α-defensins 1, 2, and 3 are expressed by granulocytes in lymphoid tissues of HIV-1-seropositive and -seronegative individuals

α-Defensins 1, 2, and 3 exert antiretroviral activity in vitro, but their role in controlling HIV-1 replication in vivo and the cells that produce them are controversial. This study sought to determine whether α-defensins are present in HIV-1-infected individuals' lymphoid tissues, the major site of HIV-1 replication, and to identify the cells that express them. α-Defensin expression was evaluated by immunostaining inguinal lymph node sections from 19 untreated HIV-1-infected individuals and 8 individuals at low risk or seronegative for HIV-1 infection. Percentages of tissue sections that stained positively for α-defensins were not significantly different between HIV-seropositive (median, 7.6%) and -seronegative (median, 5.5%) individuals. Conditions that could have produced lymph node inflammation were present in most seronegative subjects, and their lymph node weights correlated with α-defensin expression (Spearman ρ = 0.833; P = 0.010). A median of 100% (range, 95%-100%) of α-defensin-expressing lymph node cells from 8 subjects coexpressed the granulocyte marker, CD15. CD15 and α-defensin staining correlated (Spearman ρ = 0.622; P < 0.001). These data suggest that α-defensins within lymphoid tissue are expressed by granulocytes and are prevalent in HIV-1-seronegative individuals with inflammatory processes as well as HIV-1-infected individuals. The role of α-defensins in controlling HIV-1 replication merits further investigation.