Impact of hepatitis C virus co-infection on the plasma interleukin-18 level and immune reconstitution of AIDS patients during highly active antiretroviral therapy

Abstract

Objective To investigate the impact of HCV co-infection on the plasma IL-18 level and immune reconstitution of AIDS patients during HAART. Methods There were 61 AIDS patients without treatment enrolled (CD4 + T<200 cells/μL), including 31 HIV mono-infected individuals and 30 HIV/HCV coinfected individuals, whom were followed up 96 weeks by HAART. There were 43 HCV mono-infected patients without treatment and 20 healthy volunteers enrolled as control groups. Peripheral blood was collected before treatment and during HAART at week 0, 4, 12, 24, 48, 72 and 96. IL-18 levels, HIV RNA viral load, CD4 + T cells and CD8 + T cells were detected. Results The median of plasma IL-18 levels in HIV infection group, HCV infection group and HIV/HCV coinfection group were 574.66, 33.77 and 922.7 pg/mL before HAART, which were all higher than healthy control group with statistically significant differences (Z=-5.614, -2.274 and -5.709, P all <0.05). IL-18 level in HIV/HCV co-infection group was higher than that in HIV mono-infection group and HCV mono-infection group (Z=-3.232 and-6.989, P both<0.01). The IL-18 levels in HIV mono-infection group and HIV/HCV co-infection group both showed downward trend after HAART (χ2trend = 18.429 and 15.314, P both <0.05). The medians of IL-18 levels in HIV/HCV co-infection group at each time point were 689.75, 690.25, 615.45, 625.22, 605.65 and 532.83 pg/mL, which were higher than those in mono-infection group (Z=-2.190, -4.435, -3.413, -2.335, -3.000 and-3.502, P all <0.05). Following the HAART, CD4+T cell counts and CD4+/CD8+ ratio showed increasing trend in both HIV mono-infection group and HIV/HCV coinfection group (χ2trend= 51.903 and 69.485, P both<0.01). After 12-week and 96-week HAART, the CD4+T cell counts in HIV mono-infection group were 233.50 and 334.00 cells/μL, and were higher than HIV/HCV co-infection group (Z=-1.966 and -3.519, P both<0.05). After 48-week and 72-week HAART, the medians of CD4+/CD8+ ratio in HIV mono-infection group were 0.24 and 0.31, and were both higher than HIV/HCV co-infection group (Z=-2.220 and-2.143, P both <0.05). Cohort analysis showed that there was no significant correlation between IL-18 level and CD4+/CD8+ ratio, except that weak negative correlation was found between CD4+ T cells and HIV mono-infection group after 24-week HAART. Conclusions HCV co-infection elevates the plasma IL-18 level and delays the immune reconstitution of AIDS patients before and during HAART, but HCV may not delay the immune reconstitution of AIDS patients through elevating the plasma IL-18 level. Key words: Acquired immunodeficiency syndrome; HCV; Interleukin-18; Immune reconstitution