CD5+ B lymphocytes and CD4+ CD45RA+ T cells in Graves' disease

Fifteen patients affected by new-onset Graves' disease with ophthalmopathy have been examined for lymphocyte subset phenotypes by two-colour cytometric analysis. CD5+ B cells were significantly increased in comparison to the normal population (43.2 +/- 20.6% versus 19.5 +/- 6.9%; p < 0.0009); total T cells showed a normal amount (70.4 +/- 9.6%), but the levels of THLADR+ cells were significantly increased in comparison to the control group (13.7 +/- 10.5% versus 4.7 +/- 3.2%; p < 0.007). The characterization of the subset suppressor-inducer CD4+ CD45RA+, evaluated as percentage of the total CD4+ T cells, showed a significant decrease in comparison with the control group (43.8 +/- 13.5% versus 52.3 +/- 6.5%; p < 0.03). Serum immunoglobulin evaluation showed a statistically significant increase of IgM (p < 0.05) and a significant decrease of IgA (p < 0.02). A statistical correlation between IgM levels and percentage of CD5+ B cells has been found (p < 0.04). The defect of suppressor-inducer T cell subset, along with the increase of CD5+ B cells may contribute to the pathogenetic mechanism of the disease in patients with a genetically-induced aberrant immune response.