Antibody-mediated rejection with the presence of glomerular crescents in a pediatric kidney transplant recipient: A case report

Glomerular crescents in kidney transplantation are indicative of severe glomerular injury and constitute a hallmark of RPGN. Their concurrence with ABMR has been rarely described only in adult patients. We report a case of 10-year-old boy with compound heterozygous Fin-major Finnish-type congenital nephrotic syndrome, who had received a deceased-donor kidney transplant 5 years before onset of acute kidney injury and nephrotic range proteinuria without hematuria. Kidney allograft biopsy illustrated 6 glomeruli with global sclerosis and 6 with remarkable circumferential or segmental cellular crescents. Negative glomerular immunofluorescence for immune-complex deposits and the absence of serum ANCA eliminated the presence of immune-mediated and ANCA-positive pauci-immune crescentic glomerulonephritis. Diagnosis of ABMR was based on the high levels of HLA class II DSA and the histological evidence of glomerulitis, peritubular capillaritis, and acute tubular injury with positive linear peritubular capillary C4d staining. The patient despite plasmapheresis and enhanced immunosuppressive treatment progressed to end-stage renal disease. We conclude that glomerular crescents may represent a finding of AMBR and possibly a marker of poor allograft prognosis in pediatric patients.

Tacrolimus trough levels higher than 6 ng/mL might not be required after a year in stable kidney transplant recipients

Background

Little is known regarding optimal tacrolimus (TAC) trough levels after 1 year post-transplant in stable kidney transplant recipients (KTRs) who have not experienced renal or cardiovascular outcomes. This study aimed to investigate the effect of 1-year post-transplant TAC trough levels on long-term renal and cardiovascular outcomes and opportunistic infections in stable KTRs.

Methods

KTRs receiving TAC with mycophenolate-based immunosuppression who did not experience renal or cardiovascular outcomes within 1 year post-transplant were enrolled from a multicenter observational cohort study. Renal outcome was defined as a composite of biopsy-proven acute rejection, interstitial fibrosis and tubular atrophy, and death-censored graft loss. Cardiovascular outcome was defined as a composite of de novo cardiomegaly, left ventricular hypertrophy, and cardiovascular events. Opportunistic infections were defined as the occurrence of BK virus or cytomegalovirus infections.

Results

A total of 603 eligible KTRs were divided into the low-level TAC (LL-TAC) and high-level TAC (HL-TAC) groups based on a median TAC level of 5.9 ng/mL (range 1.3–14.3) at 1 year post-transplant. The HL-TAC group had significantly higher TAC trough levels at 2, 3, 4, and 5 years compared with the levels of the LL-TAC group. During the mean follow-up of 63.7 ± 13.0 months, there were 121 renal outcomes and 224 cardiovascular outcomes. In multivariate Cox regression analysis, LL-TAC and HL-TAC were not independent risk factors for renal and cardiovascular outcomes, respectively. No significant differences in the development of opportunistic infections and de novo donor-specific anti-human leukocyte antigen antibodies and renal allograft function were observed between the two groups.

Conclusions

TAC trough levels after 1 year post-transplant remained at a similar level until the fifth year after kidney transplantation and were not directly associated with long-term outcomes in stable Korean KTRs who did not experience renal or cardiovascular outcomes. Therefore, in Asian KTRs with a stable clinical course, TAC trough levels higher than approximately 6 ng/mL might not be required after a year of kidney transplantation.

Recurrence of primary glomerulonephritis: Review of the current evidence

In view of the availability of new immunosuppression strategies, the recurrence of allograft glomerulonephritis (GN) are reported to be increasing with time post transplantation. Recent advances in understanding the pathogenesis of the GN recurrent disease provided a better chance to develop new strategies to deal with the GN recurrence. Recurrent GN diseases manifest with a variable course, stubborn behavior, and poor response to therapy. Some types of GN lead to rapid decline of kidney function resulting in a frustrating return to maintenance dialysis. This subgroup of aggressive diseases actually requires intensive efforts to ascertain their pathogenesis so that strategy could be implemented for better allograft survival. Epidemiology of native glomerulonephritis as the cause of end-stage renal failure and subsequent recurrence of individual glomerulonephritis after renal transplantation was evaluated using data from various registries, and pathogenesis of individual glomerulonephritis is discussed. The following review is aimed to define current protocols of the recurrent primary glomerulonephritis therapy.

