I read your replys to several people who have autoimmune diseases (lupus,R.A.) that say they are positive for HIV.I have learned there are several autoimmune diseases that produce a false positive for HIV Wouldn't lupus be one of these and what tests need to be done to be sure? I have been researching this and The reason for my concern is my best friend was diagnosed with HIV 11 years ago and shows more symptoms of systemic lupus (Mylar rash,swollen painful knuckles,ulcers around his nose)and had signs of lupus as a child.Because he is in a high risk group no farther tests were suggested to rule out him having a false positive for HIV. What would you suggest? What test would clearly result in a correct diagnosis.

The HIV antibody test (ELISA) can be falsely positive if another kind of antibody (like the antibodies made against components of the self in autoimune diseases such as lupus) cross-reacts. However, the confirmatory Western blot test looks for actual proteins made by the virus, not for antibodies against HIV made by the body, and would not be positive in such a situation. Other tests that rely on direct detection of the virus (such as HIV RNA PCR) or a component of the virus (such as p24 antigen) would also be negative if the ELISA is falsely positive.

A positive result is not reported unless the Western blot is also positive, therby confirming the positive ELISA used for screening. Since your friend was told that he is HIV positive, one has to assume that the confirmatory test was also positive.