346 Clinical Effects of Tocilizumab, a Humanized Anti-interleukin-6 Receptor Antibody, on Patients with Autoimmune and Allergic Diseases

immunoglobulin, the clinical skin severity scores were lower in FcRg-/NC/Tnd mice by half than in conventional WT mice. On the other hand, there were no differences in both scratching behavior elicited by dermatitis and Th1/Th2 cytokine production between 2 groups of mice. In the skin lesion of FcRg null mice, mild epidermal hyperplasia and immune cell infiltration were observed. Particularly, mast cell numbers and their degranulation were significantly decreased in the skin of FcRg-deficient mice. Conclusions: FcRg was not critical to the onset of AD, because FcRg-deficient mice exhibited moderate dermatitis and scratching behavior comparable to WT. On the other hand, although scratching behavior induced the mechanical destruction of skin barriers and mast cell activation, the absence of FcRg markedly attenuated the skin severity, immune cell recruitment including lymphocytes, and mast cell degranulation. These results indicated that the FcRg-mediated immune response by specific IgG and IgE regulate the exacerbation of clinical symptoms in AD.