Depressed in vitro lymphocyte responses to PHA in patients with Hodgkin disease in continuous long remissions.

Twenty consecutive patients with Hodgkin disease in continuous complete remission and off treatment for at least 5 yr (range 5-25 yr, median 9 yr) were studied with a battery of immunologic parameters. Skin test reactivity to four common antigens, sensitization to 2,4-dinitrochlorobenzene, absolute lymphocyte count, relative percentage of T cells (as measured by spontaneous rosette formation with sheep erythrocytes) and B cells (as measured by immunofluorescence with polyvalent antiserum), and absolute number of T and B cells were normal when compared with controls. However, the mean value of lymphocyte response in vitro to the mitogen phytohemagglutinin for the study population was significantly decreased (p less than 0.001) when compared with the controls. This abnormality in response to mitogen could not be correlated with age, sex, stage, symptoms, histologic subclassification, or previous treatment. The data suggest the existence of a persisting cell-mediated immune defect in the circulating lymphocytes in patients with long-standing Hodgkin disease that might otherwise be considered "cured."