Scleroderma Induced by Pembrolizumab: A Case Series.

Immune checkpoint inhibitors are approved for select cancer treatment and have shown survival benefit in patients with advanced melanoma. Adverse events, including immune-related adverse events, are common and potentially life-threatening. We describe cases of 2 patients with scleroderma (patient 1 had diffuse scleroderma, and patient 2 had limited scleroderma) that developed while they were receiving pembrolizumab therapy for metastatic melanoma. Prompt recognition and treatment of immune-related adverse events may improve tolerance to immune checkpoint inhibitors and contribute to an understanding of the manifesting autoimmune disease.

Skin progenitor cells contribute to bleomycin-induced skin fibrosis.

OBJECTIVE: The origin of the cells that contribute to skin fibrosis is unclear. We undertook the present study to assess the contribution of Sox2-expressing skin progenitor cells to bleomycin-induced scleroderma. METHODS: Scleroderma was induced, by bleomycin administration, in wild-type mice and in mice in which CCN2 was deleted from Sox2-expressing cells. Lineage tracing analysis was performed to assess whether cells expressing Sox2 are recruited to fibrotic lesions in response to bleomycin-induced scleroderma. RESULTS: In response to bleomycin, Sox2-positive/α-smooth muscle actin-positive cells were recruited to fibrotic tissue. CCN2-conditional knockout mice in which CCN2 was deleted from Sox2-expressing cells exhibited resistance to bleomycin-induced skin fibrosis. Collectively, these results indicate that CCN2 is required for the recruitment of progenitor cells and that CCN2-expressing progenitor cells are essential for bleomycin-induced skin fibrosis. Lineage tracing analysis using mice in which a tamoxifen-dependent Cre recombinase was expressed under the control of the Sox2 promoter confirmed that progenitor cells were recruited to the fibrotic lesion in response to bleomycin, and that this did not occur in CCN2-knockout mice. The ability of serum to induce α-smooth muscle actin expression in skin progenitor cells required the presence of CCN2. CONCLUSION: Sox2-positive skin progenitor cells are required in order for bleomycin-induced skin fibrosis to occur, and CCN2 is required for the recruitment of these cells to the fibrotic lesion. Targeting stem cell recruitment or CCN2 may therefore represent a useful therapeutic approach in combating fibrotic skin disease.

The development of systemic sclerosis in a female patient with multiple sclerosis following beta interferon treatment.

We describe a 38-year-old patient with relapsing remitting multiple sclerosis who subsequently develops systemic sclerosis following a course of interferon B-1a injections. This rare association between MS and systemic sclerosis is interesting due to the added factor of beta interferon therapy prior to the onset of the systemic sclerosis. It is also important, as more patients are treated with interferon B-1a for multiple sclerosis, this is a potential association.