Case Of Mucous Membrane Pemphigoid With Immunoglobulin G Antibodies To The Beta 3 Subunit Of Laminin-332 Showing Clinically Stevens-Johnson Syndrome-Like Generalized Blistering Mucocutaneous Lesions

laminin-332. The case was diagnosed as psoriatic erythroderma with autoimmune subepidermal bullous lesion of unknown etiology. Oral prednisolone (30 mg/day) with 0.12% betamethasone 17-valerate and maxacalcitol (25 lg/g) ointment suppressed new blister formation. However, during tapering of prednisolone (at 15 mg/day) new blister formation was observed. Addition of cyclosporin 100 mg daily with prednisolone was effective for both bullous and psoriatic lesions, and the skin lesions disappeared within 2 weeks. Prednisolone discontinued, and the patient was well controlled with cyclosporin 100 mg every other day without new blister formation. The usefulness of the combination therapy of systemic steroid and cyclosporin for pemphigus has been described. According to the Japanese guideline for the treatment of pemphigus, cyclosporin is graded in C1. To the best of our knowledge, this is the first case of psoriatic erythroderma with subepidermal bullae successfully treated with cyclosporin and prednisolone. Despite the presence of autoreactive antibodies in the patient’s serum, we could not identify the target molecule of the antibody. From the indirect immunofluorescence using 1 mol NaCl-split skin showing IgG reactivity with dermal sides of the split skin, differential diagnosis included epidermolysis bullosa acquisita, anti-laminin-332 pemphigoid and anti-p200 pemphigoid. Anti-p200 pemphigoid which turned out to be anti-laminin-c1 pemphigoid is known to be closely associated with psoriasis and almost one-third of 61 cases reported were those with psoriasis. Without positive findings of the specificity of the patient’s antibodies, no definite diagnosis of this case was established. The reasons that the patient’s sera did not react with the candidate molecules may include: (i) a low titer of autoantibody in the patient’s serum; (ii) a conformational change during the extraction of dermal substance in immune blot; or (iii) a novel pathogenic molecule in our case. Further analysis of the autoantigens would be required in terms of pathophysiology of autoimmune blistering disorders, which are occasionally observed in psoriasis.