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.

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2025
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