Symposium on infections in the compromised host. Hodgkin's disease and non-Hodgkin's lymphomas.

Two areas of study have made the understanding of infections in Hodgkin's disease and non-Hodgkin's lymphoma both clearer and more complicated. First, the overly simple concepts that certain underlying diseases predispose patients to specific infections can no longer be uniformly applied. Second, while Hodgkin's patients were once thought to have cell-mediated immune defects, we now know that mixed T- and B-cell abnormalities as well as alterations in complement and phagocytic processes are seen. Therefore, we can expect to find infecting organisms against which several immune functions appear to be important. The more common organisms found in these patients include the encapsulated bacteria and fungi, intracellular microbes such as the mycobacteria and certain viruses, and, finally, some protozoa. Many are prevalent in the environment and some are considered to be normal human microbial flora. These opportunistic pathogens will continue to cause serious, often fatal infections in this group of compromised patients until more is known about the causes of lymphoproliferative disease and significant advances in immunotherapy are made.