CD8+CD28-lymphocytes in peripheral blood and serum concentrations of soluble interleukin 6 receptor are increased in patients with Graves' orbitopathy and correlate with disease activity.

BACKGROUND

The extrathyroid, orbital manifestation of Graves' disease (GD)--Graves' orbitopathy (GO)--presents a difficult clinical problem. The immunological status of GO patients is still under investigation. The aim of this study was to assess the serum concentration of interleukin 6 (IL-6), soluble interleukin 6 receptor (sIL-6R), and CD8+CD28- lymphocytes in GO patients and to evaluate if these parameters were associated with disease activity.

PATIENTS

Thirty-nine patients (29 women and 10 men, aged 24-71, mean 50.18) with newly diagnosed GD were enrolled in the study. Active GO was diagnosed in 20 patients. The control group included 12 healthy individuals.

METHODS

Serum concentrations of IL-6 and sIL-6R were estimated by ELISA. Percentages of CD8+CD28- lymphocytes in peripheral blood were assessed by flow cytometry.

RESULTS

Mean serum IL-6 and sIL-6R concentrations were significantly higher in all GD patients and in GO and non-GO patients than in normal controls. In all GD patients and the non-GO group, serum IL-6 and sIL-6R concentrations were significantly reduced after efficient treatment. In GO patients, only serum sIL-6R concentration was significantly lower after efficient treatment. In all GD patients, the mean percentage of CD8+CD28- lymphocytes was significantly lower after efficient treatment. In GO patients, the mean percentage of CD8+CD28- lymphocytes was significantly higher than in the non-GO group or in normals. Moreover, in the GO group, the mean percentage of CD8+CD28- lymphocytes was significantly lower after treatment.

CONCLUSION

Our results have shown that CD8+CD28- lymphocyte percentage in peripheral blood and serum concentration of sIL-6R are increased in GO patients and correlate with disease activity.