Differences in HIV-1 viral loads between male and female antiretroviral-untreated Mexican patients

HIV-1 viral load is used to monitor AIDS progression and effect of antiretroviral therapy (ART). Several reports have indicated that the HIV-1 viral load of infected individuals is lower in females than in males. There are no reports exploring this issue in the Mexican population. We analyzed the relationship between sex and viral load in Mexican patients differing in CD4 T-cell count, age and treatment status.

A retrospective study was performed in 3949 male and 696 female HIV-1-infected individuals. Statistical distributions were compared using the Mann-Whitney U nonparametric test.

Among the antiretroviral-untreated group, females had a significantly lower viral load than males (0.52 female/male median viral load ratio, p = 0.008). When classified according to different ranges of CD4⁺ T cell counts, females had consistently lower viral loads than males, although statistical significance was achieved only for the group in the range of 201-350 (p = 0.014). Patients with the lowest CD4⁺ T-cell counts showed similar viral loads for both sexes. No differences were observed in the ART group.

This study demonstrates a baseline difference in viral load between male and female ART-untreated Mexican patients. The overall tendency indicating a lower viral load in females in the same ranges of CD4⁺ T-cell counts than males, suggests that the lower viral load in females is not indicative of a lower risk of developing AIDS. These observations suggest a significant influence of sex on viral dynamics and immune response despite variations in demographic factors.