IgG4 Immunostaining and Its Implications in Orbital Inflammatory Disease

Abstract

ObjectiveIgG4-related disease is an emerging clinical entity which frequently involves tissue within the orbit. In order to appreciate the implications of IgG4 immunostaining, we analyzed gene expression and the prevalence of IgG4- immunostaining among subjects with orbital inflammatory diseases.MethodsWe organized an international consortium to collect orbital biopsies from 108 subjects including 22 with no known orbital disease, 42 with nonspecific orbital inflammatory disease (NSOI), 26 with thyroid eye disease (TED), 12 with sarcoidosis, and 6 with granulomatosis with polyangiitis (GPA). Lacrimal gland and orbital adipose tissue biopsies were immunostained for IgG4 or IgG secreting plasma cells. RNA transcripts were quantified by Affymetrix arrays.ResultsNone of the healthy controls or subjects with TED had substantial IgG4 staining. Among the 63 others, the prevalence of significant IgG4-immunostaining ranged from 11 to 39% depending on the definition for significant. IgG4 staining was detectable in the majority of tissues from subjects with GPA and less commonly in tissue from subjects with sarcoidosis or NSOI. The detection of IgG4+ cells correlated with inflammation in the lacrimal gland based on histology. IgG4 staining tissue expressed an increase in transcripts associated with inflammation, especially B cell-related genes. Functional annotation analysis confirmed this.ConclusionIgG4+ plasma cells are common in orbital tissue from patients with sarcoidosis, GPA, or NSOI. Even using the low threshold of 10 IgG4+ cells/high powered field, IgG4 staining correlates with increased inflammation in the lacrimal gland based on histology and gene expression.

Molecular diagnosis: Implications for ophthalmology

“…We found that none of our healthy controls and none of our samples from subjects with TED stained for a substantial amount of IgG4. However, IgG4 staining was prominent, i.e., at least 10 IgG4 positive cells per high power field, in 5 of 6 samples from subjects with GPA and in 42% and 38% respectively of subjects with either sarcoidosis or NSOI (Wong et al, 2014). We then analyzed gene expression as it correlated with IgG4 expression and found an increase in inflammation related transcripts in tissue from subjects with increased IgG4 expression.…”

“…In addition to classifying orbital tissue on the basis of a histological diagnosis, we have also scored the biopsies on the basis of IgG4 expression (Wong et al, 2014) and fibrosis (Rosenbaum et al, 2015a) and then determined how gene expression correlates with these parameters. IgG4 is the least common of all four isoforms of IgG.…”

“…Although guidelines for the diagnosis of IgG4-mediated disease have been proposed, there remains a lack of consensus about what constitutes a sufficient infiltration of IgG4 positive plasma cells to establish a diagnosis. We stained more than 100 orbital biopsies and quantified the expression of IgG4 (Wong et al, 2014). We did not include any tissue from a patient diagnosed with IgG4 disease, meaning that none of our samples came from a subject with a multisystem disease in which IgG4 was increased in serum and was deposited in multiple organs.…”

IgG4-related disease: a primer on diagnosis and management

“…Although many of these are secondary to malignant lymphomas and other forms of orbital inflammations, they can be present in IgG4-RD. 46 These tumors can affect adjacent structures such as nerves, extraocular muscles (restricting eye movement), periorbital membrane, lacrimal sac, and might rarely bone destruction. Visual disturbances might be present if the optic nerve is involved.…”

Gene Expression Profiling and Heterogeneity of Nonspecific Orbital Inflammation Affecting the Lacrimal Gland

“…Although the pathology of sarcoidosis includes granuloma, which are readily appreciated by histology, a sampling error might exclude granulomas from the tissue which is microscopically examined. The presence of IgG4 positive plasma cells is emerging as an important factor in lacrimal inflammation 4 , but the specificity of these cells has been questioned 6 . Clearly there is opportunity to improve the diagnostic yield from lacrimal gland biopsy.…”