Rapid analysis of the Vβ repertoire of CD4 and CD8 T lymphocytes in whole blood

Clinical features and treatment outcomes in patients with T-cell large granular lymphocytic leukemia: A single-institution experience

AIM

Large granular lymphocyte leukemia (LGLL) is a rare lymphoproliferative disorder associated with failure of hematopoiesis and autoimmune diseases. This study describes the clinical features and treatment responses of 108 patients with T-cell large granular lymphocyte leukemia (T-LGLL).

METHODS

Clinical data were collected from T-LGLL patients treated at an anemia treatment center within the hematology and blood diseases unit of a single hospital from January 2009 to April 2019.

RESULTS

The majority of patients (78 %) were symptomatic at the time of presentation. Splenomegaly was observed in 41 % of cases, while hepatomegaly and lymphadenopathy were rare (6 % and 7 %, respectively). Cyclosporine (CsA) monotherapy was used as first-line therapy for 16 patients, with an overall response rate (ORR) of 56 %. CsA in combination with steroids was administered in 83 patients, with an ORR of 48 %. Among patients experiencing relapse or resistance to first-line therapy, 10 received antithymocyte globulin (ATG) therapy, with an ORR of 50 %; an additional 9 patients received a modified regimen of high-dose cyclophosphamide (CTX) therapy, yielding an ORR of 78 %.

CONCLUSIONS

This study provides new information regarding the clinical features and therapeutic strategies for T-LGLL, which can be used to improve clinical decision making for T-LGLL patients. The data presented here indicate the CsA is an effective option for the treatment of T-LGLL, while modified regimens of high-dose CTX or ATG are safe and effective choices for patients with CsA refractory disease.

A new high-throughput sequencing method for determining diversity and similarity of T cell receptor (TCR) α and β repertoires and identifying potential new invariant TCR α chains

BACKGROUND

High-throughput sequencing of T cell receptor (TCR) genes is a powerful tool for analyses of antigen specificity, clonality and diversity of T lymphocytes. Here, we developed a new TCR repertoire analysis method using 454 DNA sequencing technology in combination with an adaptor-ligation mediated polymerase chain reaction (PCR). This method allows the amplification of all TCR genes without PCR bias. To compare gene usage, diversity and similarity of expressed TCR repertoires among individuals, we conducted next-generation sequencing (NGS) of TRA and TRB genes in peripheral blood mononuclear cells from 20 healthy human individuals.

RESULTS

From a total of 267,037 sequence reads from 20 individuals, 149,216 unique sequence reads were identified. Preferential usage of several V and J genes were observed while some recombinations of TRAV with TRAJ appeared to be restricted. The extent of TCR diversity was not significantly different between TRA and TRB, while TRA repertoires were more similar between individuals than TRB repertoires were. The interindividual similarity of TRA depended largely on the frequent presence of shared TCRs among two or more individuals. A publicly available TRA had a near-germline TCR with a shorter CDR3. Notably, shared TRA sequences, especially those shared among a large number of individuals', often contained TCRα related with invariant TCRα derived from invariant natural killer T cells and mucosal-associated invariant T cells.

CONCLUSION

These results suggest that retrieval of shared TCRs by NGS would be useful for the identification of potential new invariant TCRα chains. This NGS method will enable the comprehensive quantitative analysis of TCR repertoires at a clonal level.

Discrimination of T-cell subsets and T-cell receptor repertoire distribution

Flow cytometry-based analysis of T-cell receptor (TCR) repertoires is an essential tool for the detection of clonal T-cell expansions in physiologic and pathologic conditions. Individual T-cell subsets can be investigated based on their surface properties. The aims of our study were to provide reference values for various disease settings and delineate the contribution of individual TCR repertoires to the human T-cell differentiation pathway. We analyzed blood of 66 healthy subjects aged 0 (cord blood) to 72 years. Lymphocyte subpopulations and TCR repertoires were simultaneously explored using antibodies specific to CD3, CD4, CD8, CD45RA, CCR7, CD27, CD57 and a set of 25 antibodies detecting human TCR-Vβ chains. Statistical analysis included Wilcoxon, paired t and ANOVA tests. Initially, TCR expansion values were calculated based on the analysis of TCR-Vβ distribution on CD4+ and CD8+ T cells. We then established gating strategies and an algorithm for data analysis allowing for discrimination of T-cell subsets and TCR distribution. Dominant TCR expansions were present within effector as opposed to central/effector memory or naive cells, e.g., median TCR-Vβ expansion rate was highest on CD45RA+/CCR7- effector CD4+/8+ cells (eight and 11-fold, respectively). Remarkably, TCR expansions were missing (0) or very low (0.5) on CD4+ and CD8+ central memory population, respectively. No significant gender-related variability of TCR repertoires was identified, and significant impact of chronic cytomegalovirus infection was shown. Our results serve as reference for future studies elucidating clonal TCR dominance of T-cell subsets.

