Urinary immunoglobulins in patients with continent urinary reservoirs and ileal conduits

Although bowel segments are commonly used for reconstructing the urinary tract, a high incidence of bacteriuria is observed in patients with urinary intestinal diversion. The normal gastrointestinal tract possesses a potent mucosal immune system characterized by secretory immunoglobulin A (sIgA) as the major humoral defense factor. However, the significance of urinary IgA secretion as the mucosal defense mechanism in patients with urinary intestinal diversion has remained obscure. In this study, urinary levels of sIgA as well as serum-type IgA were measured in patients with continent urinary reservoirs (Kock and Indiana pouches) and ileal conduits.

Twenty-four-hour urine samples were collected in a total of 80 patients with urinary intestinal diversion (22 Kock pouch patients, 21 Indiana pouch patients and 37 ileal conduit patients). The amount of sIgA and serum-type IgA were measured by enzyme-linked immunosorbent assay (ELISA).

Urinary IgA levels showed great inter- and intra patient variability in all three groups. Indiana reservoir urine contained significantly greater amounts of sIgA (mean 32.0 mg/24 hrs) than Kock reservoir urine (11.9 mg) and conduit urine (4.9 mg), whereas Kock reservoir urine contained significantly more sIgA than conduit urine. However, the corresponding difference was not observed in regard to serum-type IgA. In none of the three modes of urinary diversion did 24-hour sIgA excretion show any correlation with the length of time after surgery.

Since the amounts of sIgA in these patients were much greater than reported in urinary tract infection as well as in normal subjects, the major portion of urinary sIgA seemed to be secreted by the intestinal segments. Long-term sIgA secretion in urinary intestinal diversion, especially continent urinary reservoirs, may be an important host defense system.