Immunostaining of Immunoglobulin G4 in the Lacrimal Sac.

Purpose: To immunohistochemically examine the lacrimal sac walls harvested during dacryocystorhinostomy using an immunostain for immunoglobulin G4 (IgG4). Methods: Forty-four lacrimal sac walls were evaluated. We determined "intensively positive," "sparsely positive," or "negative" staining when the specimens showed IgG4-positive lymphoplasmacytic staining with or without > 50 IgG4-positive cells/high-power field, or the absence of stained IgG4-positive cells. Results: Intensively positive, sparsely positive, or negative staining was observed in 8 (18.2%), 14 (31.8%), and 22 specimens (50.0%), respectively. Stained cells infiltrated the subepithelial layer in all specimens with positive staining. Four of the 8 specimens demonstrated partial epithelial denudation with loss of goblet cells. Conclusions: IgG4-positive lymphoplasmacytic infiltration was observed in the subepithelial layer in specimens with intensively positive staining, of which some showed a partially denuded epithelium with loss of goblet cells. These may lead to narrowing of the lacrimal sac lumen and adhesions of the sac walls.