Recurrent infection and deficiency of complement.

became deficient or, as seems more likely, the suppression of circulating antibody was a consequence of the increasing tumour mass. The Chester Beatty team have now confirmed that cytotoxic autoantibodies can be provoked in melanoma patients lacking them, by immunization with the irradiated cells of their own excised tumours. The immunization procedure, employing multiple inoculation sites, apparently bypasses the regional immunological unresponsiveness that is already present. It is disappointing but not really surprising that immunization had no detectable effect on the clinical course of the disease. Circulating cytotoxic antibodies would be expected to be effective only against cells to which there was good physical access-such as those in the bloodstream, which might otherwise cause distant metastases. Moreover, the artificially provoked serum antibody persisted for only one to two weeks, with a tendency toward the longer time in patients with little residual disease. Perhaps antibody was absorbed by the residual tumour, which was itself ineffective in stimulating further antibody formation because of regional immunological insufficiency. It may now be asked how can immunotherapy provide an effective anti-cancer weapon. Doubtless the rejection of solid tumours will be effected only by specifically sensitized lymphocytes and when the circumstances favour the host-such as minimal tumour mass together with a maximal immunological response. The latter can apparently be influenced by artificial immunization, and there is promise that an effective supplementary weapon will be provided by the extracorporeal culture of immune lymphocytes now going onmat Roswell Park Memorial Institute of cancer research. Methods, whether surgical or chemical, of radical reduction. of melanoma mass with minimal interference with immunological efficiency should be energetically pursued.