Autoantibodies in lung cancer patients demonstrated on fixed tissue culture cells. An immunofluorescent study

A panel of sera derived from 138 patients with primary bronchogenic carcinoma, non-neoplastic lung conditions and from blood donors was tested for presence of autoantibodies by indirect immunofluorescence on fixed cells of established lung cancer cell line and lung fibroblasts as a substrate. Autoantibodies were detected in 87% and 64% out of patient sera respectively and in 9% of donor sera. Immunofluorescence patterns permitted to distinguish 3 antibody specificities: anti-nucleolar, anti-cytoplasmic and anti-nuclear ones. The major differences were noted in incidence of anti-nucleolar antibodies, which were present in 77% of lung cancer patients and only in 14% of patients with non-neoplastic lung conditions. The autoantibodies in question belonged to IgG and to lesser degree IgA class of immunoglobulin and were not apparently cancer specific because absorption with normal tissue homogenates removed their activity.