocyte counts (correlation coefficients [r], 0.34 and 0.26, respectively), while the frequency of CD24loCD38lo mature naïve B cells was negatively correlated (r, -0.34 and -0.40). CD24loCD38lo mature naïve B cells before IST were significantly lower in 47 patients who achieved overall responses at six months compared to 13 non-responders (64% [42-71%), vs 73% [58-88%], P=.014), but CD24hiCD38hi Breg frequency was not correlated with IST responses. At six months after IST, CD24hiCD38hi Bregs in AA patients had recovered to levels present in healthy individuals (2.3% [0.98-4.8%]), in both 34 responders and five non-responders; non-responders showed non-significant increased CD24loCD38lo mature naïve B cells at six months (P=.068). Discussion: A deficit of circulating CD24hiCD38hi Bregs in immune AA with recovery after IST, as occurs with Tregs, suggests Bregs may contribute to the immune pathophysiology in AA. We unexpectedly observed a higher percentage of CD24loCD38lo mature naïve B cells to be associated with more severe disease and a lower probability of responses to IST. B cell phenotype analysis may be beneficial for monitoring of AA and predicting outcomes of therapy. Disclosures No relevant conflicts of interest to declare.

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Non-Hodgkin Lymphoma B-Cells Induce Intratumoral CD4+CD25− T Cells To Express Foxp3 and Gain Regulatory Function.

Blood ◽

10.1182/blood.v108.11.1724.1724 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1724-1724

Author(s):

Zhi-Zhang Yang ◽

Anne J. Novak ◽

Thomas E. Witzig ◽

Stephen M. Ansell

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

Regulatory T Cells ◽

B Cell ◽

Cd8 T Cells ◽

Foxp3 Expression ◽

Regulatory Function ◽

Cell Contact ◽

Cancer Pathogenesis

Abstract We have previously shown that CD4+CD25+Foxp3+ regulatory T cells from NHL tumors suppress the function of infiltrating CD4+ T cells and cytolytic CD8+ T cells. Expression of Foxp3 has been demonstrated to be crucial to the development and function of CD4+CD25+ regulatory T cells. However, the mechanistic details that drive development of Foxp3 expression in T cells, in both the normal and malignant scenario, remains to be fully elucidated. Previous studies suggest that Foxp3 expression in CD4+CD25− T cells can be upregulated by tolerizing stimuli such as activation through TCR, corticosteroids, estrogen, and TGF-beta. Because lymphoma B cells have been shown to induce T-cell tolerance, we postulated that lymphoma B cells may play a role in the generation of regulatory T cells by inducing Foxp3 expression in CD4+CD25− T cells. FoxP3 expression was initially thought to be restricted to CD4+CD25+ regulatory T cell population. However, recent literature suggests that Foxp3 may also be expressed in CD4+CD25− T cells. Using biopsy specimens from patients with B-cell NHL, we found that a subset, 15%, of infiltrating CD4+CD25− T cells express Foxp3 and are capable of suppressing the proliferation and granule production of infiltrating cytotoxic CD8+ T cells. These initial studies suggest that CD4+CD25−Foxp3+ T cells have regulatory function. To explore the underlying mechanism by which Foxp3 expression is regulated, we determined the effect of costimulatory signals on Foxp3 expression in CD4+CD25−Foxp3− T cells. Activation with OKT3/anti-CD28 Ab as well as DC-mediated activation induced Foxp3 expression in a subset of CD4+CD25− T cells. We also found that the presence of lymphoma B cells during activation augmented the induction of Foxp3 expression in CD4+CD25− T cells and that NHL B cell-mediated Foxp3 expression was cell contact-dependent. To better understand the contribution of NHL B cells in Foxp3 expression, we explored the possibility that CD27-CD70 interaction may be involved in Foxp3 expression. Lymphoma B cells express CD70, but not B7-1 and B7-2, which have been shown to be important in protecting tumor cells from lysis and contributing to cancer pathogenesis. Ligation of CD27 by receptor cross-linking enhanced Foxp3 expression in infiltrating CD4+CD25− T cells in B-cell NHL. Taken together these studies reveal a novel role for NHL B cells in development of regulatory T cells. Our data show that lymphoma B cells induce expression of Foxp3 in infiltrating CD4+CD25− T cells and may result in development of T cells with regulatory function within the tumor microenvironment. Our results also suggest a potential role for CD27-CD70 interactions in this process. The ability of malignant B cells to drive development of regulatory T cells may be one mechanism by which lymphoma B cells protect themselves from anti-tumor immunity. (Supported in part by the Iowa/Mayo Lymphoma SPORE CA97274).

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