Flow cytometry as an important tool in the diagnosis of immunodeficiencies demonstrated in a patient with ataxia-telangiectasia

2016 ◽  
Vol 40 (4) ◽  
Author(s):  
Alessandro De Stefano ◽  
Andreas Boldt ◽  
Lydia Schmiedel ◽  
Ulrich Sack ◽  
Karim Kentouche
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Ataxia Telangiectasia ◽  
T Cell Subsets ◽  
Heterozygous Mutation ◽  
B Cell Differentiation ◽  
Proliferation Response ◽  
Antibody Titers ◽  
Specific Stimulation

AbstractBackground:Ataxia-telangiectasia (AT) is a rare hereditary genetic disease caused by one of more than 500 mutations in the ataxia-telangiectasia mutated gene (Methods:We evaluated a patient (female, 15 years) with AT by estimation of antibody titers, characterization of peripheral B- and T-cell subsets and investigation of proliferation response of B- and T-cells undergoing specific stimulation with PHA, CD3/CD28, and R848/CD40L. A healthy volunteer was used as a control.Results:The patient showed a heterozygous mutation in theConclusions:Initial lymphocyte immunophenotyping suggested a defect in T- and B-cell differentiation, but normal humoral antibody titers and B-cell proliferation were inconsistent with this suspicion. Therefore, the results revealed an underlying T-cell defect and low levels of class-switched B-cells results from the lacking assistance from T-cells.

scholarly journals Naïve Regulatory T Cell Subset Is Altered in X-Linked Agammaglobulinemia

2021 ◽  
Vol 12 ◽  
Author(s):  
Pavel V. Shelyakin ◽  
Ksenia R. Lupyr ◽  
Evgeny S. Egorov ◽  
Ilya A. Kofiadi ◽  
Dmitriy B. Staroverov ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cell Subset ◽  
Cell Receptor ◽  
T Cell Subsets ◽  
Cell Compartments ◽  
Expression Of Genes ◽  
Tcr Repertoire ◽  
Antigen Presenting

The interplay between T- and B-cell compartments during naïve, effector and memory T cell maturation is critical for a balanced immune response. Primary B-cell immunodeficiency arising from X-linked agammaglobulinemia (XLA) offers a model to explore B cell impact on T cell subsets, starting from the thymic selection. Here we investigated characteristics of naïve and effector T cell subsets in XLA patients, revealing prominent alterations in the corresponding T-cell receptor (TCR) repertoires. We observed immunosenescence in terms of decreased diversity of naïve CD4+ and CD8+ TCR repertoires in XLA donors. The most substantial alterations were found within naïve CD4+ subsets, and we have investigated these in greater detail. In particular, increased clonality and convergence, along with shorter CDR3 regions, suggested narrower focused antigen-specific maturation of thymus-derived naïve Treg (CD4+CD45RA+CD27+CD25+) in the absence of B cells - normally presenting diverse self and commensal antigens. The naïve Treg proportion among naïve CD4 T cells was decreased in XLA patients, supporting the concept of impaired thymic naïve Treg selection. Furthermore, the naïve Treg subset showed prominent differences at the transcriptome level, including increased expression of genes specific for antigen-presenting and myeloid cells. Altogether, our findings suggest active B cell involvement in CD4 T cell subsets maturation, including B cell-dependent expansion of the naïve Treg TCR repertoire that enables better control of self-reactive T cells.

T cell-intrinsic Interferon Regulatory Factor-1 expression suppresses differentiation of CD4 + T cell populations that support chronic gammaherpesvirus infection.

