TCRBV Gene Research Articles

Characterization of human cytomegalovirus peptide–specific CD8+ T-cell repertoire diversity following in vitro restimulation by antigen-pulsed dendritic cells

Under conditions of impaired T-cell immunity, human cytomegalovirus (HCMV) can reactivate from lifelong latency, resulting in potentially fatal disease. A crucial role for CD8(+) T cells has been demonstrated in control of viral replication, and high levels of HCMV-specific cytotoxic T-lymphocytes are seen in immunocompetent HCMV-seropositive individuals despite very low viral loads. Elucidation of the minimum portion of the anti-HCMV T-cell repertoire that is required to suppress viral replication requires further study of clonal composition. The ability of dendritic cells to take up and process exogenous viral antigen by constitutive macropinocytosis was used to study HCMV-specific T-cell memory in the absence of viral replication. The specificity and clonal composition of the CD8(+) T-cell responses were evaluated using HLA tetrameric complexes and T-cell receptor beta chain (TCRBV) spectratypic analyses. There was a skewed reactivity toward the matrix protein pp65, with up to 40-fold expansion of CD8(+) T cells directed toward a single peptide-MHC combination. Individual expansions detected on TCRBV spectratype analysis were HCMV-specific and composed of single or highly restricted numbers of clones. There was preferential TCRBV gene usage (BV6.1/6.2, BV8, and BV13 in HLA-A*0201(+) individuals) but lack of conservation of CDR3 length and junctional motifs between donors. While there was a spectrum of TCR repertoire diversity directed toward individual MHC-peptide combinations between donors, a relatively small number of clones appeared to predominate the response in each case. These data provide further insight into the range of anti-HCMV responses and will aid the design and monitoring of adoptive immunotherapy protocols.

T cell receptor (TCR) Vbeta gene usage in bronchoalveolar lavage and peripheral blood T cells from asthmatic and normal subjects.

T cells are thought to play an important regulatory role in asthma, but little is known about the T cell repertoire of the human lung or whether asthma is associated with any specific repertoire changes. Flow cytometry and MoAbs to TCR VB (TCRBV) families were used to quantify bronchoalveolar lavage (BAL) and blood T cells from normal and atopic individuals. Clonality was then assessed by polymerase chain reaction (PCR) amplification of cDNA and gene scanning using consensus and family-specific TCRBV primers and confirmed by sequence analysis. In addition, blood and BAL T cell populations were studied pre- and post-allergen challenge in four patients with allergic asthma. The majority of TCRBV families detected in blood by MoAb staining were also represented in BAL. While differences between BAL and blood populations were evident in each individual studied, these differences were not consistent between individuals or between CD4+ and CD8+ T cell subpopulations. These results are in broad agreement with other published studies, but in contrast to previous work we found a consistent difference between TCRBV7 family usage in blood and BAL in all individuals studied, and a consistently increased proportion of CD4+ BAL T cells bearing BV5S2/3 in asthmatics only. After allergen challenge, the pattern of TCRBV gene usage was largely unchanged as judged by flow cytometry. Gene scanning of PCR products generated from consensus VB primers revealed polyclonal lymphocyte populations in blood and BAL from all seven atopic individuals: in one normal tested polyclonal populations were found in blood and oligoclonal populations in BAL. Selected families amplified with family-specific primers BV5S2/3, BV6 and BV7 (chosen because of their predominance in BAL compared with blood) were more variable and revealed predominant polyclonal populations in blood and polyclonal or oligoclonal populations in BAL. In one asthmatic patient a clonal BV5S2 family was found in BAL. Following allergen challenge there were no significant changes in polyclonality/oligoclonality/clonality in three cases, but in one case a clonal BV5S2 population was found after challenge, that had not been evident beforehand. The lung T cell repertoire is thus broadly representative of blood T cells, but shows population differences that may result from response to persistent exposure to airborne antigens common to normal and atopic individuals. Oligoclonal TCRBV family expansion appears to be primarily lung-specific but independent of atopic asthma, although our challenge data in one case support the concept that clonal populations may follow local allergen challenge. These data are consistent with selection and amplification of specific T cell families in the lung in response to local antigenic exposure.

