Short Communication: Longitudinal Changes in Peripheral Blood NK Cells During the First Year of HIV-1 Infection in CD4Low and CD4High Patient Groups

Natural killer (NK) cells may modulate the pathogenesis of primary HIV-1 infection. However, the relationship between the number and function of NK cells during an acute HIV-1 infection and HIV-1 disease progression remains to be elucidated. In this study, we enrolled two distinct patient groups. One group progressed to where their CD4 cell counts fell below 200 cells/mu l within 2 years (CD4(Low) group), while the CD4 cell counts of the other group remained above 500 cells/mu l for over 2 years (CD4(High) group). We compared the number and function of NK cells during the first year of HIV-1 infection between the two distinct groups. We found that the number of total NK cells and the number of cells in the CD56(dim)CD16(pos) subset rapidly decreased in both groups during early HIV-1 infection. The absolute number of total NK cells and CD56(dim)CD16(pos) NK cells was significantly higher in the CD4(High) group when compared to the CD4(Low) group during the first month of infection. No significant difference between the numbers of CD56(bright)CD16(neg) NK cells of the two groups was observed. However, more CD56(neg)CD16(pos) NK cells were found in the CD4(Low) group than in the CD4(High) group. We also found that NK cell function increased within the first 3 months of HIV-1 infection in the CD4(High) group and then exhibited a decreasing trend. However, in the CD4(Low) group, NK cell function did not increase significantly within the first 3 months of HIV-1 infection but then gradually increased. We concluded, therefore, that robust NK functioning cells that are present during an acute HIV-1 infection might be beneficial in controlling HIV-1 disease progression.