Leukocyte migration inhibition by cancer patients' sera

Sera from 38 of 89 melanoma patients, 4 of 15 patients with other cancers and 3 of 43 control donors inhibited the migration of autologous leukocytes. Sera from patients with clinically detectable metastatic disease and from the recipients of BCG were most frequently inhibitory. Autologous sera from 31 of 71 melanoma patients and 3 of 31 control donors increased the leukocyte migration inhibition induced by formalinized melanoma cells. This activity occurred in sera from patients at all stages of malignancy, whether bearing detectable tumour or not and whether receiving BCG or not. Abrogation of tumour-cell-induced leukocyte migration inhibition by serum was less frequent, occurring with 8 of 71 melanoma patients (6 Stage III, 1 Stage I and 1 Stage II) and no control sera. Preincubation of formalinized tumour cells had no effect on their activity in the leukocyte migration assay but the preincubation of melanoma leukocytes with either autologous serum or foetal calf serum inhibited leukocyte reactivity in around 50% of tests. However, this was also seen with control leukocytes and the effect appears to be immunologically non-specific.