Association of IL-7 with disease progression in Chinese HIV-1 seropositive individuals

Background Elevated levels of interleukin-7 （IL-7） have been correlated with CD4^＋ T cell depletion and the emergence of syncytium-inducing （SI） variants in human immunodeficiency virus type-1 （HIV-1） infection, and suggested as an indicator of acquired immunodeficiency syndrome （AIDS） disease progression. Therefore, we investigated the effects of IL-7 on disease progression and virus phenotype in Chinese HIV/AIDS patients. Methods In a cross-sectional study of 71 untreated HIV-1 seropositive individuals and 12 healthy donors, plasma IL-7 levels were determined by an ultra sensitive enzyme-linked immunosorbent assay （ELISA）, and its relations to CD4^＋ T cells, CD8^＋ T cells, plasma viral loads and HIV phenotypes were analyzed. Results Significant higher IL-7 levels were found in Chinese HIV/AIDS patients [（3.33±3.60） pg/ml] than those of health controls [（1.2±0.81） pg/ml] （P〈0.05）, and IL-7 levels were inversely associated with CD4^＋ T cell counts （r=-0.497, P〈0.01）. Furthermore, IL-7 levels were significant higher in patients with SI variants [（9.12±4.55） pg/ml] than those with non-syncytium-inducing variants [（1.50±2.69） pg/ml] （P〈0.01）. Conclusions Increased IL-7 levels were found in Chinese HIV/AIDS patients and significantly associated with disease progression, thus increased IL-7 plasma levels may indicate disease progression.