IMMUNOLOGICAL FEATURES OF SPORADIC MULTINODULAR GOITER

The origin of sporadic multinodular goiter is still uncertain. To obta in information on a number of unexplored immunological features, the d istribution and characterization of T, B, and natural killer lymphocyt e subsets were studied in the peripheral blood of 15 patients with mul tinodular goiter; 8 patients with Graves' disease (for reference purpo ses with a well-characterized autoimmune disease) and 29 age- and sex- matched healthy controls, combining double-staining immunofluorescence technique with monoclonal antibodies and flow cytometry. Although in both thyroid diseases increased CD3+ HLA-DR+ activated T cells (P<0.01 ) were detected, in Graves' disease this was associated with decreased numbers of CD8 cells (P<0.05) and an increased CD4/CD8 ratio (P<0.01) . These abnormalities were absent in multinodular goiter, which displa yed increased CD8+ CD57+ cytotoxic/suppressor cells (P<0.01). There wa s an increase in the percentage of natural killer cells expressing CD1 6 and CD57 antigens in multinodular goiter but not in Graves' disease. The B-cell associated antigens CD19 and CD19+ CD5+ were significantly increased in Graves' disease (P<0.01), while the multinodular goiter patients exhibited only an increased number of B cells coexpressing th e CD5 antigen (CD19+ CD5+), which was unrelated to the titers of antim icrosomal and antithyroglobulin autoantibodies. Our results point to t he presence of several abnormalities of peripheral T, B, and natural k iller lymphocytes in sporadic multinodular goiter, with a distribution pattern quite different from that observed in Graves' disease. These results support the notion that, in contrast to Graves' disease, in sp oradic multinodular goiter different suppressor and/or cytotoxic mecha nisms are set up by the immune system, reflecting either pathogenic me chanisms of the disease or an immune response to pathological growing tissue.