An immunohistochemical study of the dermal infiltrate and epidermal staining for interleukin 1 in 12 cases of Sweet's syndrome.

Interleukin 1 (IL-1) has been proposed as a possible mediator in Sweet's syndrome. We examined all cases of Sweet's syndrome (n = 12) presenting to the department over a 10-year period, from 1982 to 1992, for the presence of IL-1 and also assessed the nature of the dermal inflammatory infiltrate in those cases. Staining for IL-1 alpha and IL-1 beta was stronger in control tissues than in Sweet's syndrome. This may possibly be explained by the release of IL-1 alpha and IL-1 beta into the dermis in Sweet's syndrome. Contrary to recent reports, we found that neutrophils predominated in all cases examined, although histiocytes were present in increased numbers indicating their possible role in the pathophysiology of Sweet's syndrome.