This will be Giovanis best legacy. Figures and tables. the cause of hyperCKemia and potentially NAM is addressed and practical guidelines on the best therapeutic approaches and concerns regarding immunotherapies during COVID-19 pandemic are summarized. and their myopathy continues to worsen even after statin withdrawal 1,11,12. Most NAM patients have antibodies against signal recognition particle (SRP) or 3hydroxy3-methylglutaryl-coenzyme A reductase (HMGCR) 1,11,14 as discussed later. Anti-synthetase syndrome-Overlap Myositis (Anti-SS-OM) Anti-SS-OM, often presents with systemic sclerosis-like lesions, mild-to-moderate proximal muscle weakness, arthritis in the form of subluxation of the interphalangeal joints, mechanics hands, Raynaud phenomenon, and interstitial lung disease 1. The syndrome is highlighted by the presence of anti-synthetase antibodies, primarily anti-Jo-1, hence the naming of diagnosed on Embramine clinicopathologic correlations 1,17,27; in there are abundant necrotic fibers invaded or surrounded by macrophages. Lymphocytic infiltrates are sparse and MHC-I upregulation mostly in the necrotic fibers1-5,17,25. In a number of patients, the muscle biopsies show deposition of complement on blood vessels and, as expected, on necrotic fibers. Up to 65% of the patients have specific, albeit non-pathogenic, antibodies1,12-14,17. Autoantibodies Directed against nuclear RNAs or cytoplasmic antigens, autoantibodies are Embramine detected in up to 75% of all IM patients depending on methodology 1. Although their pathogenic role is unclear, some antibodies appear specific for distinct clinical phenotypes. They include: anti-that include: i) Mi-2, highlighting the typical skin lesions; ii) melanoma differentiationCassociated protein-5 (MDA-5) mostly connected with amyopathic dermatomyositis or interstitial lung disease 1,30; and iii) transcriptional intermediary factor-1 (TIF-1) and nuclear matrix protein NXP-2, highly connected with cancer-associated adult DM 30; and PD-L1: The process by which ICPIs trigger autoimmunity has been discussed elsewhere 32. Briefly, tumors, like other antigen presenting cells, express on their cell surface the inhibitory ligands PD-L1/PDL-2 and B7-1/B7-2 which are respectively engaged with PD-1 and CTLA-4 on T cells, downregulating T cell responses. These receptor/ligand interactions essentially act as an resulting in positive costimulation and strong cell activation, like taking the the immune system 32. This blockade allows the T cells to kill tumor cells, but at the same time the resulting enhanced co-stimulation causes an uncontrolled T cell activation that disrupts immune tolerance resulting in immune-related events against muscle. Among all the inflammatory myopathy subtypes, the most frequent autoimmune myopathies triggered by pembrolizumab, ipilimumab and nivolumab are DM and especially NAM. In some patients, NAM may co-exist with myasthenia gravis presenting with head drop, proximal muscle weakness, myalgia, dyspnea, ophthalmoparesis or bulbar weakness. Among 654 patients receiving ICPIs (pembrolizumab: 389; nivolumab: 264; both: 1), 5 on pembrolizumab had biopsy proven myopathies (2 NAM, 1 dermatomyositis, and 2 nonspecific myopathy) 33. Patients respond Embramine to steroids and IVIg especially if treated promptly. Viruses, including SARS-CoV-2 Among potential triggers, except of the UVO Immune checkpoint inhibitors discussed above, viruses have clearly the potential to break tolerance and trigger an immune inflammatory myopathy. Although IM have been seen during or after a viral infection, attempts to amplify viruses from the muscles, including coxsackieviruses, influenza, paramyxoviruses, mumps, cytomegalovirus and Epstein-Barr virus, have failed 1-5. The best Embramine studied viral connection until now has been with retroviruses. Patients infected with HIV or human-T-cell-lymphotropic virus-I develop polymyositis or inclusion-body myositis 1-3, 34-35 with retroviral antigens detected not within the muscle parenchyma but within some endomysial macrophages (Trojan-horse mode). The autoinvasive T cells are however clonally driven and some are retroviral-specific 35. During the present COVID-19 pandemic, there is evidence that more.
