[Immunohistologic analysis of chronic obstructive sialadenitis. I. Changes in the expression of antigens of the major...

In the course of electrolyte sialadenitis progressing towards obstructive sialadenitis, changes in the epithelial expression of antigens of the major histocompatibility complex (MHC) occur even before morphological alterations and inflammatory cells can be detected. Class I antigens are enhanced and induced, and Class II antigens are induced. These changes begin focally. Only the expression of HLA-A,B,C and -DR in acinar epithelium is linked to the close vicinity of lymphohistiocytic infiltrates. In later stages of the disease the foci tend to fuse and antigenic changes are pronounced in areas of fibrosclerosis and parenchymal atrophy. The altered MHC antigen expression induced by chronical saliva congestion probably represents an important part of the postulated "immunoreaction in the duct epithelium" supposedly giving rise to this type of immunosialadenitis.