The diffuse infiltrative lymphocytosis syndrome (DILS) in HIV-infected persons is characterized by a persistent circulating CD8+ lymphocytosis. Certain HIV-infected persons appear to respond to their infection by developing an oligoclonal expansion of CD8+ lymphocytes. These cells infiltrate multiple organs, but the salivary glands and the lung constitute the major sites involved in this process. This infiltrative process resembles in many aspects a Sjögren-like syndrome, owing to the visceral lymphocytic infiltration. Unilateral parotid gland enlargement in a patient with HIV infection should prompt clinicians to suspect DILS. In addition, clinicians should be aware that the pulmonary process associated with DILS may mimic clinically and radiographically the pneumonic process caused by Pneumocystis carinii. Other manifestations of DILS to consider include a severe form of peripheral neuropathy; lymphocytic infiltration of the liver, evident as hepatitis; myositis; and lymphocytic interstitial nephritis.