2021 ◽  
Author(s):  
C. N. Jondle ◽  
K. E. Johnson ◽  
W. P. Mboko ◽  
V. L. Tarakanova
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
T Cell Subsets ◽  
Viral Reservoir ◽  
B Cell Differentiation ◽  
Follicular Helper ◽  
Interferon Regulatory Factor 1 ◽  
Latent Viral Reservoir

Gammaherpesviruses are ubiquitous pathogens that establish life-long infection and are associated with B cell lymphomas. To establish chronic infection, these viruses usurp B cell differentiation and drive a robust germinal center response to expand the latent viral reservoir and gain access to memory B cells. Germinal center B cells, while important for the establishment of latent infection, are also thought to be the target of viral transformation. The host and viral factors that impact the gammaherpesvirus-driven germinal center response are not clearly defined. We showed that global expression of the antiviral and tumor-suppressor interferon regulatory factor 1 (IRF-1) selectively attenuates the murine gammaherpesvirus 68 (MHV68)-driven germinal center response and restricts expansion of the latent viral reservoir. In this study we found that T cell intrinsic IRF-1 expression recapitulates some aspects of antiviral state imposed by IRF-1 during chronic MHV68 infection, including attenuation of the germinal center response and viral latency in the spleen. We also discovered that global and T cell-intrinsic IRF-1 deficiency leads to unhindered rise of IL-17A-expressing and follicular helper T cell populations, two CD4 + T cell subsets that support chronic MHV68 infection. Thus, this study unveils a novel aspect of antiviral activity of IRF-1 by demonstrating IRF-1-mediated suppression of specific CD4 + T cell subsets that support chronic gammaherpesvirus infection. Importance Gammaherpesviruses infect over 95% of the adult population, last the lifetime of the host, and are associated with multiple cancers. These viruses usurp the germinal center response to establish lifelong infection in memory B cells. This manipulation of B cell differentiation by the virus is thought to contribute to lymphomagenesis, though exactly how the virus precipitates malignant transformation in vivo is unclear. IRF-1, a host transcription factor and a known tumor suppressor, restricts the MHV68-driven germinal center response in a B cell-extrinsic manner. We found that T cell intrinsic IRF-1 expression attenuates the MHV68-driven germinal center response by restricting the CD4 + T follicular helper population. Further, our study identified IRF-1 as a novel negative regulator of IL-17-driven immune responses, highlighting the multifaceted role of IRF-1 in gammaherpesvirus infection.

scholarly journals Phenotypic and functional characterization of T-BAM (CD40 ligand)+ T- cell non-Hodgkin's lymphoma

Blood ◽  
1994 ◽  
Vol 84 (3) ◽  
pp. 866-872 ◽  
Author(s):  
G Inghirami ◽  
S Lederman ◽  
MJ Yellin ◽  
A Chadburn ◽  
L Chess ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Functional Characterization ◽  
Cd40 Ligand ◽  
B Cell Differentiation ◽  
Helper Function ◽  
Unique Distribution ◽  
Hodgkin's Lymphomas

Abstract The precise mechanisms regulating T-helper function have been intensively investigated. We and others have recently identified a new T-cell-B-cell-activating molecule called T-BAM that directs B-cell differentiation by interacting with the CD40 molecule on B cells. Using a specific monoclonal antibody against T-BAM (5C8), we have previously shown that T-BAM expressing T cells are predominantly CD4+CD8- and in normal lymphoid tissue have a unique distribution. However, no information has been obtained regarding the phenotype and functional properties of human neoplastic T cells. Therefore, we investigated T- BAM expression immunohistochemically in 87 well-characterized T-cell non-Hodgkin's lymphomas and lymphoid leukemias (LL). We found that 21/81 neoplasms expressed detectable T-BAM and these positive tumors belong almost exclusively to the CD4+CD8- subtype. In addition, to determine whether T-BAM expression could be induced on T-BAM-LL cells, we activated T-BAM-LLs in vitro and showed that T-BAM could be upregulated only in CD4+CD8- tumors. Our studies clearly show that T- BAM is constitutively expressed in a large number of T-cell neoplasms with a relative mature phenotype (CD4+CD8-) and that only CD4+ neoplastic T cells can be induced in vitro to express this molecule. Additional studies are necessary to identify the biologic significance of T-BAM expression and its potential and clinical implications.

