Antibody coating of urinary bacteria in transplanted patients

24 patients with renal transplants were studied beyond the immediate postoperative period (greater than 8 weeks p.o.) for a period of 6 months in three weekly intervals. Quantitative bacteriology (dip slide method) and immunofluorescence microscopy (antibody coating of urinary bacteria) of the urine were regularly performed. Urinary tract infection was found in 13 of 24 patients, being permanent in 9 and episodic in 4 of the patients. There was no correlation between presence of urinary tract infection and deterioration of renal function. Mixed infection was found in 7 of the 13 patients and monoinfection in the others. In 7 out of these 13 patients, antibody coating of urinary bacteria could be demonstrated by immunofluorescence microscopy. In 3 of the 7 cases with antibody coating, this was permanently positive, in the other 4 it was intermittently positive. In only 1 case could conversion to positive antibody coating be attributed to urological complications (pyelostomy). Both IGG and IGA were demonstrable in 6 of 7 cases with positive antibody coating and IGG exclusively was demonstrable in 1 more case. IGM was questionably positive in 1 case and complement (beta1C) could not be demonstrated in any of the patients. This investigation shows that despite immunosuppression patients with renal transplants are able to mount an immune response against urinary tract infections.