[Complement. Evaluation of some complement fractions in patients affected by neoplasia undergoing chemotherapy...

Serum complement levels (UE50, C3, C4, act. C3, C1q) were determined in 75 healthy subjects and 130 cancer patients undergoing treatment. The results were correlated with statistical analysis. The patients were divided into the following groups: a) with local tumor; b) with tumor in complete remission; c) with tumor in incomplete remission; d) stationary. Three blood samples were obtained over a period of about two months. All cancer patients had decreased UE50 levels and increased act. C3 levels compared to normal values, while C3, C4, and C1q were normal. C4 levels were not significant in any group of cancer patients, but act. C3 levels were significantly increased (as compared to those of the healthy subjects). UE50 levels appeared significantly decreased only in the group with complete remission, C3 levels were increased in incomplete remission patients and were variable in stationary patients. C1q values were always increased except in the complete remission group. The variability of complement levels was dependent on the stage of the disease and on the therapy: our results provide considerable support for this hypothesis. We found that complement activity was triggered through classic or alternative means caused by antigen-antibody complexes or inflammatory processes, according to the increase or decrease of the tumor mass.