CLL Cells Can Diversify, Switch, and Differentiate in Response to Autologous T Cell Stimuli Present in a Murine Adoptive Transfer Model

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 315-315
Author(s):  
Piers E.M. Patten ◽  
Shih-Shih Chen ◽  
Davide Bagnara ◽  
Rita Simone ◽  
Sonia Marsilio ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Adoptive Transfer ◽  
De Novo ◽  
Conflicts Of Interest ◽  
Transfer Model ◽  
B Cell Differentiation ◽  
Cell Numbers ◽  
Nsg Mice

Abstract Abstract 315 Adoptive transfer of primary patient CLL cells into NOD/SCID/γcnull(NSG) mice results in engraftment and proliferation of CLL cells if autologous T cells are present. Formation of splenic follicles consisting of B cells interspersed and surrounded by T cells indicates engraftment. However, ultimately these CD20+ cells are lost several weeks later. We describe one of the mechanisms for this apparent loss: differentiation to plasma cells. Peripheral blood cells from 9 IgM+ CLL patients (6 U-CLL and 3 M-CLL) were adoptively transferred into NSG mice with enriched autologous CD3+ cells pre-activated with anti-CD3/28 beads. B and T cell engraftment and subset distributions were analyzed for 47 mice by immunohistochemistry (IHC) and flow cytometry (FC) at the time of sacrifice. The earliest and latest times of assessment were 12 and 124 days, respectively, after CLL cell injection. In some cases, CLL cells were labeled with CFSE to track cell division. At sacrifice, 3 engraftment patterns were observed. Pattern 1 (observed up to day 56) showed small follicles of CD20+ cells with low-moderate numbers of surrounding T cells. Intensely positive CD38 cells were inconspicuous. FC showed CD19+CD5+ cells with no increase in CD38 and variable CFSE dilution indicating lower levels of proliferation. Pattern 2 (observed throughout the study period) showed much higher T and B cell numbers. CD20+ cells were interspersed with and surrounded by principally CD4+ cells which were activated and functional as indicated by expression of Ki-67, PD-1, CD57, and T cell derived cytokines IFNγ and IL5 in plasma. Follicles contained CD20 and cytoplasmic Ig+ (cIg+) cells that double stained for IRF-4 and Blimp-1, transcription factors required for B cell differentiation. While Bcl-6 staining in these cells was minimal or absent, follicles from all 9 patients contained activation-induced deaminase (AID)+ cells. Cells with dim IgM expression localized to follicles; however, cells with intense IgM, IgA, or IgG were present both within, surrounding, and outside follicles matched by similar CD38 staining. Smaller populations of CD138+ cells surrounded follicles and were interspersed throughout non-follicular splenic areas. FC showed a novel CD19+CD5-CFSE-CD38++ population containing a CD138+ subset. Pattern 3 (observed in a limited subset of cases not before day 63) had minimal CD20+ cells by IHC, but noticeable populations of cIg+CD38+ and CD138+ cells interspersed amongst plentiful T cells. Such cells corresponded with cells with plasma cell morphology. Confirmation that differentiated cells were from the patient clone was achieved in 3 ways. First, in FACS sorted CD19+CD5+ and CD19+CD5-38++ cells from a subset of pattern 2 cases, RT-PCR revealed that all fractions contained both IGHC unswitched and switched clones identical to those found in the patients. Second, cases with pattern 3 engraftment generated CLL clonal switched and unswitched cDNA sequences. Finally, adoptive transfer of highly purified CD5+CD19+ patient cells generated IRF-4+Blimp-1+CD138+ cells. The generation of switched cells from all 9 patients indicated functional AID. In one U- CLL case, ultra-deep sequencing on pre-transfer and post-transfer human cells taken from mouse spleen revealed a significant number of new IGHVDJ mutations in spleen-derived cells. Such mutations targeted nucleotides typical for AID's action. In conclusion, CLL cells can diversify, switch, and differentiate in NSG mice in response to autologous T cell signals. The extent of this maturation is a function of T cell numbers and activity and the duration of the experiment. Differentiation without significant Bcl-6 expression suggests that follicles in NSG mice are not recapitulating classic germinal center reactions, possibly giving clues to the origin of CLL. Several features of poor prognosis disease were demonstrated (e.g., increased CD38 and AID expression with the development of clonally related switched transcripts) that might mirror clinical disease features. AID expressed by CLL cells is fully functional as indicated by de novo somatic hypermutation and class switch recombination. Both U-CLL and M-CLL clones respond in a similar manner in this model, suggesting the importance of T– B cell interactions in all types of CLL. Finally, the demonstration that cells can differentiate when appropriately induced may lead to novel therapeutic options for CLL. Disclosures: No relevant conflicts of interest to declare.

