Forty-three coeliac children, ranging from 1 year and 3 months to 14 years and 9 months, were studied. Twenty-eight patients were in an active phase of the disease, and 15 were in remission. The criteria of coeliac disease (CD) activity were established according to the results of IgA anti-endomysial antibodies (IgA-AEm). Interleukin 2 receptor (IL-2R) and CD4 and CD8 antigens were measured in serum samples by an ELISA technique using two noncompetitive monoclonal antibodies. Antigliadin antibodies of IgG (IgG-AGA) and IgA (IgAAGA) classes were also measured. The AEm-positive coeliac patient group showed values of 1,860 +/- 948 U/ml for IL-2R, 430 +/- 228 U/ml for CD8, and 36.8 +/- 25.1 U/ml for CD4. AEm-negative patients showed values of 980 +/-436 U/ml, 350 +/- 243 U/ml, and 24.1 +/- 20 U/ml, respectively. IL-2R levels were the only ones significantly elevated (p < 0.005) in the active coeliac group. On the other hand, IgG-AGA and IgA-AGA were both clearly increased (p < 0.001). IL-2R levels in active coeliac patients correlated with CD4 levels (p < 0.05), but not with CD8, IgG-AGA, and IgA-AGA levels. We also found a surprising negative correlation between AEm antibodies of IgA2 class with both IL-2R (r = 0.471; p < 0.05) and CD8 (r = 0.616; p < 0.05). The results show that in CD there is a lymphocyte activation affecting mainly CD4+ cells and not correlated with serum AGA levels, suggesting an independence of both immunological phenomena and probably with different locations of origin.