The skin of patients with systemic sclerosis softened during the treatment with anti-IL-6 receptor antibody tocilizumab

Objective. SSc is an autoimmune disease characterized by fibrosis of the skin and internal organs. Although the aetiology remains uncertain, many reports have suggested that IL-6 is involved in SSc pathogenesis. Tocilizumab, an anti-IL-6 receptor antibody, is an anti-arthritis medicine that works through the blockade of IL-6 functions. To examine the effect of tocilizumab on SSc, we administered tocilizumab to two SSc patients. Methods. Two dcSSc patients were administered tocilizumab at 8 mg/kg once a month for 6 months. One patient had pulmonary fibrosis assessed by CT and spirometry, and the other had chronic renal failure caused by scleroderma renal crisis. Their skin condition was monitored with a Vesmeter and the modified Rodnan total skin score (mRTSS). Skin biopsies were obtained before and after the tocilizumab treatment to investigate the histological changes. Results. After tocilizumab treatment, both patients showed softening of the skin with reductions of 50.7 and 55.7% in the total z-score of Vesmeter hardness and 51.9 and 23.0% in the mRTSS, respectively. Histological examination showed thinning of the collagen fibre bundles in the dermis. The creatinine clearance in the patient with chronic renal failure improved from 38 to 55 ml/min. However, the fibrotic changes in the lung in the other patient remained unchanged. Conclusions. In the two cases of SSc that we report here, softening of the skin was observed during the treatment with tocilizumab.