Therapy of B Cell Malignancies with CD19-Specific Chimeric Antigen Receptor-Modified T Cells of Defined Subset Composition

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 384-384 ◽  
Author(s):  
Cameron J Turtle ◽  
Daniel Sommermeyer ◽  
Carolina Berger ◽  
Michael Hudecek ◽  
David M Shank ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cd4 T Cells ◽  
Research Funding ◽  
T Cell Subsets ◽  
B Cell Malignancies ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

Abstract BACKGROUND: The adoptive transfer of CD19-specific chimeric antigen receptor-modified (CD19 CAR) T cells is a promising strategy for treating patients with CD19+ B cell acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), and non-Hodgkin lymphoma (NHL). Dramatic responses have been observed in a subset of patients receiving CD19 CAR T cell therapy, and prior studies suggest that persistence of transferred T cells may correlate with the extent of tumor regression. The use of unselected T cells to prepare CAR T cells results in variation in the phenotypic composition of the infused product in individual patients, making it difficult to determine whether particular T cell subsets contribute to efficacy and/or toxicity. Studies in our lab demonstrated that genetically modified effector T cells derived from purified T cell subsets differ in the capacity to persist in vivo after adoptive transfer, and that a combination of CAR-modified CD8+ central memory (TCM) and CD4+ T cells provides optimal antitumor activity in tumor xenograft models. Based on these data, we designed the first clinical trial in which patients with CD19+ B cell malignancies receive CD19 CAR T cells comprised of a defined composition of CD8+ TCM and CD4+T cells engineered to express a CD19 CAR. METHODS: Patients with relapsed or refractory CD19+ ALL, CLL or NHL are eligible for this phase I/II study. CD8+ TCM and CD4+ T cells were separately enriched by immunomagnetic selection from a leukapheresis product from each patient, and cryopreserved. The CD8+ TCM and CD4+ T cells were stimulated in independent cultures with anti-CD3/anti-CD28 paramagnetic beads, and transduced with a lentivirus encoding the murine FMC63 anti-CD19 scFv, 4-1BB and CD3 zeta signaling domains. After in vitro expansion, the cell product for infusion was formulated in a 1:1 ratio of CD4+:CD8+ CAR+ T cells. A truncated non-functional human epidermal growth factor receptor (EGFRt) encoded in the transgene cassette allowed identification of transgene-expressing T cells by flow cytometry. Lymphodepleting chemotherapy was administered followed by infusion of EGFRt+ CAR T cells at one of three dose levels (2 x 105 EGFRt+ cells/kg, 2 x 106 EGFRt+ cells/kg, 2 x 107 EGFRt+cells/kg). RESULTS: Twenty patients with relapsed or refractory ALL (n = 9), NHL (n = 10) or CLL (n = 1), including those who failed prior autologous (n = 4) or allogeneic (n = 4) stem cell transplant have been treated on the trial. Fifteen of 20 treated patients received a product that conformed to the prescribed CD8+ T­CM:CD4 composition. Five patients received a product manufactured using a modified strategy either due to low blood lymphocyte counts (n = 3) or due to failure to propagate T cells in culture (n = 2). CD8+ TCM and CD4+ T cells have been isolated from 12 additional patients and cryopreserved for therapy. Patients have been treated at all three dose levels without acute infusional toxicity. Severe cytokine release syndrome (sCRS) consisting of fever, hypotension, and reversible neurotoxicity associated with elevated serum IFN-γ and IL-6 was only observed in ALL patients with a high tumor burden. One ALL patient treated at the highest cell dose died of complications associated with sCRS. None of the NHL patients had sCRS. Of patients who are >6 weeks after CD19 CAR T cell therapy, best responses included complete (n=1) or partial (n=5) remission in 6/9 patients with NHL and complete remission in 5/7 patients with ALL. Both CD4+ and CD8+ CAR-T cells expanded in vivo and could be detected in blood, marrow and CSF. The peak level and duration of persistence of both CD4+ and CD8+ EGFRt+ T cells were associated with clinical response. TCRBV gene sequencing of flow sorted CD4+ and CD8+ EGFRt+CAR T cells from 2 patients showed that proliferating CAR T cells were polyclonal. A subset of NHL patients in whom CAR T cells became undetectable developed a T cell immune response to sequences in the murine CD19-specific scFv component of the CAR transgene. CONCLUSION: Adoptive immunotherapy with CD19 CAR T cells of defined subset composition is feasible and safe in a majority of heavily pretreated patients with refractory B cell malignancies and has potent anti-tumor activity. Persistence of CAR-T cells may be limited in some patients by transgene product immunogenicity. Data from this ongoing clinical trial will be updated at the meeting. Disclosures Turtle: Juno Therapeutics: Research Funding. Berger:Juno Therapeutics: Patents & Royalties. Hudecek:Juno Therapeutics: Patents & Royalties. Jensen:Juno: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Riddell:Juno Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Maloney:Juno Therapeutics: Research Funding.

