It seems that lupus and HIV avoid each other. Why is that?

There is only anecdotal and retrospective evidence for it, but it seems that HIV and lupus avoid each other. One might think, no wonder: HIV patients are immune-deficient and thus may be autoimmune-deficient, too. However, there ought to be patients who suffered from lupus before they were infected with HIV. Clinician-scientists tell me that of the thousands of HIV patients they have seen, none had lupus. While this does not rise to the cogent standards of scientific evidence, it may be worth thinking about.

Mice have many endogenous retroviruses (viruses that are part of the mouse genome), and so do human beings. The endogenous retroviruses in people are not infectious, but they still can produce some proteins. These proteins may prevent completion of the infection cycle by HIV. In mice, the so-called Fv-1 resistance gene, which stymies infection by a mouse retrovirus, encodes a protein similar to that of the core of the exogenous virus. By analogy, lupus patients may express a retroviral protein that interferes with the life cycle of HIV.