The study, published in the journal Annals of the Rheumatic Diseases, was coordinated by José C. Milisenda, researcher in the IDIBAPS Inherited Metabolic Diseases and Muscular Disorders group and coordinator of the Internal Medicine Muscle Diseases Group at the Clínic, along with Iago Pinal-Fernandez and Andrew Lee Mammen, coordinator of the NIH Muscle Disease Unit and associate director of the Johns Hopkins Myositis Center.
Idiopathic inflammatory myopathies (IIM) are minority autoimmune diseases, which cause inflammation in the muscles, resulting in muscle weakness. Among the most common ones are dermatomyositis, polymyositis and inclusion body myositis. The symptoms include progressive weakness, fatigue, muscle pain and, in some cases, rashes. Treatment so far includes immunosuppressive drugs and physiotherapy to reduce inflammation and improve muscle function.
Understanding the role of antibodies in myositis
The study used advanced immunofluorescence microscopy and RNA sequencing techniques to analyse muscle biopsies from patients with IIM. The researchers focused on identifying whether autoantibodies could actually enter muscle cells and cause dysfunction.
The researchers showed that the antibodies can enter the muscle cells and accumulate in specific areas, where they can interfere with the normal cell functions.
In cell culture, they observed that, when antibodies enter muscle cells, the effects observed were similar to those seen in patients, confirming that antibodies can directly cause dysfunction.
“These results suggest that future treatments could focus on preventing antibodies from entering the cells or neutralizing them once inside. This could open the door to new, more effective and personalized therapies for people with IIM”, explains José C. Milisenda.
Study reference:
Pinal-Fernandez I, Muñoz-Braceras S, Casal-Dominguez M, Pak K, Torres-Ruiz J, Musai J, Dell'Orso S, Naz F, Islam S, Gutierrez-Cruz G, Cano MD, Matas-Garcia A, Padrosa J, Tobias-Baraja E, Garrabou G, Aldecoa I, Espinosa G, Simeon-Aznar CP, Guillen-Del-Castillo A, Gil-Vila A, Trallero-Araguás E, Christopher-Stine L, Lloyd TE, Liewluck T, Naddaf E, Stenzel W, Greenberg SA, Grau JM, Selva-O'Callaghan A, Milisenda JC, Mammen AL. Pathological autoantibody internalisation in myositis. Ann Rheum Dis. 2024 Jun 20:ard-2024-225773. doi: 10.1136/ard-2024-225773. Epub ahead of print. PMID: 38902010.