scholarly journals Subspecialization of Cxcr5+ T Cells

2001 ◽  
Vol 193 (12) ◽  
pp. 1373-1382 ◽  
Author(s):  
Chang H. Kim ◽  
Lusijah S. Rott ◽  
Ian Clark-Lewis ◽  
Daniel J. Campbell ◽  
Lijun Wu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Antibody Production ◽  
B Lymphocyte ◽  
Interleukin 10 ◽  
Small Subset ◽  
Lymphoid Tissues ◽  
B Cell Differentiation ◽  
Th Cells

The T helper (Th) cell pool is composed of specialized cells with heterogeneous effector functions. Apart from Th1 and 2 cells, CXCR5+ T cells have been suggested to be another type of effector T cell specialized for B cell help. We show here that CXCR5+ T cells are heterogeneous, and we identify subsets of CXCR5+ CD4 T cells that differ in function and microenvironmental localization in secondary lymphoid tissues. CD57+CXCR5 T cells, hereafter termed germinal center Th (GC-Th) cells, are localized only in GCs, lack CCR7, and are highly responsive to the follicular chemokine B lymphocyte chemoattractant but not to the T cell zone EBI1-ligand chemokine. Importantly, GC-Th cells are much more efficient than CD57−CXCR5+ T cells or CXCR5− T cells in inducing antibody production from B cells. Consistent with their function, GC-Th cells produce elevated levels of interleukin 10 upon stimulation which, with other cytokines and costimulatory molecules, may help confer their B cell helper activity. Our results demonstrate that CXCR5+ T cells are functionally heterogeneous and that the GC-Th cells, a small subset of CXCR5+ T cells, are the key helpers for B cell differentiation and antibody production in lymphoid tissues.

scholarly journals Flow Cytometric Analysis Revealed a Significant Accumulation of Terminally Differentiated T cell Subtypes in the Circulating Lymphocytes of Cytomegalovirus (CMV) Positive Follicular Lymphoma Patients

2021 ◽  
pp. 1-9
Author(s):  
Lugos MD ◽  
◽  
Dangana A ◽  
Ntuhun BD ◽  
Oluwatayo BO ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Follicular Lymphoma ◽  
B Cell ◽  
Flow Cytometric Analysis ◽  
B Cell Lymphoma ◽  
T Cell Subsets ◽  
Cmv Infection ◽  
Flow Cytometric ◽  
The Impact

