Study: People with Sickle Cell Disease Have Lower Rates of HIV

A new lab study supports previous research that people with sickle cell disease (SCD) have lower rates of HIV infection; however, these newer studies do not reveal an explanation on why there is such a reduced risk, according to a study in PLOS ONE.¹

The researchers reviewed the Transfusion Safety Study to compare HIV status between people with SCD and other congenital anemias who were routinely exposed to blood products during the high-risk period before HIV screening implementation. Following this, the researchers conducted a lab study of immune system cells isolated from blood samples of HIV-negative patients with or without SCD. This led to the hypothesis that a lower risk of HIV infection might be related to molecular characteristics of immune system cells, known as CD4+ T cells.²

The findings showed that non-SCD congenital anemia diagnosis was associated with a higher risk of HIV acquisition compared with SCD, according to the study authors. CCR5 and CCR7 was lower and CD4 expression was higher on CD4+T cells from SCD cases compared with controls. In addition, surface expression of CD4+T cells CXCRF, CD38, and HLA-DR did not differ between the groups, according to the researchers.²

Levels of multiple cytokines were elevated in the SCD plasma, but SCD plasma compared with control plasma did not inhibit HIV infection of target cells. The researchers concluded that this data support people with SCD being resistant to HIV infection. Potential mechanisms include lower CD4+T cell expression of CCR5 and CCR7 balanced by increased CD4 expression and cytokine levels, which did not result in vitro resistance to HIV infection.²

However, the study authors said that further research is needed to determine whether the molecular differences uncovered in this study are related to the lower risk or if other mechanisms are at play.¹

"The Transfusion Safety Study which was conducted in 1985-1993 was retrospectively reviewed to compare HIV status between [SCD] and other congenital anemia participants who were routinely exposed to blood products during the high-risk period before HIV screening implementation,” the study authors said in a press release. “[SCD] participants demonstrated a lower risk of HIV acquisition compared to non-[SCD] participants."¹

REFERENCES

• Exploring mechanisms of resistance to HIV in people with sickle cell disease. ScienceDaily. https://www.sciencedaily.com/releases/2020/04/200408142732.htm. Published April 8, 2020. Accessed April 9, 2020.
• Kelly S, Jacobs ES, Stone M, et al. Influence of sickle cell disease on susceptibility to HIV infection. Plos One. Published April 8, 2020. https://doi.org/10.1371/journal.pone.0218880.