Objective To analyze the possibility of using intracellular cytokine staining (ICS) to evaluate NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC) and to detect the changes in ADCC activity among patients with chronic HIV and/or HCV infection. Methods Flow cytometry was per-formed to determine the percentages of NK cells and the expression of NK cell receptors. ImageStreamX MarkⅡ system was used to identify the expression of CD3, CD56, CD16 and CD32 on CD56brightNK and CD56dimNK subsets. Degranulation process and cytokine production in NK cells were detected using an anti-gen-antibody complex model of P815/Ab in combination with ICS. Differences in NK cell-mediated ADCC were evaluated among patients infected with HIV and/or HIV and healthy subjects by flow cytometry. Re-sults The percentages of CD107a+and IFN-γ+NK cells were positively correlated with the decrease of mean fluorescence intensity (MFI) of CD16. ICS assay revealed a positive correlation between the secretion of CD107a and IFN-γ by NK cells. CD16 was highly expressed in CD56dimNK cells. The ADCC mediated by CD56dimNK cells was stronger than that mediated by CD56brightNK cells. The rate of target cell lysis detected by rapid fluorescence assay was positively correlated with the percentage of CD107a+/IFN-γ+NK cells meas-ured by ICS. NK cell-mediated ADCC was suppressed in patients with chronic HIV and/or HCV infection. Conclusion This study suggests that ICS assay could be used to evaluate NK cell-mediated ADCC. It also reveals that NK cell-mediated ADCC is suppressed in patients with chronic HIV and/or HCV infection.

Objective To investigate the influence on anti-HCV antibody levels in spontaneous HCV seroconverters co-infected with HIV. Methods A retrospective study was conducted on people with a history of blood donation in Wangying Village,Shangcai County,Henan Province in 2009 and 2017. Accord-ing to the infection status in 2009,patients who were positive for anti-HCV antibody were divided into four groups:HIV-negative chronic HCV infection group (HCVc),HIV-negative spontaneous HCV clearance group (HCVr),HIV-positive chronic HCV infection group (HIV+HCVc),HIV-positive spontaneous HCV clear-ance group ( HIV+HCVr). All patients were followed up in 2017 and those who were lost to follow-up, received HCV treatment or were reinfected with HCV (only for those of HCV seroconverters) were excluded from this study. Altogether 167 patients met the inclusion criteria (HCVc:n=65;HCVr:n=34;HIV+HCVc:n=44;HIV+HCVr:n=24). A horizontal comparison of anti-HCV antibody levels among the above four groups in 2009 and a longitudinal comparison of changes in anti-HCV antibody in each group from 2009 to 2017 were respectively conducted. Results The horizontal comparison indicated that the levels of anti-HCV antibody were higher in chronic HCV-infected patients than in HCV seroconverters no matter whether they were co-infected with HIV or not (both P<0. 000 1). After comparison of anti-HCV antibody titers in 2017 and 2009,no significant changes were found in HCVc or HIV+HCVc group. The levels of anti-HCV antibody in HCVr and HIV+HCVr groups decreased significantly from 2009 to 2017 ( both P<0. 000 1). HIV+HCVr group showed a faster decline in anti-HCV antibody level than HCVr group (P=0. 003 9). Significant nega-tive correlations between the decline speed in anti-HCV antibody sample/cut-off ( S/CO) values and the initial anti-HCV antibody S/CO values (in 2009) were found in both HCVr (r=-0. 517 7, P=0. 001 7) and HIV+HCVr groups (r=-0. 753 2, P<0. 000 1). The decline speed in anti-HCV antibody in HIV+HCVr patients was found to be negatively correlated with their CD4+T cell counts in 2009 ( r=-0. 563 8, P=0. 004 1). Moreover,the seroreversion rate of anti-HCV antibody in patients of the HIV+HCVr group was higher than that of HCVr group (P=0. 027 5). Conclusion HIV co-infection can accelerate the decline of anti-HCV antibody in spontaneous HCV seroconverters. This study indicates that in a large-scale retrospective epidemiological investigation especially for HIV-infected populations, the prevalence of anti-HCV antibody may be underestimated.