Clinical relevance of T lymphocyte subsets in pediatric Graves' disease

Objectives Graves' disease (GD) is an autoimmune disease involving intimate response of both T cells and B cells. Immunophenotyping of peripheral blood lymphocyte subsets in GD children with different clinical characteristics can provide further information of the pathogenesis of GD. Methods We studied the lymphocyte subsets in peripheral blood of 141 children with GD. We repeatedly divided the patients into two groups in accordance with different clinical characteristics (abnormal or normal alanine aminotransferase (ALT) levels, the presence or absence of Graves' orbitopathy (GO), and the presence or absence of hematuria. Then we compared the lymphocyte subsets measurements between two paired groups. Results We found that serum ALT levels correlated positively with CD3+CD8+ T cell percentages in children with GD. Moreover, we detected higher percentages of CD3-CD19+ cells and higher ratio of CD4/CD8 in patients with GO. However, no correlation was found between GO status and lymphocyte subsets after excluding confounding effect of TRAb. No difference of lymphocyte subset percentages was found between groups with or without hematuria. Conclusions Serum ALT levels correlate positively with cytotoxic T cell percentages in the peripheral blood of children with GD. The cytotoxic T cell may play a role in the pathogenesis of hepatic dysfunction in children with GD.