Epitope focus, clonal composition and Th1 phenotype of the human CD4 response to the secretory mycobacterial antigen Ag85.

Lymphoproliferation of healthy donors was tested against mycobacterial antigens (PPD, Ag85, Ag85 peptides). All PPD responders recognized the secretory antigen Ag85 and the peptide specificity for Ag85B was defined. Peptide 91-108 was recognized by 85% of donors. In addition, all CD4 T cell lines generated from 12 donors against PPD or Ag85 responded to 91-108. When this peptide was used to generate T cell lines, the cells responded also to tuberculins from atypical mycobacterial species. Thus the cross-reactive peptide behaved as quasi-universal. The analysis of TCR-BV gene usage by cell lines showed that most Ag85-specific T cells correspond to 91-108-specific clonotypes. Intracytoplasmic staining of cell lines after phorbol myristate acetate stimulation resulted in dominance of interferon-gamma (IFN-gamma)-IL-4 double-positive cells, whereas antigen stimulation resulted in production of IFN-gamma only. The data show that peptide 91-108 is the major focus of the CD4 response to mycobacterial antigens in peripheral blood mononuclear cells and in T cell lines from PPD responders.

Analysis of the antigen specific T cell repertoires in HIV infection

In addition to HIV infection, several acquired immunodeficiencies lead to depletion of CD4 lymphocytes. These include immunosuppression resulting from high dose cancer chemotherapy or induced to control graft rejection, as well as in autoimmune diseases. The consequence of this depletion is an increased susceptibility to opportunistic infections or the inability to control primary infection in the case of HIV infection. In all instances a full or partial immunoreconstitution is desirable. In order to monitor the cellular immune state of a patient, rational information cannot be simply derived from phenotypic quantification of T lymphocytes. Instead loss or recovery of CD4 cells should be monitored by defining the specificity, the function and the clonality of the relevant cell population. Several methods are now available for this type of investigation. Here we describe an approach for the definition of clonal heterogeneity of antigen specific CD4 lymphocytes, a parameter that may help monitor loss or reconstitution in acquired immunodeficiencies. As examples of antigen specific CD4 T cell responses we focused on Pneumocystis carinii and on cytomegalovirus, as prototypic opportunistic pathogens which are responsible for severe infections in AIDS and in other immunosuppressive conditions which arise for instance following transplantation. Specific CD4 T cell lines were generated from normal controls and from seropositives in order to select antigen specific lymphocytes. The cells were subsequently analyzed for clonal diversity according to TCR BV gene family usage and according to TCR CDR3 size heterogeneity (spectratyping).

T-cell clones derived by CD3 stimulation from hepatitis C virus explanted liver tissue are not representative of dominant clones present in vivo.

Liver tissue from hepatitis C virus (HCV)-related end-stage disease contains T-cell infiltrates. The goal of this study is to determine whether CD4 T-cell clones established in vitro using an antigen-independent technique from explanted liver tissue (n = 3) are representative of dominant clones present in vivo. T-cell receptor (TCR) use by intrahepatic CD4 T cells was assessed by spectratype analysis. Clones were established from single CD4 T cells by culturing in vitro with anti-CD3 and interleukin-2 (n > 25 per patient). TCR genes expressed by each clone were identified by sequencing. When identical clones were isolated, the original spectratype was analyzed further to determine whether the clone was a dominant T-cell expansion in vivo. Evidence for clonal expansions was found in all patients by spectratyping. T cells expressing the same TCRBV genes used for spectratyping were cloned in vitro. Duplicate clones expressing the same TCR genes were observed in 2 patients. Confirmation that clones established in vitro matched those present in vivo was obtained for 2 clones. Many dominant clones identified by spectratyping did not proliferate in vitro. Although spectratyping suggested the widespread accumulation of clonal expansions in HCV-related end-stage liver disease, clones established in vitro using anti-CD3 were poorly representative of dominant clones present in vivo. Although cloning with anti-CD3 has the advantage of generating T-cell clones not biased a priori toward a specific antigen, modified cloning strategies will need to be developed to expand those clones that appear dominant in end-stage organs.

