Short Communication: Longitudinal Changes in Peripheral Blood NK Cells During the First Year of HIV-1 Infection in CD4 Low and CD4 High Patient Groups

Abstract

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/μl within 2 years (CD4_Low group), while the CD4 cell counts of the other group remained above 500 cells/μl 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^dimCD16^pos subset rapidly decreased in both groups during early HIV-1 infection. The absolute number of total NK cells and CD56^dimCD16^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^brightCD16^neg NK cells of the two groups was observed. However, more CD56^negCD16^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.