No evidence for an effect of the CCR5 Delta 32/+ and CCR2b 64I/+ mutationson human immunodeficiency virus (HIV)-1 disease progression among HIV-1-infected injecting drug users

The relationship between CCR5 and CCR2b genotypes and human immunodeficienc y virus (HIV)-1 disease progression was studied among the 108 seroconverter s of the Amsterdam cohort of injecting drug users (IDUs), In contrast to ea rlier studies among homosexual men, no effect on disease progression of the CCR5 Delta 32/+ and the CCR2b 64I/+ genotypes was found, when progression to AIDS, death, or a CD4 cell count <200/mu L was compared by a Cox proport ional hazards model. Furthermore, CD4 cell decline (by a regression model f or repeated measurements) and virus load in the first 3 years after serocon version did not differ between the CCR5 and CCR2b wild type and heterozygou s genotypes, A nested matched case-control study also revealed no significa nt effect of the CCR5 and CCR2b mutations. Immunologic differences between IDUs and homosexual men may account for the observed lack of effect. Altern atively, difference in transmission route or characteristics of the HIV-1 v ariants that circulate in IDUs could also explain this phenomenon.