While the weak association between RhD-positive blood types and HIV susceptibility is thought to result from residual confounding, other studies indicated lower rates of HIV infection among RhD-negative individuals.
Therefore, the researchers believe that there could be a degree of protection offered by the absence of the RhD antigen or that the RhD antigen in RhD-positive blood types could potentially be offering viral receptor sites to HIV, increasing the susceptibility to HIV infections.
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