Soluble CD30 is more relevant to disease activity of atopic dermatitis than soluble CD26

It is suggested that CD30 and CD26 are surface molecules expressed on activ ated Th2 and Th1 cells, respectively. We examined plasma levels of soluble CD26 (sCD26) and sCD30 in patients with atopic dermatitis (AD) when their e ruptions were aggravated and in non-atopic healthy controls, and then analy sed the possible correlation between these values and the levels of several clinical markers. The plasma levels of both sCD30 and sCD26 were significa ntly higher in AD patients than in controls, both in exacerbation status an d after conventional treatment. Multiple regression analyses showed that pl asma sCD30 was a much better predictor of the levels of serum IgE, serum LD H and plasma sCD25, and the area and the score of AD eruption than sCD26, a lthough elevated levels of both sCD30 and sCD26 are associated with these c linical predictors of AD. Importantly, sCD30 plasma levels decreased signif icantly in AD patients after conventional treatment, while no significant t ransition was noted in the concentration of sCD26. Moreover, a significant reduction of sCD30 levels was observed in the group of patients whose erupt ion score was reduced > 50%, whereas it was not in those < 50%. These findi ngs provide evidence that the successful treatment of AD is associated with down-activation of Th2.