Keep in mind that blood groups are ethnic in distribution. They are passed from parents.

Ever heard of discordant couples? The answer could be blood group discordance ...

Genetics do play a role:

The first genetic mutation associated with HIV susceptibility was identified in the mid 1990s. Known as the CCR5-Delta32 mutation, it seems to confer strong resistance to infection by HIV. This gene mutation is found most commonly in certain European populations, possibly because it was also associated with resistance to other diseases such as smallpox or the Bubonic Plague.

And also regarding Pk:

The role of ABO blood groups in infectious and non infectious diseases is well established. Much scientific evidence also exists to support the role of erythrocytes in binding viruses and facilitating infection of permissive cells. Some blood groups such as the Duffy type are implicated as candidate molecules. Other molecules such as the Pk blood group which are present in Caucasian populations have been shown to confer resistance to HIV infection. The study of blood groups in HIV infection may shed light on the dynamics of HIV epidemiology, especially in hard-hit SubSaharan Africa.

And as we all know, European populations in general have a higher percentage on an average than native populations of other continents.

If indeed the above bolded study turns out to be verified by other studies and Rh(D) positive (97.8%) was more susceptible than D negative (2.2%), that could mean that rh positive individuals are around 7 times more likely to contract the HIV virus than rh negatives.

We will keep you posted should more information come our way.

Until then: Don´t risk anything believing that you are protected by being D negative!
http://www.rhesusnegative.net/staynegative/rh-negative-blood-does-not-protect-you-from-hivaids/