Faculty Bibliography

OBJECTIVE: To determine the frequencies at which either a valine or leucine occurs at position 247 in the beta2-glycoprotein I (beta2GPI) gene of normal individuals of the Caucasian, African American, and Asian ethnic groups and to compare these data with those in patients with the antiphospholipid syndrome (APS), with and without anti-beta2GPI antibodies. METHODS: The DNA segment containing the position-247 polymorphism was amplified by seminested polymerase chain reaction, and the polymorphism was detected by restriction endonuclease digestion. DNA samples from 370 healthy controls of different racial backgrounds were analyzed, and the results were compared with those from 149 APS patients (66 primary; 83 secondary). Allele and genotype frequencies were compared using Fisher's exact test. When significant differences were detected, pairwise comparisons were made using Fisher's exact test with a Bonferroni adjustment. RESULTS: Allele and genotype expression was significantly different (P < 0.0001 for both) among the 3 races, with the V allele and the VV genotype occurring most often among Caucasians, less among African Americans, and least among Asians. Conversely, the V allele and the VV genotype were found more frequently among Asian APS patients than among controls (P = 0.0028 and P = 0.0023, respectively). No significant differences in allele or genotype frequencies were seen in comparisons of the Caucasian or the African American patients with appropriate controls. The differences in allele and genotype frequencies seen in the Asian APS patients were restricted to the anti-beta2GPI-positive patients (P = 0.0018 and P = 0.0005, respectively). CONCLUSION: In Asian patients with APS, expression of a V at position 247, especially in the homozygous state, is significantly associated with the presence of anti-beta2GPI antibodies and, therefore, can be viewed as a major risk factor in this ethnic group (odds ratio 9.19 and 16.33, respectively)

CD8 T cells are important mediators of cellular immune responses as evidenced by clonal expansions in the CD8 TCR V beta repertoire during primary HIV infection in adults. This study investigated the CD8 TCR V beta 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 V beta 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 V beta 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

The genetic basis for rheumatoid arthritis (RA) is likely to be extremely complex. Even the role of MHC genes remains to be fully defined, and may involve interactive genetic effects. The difficulty of precisely defining the clinical phenotype, as well as underlying genetic heterogeneity, complicates the problem. In addition, stochastic genetic or physiologic events may contribute to the low penetrance of susceptibility genes. This situation parallels developing paradigms for other autoimmune disorders, in which many different genes each appear to contribute a small amount to overall risk for disease, and where severity and specific phenotypic subtypes are subject to genetic effects. The completion of the human genome project, along with advances in informatics, will be required to reach a deeper understanding of RA. It is likely that this will involve an iterative and interactive process between several different scientific disciplines

To investigate the diversity of the T cell repertoire involved in human T lymphotropic virus type I (HTLV-I) infections, peripheral blood T cell subsets were analyzed by using a PCR-based assay that permits determination of complementarity-determining region 3 (CDR3) length variation in TCR Vbeta transcripts. In two of four asymptomatic HTLV-I carriers and in four of five patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), mono- or oligoclonal expansions were detected in the CD4+ T cell subset. In one patient with adult T cell leukemia, a specific clone bearing Vbeta7 was detected in the CD4+ T cell subset. In contrast, clonal expansion was not observed in the CD4 T cell subsets of three individuals with asymptomatic HTLV-II infection or in our previous studies of a large number of uninfected individuals. Oligoclonal expansions in the CD8+ T cell subset were detected in all subjects, including the patient with adult T cell leukemia. No differences in the number of expanded clones were noted between asymptomatic carriers and in patients with HAM/TSP and there was no obvious restriction in the TCR V region usage. Direct sequencing revealed no significant bias in the CDR3 motifs utilized by the predominant clones. This report is the first direct demonstration of clonal expansions within fractionated T cell subsets (CD4+ and CD8+) in HTLV-I infections and suggests that 1) clonal expansion of CD4+ T lymphocytes likely occurs as a direct result of infection and 2) polyclonal CD8+ T cell expansion occurs frequently and independently of disease association

BACKGROUND: The development of effective adjuvant therapies for the treatment of high-risk melanoma patients is critical for the prevention of metastatic disease and improvement of patient survival. Active specific immunotherapy has been tested as an adjuvant treatment in numerous clinical trials with overall limited, but occasionally promising, success rates. Newcastle disease virus (NDV) oncolysate has been utilized as an adjunctive immunotherapeutic agent in the postsurgical management of these patients. A phase II study initiated in 1975 using adjuvant vaccine therapy composed of allogeneic and autologous human melanoma cells infected with live NDV (NDV oncolysate) in patients with AJCC stage III melanoma following therapeutic lymph node dissection has shown >60% survival rate at 10 years with no adverse effects. Continued long-term analysis of trials with promising early results as well as assessment of immunologic responses generated in these patients may result in improved therapeutic decisions for clinical trials in the future. MATERIALS AND METHODS: We analyzed the 15-year survival of patients treated postsurgically with NDV oncolysate in the phase II study described above. In an attempt to understand the immunological effects of this treatment, we have also carried out a comprehensive analysis of the peripheral blood T cell repertoire in these patients. RESULTS: The overall 15-year survival of this group of patients is 55%. Previous studies have suggested that improved outcome in patients undergoing immunotherapy is correlated with increased numbers of CD8(+)CD57(+) cells. In surviving patients, we observed a striking oligoclonality in the CD8(+) T cell population in peripheral blood, which reflects clonal expansions in the CD8(+)CD57(+) subset. CONCLUSIONS: The data suggest that adjuvant vaccination with NDV oncolysates is associated with prolonged survival of patients with lymph node-positive malignant melanoma and that CD8(+) T cells may be an important component of therapeutic efficacy

To gain insight into the timing of twinning, we have examined a closely related event, X-chromosome inactivation, in female MZ twin pairs. X-inactivation patterns in peripheral blood and buccal mucosa were compared between monochorionic MZ (MC-MZ) and dichorionic MZ (DC-MZ) twins. Overall, the MC-MZ twins displayed highly similar X-inactivation patterns, whereas DC-MZ twins frequently differed in their X-inactivation patterns, when both tissues were tested. Previous experimental data suggest that commitment to X inactivation occurs when there are 10-20 cells in the embryo. Simulation of embryo splitting after commitment to X inactivation suggests that MC-MZ twinning occurs three or four rounds of replication after X inactivation, whereas a DC-MZ twinning event occurs earlier, before or around the time of X inactivation. Finally, the overall degree of skewing in the MZ twins was not significantly different from that observed in singletons. This indicates that X inactivation does not play a direct role in the twinning process, and it further suggests that extreme unequal splitting is not a common mechanism of twin formation