Decreased Serum Concentration of Total IgG Is Related to Tumor Progression in Gastric Cancer Patients

Background There is accumulating evidence that shows cell-mediated immunity regulated by T cells is impaired in cancer patients. Unfortunately, the mechanisms by which B cells participate in tumor immunity are only partially understood. Methods The serum concentration of Immunoglobulin G (IgG) was measured by Enzyme-Linked ImmunoSorbent Assay (ELISA) in patients with gastric cancer. Immunohistochemistry was also performed using the anti- cluster of differentiation (CD)134 antibody to evaluate the number of plasma cells in the tumor tissue. Results The total serum IgG concentration was significantly lower in patients with lymph node metastasis compared with patients without metastasis. The serum concentration of total IgG at stage III/IV was significantly lower compared with tumors classified as stage I/II. A decreased serum concentration of total IgG and IgG1 was significantly related to a poor prognosis for gastric cancer patients. Furthermore, multivariate analysis indicated that the serum concentration of IgG and lymph node metastasis were independent prognostic indicators for poorer survival. The number of plasma cells was significantly lower in gastric cancer tissue compared with non-cancerous gastric mucosa. Conclusion A decreased serum concentration of IgG was closely related to poor prognosis, indicating the possibility that impaired antibody-mediated immunity is associated with tumor progression in patients with gastric cancer.