Incidence of alloantibodies and immune complexes in bronchial secretions of lung cancer patients.

Bronchial secretions may accumulate immunoglobulins (Igs) produced by lymphocytes infiltrating tumor and its vicinity, and tumor associated antigens to higher degree than cancer patient serum. All three classes of Igs were increased in bronchial secretions from lung cancer patients as compared to control patients. Similar relationships were found for IgG and IgA/albumin ratios and IgG and IgA indices. The level of alloantibodies to fetal cells (measured by immunoradiometric--IRMA--assay) and immune complexes (IC, measured by IRMA--Clq and ELISA--anti C3) were significantly higher in lung cancer patients versus control patients in bronchial secretions. The differences were similar in sera but they were not significant. On the contrary, alloantibody binding to tumor cells was higher in control group. Absorption experiments with normal cells abolished antitumor and antifetal activity, what indicates natural character of these alloantibodies. Significant correlations between alloantibody to fetal cells and IC levels indicate that fetal antigens may contribute to antigenic component of IC. These findings suggest the link of alloantibodies and IC levels in bronchial secretions with neoplastic growth.