HIV-1–Infected SCD patients exhibit milder sickle cell disease and suppressed antiviral innate immune responses

Abstract Sickle cell disease (SCD) is an inherited hemoglobinopathy characterized by chronic hemolytic anemia and complex pathology. SCD patients have a lower risk of HIV-1 infection and progress more slowly to AIDS (Bagasra O et al. Am. J. Hematol. 1998; 59:199). We recently showed that SCD PBMCs express antiviral factors and resist HIV-1 infection (Kumari N et al. iScience. 2024; 27:108813). We also observed suppression of mouse-adapted EcoHIV infection in SCD Townes mice. While HIV-1 infection of SCD patients is extremely rare, we were able to recruit several SCD patients with HIV-1 infection (SCD HIV+) from Montefiore Medical Center and Howard University Centers for Sickle Cell Disease. We analyzed expression of antiviral factors and ex vivo HIV-1 infection and compared the SCD HIV+ samples to those from SCD patients (SCD HIV-), HIV-1+ participants (HIV+), and healthy controls without SCD and HIV-1 (HIV-). To determine factors contributing to HIV-1 inhibition, we isolated PBMCs from the whole blood of SCD HIV+, SCD HIV-, HIV+, and HIV- participants. RNA Seq analysis was conducted on Illumina NextSeq 500 and normalized gene counts were used for gene set enrichment analysis (GSEA). As HIV-1 infection requires activation of PBMCs, we focused our analysis on the gene expression in activated PBMCs. GSEA analysis of hypoxia- and iron- regulatory genes showed positive enrichment in SCD HIV- compared to SCD HIV+ PBMCs (normalized enrichment score (NES) = 0.82, 18 genes upregulated). The upregulated genes in SCD HIV- PBMCs included FTL and HMOX-1, indicating increased levels of iron accumulation and elevated hemolysis. GSEA analysis also showed positive enrichment of antiviral factors in SCD HIV- PBMCs, including SERINC5, CH25H, SAMHD1, and APOBEC3A (NES=0.91, 26 genes upregulated), suggesting robust antiviral responses in SCD HIV- compared to SCD HIV+ PBMCs. We examined ex vivo one round HIV-1 infection using VSV-G pseudo-typed HIV-1 pNL4-3 virus expressing luciferase. Significantly lower levels of luciferase activity were observed in SCD HIV- PBMCs compared to HIV (3.3-fold reduction, p<0.0001) or SCD HIV+ (1.9-fold reduction, p=0.003). Labile iron levels were analyzed with a fluorescent dye (Ferro Orange). Fluorescence (F/F0), proportional to the labile iron levels, decreased in activated SCD HIV- compared to HIV- PBMCs (p=0.04). Labile iron levels were higher in SCD HIV+ compared to SCD HIV- PBMCs (p=0.023). ANOVA analysis of clinical and laboratory variables from 6 SCD HIV+ participants to 8 matching SCD HIV- patients, 7 HIV-1+ patients and 8 HIV- controls indicated differences in the levels of hemoglobin (p<0.001), RBC (p<0.018), RDW (p<0.007), eosinophils (p<0.03), LDH (p<0.005), bilirubin (p<0.02) and eGFR (p<0.04). Pairwise t-test comparisons showed that SCD HIV-1+ compared to SCD HIV patients had higher levels of hemoglobin (p<0.03), hematocrit (p<0.031), and a trend toward higher RBC counts. CRP levels were elevated in HIV-1+ patients compared to HIV- controls (p<0.03). There was also a trend toward elevated CRP levels in SCD HIV-1+ versus SCD (p=0.07). In comparison to SCD HIV patients, levels of LDH and ferritin were closer to normal levels in SCD HIV+ patients. Our study shows that SCD HIV+ patients have reduced expression of iron metabolism regulatory and innate antiviral response factors compared to SCD HIV- patients. SCD HIV+ PBMCs had higher levels of HIV-1 transfection and increased labile iron levels compared to SCD PBMCs. Hematological parameters in SCD HIV+ were closer to the non-infected individuals. Our findings indicate that HIV-1 infection might occur in SCD patients and that the SCD HIV+ patients exhibit less severe SCD manifestations. Whether HIV-1 infection is suppressed in SCD with more severe disease, or whether HIV-1 infection in SCD reduces the severity of SCD by tamping down the intrinsic inflammatory response remains to be investigated. ACKNOWLEDGMENTS: This work was supported by 1R01HL125005, U54MD007597, 2P30AI117970 and 1SC1HL150685.