Symptomatic myopathy during interferon alfa therapy for chronic myelogenous leukemia

Environmental exposures as risk factors for idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of rare autoimmune diseases, with increasing incidence rates observed in the recent years. The pathogenesis of IIM remains not fully understood, and the interaction of genetic and environmental factors is suspected. It is unclear whether the observed upward trend in the IIM incidence is solely due to improved access to effective diagnostics or perhaps due to increased exposure to external risk factors. The PUBMED database was thoroughly searched for articles describing environmental exposures potentially triggering the onset of IIM. The article summarizes the current knowledge available on this subject, taking into account various environmental factors, including among others UV radiation, infectious agents with SARS-CoV-2, inhaled particles, or iatrogenic effects. Limitations and unmet needs requiring further studies were highlighted.

Dermatomyositis as a complication of interferon-α therapy: a case report and review of the literature

Autoimmune disorder is one of the important side effects of interferon-α therapy. Some polymyositis cases as complication of interferon-α therapy were reported, but dermatomyositis were rarely. We report a case of dermatomyositis as a complication of interferon-α therapy for hepatitis C. A 52-year-old Japanese man was treated by combination therapy with pegylated interferon-α-2b and ribavirin for hepatitis C. Three months after the initiation of therapy, he showed erythema in the posterior cervical to dorsal and anterior cervical to thoracic regions, weight loss, general malaise, muscle pain, and severe increase in levels of muscle enzymes. We made a diagnosis of dermatomyositis according to these clinical features, proximal muscle-predominant myogenic change on electromyography, and infiltration of monocytes and CD4+-dominant lymphocytes on skin biopsy, although myositis-associated antibodies were absent. He was successfully treated with intravenous immunoglobulin and tacrolimus in addition to glucocorticoid. This is a very rare case of dermatomyositis associated with interferon-α therapy. We reviewed several similar published cases and the association of dermatomyositis and type I interferon.

Reversible myopathy during successful treatment with pegylated interferon and ribavirin for acute hepatitis C

There is no standard approved treatment for acute hepatitis C and the combination of pegylated interferon-alpha and ribavirin, currently recognized as the standard of care for chronic hepatitis C, has not been evaluated for acute hepatitis C. Adverse events induced by interferon therapy are numerous but myopathy is rare and has not been described with the use of pegylated interferon-alpha. We report the case of a 33-year-old Caucasian man who was successfully treated for acute hepatitis C with the combination of pegylated interferon-alpha2b and ribavirin, and who during treatment developed myopathy which proved reversible.

Inflammatory myopathy associated with imatinib mesylate therapy

We report a patient with chronic myelogenous leukemia (CML) who developed an inflammatory myopathy while being treated with imatinib mesylate. We found serum antibodies directed against a component of the human exosome. Similar antibodies have been demonstrated in patients with CML following immune-induced remission and also are occasionally found in patients with polymyositis. It is known that the previous use of alpha-interferon followed by imatinib leads to rapid apoptosis of leukemic cells. We speculate that the subsequent release of a large bolus of leukemia antigens could have crossreactivity with muscle antigens and generate an autoimmune response.

Possible contribution of interferon-alpha to febrile seizures in influenza

The systemic symptoms associated with influenza infection are mainly attributable to cytokines. To elucidate whether the high incidence of creatine kinase elevation and febrile seizures in influenza infection could be related to cytokines, we examined the serum levels of creatine kinase and cytokines (interferon-alpha, interleukin-6, and tumor necrosis factor-alpha) in patients with influenza and other febrile illness. Among those in the influenza group, 12 of 43 patients demonstrated elevated levels of creatine kinase (more than 200 IU/L), whereas in the control group two of 14 patients demonstrated elevated creatine kinase levels. When age was limited to under 7 years, seven of 32 patients (21.9%) in the influenza group had febrile seizures, whereas one of seven patients (14.3%) had a seizure in the control group. The influenza group demonstrated significantly high levels of interferon-alpha and interleukin-6. There was no correlation between cytokine levels and duration of fever or serum creatine kinase levels. The number of patients with high levels of interferon-alpha (>400 pg/mL) was significantly larger in the febrile seizure group than in the control group (six of seven patients in the febrile seizure group, 16 of 36 in the control group; P < 0.05). The present findings suggest the possible contribution of interferon-alpha in the pathogenesis of febrile seizures.