Acquired immune deficiency syndrome (AIDS): speculations about its etiology and comparative immunology.

Acquired immune deficiency syndrome (AIDS) in many aspects resembles formerly recognized immune deficiencies, but in its complexity and presumed viral etiology, it is a unique entity. Examples of overlapping features of AIDS and immune defects, infectious complications, and neoplasms are discussed. It is not known what are the exact underlying mechanisms that permit or prohibit infectious and neoplastic complications among the immunodeficiency syndromes compared, but both overlapping and differing features of these entities are significant enough to hold a clue for future understanding. AIDS resembles feline leukemia as this latter syndrome was described 10 years ago. The retrovirus causing feline leukemia is highly immunosuppressive; preleukemic and viremic cats often succumb to opportunistic infections. If patients with early AIDS harbor retroviruses related to the human T cell leukemia virus in their organs (lymph nodes, bone marrow), serotherapy with monoclonal antibodies directed to this virus may stop and reverse the severe immunosuppression, thus preventing the development of opportunistic infections.