Immunohistochemical analysis of the retrobulbar tissues in Graves' ophthalmopathy.

TLDR

The study used antibody staining of paraffin‑embedded extraocular muscle tissue from three Graves' disease patients to characterize mononuclear cell infiltrates. The analysis revealed that Graves' ophthalmopathy is characterized by a predominance of CD3⁺/UCHL1⁺ T cells (with few SN130⁺ cells), occasional B‑cell aggregates, and Ia‑positive interstitial and endothelial cells, indicating a T‑cell–driven, with some B‑cell involvement, immune response targeting retrobulbar tissues and possibly fibroblasts.

Abstract

We have characterized the mononuclear cell infiltrate in the extraocular muscle of three patients with Graves' disease, using antibodies which permit staining of paraffin-embedded tissue. The majority of lymphocytes, occurring in foci or interstitially, were T cells, most of which stain for CD3 or with UCHL1. T cells few, if any, stained with SN130, directed against the CD45R determinant. This suggests that these lymphocytes comprise a recently activated population within which memory cells may reside. B cells were also found but were predominantly confined to focal aggregates, and in one patient lymphoid follicles were seen. The orbital fat and connective tissue from a further two patients contained very few infiltrating cells which were mainly UCHL1-positive. Eye muscle cells did not express Ia antigens but the interstitial cells between them were Ia-positive and the vascular endothelium in four of the five specimens also stained with Ia. These results indicate that Graves' ophthalmopathy is associated with T cell, and to a lesser extent B cell, responses against the retrobulbar tissues; the extraocular muscle interstitial cells, probably including fibroblasts, may be targets of activation resulting from this infiltration.