Increased immunoreactive interleukin-5 levels in blister fluids of bullous pemphigoid.

Abstract

An intense eosinophil infiltration into the cutaneous inflammatory lesions is one of the histopathological characteristics of bullous pemphigoid (BP) [10], which is often associated with blood eosinophilia [3]. Eosinophil granule proteins have been found in blister fluids of patients with BP, and eosinophil peroxidase has been found along the basement membrane [6]. It has also been suggested that the eosinophils in BP lesions could be degranulating and damaging the basement membrane [7]. Several reports testify to the presence of eosinophil chemotactic activity in blister fluids or sera of BP [1, 5] including leukotriene B 4 [8, 9]. It has recently been shown that interleukin-5 (IL-5) is a major cytokine of CD4 § T cells to support the terminal differentiation and proliferation of eosinophils [4, 15]. IL-5 has also been shown to be chemotactic for eosinophils [16] and to prolong the survival of eosinophils in tissue [11, 16]. The present study was undertaken to investigate whether IL-5 is involved in eosinophil infiltration into BP lesions. For this purpose, we evaluated the amount of IL-5 in blister fluids and sera of patients with BP. We also studied the capacity for IL-5 production of peripheral blood mononuclear cells (PBMC) in these patients. Five patients with BP and one patient with herpes gestationis (HG) attending our dermatology clinic were enrolled in this study. This diagnosis of BP and H G was established on the basis of the clinical features and the findings of the skin biopsy examination by light microscopy and immunofluorescence. The titre of anti-basement membrane IgG antibody in the serum was determined by indirect immunofluorescence staining using a fluorescein isothiocyanate-conjugated rabbit anti-human IgG antibody. The clinical data of the patients are shown in Table 1. The patients had received no systemic cortico-