Effects of CCR5 genetic polymorphism and HIV-1 subtype in antiretroviral response in Brazilian HIV-1-infected patients.

The authors examined whether CCR5delta32 heterozygosity alone or in combination with the HIV-1 subtype profile was associated with response to antiretroviral therapy in a trial in Brazil. A total of 177 antiretroviral-naive patients who had CD4+ cell counts between 50 and 250 cells/ml were enrolled in the study. Patients were randomly assigned in a double-blind fashion to receive indinavir (IDV) at 800 mg 3 times daily plus zidovudine (ZDV) 200 mg 3 times daily plus lamivudine (3TC) 150 mg 2 times daily (group 1 n = 58) IDV alone (group 2 n = 62) or ZDV plus 3TC (group 3 n = 57). Statistical analyses were carried out using Statistica 6.0 Windows 1998. Overall 11.9% of the study subjects were heterozygous CCR5/CCR5delta32 a prevalence similar to that reported in Europe and North America. Patients were more likely to respond to treatment as indicated by the median increase in the CD4+ cell counts if they were heterozygous for the CCR5 gene. In addition there was no statistical significance on viral load response between the two groups or for the CCR2 polymorphism profile. Moreover 144 patients were found to be infected with clade B viruses 6 patients with clade F (randomly distributed in all three groups) and 1 patient with clade C. Viral load declines were greater in the patients infected by clade B viruses compared with clade F.