Etiological analysis of graft dysfunction following living kidney transplantation: a report of 366 biopsies

Evolution of human kidney allograft pathology diagnostics through 30 years of the Banff classification process

The second half of the previous century witnessed a tremendous rise in the number of clinical kidney transplants worldwide. This activity was, however, accompanied by many issues and challenges. An accurate diagnosis and appropriate management of causes of graft dysfunction were and still are, a big challenge. Kidney allograft biopsy played a vital role in addressing the above challenge. However, its interpretation was not standardized for many years until, in 1991, the Banff process was started to fill this void. Thereafter, regular Banff meetings took place every 2 years for the past 30 years. Marked changes have taken place in the interpretation of kidney allograft biopsies, diagnosis, and classification of rejection and other non-rejection pathologies from the original Banff 93 classification. This review attempts to summarize those changes for increasing the awareness and understanding of kidney allograft pathology through the eyes of the Banff process. It will interest the transplant surgeons, physicians, pathologists, and allied professionals associated with the care of kidney transplant patients.

Clinical outcomes for kidney transplantation in 81 adults with IgA nephropathy

OBJECTIVES

Immunoglobulin A nephropathy (IgAN) is one of the most common types of kidney disease, and kidney transplantation is the most effective treatment for end-stage renal disease. This study aims to analyze the clinical curative effect of renal transplantation for adults with IgAN and to discuss the efficacy and safety of kidney transplantation for IgAN at the perioperative period and medium- and long-term follow-up.

METHODS

This retrospective study included the clinical and follow-up data of 81 adult patients with IgAN who underwent kidney transplantation at the Second Xiangya Hospital, Central South University from January 2018 to January 2022. Of the 81 patients whose age at (34.1±9.9) years old, 47 (58.0%) were male. The body mass index was (20.8±3.2) kg/m2, and the human leukocyte antigen (HLA) mismatch number was 3.5±1.2. The estimated glomerular filtration rate (eGFR) and daily 24-hour urine output for the recipients on the 1st, 5th, and 7th day after kidney transplantation and when they were discharged were analyzed. The recovery of the transplanted kidney and occurrence of complications were comprehensively evaluated. The eGFR, urinary protein, and occult blood were evaluated at the 6th, 12th, 24th, 36th, and 48th month and at the last follow-up.

RESULTS

The follow-up time was (25.7±15.8) months. No primary non-function occurred in any patient during the perioperative period time. Fifty-one (63.0%) patients had immediate graft function recovery, and 16 (19.8%) patients had slow graft function recovery. Delayed recovery of graft function was observed in 14 (17.3%) patients. A total of 19 perioperative complications occurred, including 9 patients with acute rejection, 5 patients with urinary fistula, 1 thrombosis in both lower limbs, and 4 lymphatic fistula. The eGFR at 6th, 12th, 24th, 36th, and 48th month of follow-up were (65.3±22.9), (67.6±23.0), (64.3±21.8), (65.9±24.7), and (68.7±31.2) mL/(min·1.73 m2), respectively. The eGFR remained high during the medium- and long-term follow-ups. At the longest follow-up of 56 months, eGFR fluctuation was still mild, and the positive rate of urine protein and occult blood was low. IgAN recurred in 4 transplanted kidneys, accounting for 4.94% of the total patients, without severe renal insufficiency. Three patients had kidney dysfunction due to severe pneumonia, rejection, and stone in the transplanted kidney. The overall survival rate of the transplanted kidney was higher than 95%, and the survival rate of all patients was 100% till Januray 2022.

CONCLUSIONS

Renal transplantation for adults with IgAN had a remarkable short-term effect. The recipients can be beneficial significantly to favorable midium- and long-term outcomes. IgAN recurrence is infrequent and rarely causes severe renal function damage.

Color Doppler Ultrasound and Hemodynamics for Evaluating Graft Dysfunction in Recurrent Immunoglobulin A Nephropathy