T-cell response to superantigen restimulation during menstrual toxic shock syndrome

Menstrual toxic shock syndrome (MTSS) is a severe toxin-mediated disease associated with Staphylococcus aureus producing toxic shock syndrome toxin 1 (TSST-1), a superantigen that mediates a potent activation of Vβ-2 T cells. In animal models, superantigen treatment of responsive T cells induces their initial proliferation, followed by unresponsiveness upon further superantigen stimulation. To determine whether T cell unresponsiveness occurs in humans during the acute phase of MTSS, we collected T cells from a patient with MTSS and restimulated them ex vivo with recombinant TSST-1. The expansion of T cells collected during the acute phase of disease was compared with positive controls including basal-state T cells (collected 70 days after MTSS) restimulated with TSST-1, and T cells stimulated with enterotoxin B superantigen. We found that TSST-1-induced expansion of acute phase T cells was not inferior to that observed in positive controls. We conclude that T cells were still reactive to TSST-1 during the acute phase of MTSS in this patient. As the persistence of TSST-1 production could thus be associated with further expansion of TSST-1-reactive T cells and a rapid worsening of symptoms, this study adds further support to the need for immediate eradication of the focus of infection as soon as MTSS is suspected.

Efficient characterization of the TCR repertoire in lymph nodes by flow cytometry

Analysis of the T-cell receptor (TCR) repertoire by flow cytometry proved to be relevant for investigating T-cell diversity and detecting reactive cells in blood samples. We used this approach to characterize non-malignant T-lymphocytes in lymph nodes and give insights into their origin. The TCR repertoire of CD4+ and CD8+ T-cells from 81 lymph nodes was analyzed with a four-color flow cytometer using a wide panel of 25 anti-Vbeta monoclonal antibodies. Flow cytometry proved to be a useful and informative technique. We demonstrated a diversified TCR-Vbeta repertoire, and only low level expansions, in 53% of the samples. They involved nearly all Vbeta families, were more frequent in the CD8+ subset of older patients, but were not related to pathology. No evidence could be demonstrated in favor of stimulation by common antigens. Interestingly, the TCR-Vbeta repertoire proved to be very similar in lymph nodes and blood samples. Our results argue that in the cases studied, lymph node enlargement is mainly due to an increased homing of circulating T-cells. They also provide reference values for expression of 25 TCR-Vbeta in lymph nodes, which could serve as a basis for further applications in diagnosis of T-cell lymphoproliferative disorders.

Depletion of autoreactive immunologic memory followed by autologous hematopoietic stem cell transplantation in patients with refractory SLE induces long-term remission through de novo generation of a juvenile and tolerant immune system

Clinical trials have indicated that immunoablation followed by autologous hematopoietic stem cell transplantation (ASCT) has the potential to induce clinical remission in patients with refractory systemic lupus erythematosus (SLE), but the mechanisms have remained unclear. We now report the results of a single-center prospective study of long-term immune reconstitution after ASCT in 7 patients with SLE. The clinical remissions observed in these patients are accompanied by the depletion of autoreactive immunologic memory, reflected by the disappearance of pathogenic anti-double-stranded DNA (dsDNA) antibodies and protective antibodies in serum and a fundamental resetting of the adaptive immune system. The latter comprises recurrence of CD31(+)CD45RA(+)CD4(+) T cells (recent thymic emigrants) with a doubling in absolute numbers compared with age-matched healthy controls at the 3-year follow-up (P = .016), the regeneration of thymic-derived FoxP3(+) regulatory T cells, and normalization of peripheral T-cell receptor (TCR) repertoire usage. Likewise, responders exhibited normalization of the previously disturbed B-cell homeostasis with numeric recovery of the naive B-cell compartment within 1 year after ASCT. These data are the first to demonstrate that both depletion of the autoreactive immunologic memory and a profound resetting of the adaptive immune system are required to reestablish self-tolerance in SLE.

