CD4 and hepatitis C virus infection: We then assessed the associations between log-transformed levels of neopterin and those of sTNFR-1, sTNFR-2, IL-6, and CRP in all participants as well as HIV+ and HIV− participants, adjusting for age, sex, race, BMI, cigarette smoking, number of comorbidities, hepatitis C infection, number of injections in the past 30 days, HIV status (for all participants), as well as CD4+ T-cell counts, HIV viral load, and cART (for HIV+ group only).