BACKGROUND The aim of this study was to investigate the diagnostic and prognostic utility of color Doppler ultrasound for graft dysfunction in recurrent immunoglobulin A nephropathy (IgAN). MATERIAL AND METHODS We selected a series of 78 biopsies diagnostic of recurrent IgAN following living-donor transplantation from July 2004 to January 2019. Based on Lee's classification, Doppler parameters in different degrees of histopathological injury were retrospectively analyzed. RESULTS The 4-year cumulative graft survival rate after biopsy was 66.3%, and the difference among the Kaplan-Meier curves of Lee's classification (P<0.01) was significant. Doppler parameters showed that echo enhancement, decreasing blood flow distribution, decreasing end-diastolic velocity (EDV) of the main renal artery (MRA), segmental renal atery (SRA) and interlobar renal artery (IRA), and an elevated resistance index (RI) of the arcuate renal artery (ARA) were significantly different among grades I-V of Lee's classification (P<0.05). Logistic multivariate analysis indicated that echo enhancement (HR 13.6, 95% CI 2.7-68.4) and decreasing EDV of the SRA (HR 1.1 for a 1-cm/s, 95% CI 1.0-1.2) were independent predictors of severe injury (IV-V). The ROC curve fitted by echo enhancement and decreasing EDV of the SRA had an area under the curve of 0.87. The cutoff was 17.5 cm/s (decreasing EDV of the SRA) without echo enhancement. The sensitivity and specificity were 72.2% and 91.7%, respectively. CONCLUSIONS Color Doppler ultrasound successfully evaluated the graft dysfunction in recurrent IgAN; a decreasing EDV of the SRA indicated severe histopathological injury and poor prognosis.

Graft failure of IgA nephropathy in renal allografts following living donor transplantation: predictive factor analysis of 102 biopsies

Background

To investigate predictive factors related to graft failure of IgA nephropathy(IgAN) in renal allografts following living donor transplantation.

Methods

We identified a series of 102 biopsies diagnosed as IgAN in renal allografts following living donor transplantation from July 2004 to January 2017 at our center, and assess the predict value of the Lee’s classification and the 2009 Oxford classification in IgAN in renal allografts, clinical, ultrasonic and pathological characteristics at biopsy and the outcomes were retrospectively analyzed.

Results

The 5-year graft cumulative survival rate after transplantation was 91.4%. The 4-year graft cumulative survival rate after biopsy diagnosis of IgAN in renal allografts was 59.6%. The mean time ± SD to disease was 4.7 ± 3.5 years. The color doppler ultrasound and blood flow imagine showed the echo enhancement, the reduced blood flow distribution, the reduced peak systolic velocity of main renal artery, and the increased resistance index of arcuate renal artery were valuable in evaluating the graft dysfunction. The Cox multivariate analysis revealed that the 24-h urinary protein level (HR 1.6 for 1-g increase, 95%CI 1.2–2.0), estimated glomerular filtration rate (eGFR) (HR 1.0 for 1-mL/min/1.73 m^2 decline, 95%CI 1.0–1.1), and mesangial C1q deposition (HR 3.0, 95%CI 1.2–7.4) at biopsy were independent predictive factors of graft failure of IgAN in renal allografts.

Conclusions

IgAN in renal allografts occurred frequently within 5 years after transplantation. The risk of graft failure should be taken seriously in patients who exhibit heavy proteinuria and/or a declined eGFR as the initial symptoms; a high lesion grade (grade IV-V of Lee’s classification) and/or mesangial C1q deposition may also indicated a poor outcome.

Long-term Trends in the Clinicopathologic Features of Kidney Transplant Recipients With Graft Dysfunction

BACKGROUND

Graft biopsy is the gold standard for the differential diagnosis of graft dysfunction. The time interval between transplant surgery and biopsy often provides clinicians with diagnostic clues. However, the clinicopathologic features of late graft biopsy, especially those obtained at more than 5 years after kidney transplant, are not well understood.

MATERIALS AND METHODS

We retrospectively collected graft biopsy tissues obtained from kidney transplant recipients who underwent indication biopsy between February 2012 and March 2017. Patients were divided according to their post-transplant period, and their clinical characteristics, pathologic diagnosis, and Banff scores were compared across groups.

RESULTS

A total of 410 indication biopsy specimens obtained from 321 kidney transplant recipients were analyzed in this study. Overall, the incidence of T cell-mediated rejection, borderline rejection, and BK virus-associated nephropathy decreased while that of antibody-mediated rejection, nonspecific interstitial fibrosis and tubular atrophy, and glomerulonephritis increased over time. Most samples obtained over 5 years after kidney transplant exhibited chronic glomerular and tubulointerstitial injuries irrespective of their pathologic diagnosis. In patients whose post-transplant period was less than 5 years, urine protein-to-creatinine ratio was significantly elevated in the glomerulonephritis and chronic active antibody-mediated rejection groups only. In contrast, patients who underwent graft biopsy more than 5 years after kidney transplant showed significantly high levels of proteinuria irrespective of the pathologic diagnosis, and there was no statistical difference between groups.

CONCLUSION

We demonstrated that the etiology of graft dysfunction is largely influenced by the biopsy time point.