Immune reconstitution after antiretroviral therapy in human immunodeficiency virus (HIV)infected patients may result from the recovery of thymus function, peripheral redistribution, or decreased T cell destruction. This study investigated levels of T cell receptor gene rearrangement excision circles (TRECs) as a measure of recent thymic emigrant cells in peripheral blood lymphocytes of 50 HIV-infected infants and children who were followed-up for 40 months after the start or change of antiretroviral therapy. At baseline, patients exhibited fewer TRECs than did uninfected control subjects. The increase in TRECs after antiretroviral therapy was greater in infants than in older HIV-infected children. Of interest, patients who demonstrated discordant responses (i.e., increased CD4 T cell counts without significant virologic suppression) also had substantial gains in TRECs. Furthermore, TRECs correlated positively with the number of CD4 and naive T cells and negatively with age and virus load. Measurement of TRECs may serve as a useful tool for evaluating immune reconstitution in HIV-infected children receiving antiretroviral therapy.

Perturbations in the T-cell receptor (TCR) V␤ repertoire were assessed in the CD4 and CD8 T lymphocytes of human immunodeficiency virus (HIV)-infected children who were receiving therapy during the chronic phase of infection by flow cytometry (FC) and PCR analysis. By FC, representation of 21 TCR V␤ subfamilies was assessed for an increased or decreased percentage in CD4 and CD8 T cells, and by PCR, 22 TCR V␤ subfamilies of CD4 and CD8 T cells were analyzed by CDR3 spectratyping for perturbations and reduction in the number of peaks, loss of Gaussian distribution, or clonal dominance. The majority of the TCR V␤ subfamilies were examined by both methods and assessed for deviation from the norm by comparison with cord blood samples. The CD8-T-lymphocyte population exhibited more perturbations than the CD4 subset, and clonal dominance was present exclusively in CD8 T cells. Of the 55 total CD8-TCR V␤ families classified with clonal dominance by CDR3 spectratyping, only 18 of these exhibited increased expression by FC. Patients with high numbers of CD8-TCR V␤ families with decreased percentages had reduced percentages of total CD4 T cells. Increases in the number of CD4-TCR V␤ families with increased percentages showed a positive correlation with skewing. Overall, changes from normal were often discordant between the two methods. This study suggests that the assessment of HIV-induced alterations in TCR V␤ families at cellular and molecular levels yields different information and that our understanding of the immune response to HIV is still evolving.The majority of peripheral blood CD4 and CD8 T cells express the ␣␤ T-cell receptor (TCR), with the ␤ chain represented by variable segments which are grouped into families based on sequence homology (16). A complete T-cell repertoire is indicative of an intact T-cell population with the potential to recognize a wide range of immunogens. Numerous reports have documented changes in the TCR V␤ repertoire during human immunodeficiency virus (HIV) infection in relation to disease progression and the effect of therapy (4,5,(8)(9)(10)(19)(20)(21)(22)(23). CDR3 length spectratyping (8,19,21) and flow cytometric (FC) analysis of TCR V␤ families labeled with specific monoclonal antibodies (MAbs) (4,7,26) are among the most frequently used assays for the analysis of TCR V␤ repertoire in HIV infection. The CDR3 spectratype is an indicator of the relative proportion of cells in each TCR V␤ family with CDR3 of particular lengths, while labeling of cells with TCR-V␤-specific MAbs provides a quantitative assessment of the percentages of particular TCR V␤ families in T cells. Thus, evaluation of the TCR V␤ repertoire with MAbs, in combination with CDR3 spectratyping, is expected to provide complementary information. In the present study, we analyzed the TCR V␤ repertoire in the CD4 and CD8 T cells of 22 HIV-infected children by CDR3 length analysis and by FC. MATERIALS AND METHODSPatient population. TCR V␤ repertoire analyses by PCR and FC were performed concurrently in 22 HIV-infected c...

Children with chronic HIV infection manifest CD8 T cell clonal dominance, which appears to be dependent upon the adequacy of the CD4 cells. With optimization of therapy, a gain in clonal dominance is the predominant response, except in situations of failure to contain viral replication.

CD8 T cells are important mediators of cellular immune responses as evidenced by clonal expansions in the CD8 TCR Vβ repertoire during primary HIV infection in adults. This study investigated the CD8 TCR Vβ repertoire by complementarity-determining region 3 length analysis using multiplex PCR in purified peripheral blood CD8 T cells of 22 HIV-infected children (age range was 0.75–15 yr, mean was 8.2 ± 4.1 yr). Evidence of clonal dominance in one or more Vβ families was obtained in 15 of 22 children. The patterns of clonal dominance were designated as major, minor, single, and none to indicate the involvement of three or more, two, one, or no Vβ families, respectively. A pattern of major or minor clonal dominance was observed in 12 children (group 1), whereas 10 children had single or no clonal dominance (group 2). In comparison with group 2, the children in group 1 had a higher percentage of CD4 cells (28.3 ± 11.6 vs 8.6 ± 4.8, p < 0.001); a higher stimulation index in lymphoproliferative responses to Candida (92.0 ± 59.5 vs 12.3 ± 14.4, p = 0.002), tetanus (76.3 ± 51.2 vs 11.2 ± 12.7, p = 0.002), and alloantigens (178.3 ± 298.9 vs 32.9 ± 35.2, p < 0.001); and a lower percentage of CD8+HLA-DR+CD38+ cells (37.4 ± 13.1 vs 54.6 ± 14.2, p < 0.01). The number of dominant CD8 T cell clones was significantly correlated with the percentage of CD4 T cells (r = 0.669, p < 0.001) but not with plasma HIV RNA. Compared with group 1, patients in group 2 had a 4.8 times greater probability of having <15% CD4 cells. These findings indicate that CD8 clonal dominance in HIV-infected children reflects robustness of immune responses, regardless of time since infection and virus load.