Eosinophilia-associated muscle disorders: an immunohistological study with tissue localisation of major basic protein in distinct clinicopathological forms

Abstract

MBP immunohistology on skeletal muscle, previously performed only for acute eosinophilic polymyositis, suggests that eosinophil-mediated injury of muscle cells may occur in a wider spectrum of less aggressive eosinophilia-associated myopathies than previously thought. As conventional histology is likely to underestimate this leucocyte subset, MBP staining may be a useful tool in the analysis of tissue infiltration of eosinophils as a possible treatment target.

Eosinophilic Polymyositis: A Rare Cause of Atraumatic Compartment Syndrome of the Forearm

“…7 As eosinophils degranulate, histologic examination of a patient with possible eosinophilic polymyositis should ideally include immunostaining for extracellular eosinophil major basic protein, whose diffusion is considered a hallmark for eosinophilic cytotoxicity. 8 Eosinophilic infiltration of muscle and supporting connective tissue structures can resemble autoimmune or immunologically mediated disease. Activation of eosinophils is followed by the release of cytotoxic major basic protein, which can, in turn, further exacerbate local muscle injury.…”

Eosinophilia in Rheumatologic/Vascular Disorders

“…It is generally thought that eosinophils and cytotoxic proteins released by eosinophils as well as cytotoxic T cells Tamaki et al elicit muscular injury. 125 Muscle biopsy specimens from 3 patients with EP revealed elevated IL-5 messenger RNA levels, suggesting that local expression of IL-5 led to an accumulation of eosinophils in the muscle. 126 …”

“…These criteria are based on the main clinical, laboratory, and histologic features that have been described in these diseases. [121][122][123][124][125][126][127][128][129] Box 5 Proposed diagnostic criteria for focal eosinophilic myositis, eosinophilic polymyositis, and eosinophilic perimyositis Proposed diagnostic criteria for focal eosinophilic myositis Deep vein thrombosis, cellulitis, and parasitic infections must be excluded to apply these criteria.…”

Management of Hypereosinophilic Syndromes

“…Positive immunohistologic staining for eosinophil cationic protein (ECP), major basic protein (MBP), 8,9 or eosinophil protein X (EPX), 10 conducted by expert hands and interpreted carefully, may be sufficient to conclude that a patient has HES. However, to date it remains unknown as to how long these products remain detectable or whether their presence can be held responsible for ongoing damage, namely in a treated patient with normal blood eosinophil counts.…”