Myxovirus resistance protein A (MxA) expression in myositides: Sarcoplasmic expression is common in both dermatomyositis and lupus myositis.
Muscle Nerve
; 69(5): 548-555, 2024 May.
Article
en En
| MEDLINE
| ID: mdl-38372203
ABSTRACT
INTRODUCTION/AIMS:
Myxovirus resistance protein A (MxA) is a type I interferon (IFN1) pathway activation marker and MxA sarcoplasmic expression is currently recognized as a highly specific marker for dermatomyositis (DM). However, we have frequently observed endothelial tubuloreticular inclusions (TRI), another surrogate IFN1 activation marker, in a variety of overlap myositides. The aim of this study was to examine MxA expression in those myositides.METHODS:
We retrospectively performed MxA immunostaining on a wide range of myositides.RESULTS:
MxA sarcoplasmic expression was present in DM (94.4%, 17/18), active lupus myositis (LM, 80%,16/20), inactive LM (36%, 4/11), antisynthetase syndrome (ASyS, 20%, 2/10), systemic sclerosis (13%, 2/15), Sjogren's syndrome (7.7%, 1/13), and human immunodeficiency virus (HIV) myositis (5.6%, 1/18) and was absent in immune-mediated necrotizing myopathy (IMNM, 0/16) and hydroxychloroquine myopathy (0/5). The sensitivity and specificity of MxA sarcoplasmic expression for LM and DM combined compared with all other myositides were 84.6% (95% CI 69.5-94.1) and 92.1 (95% CI 83.6-97.0), respectively, and superior to TRIs. MxA capillary expression was nonspecific. Histologically, 35% of LM cases demonstrated a unique panfascicular necrotizing myopathy pattern. The remainder of the LM cases had significant morphological overlap with DM/ASyS (20%), IMNM (20%), or polymyositis (15%).DISCUSSION:
MxA sarcoplasmic expression is highly prevalent in LM and DM and is a useful marker in differentiating DM and LM from other myositides. LM can manifest in various pathology patterns that need to be differentiated from DM, IMNM, ASyS, and polymyositis.Palabras clave
Texto completo:
1
Colección:
01-internacional
Asunto principal:
Orthomyxoviridae
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Polimiositis
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Dermatomiositis
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Enfermedades Musculares
/
Miositis
Límite:
Humans
Idioma:
En
Revista:
Muscle & nerve
/
Muscle Nerve
/
Muscle nerve
Año:
2024
Tipo del documento:
Article
País de afiliación:
Estados Unidos