The differential diagnosis of renal disease in an HIV patient is fairly long. Perhaps the most well-known amongst the list is HIV-associated nephropathy (HIVAN), which involves massive protein wasting, collapsing FSGS, and rapidly-progressive renal failure.
Another entity on the list of HIV-associated renal diseases which I just recently learned about, however, is diffuse infiltrative lymphocytosis syndrome (DILS). The disease is due to an infiltration of CD8+ T-cells within the renal interstitium leading to an interstitial nephritis, enlarged kidneys, and declining renal function. The condition may involve other organs as well, typically the salivary glands (where the patient may demonstrate bilateral parotid gland enlargement or sicca symptoms) or the lungs (where it causes "lymphocytic interstitial pneumonitis").