B-lymphocyte subset distribution and serum immuno-globulin levels in Graves' ophthalmopathy patients

Abstract

The B-lymphocyte subset distribution was studied in 52 Graves' ophthalmopathy patients and 13 healthy controls. In a previous study an increase in total peripheral blood B cells was found in these patients when compared to controls (p < 0.001). In the present study the patients were classified according to their ocular symptoms, using the NOSPECS classification (five groups) or according to their thyroidal disease state (seven groups). The B cell subset distribution was studied for each of the subgroups. The B cell increase is polyclonal; both kappa and lambda bearing B cell numbers are increased. A significant increase of IgG-bearing B-cells is seen in seven out of ten patient subgroups. lncreased levels of IgM- and/ or IgD-bearing cells are found only in three out of ten patient subgroups and increased levels of IgA-bearing cells are found in two out of ten patient subgroups.

In 42 of the 52 Graves' ophthalmopathy patients the serum immunoglobulin levels were studied and correlated with the B-cell abnormalities. Serum IgG levels were normal in all the patients. Increased levels of serum IgM were found in five subgroups and increased serum IgA levels in one subgroup.

In conclusion, in Graves' ophthalmopathy patients mainly IgG kappa and IgG lambda bearing B-cells seem to proliferate in response to an as yet unknown signal. This B-cell proliferation occurs independently of the thyroidal or ocular symptoms. This polyclonal activation does not, however, appear to result in active secretion of immunoglobulins by the majority of the B-cells.

Key Words:

• Graves'
• ophthalmopathy
• B-lymphocyte
• serum immunoglobulin levels