HIV infection is commonly associated with LIP in children, with an incidence ranging from 16 to 50%, in which it is considered an AIDS-defining illness. In adults with HIV, LIP is far less frequent and was found in < 5% of patients at necropsy. The association between LIP and HIV infection was first reported in the 1980s in several case reports. Whether or not LIP is caused by the lung immune response to the direct presence of HIV is still debatable. The pathogenesis of LIP in HIV remains unclear. HIV reverse transcriptase was simultaneously recovered from the serum and BAL fluid of a patient with AIDS and LIP. However, other studies reported the lack of HIV detection in BAL in four patients with HIV and LIP. Why only a minority of HIV patients acquire LIP is unknown; however, it seems that certain host factors, particularly human leukocyte antigen DR5, are concerned with the regulation of the immune response to HIV. Some reports suggested the association between HIV-positive status, human leukocyte antigen DR5, and the increase in the level of circulating CD8 lymphocytes with significant visceral infiltration, particularly the salivary glands, and the lungs, which is the most common manifestation of LIP. This association was named the diffuse infiltrative lymphocytic syndrome and is found only in a subset of HIV-positive patients.