Pulmonary pathology in AIDS: atypical Pneumocystis carinii infection and lymphoid interstitial pneumonia.

Reprint requests to: Dr M J Saldana, Department of Pathology and Laboratory Medicine, Blum Building, 2nd Floor, Mount Sinai Medical Center, 4300 Acton Road, Miami Beach, Florida 33140, USA. It is generally agreed that the acquired immunodeficiency syndrome (AIDS) results from infection by the human immunodeficiency virus (HIV). The latter agent destroys primarily T helper lymphocytes and produces a progressive impairment of cell mediated immunity with increased susceptibility to various opportunistic infections and malignant tumours.'2 The accepted definition of AIDS,3 as of 1 January 1993, includes all HIV-infected individuals with severe immunosuppression that is, less than 200 x 106/1 CD4 + T lymphocytes, or a percentage of CD4 + T lymphocytes below 14% of the total count of lymphocytes. The definition also includes the presence of tuberculosis, recurrent pneumonia, or invasive cervical cancer. The lung is a major target of disease and the cause of death in most patients with AIDS. About 80% of children infected with AIDS develop pulmonary problems and, if left untreated, 70% will die within two years of diag*4 nosis. The purpose of this paper is to review and illustrate two lesser known areas of pulmonary disease in AIDS, namely (1) atypical Pneumocystis carinii infection; and (2) lymphoid interstitial pneumonia.