treatment-naive patients of the Swiss HIV Cohort Study. AIDS.

African descent is associated with slower CD4 cell count decline in treatment-naive patients of the Swiss HIV Cohort Study. AIDS.

Miller and colleagues investigated the effect of descent (African versus European) on the progression of untreated HIV infections in a prospective cohort study of HIV-1-infected individuals. They estimated the linear rate of decline of the CD4 cell count and the setpoint viral load in patients with sufficient data points. The effect of descent was assessed by multivariate regression models including descent, sex, viral subtype, the earliest date of confirmed infection, age, and the baseline CD4 cell count; the rate of CD4 cell count decline was also analyzed with mixed-effect models and with matched comparisons between patients of African and European descent based on the baseline CD4 cell count. The authors found that the decline slope of the CD4 cell count was significantly less steep , patients of African descent (n = 123) compared with patients of European descent (n = 463), and this effect was independent of differences in the infecting viral subtypes. Matched comparisons confirmed the effect of African descent (P < style="text-decoration: underline;">Slower disease progression in patients of African descent might be related to host factors allowing better tolerance of high virus levels in patients of African descent compared with patients of European descent.

Editors’ note: Faster rates of HIV disease progression have been associated with immune activation. Even HIV-negative Africans have evidence of increased immune activation, likely due to prevalent co-infections. Comparing HIV–infected individuals of African and European descent who are exposed to the same low-antigen environment of Switzerland can narrow down differences in disease progression to viral and host factors. This study found no effect of viral sub-type suggesting that host factors must be key in the slower CD4 count decline observed in people of African origin living with HIV in Switzerland. Perhaps it is the lack of Duffy antigen receptors for chemokines (DARC-negative status) on the red blood cells in patients of African descent (see Weijing et al in HIV This Week issue 56).