Secretory immune responses in XXXX kidneys.

@entity1 @entity8 @entity4295 @entity740 @entity1986
The secretory immune system has been well studied in the intestinal, bronchial, and biliary systems and breast. Tissue studies of secretory immunoglobulins in the kidney are scanty, mostly related to @entity8 with IgA. Renal tissues from 37 autopsies selected for any history of @entity8 were processed for immunohistologic studies on frozen sections with several antisera, including a purified rabbit anti-human secretory component (SC). By immunohistology, gel diffusion, and immunoblotting, the anti-SC antibody reacted appropriately with purified @entity1 SC, saliva, intestinal epithelium, and breast milk and did not cross-react with immunoglobulin heavy or light chains, lactoferrin, and other tissue proteins. IgA and SC were seen in tubular casts in 70% of @entity1 , whereas less impressive staining with IgM, IgG, and albumin was seen, respectively, in 24%, 13%, and 22% of the @entity1 . SC was present in the cytoplasm of distal tubule and Henle's loop cells in 78% of specimens. A control group of 10 healthy individuals who died suddenly showed minimal staining of casts and tubules in 2 specimens. Renal pathology in the group with IgA-SC+ casts included @entity4295 (54%), severe @entity740 (61%), and mild @entity8 (38%). The group with negative IgA-SC casts included @entity4295 (64%), infectious @entity1986 (36%), and negligible @entity8 (36%). This study suggests that discrete distal segments of the nephron may have the capability of secreting SC, which is probably coupled with serum-derived IgA and incorporated into luminal tubular secretions. The low level of immunosecretions in kidneys which are normal or minimally damaged suggests that this system may need to be turned on by unknown, probably pathogenic stimulating factors.
