Recurrent Glomerulonephritis in Renal Transplantation: Experience in Our Renal Transplantation Center

Incidence, Risk Factors, and Effect on Allograft Survival of Glomerulonephritis Post-transplantation in a United Kingdom Population: Cohort Study

Background

Post-transplant glomerulonephritis (PTGN) has been associated with inferior long-term allograft survival, and its incidence varies widely in the literature.

Methods

This is a cohort study of 7,623 patients transplanted between 2005 and 2016 at four major transplant UK centres. The diagnosis of glomerulonephritis (GN) in the allograft was extracted from histology reports aided by the use of text-mining software. The incidence of the four most common GN post-transplantation was calculated, and the risk factors for disease and allograft outcomes were analyzed.

Results

In total, 214 patients (2.8%) presented with PTGN. IgA nephropathy (IgAN), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), and membranoproliferative/mesangiocapillary GN (MPGN/MCGN) were the four most common forms of post-transplant GN. Living donation, HLA DR match, mixed race, and other ethnic minority groups were associated with an increased risk of developing a PTGN. Patients with PTGN showed a similar allograft survival to those without in the first 8 years of post-transplantation, but the results suggest that they do less well after that timepoint. IgAN was associated with the best allograft survival and FSGS with the worst allograft survival.

Conclusions

PTGN has an important impact on long-term allograft survival. Significant challenges can be encountered when attempting to analyze large-scale data involving unstructured or complex data points, and the use of computational analysis can assist.

Effect of Glomerulopathy Recurrence in the Outcome and Graft Survival of Kidney Transplanted Patients

BACKGROUND

Recurrent glomerulopathy (GP) after kidney transplantation is a complication of kidney transplantation that could negatively affect kidney function and graft survival. This study aimed to evaluate the outcome, graft survival, and GP recurrence and its predictive factors in kidney-transplanted patients.

METHODS

Patients were divided into 2 groups: G1 (with GP; n = 95) and G2 (with other causes of end-stage renal disease; n = 373). Graft survival analyses were performed using the Kaplan-Meier for living donor (LD) and deceased donor (DD). Cox proportional hazards regression were used to investigate the predictors for graft loss and for GP recurrence.

RESULTS

Disease recurrence was observed in 9 patients who received a kidney from an LD, of which 4 lost their grafts. In patients who received a kidney from a DD, recurrence was also observed in 9 patients, of which 3 lost their grafts. No statistically significant differences in graft survival between G1 and G2 in relation to LD and DD were noted (P = .299 and .434, respectively). However, differences in graft survival were found when GP subtypes and GP recurrence were analyzed. The predictors of graft loss were delayed graft function (hazard ratio [HR] = 2.226, P = .002), rejection episodes (HR = 1.904, P = .017), and recurrence or transplant GP (HR = 3.243, P = .006). The predictors of disease recurrence or transplant GP were age (HR = 0.945, P = .028) and cold ischemia time (HR = 1.117, P = .003).

CONCLUSION

Kidney transplantation could be a reasonable treatment for GP with end-stage renal disease. Despite the disease recurrence, which is a significant cause of graft loss in transplant recipients, graft survival remains satisfactory.

Membranous Nephropathy Posttransplantation: An Update of the Pathophysiology and Management

Membranous nephropathy (MN) is a common cause of nephrotic syndrome after transplantation and is associated with an increased risk of allograft loss. MN may occur either as a recurrent or as a de novo disease. As in native kidneys, the pathophysiology of the MN recurrence is in most cases associated with antiphospholipid A2 receptor antibodies. However, the posttransplant course has some distinct features when compared with primary MN, including a lower chance of spontaneous remission and a greater requirement for adjuvant immunosuppressive therapy to induce complete remission. Although the efficacy of rituximab in primary MN is now well established, no randomized studies have assessed its effectiveness in MN after transplant, and there are no specific recommendations for the management of these patients. This review aims to synthesize and update the pathophysiology of posttransplant MN, as well as to address unsolved issues specific to transplantation, including the prognostic value of antiphospholipid A2 receptor, the risk of living-related donation, the link between de novo MN and rejection, and different therapeutic strategies so far deployed in posttransplant MN. Lastly, we propose a management algorithm for patients with MN who are planning to receive a kidney transplant, including pretransplant considerations, posttransplant monitoring, and the clinical approach after the diagnosis of recurrence.

Genetics of Childhood Steroid Sensitive Nephrotic Syndrome: An Update

Advances in genome science in the last 20 years have led to the discovery of over 50 single gene causes and genetic risk loci for steroid resistant nephrotic syndrome (SRNS). Despite these advances, the genetic architecture of childhood steroid sensitive nephrotic syndrome (SSNS) remains poorly understood due in large part to the varying clinical course of SSNS over time. Recent exome and genome wide association studies from well-defined cohorts of children with SSNS identified variants in multiple MHC class II molecules such as HLA-DQA1 and HLA-DQB1 as risk factors for SSNS, thus stressing the central role of adaptive immunity in the pathogenesis of SSNS. However, evidence suggests that unknown second hit risk loci outside of the MHC locus and environmental factors also make significant contributions to disease. In this review, we examine what is currently known about the genetics of SSNS, the implications of recent findings on our understanding of pathogenesis of SSNS, and how we can utilize these results and findings from future studies to improve the management of children with nephrotic syndrome.

