Patients with sickle cell disease (SCD) appear to be resistant to HIV infection, though the cause for this observation is not yet clear, according to an epidemiological study published in PLoS One.
Previous data suggest that patients with SCD have both a lower risk of contracting HIV and a lower risk of HIV progressing to AIDS. While some speculations suggest behavioral factors may lower the risk of exposure in this population, no confirmed variables have been implicated.
Researchers retrospectively evaluated data from the Transfusion Safety Study (TSS) to confirm whether HIV is less prevalent among patients with SCD compared to other congenital anemias. Following the retrospective study, they conducted a prospective analysis that enrolled participants with SCD and controls to investigate any possible mechanisms of HIV resistance in this population.
Overall, data from 274 patients with congenital anemia enrolled in the TSS were analyzed. Of the 143 patients with SCD, 1 (0.7%) was HIV positive, while 20 of the 113 (15.3%) patients with thalassemia or Diamond Blackfan anemia were HIV positive (P <.0001). These data corresponded to an odds ratio of 13.1 (95% CI, 1.6-108.9) of HIV incidence among non-SCD patients with congenital anemia compared with those with SCD.
The researchers enrolled 30 patients with SCD and 30 non-SCD controls in their prospective analysis. Among patients with SCD, CD4+ T cells had lower expression of CCR5 and CCR7, but higher expression of CD4, compared to those of controls; however, these cells were not less susceptible to HIV infection compared with control cells.
While multiple cytokine levels were higher in plasma samples from patients with SCD, plasma from these patients did not appear to prevent HIV infection.
“Of note, our study focused on CD4+ T cells as the target of HIV infection, and it is possible that monocytes or other cells from SCD patients may exhibit differential susceptibility to HIV infection,” the authors wrote. “Unlocking these mechanisms of HIV resistance is important not only for understanding the interplay of SCD pathophysiology with potential infections in persons with SCD, but also for identification of potential therapeutic targets for HIV in general.”
Kelly S, Jacobs ES, Stone M, et al. Influence of sickle cell disease on susceptibility to HIV infection. PLoS One. 2020;15(4):e0218880.