Dermatitis herpetiformis (DH) is a pruritic papulovesicular disease that is symmetrically distributed over the shoulders, elbows, back and knees. Immunofluorescence has revealed granular IgA deposition in the papillary dermis. IgA antibodies to both epidermal transglutaminase (eTG) and tissue transglutaminase (tTG) are usually detected in patients with DH. DH is commonly thought to be a cutaneous manifestation of gluten-sensitive enteropathy (GSE) (1, 2). We refer to this condition as "granular-type DH". Although DH is a relatively common disease in Caucasian populations, it is rare in Japan. Most Japanese patients with DH show unique features, including a high frequency of fibrillar IgA deposition in the papillary dermis, rare occurrence of GSE, absence of the HLA-DQ2/DQ8 haplotype and rare associations with autoimmune disease and lymphoma, although the histological findings appear to be similar to those of granulartype DH (3, 4). Furthermore, as reported previously, these patients appear to have IgA antibodies to eTG, but not tTG (5). We refer to this condition as "fibrillar-type DH". The clinical and histological findings of typical fibrillar-type DH are shown in Fig. S1 1 . Fibrillar-type DH appears to be rare in Caucasian populations (6). While the pathogenesis of DH is unclear, previous studies have suggested that the expression of interleukin (IL)-8, granulocyte-macrophage colony-stimulating factor (GM-CSF) and Th2-type cytokines could be important in the tissue infiltration process of eosinophils and neutrophils in granular-type DH (7,8). The present study investigated the levels of serum cytokines and chemokines in order to clarify their presence and activity in the pathogenesis of fibrillar-type DH.
MATERIALS AND METHODS (see Appendix S11 )
RESULTSThe study population included 5 patients with fibrillartype DH (mean age 67.4 years; age range 41-81 years) in the active stage of the disease, who had not received any treatment and in whom the development of new lesions had been observed ( Table I). The levels of IgA antibodies against eTG were markedly increased in all patients. However, no IgA antibodies against tTG were detected in any of the patients. None of the patient's intestinal tissue specimens showed villous atrophy or lymphocytic cell infiltration.The serum level of interferon (IFN)-γ, a Th1-like cytokine, was increased slightly in the patients with DH (mean 0.414 ± 0.23; range 0.21-0.80 pg/ml) in comparison with the control subjects; however, the difference was not statistically significant. IL-12, another Th1-like cytokine, was not detected in either the patients with DH or the control subjects (Fig. S2a 1 ). The patients' serum levels of Th2-like cytokines IL-4 (mean14.55 ± 5.3 pg/ml; range 6.84-21.71 pg/ml, p < 0.005), IL-5 (mean 6.09 ± 0.99 pg/ml; range 4.84-7.49 pg/ml, p < 0.001) and IL-13 (mean 1.14 ± 0.20 pg/ml; range 0.85-1.36 pg/ml, p < 0.005) were significantly increased in comparison with the normal subjects: IL-4: mean 0.04 ± 0.09 pg/ml; range 0-0.21 pg/ml, IL-5: mean 0.55 ± 0.14 p...