[Autoantibodies directed against membrane phospholipid in serum in patients with malignant tumors]

Modifications of membrane lipids in the levels of fatty acids and phospholipids are associated with malignant tumors. In order to evaluate if these changes are recognized by the immune system, we have attempted to assay the possible presence of autoantibodies directed against the following lipids: phosphatidylinositol (PI), phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine, gangliosides, galactocerebrosides, sphingomyelin, sphingosin, and cardiolipin, in the sera of patients with malignant tumors (n = 324) and from controls [healthy subjects (n = 20) and patients suffering of other diseases (n = 60)]. Using an adaptated immunoenzymatic assay (ELISA method), a highly significant difference (p less than 0.001) was found between the mean absorbances read on the cancer and control group for only one lipid, the PI. Whatsmore, these auto anti-PI were found in all sera (diluted 15,000 times) of patients with malignant tumors, whatever type, grade, or organ localization defined. These data indicated that the immune system recognized the PI antigenic modifications which appear to be linked to the cell transformation. This PI-immunological binding may have a predictive value as we have recently noticed in animals bearing chemically-induced malignant tumors.