To investigate the cellular immune response in myasthenia gravis (MG), serum levels of interleukin-2 (IL-2), soluble IL-2 receptor (sIL-2R) and neopterin were measured in 48 patients with MG, and these levels were compared with those in 22
healthy
controls. Also, the relationship of serum levels of IL-2 sIL-2R and neopterin to disease severity and thymic histology, and the changes of above laboratory indexes were observed according to thymectomy.
Serum IL-2 was not detected in controls, but was detected in 56% of MG patients. Mean levels of serum sIL-2R were significantly increased in MG patients compared with controls (p<0.01), and mean levels of serum neopterin were increased, but not
statistically significant in MG patients compared with controls Mean levels of serum sIL-2R were significantly increased in the groups of grade IIB and III compared with the groups of grade I and II A(p<0.01). Among 20thymectomized MG patients.
Mean
levels of serum sIL-2R were significantly increased in patients with thymoma compared with those with involuted thymus (p<0.05). In the follow-up study of serum levels of IL-2, sIL-2R and neopterin after thymectomy, the detection rate of serum
IL-2
was
significantly decreased in patients more than 1 year after thymectomy compared with those before thymectomy (p<0.05), and mean levels of serum sIL-2R and neopterin were significantly decreased in patients more than 1 year after thymectomy
compared
with
those before thymectomy (p<0.01, p<0.05). These decrements reflected the clinical improvement.
These results suggest that the cellular immune responses with T cell and macrophage activation are relevant to the pathogenesis of MG. Serum sIL-2R level is correlated with disease severity, and serum IL-2, sIL-2R and neopterin levels may
represent
markers of disease activity after thymectomy.
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