Immunofluorescent study of the endolymphatic sac in Menière's disease.

Immunofluorescent and light microscopic studies were performed on 21 small endolymphatic sac specimens biopsied during endolymphatic sac drainage surgery. The biopsies were taken from the extraosseous portions of the lateral side of the sac. Of the 21 specimens, only 5 displayed prominent histologic signs, including 1 with brown pigmentation and 4 with positive immunofluorescent reactions to either IgG, IgA, or IgM. No such histologic signs were seen in any of the other 16 specimens, although severe fibrous tissue change was found. One of the 4 specimens showing immunofluorescent reactions displayed a triple-layered ring structure in which the outer layer was IgM positive, the middle layer IgG positive, and the inner layer IgA positive (case 1). This ring-like structure, located in the fibrous tissue, appeared to be an occluded blood vessel. Another specimen showed positive reactions to IgG and IgA in a section which appeared to be part of the lumen, and which contained a macrophage-like cell and a lymphocyte. These results tend to support the idea that certain types of Meniere's disease are caused by immunologic injuries to the endolymphatic sac.