Follicular lymphoma (FL), a non-Hodgkin lymphoma, is an indolent cancer of the B cell lineage that runs a chronic deterioration course that can result in multiple treatment episodes leading to resistance and possible transformation to diffuse large B cell lymphoma. Cytomegalovirus (CMV) reactivation during chemotherapy or after an organ or hematopoietic stem cell transplantation is a major cause of morbidity and mortality. This study tests the hypothesis that some of the heterogeneity of FL might result from chronic infection with Cytomegalovirus (CMV). This research was intended to appraise the impact of CMV infection on the subtypes of T cells in follicular lymphoma patients. We accessed stored peripheral blood mononuclear cells (PMBCs) from patients of known CMV serostatus recruited into an FL clinical trial. We undertook a multicolour flow cytometric analysis of the PBMCs and compared the number of lymphocyte subtypes of CMV-positive and CMV-negative FL patients. Data showed a significant increase in the quantity of terminally differentiated (TEMRA) T cell subsets, including EM3-CD8 (P=0.005), EM3-CD4 (P=0.018), E-CD4 (P=0.029), E-CD8 (P=0.033) and pE2-CD4 (P=0.046) phenotypes, as well as increased NKT cells (P=0.031) among CMV-positive patients compared to the negative group. Our findings support the hypothesis that recurrent infections characterise CMV infection in FL due to accelerated immune senescence and the accumulation of exhausted T cells. Based on the data, a case could be argued for the routine application of CMV screening in FL before treatment with chemo-immunotherapy to implement enhanced infection surveillance in CMV-positive patients. These discoveries can eventually help improve the treatment approaches in the management of FL toward a combinatorial viewpoint for direct cytotoxic and indirect immunomodulatory outlook

scholarly journals Role of E4 in Eliciting CD4 T-Cell and B-Cell Responses to Adenovirus Vectors Delivered to Murine and Nonhuman Primate Lungs

1998 ◽  
Vol 72 (7) ◽  
pp. 6138-6145 ◽  
Author(s):  
Narendra Chirmule ◽  
Joseph V. Hughes ◽  
Guang-Ping Gao ◽  
Steven E. Raper ◽  
James M. Wilson
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Nonhuman Primate ◽  
Neutralizing Antibodies ◽  
T Cell Subsets ◽  
Cd4 T Cell ◽  
Cell Responses ◽  
Adenovirus Vectors ◽  
B Cell Responses

ABSTRACT Adenovirus vectors delivered to lung are being considered in the treatment of cystic fibrosis (CF). Vectors from which E1 has been deleted elicit T- and B-cell responses which confound their use in the treatment of chronic diseases such as CF. In this study, we directly compare the biology of an adenovirus vector from which E1 has been deleted to that of one from which E1 and E4 have been deleted, following intratracheal instillation into mouse and nonhuman primate lung. Evaluation of the E1 deletion vector in C57BL/6 mice demonstrated dose-dependent activation of both CD4 T cells (i.e., TH1 and TH2 subsets) and neutralizing antibodies to viral capsid proteins. Deletion of E4 and E1 had little impact on the CD4 T-cell proliferative response and cytolytic activity of CD8 T cells against target cells expressing viral antigens. Analysis of T-cell subsets from mice exposed to the vector from which E1 and E4 had been deleted demonstrated preservation of TH1 responses with markedly diminished TH2 responses compared to the vector with the deletion of E1. This effect was associated with reduced TH2-dependent immunoglobulin isotypes and markedly diminished neutralizing antibodies. Similar results were obtained in nonhuman primates. These studies indicate that the vector genotype can modify B-cell responses by differential activation of TH1 subsets. Diminished humoral immunity, as was observed with the E1 and E4 deletion vectors in lung, is indeed desired in applications of gene therapy where readministration of the vector is necessary.

Activation of T and NK Cells Following Lenalidomide Therapy in Patients with Follicular Lymphoma.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2766-2766
Author(s):  
Seema Rawal ◽  
Nathan Fowler ◽  
Min Zhang ◽  
Zhiqiang Wang ◽  
Tariq Muzzafar ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Nk Cells ◽  
Research Funding ◽  
Memory T Cells ◽  
T Cell Subsets ◽  
Central Memory T Cells