Utility of Oxford Classification in Post-Transplant Immunoglobulin A Nephropathy

BACKGROUND

With increasing graft survival, post-transplant immunoglobulin A nephropathy (IgAN) has emerged as an important cause of chronic graft dysfunction in renal allograft recipients. We studied the clinico-pathological features of post-transplant IgAN regardless of the primary disease. The aim was to study the usefulness of the Oxford classification in predicting survival.

METHODS

Indication graft biopsy specimens (n = 915) were received during a 10-year period; 27 biopsy specimens from 22 patients were diagnosed as IgAN.

RESULTS

Post-transplant IgAN was seen in 2.6% of biopsy specimens. Mean time to occurrence was 71.6 ± 47.6 months (range, 6.8 months to 16 years), occurring most commonly 4 to 8 years after transplant. Associated rejection was present in 4 biopsies; 72.7% (16/22), 91% (20/22), and 31.8% (7/22) presented with rise in serum creatinine, proteinuria, and hematuria, respectively. Four (21%) patients had nephrotic range proteinuria. Mesangial hypercelullarity (M1), endocapillary hypercelullarity (E1), segmental glomerulosclerosis (S1), and tubulo-interstitial fibrosis (T1-2) was present in 36.6%, 22.7%, 54.5%, and 31.8% biopsies, respectively. The most frequent Haas class was III (n = 7; 29.1%), followed by classes IV and I (n = 5; 20.8% each). The 2- and 5-year graft survival rates were 75% and 56%, respectively. High serum creatinine, low estimated glomerular filtration rate, E1 and T lesions, and degree of interstitial inflammation predicted graft survival. Interestingly, percentage (>25%) of segmentally sclerosed glomeruli and not S1 correlated with graft outcome.

CONCLUSIONS

The Oxford MEST scheme is useful in predicting graft survival in post-transplant IgAN. The degree of interstitial inflammation is also an important feature for determining graft outcomes in post-transplant IgAN.

IgA nephropathy: an update

PURPOSE OF REVIEW

To provide an update on recent developments since the publication of the Oxford Classification of IgA nephropathy and to consider lesions that were not included in the original classification.

RECENT FINDINGS

Over 20 validation studies of the Oxford Classification have been published. Tubular atrophy/interstitial fibrosis is consistently the strongest predictor of renal survival, whereas mesangial hypercellularity predicts rate of loss of renal function. Endocapillary hypercellularity and crescents are associated with lower renal survival and more rapid loss of renal function in patients not receiving immunosuppression, whereas crescents in at least 25% of glomeruli predict lower renal survival irrespective of treatment; a C score has been added to the MEST scores in the 2016 revision of the classification. Repeat biopsy studies have demonstrated response of endocapillary and extracapillary hypercellularity to immunosuppression. Podocytopathic changes in segmental sclerosis are associated with higher levels of proteinuria, renal function decline and worse renal survival. Combination of histological and clinical variables allow for earlier outcome prediction.

SUMMARY

Recent evidence supports the use of the Oxford Classification of IgA nephropathy in wider populations. Combination of histological, clinical and biomarker data promises more accurate prognostication and identification of patients who will benefit from immunosuppression.

Higher Incidence of Renal Allograft Glomerulonephritis in Living-Related Donor Kidney Transplantation

Glomerulonephritis recurrence has emerged as one of the leading causes of allograft loss. We aimed to investigate the effect of living-related and deceased donation on the incidence of renal allograft glomerulonephritis and its effect on renal allograft survival.

METHODS

Adult renal allograft recipients with primary glomerulonephritis were enrolled. Transplantation date was from Feb 2004 to Dec 2015. Exclusion criteria included combined organ transplantation, structural abnormality, diabetic nephropathy, hypertension nephropathy, obstructive nephropathy, and primary uric acid nephropathy. The incidence of biopsy-proven allograft glomerulonephritis was compared between the living-related donor group and the deceased donor group. Graft survival was assessed with Kaplan-Meier method, and Cox proportional hazard model was used to evaluate the effect of posttransplant glomerulonephritis on graft outcome.

RESULTS

There were 525 living-related donor kidney transplant recipients (LRKTx) and 456 deceased donor kidney transplant recipients (DDKTx) enrolled. The incidence of IgA nephropathy was 8.8% in the LRKTx group and 1.3% in the DDKTx group (P < .001); the incidence of focal segmental glomerulosclerosis (FSGS) was 3.8% in the LRKTx group and 1.5% in the DDKTx group (P = .03). FSGS increased the risk of graft failure compared with non-FSGS (hazard ratio [HR], 3.703 [1.459-9.397]; P = .006). IgA nephropathy increased the risk of graft failure by over 5 times 5 years after kidney transplantation compared with non-IgA nephropathy, but it did not affect early allograft survival (HR for ≥5 years, 6.139; 95% CI, 1.766-21.345; P = .004; HR for <5 years, 0.385 [0.053-2.814]; P = .35).

CONCLUSIONS

Higher incidence of IgA nephropathy and FSGS in renal allograft was observed in living-related donor kidney transplantation compared with deceased donor kidney transplantation. De novo or recurrent IgA nephropathy and FSGS impaired long-term renal allograft survival.