Detection of elevated serum β-chemokine levels in seronegative Chinese individuals exposed to human immunodeficiency virus type 1

The mutations in the CCR5 coding region, such as CCR5Δ32 and CCR5m303, that suppress the transmission of human immunodeficiency virus (HIV) type 1 do not exist in Chinese people. However, 9 Chinese subjects in Taiwan with histories of multiple sexual exposures to HIV remained uninfected, suggesting that certain anti-HIV factors do indeed exist. Experiments were therefore designed to investigate the immune mechanism that protects this cohort against HIV infection. Peripheral blood samples from these 9 subjects and 7 healthy people who had not been exposed to HIV were obtained for the quantitation of the levels for β-chemokines and interleukin 16 (IL-16) in serum samples or secreted by peripheral blood lymphocytes. Significantly higher serum levels for nearly all 3 β-chemokines, regulation on activation, normal T cell-expressed and secreted, macrophage inflammatory protein (MIP)-1β, and MIP-1β (P < .05, P < .05, and P = .05, respectively), but not IL-16, were detected in the 9 HIV-uninfected subjects as compared with control subjects. The result suggests that among the host genes and cellular factors thus far identified, β-chemokines are the major HIV-suppressive factors that protect Chinese people from infection with HIV.