Effect of Sickle Cell Trait on Human Immunodeficiency Virus Type 1 Infection

INTRODUCTION: Whereas several studies show that homozygous (HbSS) sickle cell disease protects against human immunodeficiency virus infection, it is not clear if human immunodeficiency virus infection is affected by the heterozygous state of the sickle globin gene (HbAS or sickle cell trait). OBJECTIVE: To evaluate the effects of sickle cell trait on the prevalence and severity of human immunodeficiency virus type 1 infection in a large patient population. METHODS: Hemoglobin genotype was determined by high performance liquid chromatography (HPLC) in 1,226 HIV-1 patients in Nigeria. Their demographic data were documented. Blood CD4+ cell counts and HIV-1 viral load previously determined on the same blood samples to guide clinical care were used as indices of severity of HIV-1 infection. Statistical analysis of the data was done to evaluate the effects of sickle cell trait on the severity and prevalence of HIV-1 infection, relative to the prevalence of 1.4% in the general population of Nigeria. RESULTS AND DISCUSSION: The distribution of hemoglobin genotypes among the HIV-1 patients was comparable to that in the general population of Nigeria (Chi-squared statistic =1.025; p value = 0.31, not significant). Neither viral load (p = 0.32) nor blood CD4+ cell count (p = 0.30) was significantly different between all HbAS versus all HbAA patients. There was a trend towards lower viral load in females and a significant interaction between gender and HbAS for viral load (P = 0.018), suggesting that sickle cell trait might be associated with the severity of HIV-1 infection in females. CONCLUSION: The findings suggest that sickle cell trait might be associated with severity of HIV-1 infection in female, but not all, patients. Larger, prospective studies are required to further investigate the effect of sickle cell trait on HIV-1 infection.