In this study we evaluated some immunological features in both patients and healthy relatives within five families with multiple cases of Hodgkin's disease (HD). Such familial groups (at 'high risk' of HD), represent, in our opinion, a suitable opportunity to investigate the role of immune-deficiency in HD. The results obtained in the patient group confirm the well known persistent immune derangement in long term HD survivors. Regarding the group of relatives, we found a pattern similar to that of the patients. In particular, a decrease in the T helper lymphocyte subset and a lower response to Con-A mitogen were detected, which were statistically significant. These findings, confirmed in other studies of multiple case families, could support the hypothesis of a preexisting immune-deficiency in HD. This in turn would greatly contribute towards a better understanding of the role of immune-deficiency in the etiopathogenesis of the disease.