Serum Levels of Second Component of Complement in Cancer Patients

The levels of the second component of complement (C′2) in the serum of cancer patients were determined. The average of C′2 titers in the cancer group was slightly higher than in the healthy control group but the differences were not statistically significant. Among patients with lymphosarcoma and reticulum cell sarcoma, a few had very low C′2 levels, and all patients with Hodgkin's disease and multiple myeloma had moderately high levels. The biologic significance of these differences is obscure. They are not explained by such variables as technique, sex, age or therapy. Impending death was often, but not consistently, associated with low C′2 levels. In a small group of patients with various non-neoplastic diseases the only abnormality of note was a very low C′2 titer in a patient with lupus erythematosus.