Inclusion-body myositis and primary Sjögren syndrome: mechanisms for shared etiologies.

Abstract

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.

• Authors: Vidya S Limaye, Kathy Cash, Caroline Smith, Barbara Koszyca, Sandy Patel, Steven A Greenberg, Pravin Hissaria
• Journal: Muscle & nerve (Muscle Nerve) Vol. 61 Issue 5 Pg. 570-574 (05 2020) ISSN: 1097-4598 [Electronic] United States
• PMID: 32035011 (Publication Type: Case Reports, Journal Article)
• Copyright: © 2020 Wiley Periodicals, Inc.

Chemical References

• Autoantibodies
• HLA Antigens
• Immunoglobulins, Intravenous
• Immunologic Factors
• Rituximab
• Hydroxychloroquine
• Prednisolone
• 5'-Nucleotidase
• NT5C1A protein, human
• Azathioprine
• Methotrexate

Topics

• 5'-Nucleotidase (immunology)
• Adult
• Autoantibodies (immunology)
• Azathioprine (therapeutic use)
• CD8-Positive T-Lymphocytes (pathology)
• Female
• HLA Antigens (genetics)
• Haplotypes
• Humans
• Hydroxychloroquine (therapeutic use)
• Immunoglobulins, Intravenous (therapeutic use)
• Immunologic Factors (therapeutic use)
• Leukemia, Large Granular Lymphocytic (complications, immunology)
• Magnetic Resonance Imaging
• Methotrexate (therapeutic use)
• Muscle, Skeletal (diagnostic imaging, pathology)
• Myositis, Inclusion Body (complications, immunology, pathology, therapy)
• Prednisolone (therapeutic use)
• Rituximab (therapeutic use)
• Sjogren's Syndrome (complications, immunology, therapy)