Immunological status may predict clinical outcome in BCG treated melanoma.

Twenty-seven patients with surgically resected stage II or III malignant melanoma were treated with bacillus Calmette-Guérin (BCG) and followed prospectively to determine whether relapse could be predicted. Peripheral blood mononuclear (lymphocyte plus monocyte) counts (PBM), T and B cell counts, phytohaemagglutinin (PHA) cytotoxicity, PHA transformation, antibody-dependent cell-mediated cytotoxicity (ADCC) and serum immunoglobulin concentrations were studied before and during therapy. Patients ultimately classified as having a poor clinical outcome (inoperable recurrence) were compared with those with a more favourable outcome. Prior to therapy, poor outcome patients had lower PBM and T cell counts but there was some overlap. After three months, these differences were more pronounced. Low PHA cytotoxicity was also associated with poor outcome; again the differences were more apparent at 3 months than prior to therapy. These results suggest that PBM, T cell counts and PHA cytotoxicity may predict poor outcome some months before inoperable recurrence in apparent clinically.