Immunomodulation of NK and ADCC by Corynebacterium parvum in acute myeloid leukaemia patients.

Natural killer (NK)- and antibody dependent cellular cytotoxicity assays were performed using cryopreserved effector cells in AML patients receiving i.c. and s.c. injections of Corynebacterium parvum. A dose related increase in NK could be demonstrated with peaks in NK at day 1 with full Cp dosage and at day 14 with 50% doses. This increase was attributable to the Cp vaccine since normal donors receiving tetanus toxoid or pneumococcal polysaccharide and AML patients randomized not to receive Cp did not show similar NK boosting. The increase was probably due to interferon induction in vivo and could be demonstrated with purified T- and non-T-lymphocyte subsets. However, longitudinal measurements showed that the ability of Cp to boost NK was gradually lost over 4-6 months. ADCC studies showed that while lymphocyte-ADCC was not consistently affected by Cp, monocyte-ADCC was enhanced with maximal cytotoxicity at day 14.