IMMUNOLOGICAL FEATURES OF SPORADIC MULTINODULAR GOITER

The origin of sporadic multinodular goiter is still uncertain. To obtain information on a number of unexplored immunological features, the distribution and characterization of T, B, and natural killer lymphocyte subsets were studied in the peripheral blood of 15 patients with multinodular goiter; 8 patients with Graves' disease (for reference purposes 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 displayed increased CD8+ CD57+ cytotoxic/suppressor cells (P<0.01). There was an increase in the percentage of natural killer cells expressing CD16 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 the CD5 antigen (CD19+ CD5+), which was unrelated to the titers of antimicrosomal and antithyroglobulin autoantibodies. Our results point to the presence of several abnormalities of peripheral T, B, and natural killer 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 sporadic multinodular goiter different suppressor and/or cytotoxic mechanisms are set up by the immune system, reflecting either pathogenic mechanisms of the disease or an immune response to pathological growing tissue.