| Abstrakt: |
Objective: The detection of C4d along peritubular capillaries in dysfunctioning kidney grafts with histological signs of acute rejection typically indicates a humoral mediated rejection episode. In these grafts, C4d has been established as a significant independent predictor of poor graft survival. However, only very little is known about the clinical significance of C4d deposits in grafts with normal histology. Aim: To evaluate one year graft function and survival of C4d positive kidney transplants lacking histological signs of cellular or humoral rejection. Methods: Retrospective analysis of all renal allograft biopsies performed at the University Hospital in Basel from 1993 to 2003. Inclusion criteria (index biopsy): Focal or diffuse positivity for C4d along peritubular capillaries in the absence of any morphological signs of acute cellular or humoral rejection including Banff 'borderline' changes. Two patient groups were defined and compared: (1) Patients who were treated with anti-rejection therapy or an increase in maintenance immunosuppression subsequent to the index biopsy (intervention group; IG). (2) Patients with no therapeutic intervention (standard group; SG) subsequent to the index biopsy. Results: 22 biopsies/patients, 17 in the SG and 5 in the IG met the inclusion criteria. Both groups were similar with regard of demographic and pretransplant data. 21/22 grafts showed focal, 1/22 diffuse C4d positivity. Time from transplantation to index biopsy (days): SG 1,645 ± 1,606, IG 718 ± 1,558; p = NS. Serum creatinine at index biopsy (µmol/l): SG 226 ± 69, IG 216 ± 100; p = NS. Serum creatinine after one year (µmol/l): SG 204 ± 75, IG 143 ± 28; p = NS. Delta creatinine between index biopsy and one year afterwards (µmol/l): SG - 10 ± 64, IG - 96 ± 114; p = NS. One year patient survival: SG 100%, IG 80%; p = NS. One year graft survival: SG 82.5%, IG 80%; p = NS. None of the grafts were lost due to acute rejection. Conclusions: (1) C4d accumulation along peritubular capillaries in grafts lacking any histological signs of cellular or humoral rejection is not associated with rapid deterioration of graft function or graft loss. (2) Patients treated with increased immunosuppression showed a trend towards improved longterm graft function. These pilot data indicate that C4d deposits in grafts with normal histology may also detrimentally impact graft function longterm, although less dramatic than in grafts with histological signs of acute rejection. Larger prospective studies with patient follow-up for several years are required to further elucidate the role of C4d deposits in grafts with normal histology. [ABSTRACT FROM AUTHOR] |
