Tissue Transglutaminase Appears in Monocytes and Macrophages but Not in Lymphocytes in White Matter Multiple Sclerosis Lesions

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Abstract

Leukocyte infiltration is an important pathological hallmark of multiple sclerosis (MS) and is therefore targeted by current MS therapies. The enzyme tissue transglutaminase (TG2) contributes to monocyte/macrophage migration and is present in MS lesions and could be a potential therapeutic target. We examined the cellular identity of TG2-expressing cells by immunohistochemistry in white matter lesions of 13 MS patients; 9 active and chronic active lesions from 4 patients were analyzed in detail. In these active MS lesions, TG2 is predominantly expressed in leukocytes (CD45 þ) but not in cells of the lymphocyte lineage, that is, T cells (CD3 þ) and B cells (CD20 þ). In general, cells of the monocyte/macrophage lineage (CD11b þor CD68 þ) are TG2 þbut no further distinction could be made regarding pro- or anti-inflammatory macrophage subtypes. In conclusion, TG2 is abundantly present in cells of the monocyte/macrophage lineage in active white matter MS lesions. We consider that TG2 can play a role in MS as it is associated with macrophage infiltration into the CNS. As such, TG2 potentially presents a novel target for therapeutic intervention that can support available MS therapies targeting lymphocyte infiltration.

Original languageEnglish
Pages (from-to)492-500
Number of pages9
JournalJournal of Neuropathology and Experimental Neurology
Volume78
Issue number6
DOIs
Publication statusPublished - 1 Jan 2019

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