Immunological changes in cancer patients receiving BCG.

We employed immunological tests to assess patients with cancer, mainly melanoma, receiving BCG alone or combined with chemotherapy. A comparison of BCG recipients with similar cancer patients not receiving BCG showed differences in the frequency of Mantoux reactivity positivity in the leucocyte migration assay against tumour antigens and positivity in membrane immunofluorescence. Short term sequential studies showed conversion from negativity to positivity or strengthening of reaction to occur during initiation of BCG therapy. Extended sequential studies employing the leucocyte migration assay against tumour antigens and modifications to assess serum effects indicate that the changes are more related to the changing clinical status than to BCG. It may be possible to devise quantitative in vitro techniques to assay sensitivity to tuberculoproteins which may allow assessment of BCG effects in vitro. Current technology permits monitoring for varying clinical stage rather than the effects of immunotherapy.