Manifestations of renal allograft rejection in small children receiving adult kidneys

We were concerned that clinical manifestations of rejection (R) might be subtle in small children transplanted with adult kidneys. We retrospectively analyzed the first rejection episode (biopsy proven) in 22 children (R group) under age 4 years [mean age, 23.7±2.2 months (±SEM); mean weight, 9.4±0.4 kg] receiving an adult-related donor kidney. We matched these patients for age, date of transplant, donor source and immunosuppression with 36 children without R (control or C group). We compared both groups at similar intervals from transplantation, based on the time of R (5.38±1.2 months) in the R group and analyzed the immediate 8-week period prior to R and the corresponding interval in the C group. Hypertension occurred in 82% (18/22) of the R versus 8% (3/36) of the C group (P<0.01). Fever longer than 7 days occurred in 45% (10/22) of the R versus 0% (0/36) of the C group (P<0.01). Increased creatinine occurred in only 45% (10/22) of the R versus 3% (1/30) of the C group (P<0.01). Cyclosporine did not influence these manifestations of R. The clinical manifestations did not predict the R grades on biopsy, which were moderate to severe in 13 and mild in 9 of the R patients. Graft survival was higher at 3 years in the C (95%) than in the R patients (65%), (P<0.004). Thus, clinical manifestations of acute R can be subtle in small children with adult renal allografts. Renal biopsy should not be delayed until the creatinine is elevated in these patients.