Clinical pathology and prognosis of allograft IgA nephropathy / 中华肾脏病杂志

ABSTRACT

Objective:To investigate the cause of the allograft IgA nephropathy (IgAN) recurrence or de novo, and the risk factors for the graft-survival in allograft IgAN. Methods:Patients from the First Affiliated Hospital of Zhejiang University Medical College who were diagnosed as a transplanted kidney IgAN by allo-renal biopsy during November 2012 to December 2018 were selected. According to the increased levels of serum creatinine and the descent rate of estimated glomerular filtration rate (eGFR) on the last follow up, the patients were divided into the graft-function stable group (increased Scr<20 μmol/L, eGFR descent rate<10%), the graft-function inadequacy progressive group (Scr increased but less than doubling increase, 30%<eGFR descent rate<60%) and the graft-function lost group [double increase in serum creatinine and eGFR down to<15 ml·min -1· (1.73 m 2) -1 to chronic kidney disease stage V]. The clinical data and pathological characteristics were retrospectively analyzed and compared in the three groups. Taking the eGFR drop to<15 ml·min -1·(1.73 m 2) -1 to chronic kidney disease stage V as the end point event of follow-up, the effects of tacrolimus (FK506) concentration, the quantity of proteinuria and pathological changes of graft-renal on the survival rate of graft-renal were analyzed by Kaplan-Meier survival curve. Results:At the time of allograft biopsy, the urine protein/creatinine ratio (UP/Cr) was (2.00±2.38) g/g in the 38 cases, and the serum creatine increased in 17 cases (44.7%). Meanwhile, the blood concentration of FK506 was< 4 μg/L in 16 of 29 (55.2%) cases who taken FK506. With (23.2±22.2) months follow-up after renal biopsy, 11 cases (28.9%) progressed in renal insufficiency (graft-function inadequacy progressive group), and 7 cases (18.4%) lost their graft-function (graft-function lost group). The UP/Cr on the biopsy was significantly higher in graft-function lost group than that in graft-function stable group ( P=0.001), and the blood concentration of tacrolimus before biopsy was significantly lower in graft-function lost group than that in graft-function stable group [(3.05±0.71) μg/L vs (5.03±1.62) μg/L, P<0.010]. Kaplan-Meier survival analysis showed the kidney graft survival rate was significantly lower in the groups with a lower concentration of tacrolimus before the biopsy, with a large amount of proteinuria at the time of biopsy than that in the concentration of tacrolimus≥4.0 μg/L, and UP/Cr<2.3 g/g groups ( P=0.020, P=0.001, respectively), and with a infiltrated inflammatory cells in renal glomerular capillary loops and a co-deposition of C1q in mesangial region groups than that no infiltrated inflammatory cells in renal glomerular capillary loops and no co-deposition of C1q in mesangial region groups ( P=0.042, P=0.015, respectively). Conclusions:The low concentration of tacrolimus is the cause of the recurrence or de novo of allograft IgAN. A large amount of proteinuria, the inflammatory cells infiltration in glomerular capillary, the C1q deposition in mesangial region and the low concentration of tacrolimus are the factors that affect the survival rate of graft-renal IgAN.