Flexibility of TCR Repertoire and Permissiveness of HLA-DR3 Molecules in Experimental Autoimmune Thyroiditis in Nonobese Diabetic Mice

Experimental autoimmune thyroiditis (EAT) is inducible in genetially susceptible mice by immunization with mouse thyroglobulin (mTg). With susceptibility linked to MHC class II, EAT is useful in studying human leukocyte antigen (HLA) associations with Hashimoto's thyroiditis. In non-obese diabetic (NOD) mice, ∼10% thyroiditis incidence occurs with aging. This potential was exploited to examine the T cell repertoire and HLA association in EAT. Similar to B10.K-Vβcmice with TCRBV genes reduced by ∼70%, mTg-immunized NOD-Vβcmice developed thyroiditis comparable to controls, indicating plasticity of the TCR repertoire for pathogenic epitopes. HLA association was evaluated by introducing HLA-DRA/DRB1*0301 (DR3) transgene into class II-negative NOD mice (Ab0/NOD). Previously, this HLA-DR3 transgene rendered EAT-resistant B10.M and Ab0mice susceptible to both mTg- and hTg-induced EAT. These results are now confirmed. mTg-induced thyroiditis in DR3+Ab0/NOD mice was comparable to that in NOD and DR3−NOD mice, and the proliferative response was stronger. By comparison, NOD mice were only moderately susceptible to hTg-induced EAT. However, thyroiditis was more severe in DR3+Ab0/NOD than in DR3−NOD mice, with no difference in proliferative response to hTg harbouring heterologous epitopes. The confirmed permissiveness of HLA-DR3 molecules on an NOD background for EAT induction by both mTg and hTg supports the importance of this class II gene implicated in some patient studies.

Oligoclonal T cell repertoire in cerebrospinal fluid of patients with inflammatory diseases of the nervous system

OBJECTIVETo evaluate the T cell receptor β chain variable region (TCRBV) gene usage ex vivo in CSF cells and peripheral blood mononuclear cells (PBMCs) collected from patients with autoimmune and...

Long term persistence of herpes simplex virus-specific CD8+ CTL in persons with frequently recurring genital herpes.

Herpes simplex virus (HSV) establishes a lifelong infection in humans. Reactivation of latent virus occurs intermittently so that the immune system is frequently exposed to viral Ag, providing an opportunity to evaluate memory T cells to a persistent human pathogen. We studied the persistence of genital herpes lesion-derived HSV-specific CD8+ CTL from three immunocompetent individuals with frequently recurring genital HSV-2 infection. All CTL clones were HSV-2 type specific and only one to three unique clonotypes were identified from any single biopsy specimen. The TCRBV genes utilized by these clonotypes were sequenced, and clonotype-specific probes were used to longitudinally track these clonotypes in PBMC and genital lesions. CTL clonotypes were consistently detected in PBMC and lesions for at least 2 and up to 7 years, and identical clonotypes infiltrated herpes lesions spaced as long as 7.5 years apart. Moreover, these clones were functionally lytic in vivo over these time periods. Additionally, CTL clones killed target cells infected with autologous viral isolates obtained 6.5 years after CTL clones were established, suggesting that selective pressure by these CTL did not result in the mutation of CTL epitopes. Thus, HSV recurs in the face of persistent CD8+ CTL with no evidence of clonal exhaustion or mutation of CTL epitopes as mechanisms of viral persistence.

