Rheumatology Department, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
Anatomical Pathology, SA Pathology, Adelaide, South Australia, Australia.
Muscle Nerve. 2020 May;61(5):570-574. doi: 10.1002/mus.26830. Epub 2020 Feb 15.
Herein we report a case of sporadic inclusion-body myositis (sIBM) occurring at an unusually young age in a patient with primary Sjögren syndrome, and use the case to explore possible shared mechanisms for disease susceptibility. Possible factors may include the association of both conditions with the 8.1 ancestral haplotype; the presence of anti-cN1A antibodies, which, although considered specific for sIBM, are also seen in pSS; and the shared association with T-cell large granular lymphocyte leukemia (T-LGLL). Further evaluation of this patient did in fact reveal underlying T-LGLL and mechanisms by which T cells in sIBM may escape immune regulation and contribute to disease phenotype are explored. Despite myofiber infiltration with CD8-positive T cells in sIBM, and, although sIBM is traditionally considered treatment-refractory, we report a significant response to the anti-CD20 monoclonal antibody, rituximab, and discuss possible mechanisms by which this response may be mediated.
在此，我们报告了一例散发性包涵体肌炎（sIBM）在原发性干燥综合征患者中发生的异常年轻病例，并通过该病例探讨了疾病易感性的可能共同机制。可能的因素包括这两种情况与 8.1 祖先单倍型的关联；存在抗 cN1A 抗体，尽管被认为是 sIBM 的特异性抗体，但也可见于 pSS；以及与 T 细胞大颗粒淋巴细胞白血病（T-LGLL）的共同关联。对该患者的进一步评估确实揭示了潜在的 T-LGLL，并且探讨了 sIBM 中的 T 细胞如何逃避免疫调节并导致疾病表型的机制。尽管 sIBM 中有 CD8 阳性 T 细胞浸润，并且尽管 sIBM 传统上被认为是难治性的，但我们报告了对抗 CD20 单克隆抗体利妥昔单抗的显著反应，并讨论了这种反应可能介导的可能机制。
