Elevated serum levels of IgE-binding factor/soluble CD23 in bullous pemphigoid.

IgE-related abnormalities and impaired B cell function have been reported in patients with bullous pemphigoid (BP). CD23 is a low affinity Fc epsilon RII on haematopoietic cells and its soluble form (sCD23) is involved in B cell growth and differentiation. In order to determine the role of CD23 in the pathomechanisms of BP, the present study assayed the level of sCD23 in sera of BP patients using an ELISA method. Levels of sCD23 were elevated in BP patients compared with mean levels in the sera of normal control. Furthermore, the increase in sCD23 levels correlated with the degree of disease activity. A significant correlation was found between sCD23 and serum IgE levels in BP sera, but not in normal control sera. These results suggest that sCD23 is an important index for monitoring BP with respect to IgE-related abnormalities and impaired B cell function.