Intestinal αβ T cells of symptomatic celiac disease patients show oligoclonal TCRBV repertoire but polyclonal rearrangement patterns

Celiac disease is an immunological disease provoked by some cereal proteins in HLA-DQ–mediated susceptible individuals. The role of intestine infiltrating αβ T cells in the pathogenesis of the disease has been functionally established. In the present report, we have studied the repertoire of TCRBV genes, spectratype distribution, and CDR3 sequences of intestinal T cell populations isolated from three CD patients at diagnosis and two normal control biopsies. Oligoclonal TCRBV usage was observed both in CD and control samples. However, a much more restricted TCRBV usage was evident in normal mucosa. The use of BV gene families was linked to no dominant rearrangements in CD, while apparent oligoclonal patterns were found in normal biopsies. Only 3 out of 73 sequenced transcripts derived from preponderant TCRBV genes in the three celiac samples were obtained twice. In contrast, only 13 different rearrangements were found out of 32 analyzed in control samples. In spite of the polyclonal behavior of T cells in CD mucosa, some conserved motifs in the CDR3 region were noticed among rearrangements derived from different TCRBV genes and patients. The lack of expanded T cell clones in the damaged tissue could be explained in terms of antigen diversity or by non-specific immunological responses in the symptomatic phase of the disease.

Pulmonary T cell repertoire in patients with graft-versus-host disease following blood and marrow transplantation.

Pulmonary inflammation is one of the risk factors associated with blood and marrow transplantation (BMT). To determine the potential role of T cells in pulmonary complications after transplantation, we analyzed the T-cell repertoire expressed in bronchoalveolar lavage fluids from eleven patients with graft-versus-host disease following BMT. A reverse transcriptase-polymerase chain reaction was used to amplify rearranged TCR transcripts in unfractionated, CD4+, and CD8+ T cells from bronchoalveolar lavage fluids. The relative expression of TCR variable (V) gene families and the diversity of junctional region lengths associated with different AV and BV gene families were analyzed. Nearly all TCR AV and BV gene families were detected in bronchoalveolar lavage cells from BMT recipients. Oligoclonal patterns of TCR junctional region lengths were observed in unfractionated, CD4+, and CD8+ bronchoalveolar T cells. The oligoclonal expansion of bronchoalveolar T cells in patients was confirmed by DNA sequencing. TCRV gene expression is almost completely restored in the lungs of BMT recipients as early as two weeks after transplantation. Increased oligoclonality among TCR gene families suggests either an incomplete restoration of TCR diversity or an antigen-driven expansion of T cells in the lungs of BMT recipients with graft-versus-host disease, not necessarily related to pulmonary infection.

Non-productive human TCR β chain genes represent V-D-J diversity before selection upon function: insight into biased usage of TCRBD and TCRBJ genes and diversity of CDR3 region length

The aim of the study was to assess the influence of constraints of V-D-J rearrangement on the nonrandom junctional diversity of productive T-cell receptor β-chain genes in peripheral T-cells. Mature peripheral T lymphocytes are expected to display a biased repertoire of T cell receptors (TCRs), enriched for those that can recognize peptides presented by the major histocompatibility complex (MHC) molecules. Therefore, functional TCR rearrangements of peripheral T-cells are unsuitable to reveal the bias of the TCR repertoire, introduced by V-D-J rearrangement. To overcome this problem, we have studied nonfunctional TCR genes representing a repertoire of rearranged TCR gene sequences without any known post-rearrangement selection. Detailed molecular analysis of a database generated from more than 500 functional (TCRBV20S1) and nonfunctional (TCRBV10S1P and TCRBV19S1P) T-cell receptor genes from peripheral blood T-cells permitted a comparative analysis of recombination frequencies of each germline-encoded V, D, and J-segments, as well as exonucleolytic nibbling and addition of nucleotides in functional and nonfunctional transcripts. Our data demonstrate that V-D-J recombination generates a more diverse CDR3 length distribution than found among productive TCRBV genes, suggesting that selection constrains the CDR3 to an optimal junctional region length. Furthermore, the well established biased patterns of D- and J-usage in the rearranged TCRBV genes in human peripheral blood lymphocytes were also present in nonfunctional transcripts. Therefore, V-D-J diversity is biased mainly by constraints of the rearrangement process rather than intrathymic T-cell selection and peripheral expansion of particular T-cell clones.

