Two new publications provide new information that could help better diagnosis and treatment of inclusion body myositis (IBM), a rare musculoskeletal condition.
IBM is characterised by chronic, progressive muscle inflammation and weakness. Symptoms usually begin after the age of 50, although the condition can occur earlier. Currently, there is no proven treatment for IBM.
Dr James Lilleker (pictured above left) works at Salford Royal and is also a Clinical Research Fellow at the NIHR Manchester Musculoskeletal Biomedical Research Unit. He recently had a paper published in the Annals of the Rheumatic Diseases. His retrospective study investigated the association between anticytosolic 5′-nucleotidase 1A antibody status and clinical, serological and histopathological features to explore the possibility of using the antibody to identify IBM subgroups and to predict disease outcomes.
The study shows that antibody-positive patients had a higher adjusted mortality risk, lower frequency of proximal upper limb weakness at disease onset and an increased prevalence of excess of cytochrome oxidase deficient fibres on muscle biopsy analysis. Stratification of IBM patients by this antibody may be useful to clinicians, potentially highlighting a distinct IBM subtype with a more severe phenotype.
Dr Simon Rothwell, Research Associate at The University of Manchester, undertook research exploring genetic risk factors in IBM that was recently published in the journal Arthritis and Rheumatology. This research was the largest IBM genetic association study to date, and set out to explore immune-related genes that may influence disease susceptibility.
The strongest risk factor was in a region of the genome known as the major histocompatibility complex (MHC) that contains many genes that are important in the immune system. Three different versions of a gene called DRB1 were found to be associated with IBM. These versions of DRB1 shared a common amino-acid signature that may differentiate between other forms of myositis, such as dermatomyositis and polymyositis.
Dr Hector Chinoy (above right), Honorary Clinical Consultant at Salford Royal, Senior Clinical Lecturer in Rheumatology and supervisor for both these studies, added: “Both these papers bring new information that will help us to better identify patients with IBM and those who may be susceptible to developing it in the future. We hope to further this research under the musculoskeletal research theme under NIHR Manchester Biomedical Research Centre funding from April.”