Psychological side effects induced by interleukin-2/α interferon treatment

Treatment of certain cancers by interleukin-2 (IL-2) and alpha interferon (INF) is currently widely-used in oncology and serious psychological side effects of such treatments have been reported. This study attempts to describe and analyse such side effects in a series of hospitalized cancer patients. Fifty-two patients undergoing a protocol of cisplatinum, intravenous interleukin-2 infusions and subcutaneous alpha interferon injections for metastatic melanoma and renal cancer were systematically screened for psychiatric disorders before, during and after each of four cycles of 4–5 day EL-2 infusions. Fatigue was constant and treatment-limiting in some cases and was highly correlated with depressive symptoms, which were very frequent at the end of the treatment cycle. Patients regularly showed varying degrees of obtundedness at the height of physical symptoms induced by IL-2. Some patients also had transient, predominantly hallucinatory deliria occurring or persisting several days after the termination of the infusions and complete resolution of concurrent somatic distress; neuroleptics were effective treatment. Certain lymphocyte phenotype counts (total lymphocytes, total CD8 cells, total T3s, stimulated Ts, non-stimulated Ts) correlated negatively with depressive symptomatology whereas fatigue tended to correlate negatively with polymorphonuclear leukocyte counts. Delirium correlated positively with total CD8 cells. Hallucinatory delirium, but not fatigue or depression, seems to be a direct cerebral effect of the interleukin-2α interferon combination that is not merely a consequence of the somatic effects. Patients undergoing lymphokine treatments should be carefully screened for psychological side effects and preventive or curative treatments should be given.