Lack of restriction of T cell receptor β variable gene usage in cerebrospinal fluid lymphocytes in acute optic neuritis

OBJECTIVESThere have been many studies reporting restricted patterns of T cell receptor usage in established multiple sclerosis and these have led to clinical trials of immunomodulation directed at deleting clonal...

Identification of seven new TCRBV subfamilies in cattle (Bos taurus).

In cattle, the repertoire of TCRBV genes that encode the variable region of T-cell receptor beta-chains has not been fully characterized. In this study, cattle TCRBV genes were amplified from mRNA by anchored polymerase chain reaction and sequenced. Eleven new TCRBV gene sequences were found, and classified into seven subfamilies distinct from those previously identified.

Sequence and diversity of T-cell receptor beta-chain V and J genes of the owl monkey Aotus nancymaae.

The New World primate Aotus nancymaae is susceptible to infection with the human malaria parasite Plasmodium falciparum and has therefore been recommended by the World Health Organization as a model for the evaluation of malaria vaccine candidates. Recently, we have shown that Aotus TCRVA genes and TCRJA segments exhibit a high degree of similarity to human counterparts. In the present report we used reverse transcription polymerase chain reaction to analyze the sequences of A. nancymaae TCR beta-chain gene rearrangements. Alignment with human sequences and phylogenetic comparison identified 18 distinct Aotus TCRBV genes homologous to the human TCRBV gene families 2, 4, 5, 6, 7, 9, 12, 15, 24, and 28. Multiple Aotus genes were found in the TCRBV4, 5, 6, and 7 families. Some of these TCRBV genes aligned best to the same human gene and thus do not seem to have separate human homologues. Amino acid sequences of the Aotus TCRBV genes were 77 to 90% identical to their closest human counterparts. Ten distinct Aotus TCRBJ segments homologous to the human segments J1-1, J1-2, J1-4, J1-5, J1-6, J2-1, J2-2, J2-3, J2-4, J2-5 were found. In some cases the amino acid sequences of Aotus and human TCRBJ segments were completely identical. A comparison of the proportion of synonymous and non-synonymous substitutions in Aotus vs human beta-chain-encoding genes revealed a dominance of synonymous substitutions in TCRBJ segments and of nonsynonymous substitutions in TCRBV segments. Dominance of nonsynonymous substitutions was more pronounced in TCRBV CDR1 and CDR2 regions than in the framework regions. No evidence for the emergence of new TCRBJ segments or TCRBV families was found. These results confirm that the TCR repertoire in primates is remarkably stable and support the concept of using Aotus monkeys as an infection model for the evaluation of future subunit vaccine candidates.

Association of HLA and T-cell receptor gene polymorphisms with Semple rabies vaccine-induced autoimmune encephalomyelitis.

Semple rabies vaccine is derived from brain tissue infected with rabies virus that is subsequently inactivated with phenol. Semple rabies vaccine-induced autoimmune encephalomyelitis (SAE) occurs in 1 in 220 immunized individuals. The immune response to myelin basic protein and pathological changes of demyelination in SAE suggest that this disease is the human homologue of experimental autoimmune encephalomyelitis (EAE). SAE and EAE are frequently studied as models for the human demyelinating disease multiple sclerosis. Major histocompatibility complex (MHC) class II and T-cell receptor (TCR) gene polymorphisms play important roles in rodent susceptibility to EAE and were analyzed to determine if the same was true in humans with SAE. HLA-DRB1, HLA-DQB1, and TCRBV gene polymorphisms were studied in Thai individuals with SAE (n = 18), with vaccination without neurological complications (n = 43), and without vaccination (n = 140). The allele frequencies of HLA-DR9 (DRB1*0901) and HLA-DR17 (DRB1*0301) were increased in SAE patients (DR9 = 22%, DR17 = 14%) compared with vaccinated controls (DR9 = 13%, DR17 = 6%) and with unvaccinated controls (DR9 = 9%, DR17 = 4%). The allele frequency of HLA-DQ7 (DQB1*0301) was decreased in SAE patients (8%) compared with vaccinated controls (15%) and with unvaccinated controls (25%). These susceptibilities are distinct from those associated with multiple sclerosis. The frequencies of TCRBV alleles and haplotypes were similar in SAE patients and vaccinated controls. These data suggest that genetic susceptibility associated with MHC class II alleles may have a role in the pathogenesis of SAE and its mechanism may be different from those involved in multiple sclerosis.

