PubMed · 11366684
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L Hanna. 1999. Syphilis.. https://pubmed.ncbi.nlm.nih.gov/11366684/
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CD4(+) T cells are critical for inducing and maintaining efficient humoral and cellular immune responses to pathogens. The CD4(+) T-cell response in human T-lymphotropic virus 1 (HTLV-1) infection has not been studied in detail. However, CD4(+) T cells have been shown to predominate in early lesions in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). We present direct estimates of HTLV-1 Env- and Tax-specific CD4(+) T-cell frequencies in patients infected with HTLV-1. We first showed that there was a strong bias toward the Th1 phenotype in these HTLV-1-specific CD4(+) T cells in patients with HAM/TSP. We then demonstrated significantly higher frequencies of HTLV-1-specific Th1-type CD4(+) T cells in HAM/TSP patients than in asymptomatic HTLV-1 carriers. The majority of these HTLV-1-specific CD4(+) T cells did not express HTLV-1 Tax and were therefore unlikely to be infected by HTLV-1. High frequencies of activated HTLV-1-specific CD4(+) T cells of the Th1 phenotype might contribute to the initiation or pathogenesis of HAM/TSP and other HTLV-1-associated inflammatory diseases.
T cell proliferation failure is commonly associated with human immunodeficiency virus (HIV) infection. By examining T cell function on a single-cell basis, we found that CD4(+) T cell proliferation failure was often accompanied by CD8(+) T cell proliferation defects in patients with HIV disease. The defects are characterized by a proportional failure and reduced efficiency of precursor T cell proliferation after stimulation. In this study, patients who historically had low levels of circulating CD4(+) T cells were most likely to demonstrate cellular proliferation failure, regardless of current CD4(+) T cell counts. In contrast, neither historical nor current plasma HIV RNA levels were predictive of proliferation failure. These results suggest that mechanisms of T cell proliferation failure are more complex than can be explained by the direct effects of HIV replication and that therapeutic intervention to avoid prolonged periods of CD4(+) lymphopenia may be desirable for the preservation of immune function in patients with HIV disease.
OBJECTIVES: To determine indirectly the effect of changes in levels of reproductive hormones on CD4 lymphocyte counts by investigating the impact of pregnancy and menopause on CD4 lymphocyte counts in HIV-infected women. METHODS: Participants were 382 women with a known interval of HIV seroconversion. Review of questionnaires or patient charts provided information on pregnancy and menopause. A linear regression model with a random intercept and slope, which adjusts for multiple CD4 lymphocyte counts per woman, was applied to estimate the CD4 decline following HIV seroconversion and to evaluate the effect of pregnancy and menopause on the CD4 path. RESULTS: The 382 women had a median age of 25 years at seroconversion and yielded 1428 CD4 lymphocyte counts from 3 to 10 years after seroconversion. At 3 years from seroconversion, 20 women had passed the menopause (i.e., the last menses) and five more subsequently passed this point during follow-up; 25 women had a pregnancy after study entry. Postmenopausal women had lower CD4 lymphocyte counts 3 years after seroconversion than premenopausal women (333 vs 399 x 106 cells/l; P = 0.09), and pregnant women had lower counts than non-pregnant women (375 vs 399 x 106 cells/l; P = 0.36). The monthly CD4 decline was not associated with pregnancy and menopause. Adjustment for age did not change the results. CONCLUSIONS: The results suggest that CD4 lymphocyte counts differ between pre- and postmenopausal women, perhaps because of changes in the level of reproductive hormones in the menopause, but associations were not statistically significant. Pregnancy had no statistically significant effect on CD4 lymphocyte counts.