Reader response: Immune myopathy with large histiocyte-related myofiber necrosis
KenichiroTaira, Neurologist, National Center Hospital, National Center of Neurology and Psychiatry
Submitted April 21, 2019
I read with special interest the Pestronk et al.1 article about large histiocytic cells or macrophages invading non-necrotic myofiber potentially caused by autoimmune disorders. As Pestronk et al. stated, patients with large-histiocyte-associated myopathy (LHIM) form "a pathologically distinctive pattern of large histiocyte-associated muscle fiber necrosis."1 Large histiocytic cells or macrophages may have a key role in the pathogenesis of inflammatory myopathies. Recently, the aberrant macrophages invasion—mainly CD11c+ M1 macrophage—were described in case series of immune checkpoint inhibitor-related myositis (irMyositis).2 The programmed cell death protein 1 (PD-1) and its ligand (PD-L1) inhibition as immune checkpoint inhibitors have direct effects on macrophages.3 In another article on myopathological findings of patients with irMyositis, an inflammatory cell collection consisting mainly of CD68+ cells (macrophages) expressing PD-L1 and CD8+ cells expressing PD-1 was shown.4 These reports can open new avenues for studying macrophage invasion in inflammatory myopathies.
Disclosure​
The author reports no relevant disclosures. Contact journal@neurology.org for full disclosures.
References
Pestronk A, Sinha N, Alhumayyd Z, Ly C, Schmidt R, Bucelli R. Immune myopathy with large histiocyte-related myofiber necrosis. Neurology 2019;92:e1763–e1772.
Uchio N, Taira K, Ikenaga C, et al. Granulomatous myositis induced by anti–PD-1 monoclonal antibodies. Neurol Neuroimmunol NeuroInflamm 2018;5:e464.
Gordon SR, Maute RL, Dulken BW, et al. PD-1 expression by tumour-associated macrophages inhibits phagocytosis and tumour immunity. Nature 2017;545:495–499.
Touat M, Maisonobe T, Knauss S, et al. Immune checkpoint inhibitor-related myositis and myocarditis in patients with cancer. Neurology 2018;91:e985–e994.
I read with special interest the Pestronk et al.1 article about large histiocytic cells or macrophages invading non-necrotic myofiber potentially caused by autoimmune disorders. As Pestronk et al. stated, patients with large-histiocyte-associated myopathy (LHIM) form "a pathologically distinctive pattern of large histiocyte-associated muscle fiber necrosis."1 Large histiocytic cells or macrophages may have a key role in the pathogenesis of inflammatory myopathies. Recently, the aberrant macrophages invasion—mainly CD11c+ M1 macrophage—were described in case series of immune checkpoint inhibitor-related myositis (irMyositis).2 The programmed cell death protein 1 (PD-1) and its ligand (PD-L1) inhibition as immune checkpoint inhibitors have direct effects on macrophages.3 In another article on myopathological findings of patients with irMyositis, an inflammatory cell collection consisting mainly of CD68+ cells (macrophages) expressing PD-L1 and CD8+ cells expressing PD-1 was shown.4 These reports can open new avenues for studying macrophage invasion in inflammatory myopathies.
Disclosure​
The author reports no relevant disclosures. Contact journal@neurology.org for full disclosures.
References