Immune complexes and human neoplasia. I.

Recent technical improvements in circulating immune complexes (CIC) detection have resulted in a proliferation of data reporting increased CIC levels in a variety of human diseases. The overall result being a better understanding of the inferred pathogenic role of IC in disease, and their possible clinical significance. We will pay particular attention to human neoplasia and those clinical conditions which may provide relevant pathophysiologic information. The immunobiology of cancer derangement involving CIC is dependent on a number of factors such as size, number, valence and composition. In addition, mechanisms involved in IC formation, removal, deposition, IC-induced inflammatory reaction, and the role of IC in regulation of humoral and cellular immune response are discussed. While CIC are frequently detected in cancer patients, a uniformly predictable pathologic role has not been fully identified nor is there always proven evidence that CIC are involved either in the pathogenesis or as products of the disease progression. In spite of several methods of CIC detection that have been reported, none of them has been entirely satisfactory for clinical use. Effective management of CIC positive cancer patients require knowledge of the number of IC and their molecular size composition, as well as a concomitant evaluation of antigen and antibody components interacting in the system. In view of the complexity in this extensive field, we present this review in two parts: Review I comprises biological and physicochemical mechanisms involved in IC formation, removal, deposition and its pathogenic significance, and Review II contains a concised nonexhaustive discussion of possible clinical significance of CIC in human neoplasia.