Acquired immune deficiency syndrome (AIDS). Light microscopic, ultrastructural and immunocytochemical studies of one case.

The lung and axillary lymph node biopsies of a 33-year-old male drug-abuser with clinical and immunologic evidences of AIDS were studied by light and electron microscopy. Encysted Pneumocystis carinii organisms with attached membranous expansions and virus-like particles were demonstrated in the alveolar spaces and, occasionally, in macrophages. The lymph node biopsy revealed areas of angioimmunoblastic proliferation associated with lymphocytic depletion of the interfollicular zones. Tubuloreticular structures (TRS) were prominent in lymphocytes and endothelial cells. Test-tube and ring-shaped forms (TRF) were less frequently seen and were present only in lymphocytes and immunoblasts. The combination of TRS and TRF appears to be an useful marker for AIDS. The possible significance of the angioimmunoblastic changes observed in the lymph nodes is also discussed.