Abstract Abstract 2766 Background: Lenalidomide plus rituximab therapy is a highly effective and well-tolerated therapy in patients (pts) with follicular lymphoma (FL). In a Phase II trial, this combination induced a complete remission rate of 87% in pts with advanced stage untreated FL (Fowler et al, Ann Oncol, 2011; 22; suppl 4:137). A randomized Phase III trial was recently initiated to compare this combination with current standard of care therapies in pts with FL. Although lenalidomide is known to be an immunomodulatory drug with effects on a variety of immune cells in vitro, its effects have not been well studied in vivo in humans. Understanding the in vivo effects of lenalidomide could lead to novel combination strategies to enhance the efficacy and improve clinical outcome in FL and other malignancies. Methods: Pts received lenalidomide 20 mg/day on days 1–21 of each 28-day cycle and rituximab was given at 375 mg/m2on day 1 of each cycle. Peripheral blood mononuclear cells (PBMC) were phenotyped by multiparametric flow cytometry at baseline, on cycle 2 day 15 (C2D15), and at the end of cycle 6. In addition, peripheral blood (PB) samples were collected in PAXgene Blood RNA tubes at baseline and on C2D15 for whole genome gene expression profiling (GEP). Results: Immunophenotyping of baseline and end of cycle 6 PBMC (n=17) showed that the percentages and absolute numbers of CD3+, CD4+, CD8+, TCRgd, and Foxp3+ regulatory T cells; and NK, NKT, and myeloid dendritic cells were not significantly different between the two time points. However, a significant increase in CD4+CD45RO+ (p<0.01) and CD8+CD45RO+ (p=0.04) memory T cells was observed post-therapy. Further characterization of CD4+ T cells showed a significant increase in central memory T cells (p<0.001) and a decrease in naïve (p<0.01) and terminally differentiated (p<0.01) T cells, but no change in effector memory T cells. The increase in CD8+ central memory T cells was marginally significant (p=0.06). Plasmacytoid dendritic cells (PDC) were also significantly increased (p=0.02). In contrast, no such changes in T cell subsets or PDC were observed in FL pts (n=9) treated with 6 cycles of R-CHOP chemotherapy that received equal number of rituximab doses and analyzed at similar time points (baseline and end of cycle 6). To understand lenalidomide-induced changes on a molecular level, we compared GEP data at C2D15 vs. baseline for 7 pairs of PB samples. The paired significance analysis of microarrays method, based on Student's t test, identified 1,748 differentially expressed genes (DEG; 713 up, 1035 down), without a fold-change threshold, in C2D15 samples vs. baseline. Results were influenced by rituximab-induced depletion of B cells in C2D15 samples, but there were many changes that suggested altered PBMC physiology. Noteworthy up-regulated genes (>1.5 fold) included genes associated with T and NK cell activation including BATF, CCR2, CD1B, CD2, CD160, CTLA4, CXCR3, ICOS, and LAG3; and CD163 and CD209, phagocytic receptors expressed on monocytes/macrophages. Down-regulated genes (>1.5 fold) included CXCR5, which mediates B cell migration into follicles; and IL1B and TNFSF13B (BAFF), which are produced by activated macrophages and induce B cell proliferation. Gene set enrichment analysis of all GEP results, and Ingenuity Pathway Analysis of DEGs, indicated up regulation of multiple pathways and processes including ribosomal and mitochondrial components involved in translation and oxidative phosphorylation, CTLA4 signaling in cytotoxic T cells, and differentiation and signaling by ICOS and CD28 in T helper cells. We confirmed up regulation of CTLA4, ICOS, and LAG3 at the protein level in C2D15 PBMC by flow cytometry. Furthermore, treatment of PBMC derived from untreated FL pts with lenalidomide in vitro resulted in up regulation of these molecules in T and/or NK cells consistent with our in vivo results. Conclusions: In FL pts, lenalidomide induced multiple changes in the immune system including increases in PDC and memory T cell subsets, activation of T and NK cells, and down-regulation of certain genes mediating B cell migration and proliferation. These results provide insights into the mechanism of action of lenalidomide and suggest that it can be combined with other immunostimulatory agents such as therapeutic vaccines, adoptive T cell therapy strategies, and immune checkpoint inhibitors to further enhance its efficacy in FL and other malignancies. Disclosures: Fowler: Celgene: Research Funding. Heise:Celgene Corporation: Employment, Equity Ownership. Lacerte:Celgene: Honoraria. Samaniego:Celgene: Research Funding. Neelapu:Celgene Corporation: Research Funding.

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