Diverse T-cell receptor CDR3 length patterns in human CD4+ and CD8+ T lymphocytes from newborns and adults.

T cells are essential in the initiation and maintenance of immune responses. Specific interaction between T cells and a presumptive antigen occurs through recognition of an MHC-peptide complex by the T-cell receptor (TCR). The complementarity-determining region (CDR) 3 of the TCR has direct contact with the peptide. Here we describe CDR3 length variability of six different TCRBV gene families of CD4+ and CD8+ umbilical cord (UC) and peripheral blood (PB) T cells. Amplified products spanning the TCR CDR3 regions from CD4+ PB, CD4+ UC and CD8+ UC blood T cells typically displayed Gaussian-like distributions. In contrast, profound and frequent perturbations were recorded in CD8+ PB lymphocytes, with a non-Gaussian pattern in more than half of the samples studied. A substantial portion of the perturbed CD8+ subsets were clonal or oligoclonal, as determined by CDR3-length restriction, TCRBJ gene usage and nucleotide sequencing. This implies that the conditions for shaping and maintenance of the peripheral TCR repertoire are profoundly different for CD8+ and CD4+ T cells.

Identification of overrepresented T cell receptor genes in blood and tissue biopsies by PCR-ELISA

The analysis of T cell receptor variable (TCR V) gene repertoires in blood or tissues may provide important information when studying immunopathological mechanisms. The overexpression of a TCR gene may indicate the expansion of the corresponding T cell subset. In autoimmune diseases, clonally expanded T cell subsets in the affected organs may represent pathogenic lymphocytes. We describe a simple, rapid and sensitive method to determine the TCR AV and BV gene repertoire using a PCR-ELISA method. RNA is extracted from lymphocytes, transcribed to cDNA, which is then used as a template for PCR with 19 different TCR AV gene and 20 BV gene specific primers as the forward primer, and a digoxigenin (DIG) labeled AC/BC primer as the reverse primer. The DIG labeled PCR amplicons are hybridized with a fluorescein isothiocyanate (FITC) labeled TCR C region specific probe. Finally, the amplicons are quantified by ELISA using anti-FITC coated microtiter plates, and an anti-DIG conjugated peroxidase. Although PCR-ELISA cannot accurately quantify the expression level of a given TCR gene, overrepresented TCR V genes are easily identified by comparing the relative expression levels of each individual V gene in the total V gene repertoire. We demonstrate that this technique can be used to determine TCR profiles in blood and tissue samples containing as few as 50,000 T cells. In combination with CDR3 fragment size analysis, this method is an efficient tool to identify clonally expanded T cell subsets in the synovial biopsies of rheumatoid arthritis patients.

Detection of clonotypic changes of T cells after stimulation with Porphyromonas gingivalis.