Early diagnosis of staphylococcal toxic shock syndrome by detection of the TSST-1 Vbeta signature in peripheral blood of a 12-year-old boy

We report the case of a 12-year-old boy who developed staphylococcal toxic shock syndrome associated with S. aureus pharyngeal colonization or infection. The diagnosis was rapidly confirmed by detecting the Vbeta signature of the toxic shock syndrome toxin-1 in peripheral blood, based on transient T cell depletion rapidly followed by massive expansion of Vbeta 2-positive T cells.

Analysis of the T-cell receptor repertoire of synovial T-cells

The recognition of a wide diversity of antigens by lymphocytes is made possible by the expression of a large range of highly variable antigen specific receptors, coded for by tandem arrays of genes, which undergo rearrangement during T- and B-cell development. The study of T-cell receptor (TCR) diversity and clonal composition of mixed T-cell populations has taken advantage of the features of the TCR molecule in various ways. This chapter focuses on the study of T-cells obtained from the synovial fluid of patients with inflammatory arthritis. Methods to process and store the samples and to separate cell populations are described. Two alternative molecular methods to analyse TCR diversity, identify clonal expansions, and track specific T-cell populations over both time and location are also detailed.

Flow Cytometry Evaluation of the T-Cell ReceptorVβ Repertoire Among HIV-1 Infected Individuals Before and After Antiretroviral Therapy

HIV-1 infection leads to serious impairment of the immune system and perturbations in the T cell receptor Vbeta repertoire are also described. Immune reconstitution can be potentially achieved in response to HAART. In the present study 10 patients were investigated for the Vbeta pattern expression before and after six months of HAART. TCR were analyzed for T CD4+ and CD8+ subsets, separately, by flow cytometry, using a monoclonal antibody set of 24 different Vbeta chains. Compared to eight Brazilian healthy controls, no differences in Vbeta pattern of expression was observed for patients before or on antiretroviral therapy. Some chains such as Vbeta 3, 14, 16, 20 and 21.3 were over utilized by both T subsets, independently of HIV infection and/or antiretroviral treatment, differing from the ones described for individuals of other nationalities. However, when each patient was taken individually, particular alterations were detected for the Vbeta gene usage, compared to controls, for all individuals. After treatment, significant Vbeta usage changes were observed for seven patients. One or more chains on both T subsets were engaged in this process, defining a preferential oligoclonal profile for TCR repertoire distribution, after HAART. Although no pattern of specific Vbeta changes was detected in the circulating T cells, we cannot exclude that differential immune responses to HIV or other important antigens are being focused by these cells.

Functional and molecular evaluation of lymphocytes

The laboratory plays a central role in the evaluation of immune function and is critical in the diagnosis and treatment of immune deficiencies. The range of options available to evaluate lymphocyte function has expanded dramatically as our understanding of the immune system has expanded. As the choices of laboratory tests increase, so also does the need to choose testing in such a way as to appropriately direct the evaluation. Typically, this approach involves starting with screening tests and, on the basis of the results of these tests, deciding whether more sophisticated and expensive testing is warranted. The remarkable developments over the past decade leading to the identification of numerous gene defects underlying a variety of immune deficiencies has moved mutation analysis into the realm of the clinical laboratory. This information could be indispensable for immune deficiency diagnosis, prenatal screening, carrier detection, and family counseling. In this review a sequential approach to evaluating lymphocyte function is presented, starting with readily available screening tests and followed by more complex in vitro testing, including the application of newer assays. The various approaches are presented from the perspective of appropriate use and information garnered, whereas actual details of test procedures are not discussed but are referenced. The evolution of immune function testing suggests that it will continue to develop, and future assays are likely to provide even more insight into specific aspects of the immune response and be linked to immune deficiencies not yet defined.

Fatal case of toxic shock-like syndrome due to group C streptococcus associated with superantigen exotoxin

Group C streptococci have been reported to cause invasive disease similar to that classically associated with group A streptococcus (GAS). We describe a fatal case of toxic shock-like syndrome due to Streptococcus equi subsp. zooepidemicus. The causative organism did not possess any known GAS superantigen exotoxin genes but did show evidence of superantigen production.