pci-32765 and Myositis

Recipients of allogeneic hematopoietic stem cell transplantation (HSCT) are at increased risk for inflammatory myositis; histological subsets reported include dermatomyositis, necrotising myopathy and chronic graft-versus-host disease (cGVHD)-related myositis. Though corticosteroids and various immunosuppressive therapies have been used, there is a lack of consensus guidelines dictating therapy.. Recent evidence suggests the fascia as a preferential target in cGVHD myositis, with conditioning regimens promoting fascial microtrauma. Positron emission tomography (PET) can be a useful diagnostic tool, and case reports suggest that the Bruton's tyrosine kinase inhibitor ibrutinib may have therapeutic potential. Emerging therapies include targeted B cell depletion with rituximab, and extracorporeal photophoresis. Clinicians need to be vigilant for the development of inflammatory myositis post-allogeneic HSCT as most patients respond to treatment. Advances in immunohistochemistry to determine the dominant cell type and cytokine profile may enable targeted and individualised therapies.

Topics: Adenine; Chronic Disease; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Myositis; Piperidines; Pyrimidines; Rituximab

Myositis is a known complication of chronic graft-vs-host disease (cGVHD) following allogeneic haematopoietic stem cell transplantation, but can be difficult to diagnose and manage. We present the case of a 57 year old man with cGVHD in whom the full manifestations of myositis were suppressed for some time, likely due to partial treatment of his condition with immunosuppression including ibrutinib. Though initial muscle biopsy showed necrotising myopathy without significant inflammation, on cessation of ibrutinib he developed increasing weakness and creatine kinase levels, with repeat muscle biopsy showing histological changes more in keeping with dermatomyositis. The close temporal correlation of his clinical course with commencement and cessation of ibrutinib suggests a potential role for ibrutinib in treating inflammatory myopathy in cGVHD.

Topics: Adenine; Biopsy; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Male; Middle Aged; Myositis; Piperidines; Treatment Outcome