The aim of this study was to investigate whether Porphyromonas gingivalis stimulation would induce a selective activation and expansion of a limited T-cell receptor V beta repertoire or T-cell clonotype. Using samples from patients with chronic inflammatory periodontal diseases, we examined TCRBV gene usage and T-cell clonotypes of peripheral blood mononuclear cells incubated in the presence or absence of P. gingivalis outer membrane through a combination of reverse transcription polymerase chain reaction (RT-PCR) and subsequent single strand conformation polymorphism (SSCP) analysis. There was no difference in the mean expression for most BV families with or without P. gingivalis outer membrane in the culture. However, in individual cases, a few BV gene families did become overexpressed or underexpressed following stimulation, although a consistent pattern did not emerge. SSCP analysis showed that several new distinct bands appeared after stimulation, indicating distinct clonal accumulations, although the number of distinct bands decreased in most cases. These data suggest that clonotypic change occurred following stimulation with P. gingivalis outer membrane. Furthermore, the possibility of superantigen stimulation by P. gingivalis is unlikely to be due to the small change in BV gene usage and clonal T-cell accumulations with P. gingivalis outer membrane stimulation, as evidenced by SSCP. Thus, RT-PCR and SSCP analysis is useful in evaluating the host response to periodontopathic antigens.

Oligoclonal expansion of HIV-specific cytotoxic CD8 T lymphocytes in the skin of HIV-1-infected patients with cutaneous pseudolymphoma.

A massive infiltration of the skin by activated CD8+ T lymphocytes involving both the dermis and the epidermis has been found in HIV-1-infected patients presenting with a chronic skin rash. We characterized the T cell receptor (TCR) BV-BJ junctional diversity of the skin-infiltrating lymphocytes (SILs) in four patients. The SILs expressed a limited set of TCRBV gene segments. Complementarity determining region 3 length analysis further emphasized their oligoclonality, suggesting that antigen stimulation might be responsible for the cutaneous T cell expansion. Furthermore, independent skin biopsies obtained from the same individual were shown to harbor distinct T cell repertoires, possibly reflecting the spatial heterogeneity of the antigenic stimuli. The CD8+ cytotoxic T lymphocyte (CTL) lines isolated from the skin rash in one patient exhibited a specific, class I MHC-restricted cytotoxic activity against HIV-1 Gag- and Pol-expressing target cells, whereas CTL lines derived from the skin lesions of a second patient were shown to be predominantly Env-specific. Taken together, these data demonstrate the infiltration of HIV-specific CTLs in the skin of HIV-infected patients, and suggest that in addition to their known role in controlling the retroviral infection, these CTLs may also be involved in the pathogenesis of cutaneous inflammatory disorders occurring during the course of HIV infection.

Correction of Abnormal T-Cell Receptor Repertoire During Interferon-α Therapy in Patients With Hairy Cell Leukemia

Patients with the B-cell malignancy hairy cell leukemia (HCL) exhibit a skewed T-cell repertoire with oligoclonal expression or absence of many members of the T-cell receptor (TCR) BV gene families. To evaluate whether interferon-α (IFN-α) therapy would not only restore normal hematopoiesis, but also the abnormal T-cell repertoire, we studied T lymphocytes from a cohort of HCL patients treated by IFN-α in the past, at initiation, and at several intervals up to 6 years of IFN-α treatment. The junctional regions from 22 TCRBV gene families were analyzed after polymerase chain reaction amplification of cDNA (RT-PCR) using family specific primers. In all seven patients improvement of the skewed T-cell repertoire was not seen until 2 years of treatment. It consisted of disappearance of oligoclonal subpopulations and (polyclonal) reappearance of absent TCRBV gene families. The RT-PCR results were correlated with the TCRBV protein expression using TCRBV-specific monoclonal antibodies. T lymphocytes from four patients with active HCL contained large expansions of particular TCRBV-expressing cells (up to 25% of the CD3+cells; 600 to 700/μL whole blood), which decreased during IFN-α therapy in both patients tested. Finally, restoration of the TCR repertoire matched normalization of the functional immune repertoire as measured by proliferative, helper, and cytotoxic T-lymphocyte precursor frequencies against major histocompatibility complex–unrelated individuals. In conclusion, oligoclonal bands of TCRBV gene families found by RT-PCR correspond with a dramatic increase in circulating T lymphocytes expressing the same TCRBV family. Moreover, IFN-α can restore the skewed T-cell repertoire and suppress persistent T-cell clones upon treatment of the accompanying malignancy.