Some reference has been made to possible resistance to HIV among a subset of humans. Here is the full text of the paper Evaluating plague and smallpox as historical selective pressures for the CCR5-{Delta}32 HIV-resistance allele:

...HIV has not infected humans long enough to account for the selective rise of this resistance allele, the frequency of which is estimated at an average of ~10% in European populations (4, 12, 15-18). The allele is virtually absent in African, Asian, Middle Eastern, and American Indian populations....