Prediction of liver disease, AIDS and mortality based on discordant absolute and relative peripheral CD4 T lymphocytes in HIV/HCV co-infected individuals.

BACKGROUND: Hepatitis C virus induced liver fibrosis and splenomegaly may lead to discordance between absolute numbers and percentages of lymphocytes and subpopulations because of sequestration. We investigated lymphocyte discordance in HIV/HCV co-infected individuals and its relationship to progression to liver disease, AIDS and all-cause mortality.

METHODS: Observational retrospective cohort study. Adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI) associated with liver disease, AIDS or mortality were computed by time-updated Cox proportional hazards regression.

RESULTS: Of 380 HIV/HCV co-infected adult individuals followed for a median of 8.2 years, 360 individuals had a median of 11 discordant measurements corresponding to 5080 of 9091 paired samples (56%). Discordance alone was not associated with any of the outcomes. By multivariable analysis, a doubling of absolute or percentage CD4 cells was associated with a comparable lower risks of mortality (aHR:0.60, CI:0.53-0.67, P<.0001 and aHR:0.67, CI:0.56-0.79, P<.0001), respectively). Higher CD4/CD8-ratio was associated with a lower mortality risk (aHR:0.39, CI:0.22-0.71 per doubling, P=0.002). Only absolute CD4 cell measurements predicted AIDS. Development of liver disease was not predicted by total lymphocyte count or subpopulations.

CONCLUSION: Despite a high prevalence of lymphocyte-subpopulation discordance with HIV/HCV coinfection, absolute CD4 cell count predicted mortality and AIDS, whereas CD4 percentage only predicted mortality. Neither CD4 T lymphocyte count nor CD4 percentage was associated with liver disease in this cohort. These findings may be necessary and useful tools in countries, where ART is not initiated for all HIV infected individuals.