HIV is a serious condition, as I am sure you are aware. In fact, below a certain level HIV actually is classified as AIDS. This requires active medical attention. I encourage you to talk to your doctor
. An infectious disease specialist
may also be of assistance if you have further questions.
In general, HIV causes a weakened immune system by decreasing your white blood cells--the type of cells that fight infection. Therefore, the only medically proven way to increase your white blood cell count is to treat the HIV. Medications, specifically anti-retrovirals, can make HIV a treatable disease. A combination of these drugs, known as HAART, is considered the most effective. There are many different types of the medicines, so even if some don't work, others might. I encourage you to discuss these options.
There are no proven natural ways to increase your white count. Exercise does not. It is possible that extreme and severe exercise (such as a marathon) will transiently increase your white count--but this does not likely help your immune system (just the number is higher). The way this occurs is by the release of steroids--which causes an increase in the white count. The steroids however depress the white cells function. In general, exercise does increase your overall health. This can be helpful in that your body will be overall stronger and more able to withstand any infection. Therefore I would still encourage exercise--but don't expect it to drastically help your white blood cell count.
I encourage you to discuss your options with your doctor.