Ophthalmic immunoglobulin G4-related disease IgG4-RD Current concepts

IgG4-related disease (IgG4-RD) is a distinct entity that frequently occurs in an ophthalmic location. As such, IgG4-RD is not limited to the orbit but may also involve other anatomical structures in and around the eye. Hence, the term 'ophthalmic IgG4-RD' is preferred over 'orbital IgG4-RD.' A high level of suspicion for the diagnosis can be derived from careful clinicoradiologic examination; the use of immunohistochemical staining for IgG4 in the context of characteristic histopathologic features is needed to reach a correct diagnosis. Recently described diagnostic criteria for ophthalmic IgG4-RD address subtle, yet significant, differences from IgG4-RD as seen in other systemic sites. Serum IgG4 titers are neither sensitive nor specific for the diagnosis of IgG4-RD and should not relied upon solely. Although most cases respond well to therapy with glucocorticoids, refractoriness to treatment and relapses are common. They necessitate the use of additional immunotherapy in such patients.