Selection of Patients for Initial Clinical Trials of Solid Organ Xenotransplantation

Several groups have reported extended survival of genetically engineered pig organs in nonhuman primates, varying from almost 10 months for life-supporting kidney grafts and more than 2 years for non-life-supporting heart grafts to less than 1 month for life-supporting liver and lung grafts. We have attempted to define groups of patients who may not have an option to wait for an allograft. These include kidney, heart, and lung candidates who are highly-allosensitized. In addition, some kidney candidates (who have previously lost at least 2 allografts from rapid recurrence of native kidney disease) have a high risk of further recurrence and will not be offered a repeat allotransplant. Patients with complex congenital heart disease, who may have undergone previous palliative surgical procedures, may be unsuitable for ventricular assist device implantation. Patients dying of fulminant hepatic failure, for whom no alternative therapy is available, may be candidates for a pig liver, even if only as a bridge until an allograft becomes available. When the results of pig organ xenotransplantation in nonhuman primates suggest a realistic potential for success of a pilot clinical trial, highly selected patients should be offered participation.

Immune-mediated nephropathies in kidney transplants: recurrent or de novo diseases

IMN contribute to ESRD in 13% children with renal transplant (txp). Recurrent or de novo IMN can cause graft dysfunction and/or failure, but the details regarding incidence, therapy, and outcome remain poorly understood. Retrospective single-center study of all pediatric kidney txp was carried out since 1998. Clinical presentation, pathology, therapy, and graft outcomes of children with recurrent or de novo IMN were reviewed. IMN was the primary etiology of ESRD in 28 of the 149 txp recipients. Eleven children had biopsy-proven post-txp IMN-six were recurrent and five had de novo. Presentation varied with changes in SCr and/or proteinuria. Initial therapy included higher doses of steroids, MMF, and tacrolimus. Outcome was excellent with only one late graft loss. Full remission was achieved in all other patients, but some had re-recurrence of the IMN. Median follow-up time was 11.8 years. IMN (recurrent or de novo) occurred in 7.4% (11 of 149) of all kidney txp performed at our center. IMN post-txp was often seen late post-txp, usually asymptomatic and noted to have relapsing pattern. Early diagnosis and prompt therapy resulted in excellent long-term outcome in children diagnosed with post-txp IMN.

Membranous Nephropathy: A Journey From Bench to Bedside

Lessons from an animal model that faithfully resembles human membranous nephropathy (MN) have informed our understanding of the pathogenesis of this organ-specific autoimmune disease and common cause of nephrotic syndrome. After it was established that the subepithelial immune deposits that characterize experimental MN form in situ when circulating antibodies bind to an intrinsic podocyte antigen, it was merely a matter of time before the human antigen was identified. The M-type phospholipase A2 receptor 1 (PLA2R) represents the major target antigen in primary MN, and thrombospondin type 1 domain-containing 7A (THSD7A) was more recently identified as a minor antigen. Serologic tests for anti-PLA2R and kidney biopsy specimen staining for PLA2R show >90% specificity and 70% to 80% sensitivity for the diagnosis of primary MN in most populations. The assays distinguish most cases of primary MN from MN associated with other systemic diseases, and sequential anti-PLA2R titers are useful to monitor treatment response. A positive pretransplantation test result for anti-PLA2R is also helpful for predicting the risk for posttransplantation recurrence. Identification of target epitopes within PLA2R and the genetic association of primary MN with class II major histocompatibility and PLA2R1 variants are 2 additional examples of our evolving understanding of this disease.

Acute and Chronic Allograft Dysfunction in Kidney Transplant Recipients

Allograft dysfunction after a kidney transplant is often clinically asymptomatic and is usually detected as an increase in serum creatinine level with corresponding decrease in glomerular filtration rate. The diagnostic evaluation may include blood tests, urinalysis, transplant ultrasonography, radionuclide imaging, and allograft biopsy. Whether it occurs early or later after transplant, allograft dysfunction requires prompt evaluation to determine its cause and subsequent management. Acute rejection, medication toxicity from calcineurin inhibitors, and BK virus nephropathy can occur early or later. Other later causes include transplant glomerulopathy, recurrent glomerulonephritis, and renal artery stenosis.

Conventional induction and maintenance treatment of Antineutrophil cytoplasmic antibodies-associated vasculitis - still of value for our patients?

INTRODUCTION

Antineutrophil cytoplasmic antibodies-associated vasculitis (AAV) is a group of autoimmune diseases characterized by the necrotizing inflammation of small vessels and associated with the antineutrophil cytoplasmic antibodies. Treatment of AAV can be divided into the induction phase aimed at achieving remission of the disease and the maintenance phase aimed at prevention of relapses. Long-term outcome of AAV dramatically improved with the introduction of cyclophosphamide. Recent clinical studies resulted in the reduction of the cumulative dose of cyclophosphamide and introduction of new treatment options, namely B-cell-depleting antibody rituximab, into both induction and maintenance treatment. This paper aims to evaluate the current role of the conventional induction and maintenance treatment in view of the gradually increasing use of rituximab.

AREAS COVERED

This paper provides an overview of the main clinical studies in induction and maintenance treatment of adult patients with AAV, treatment of relapses of AAV and shortly comments also on the treatment of refractory AAV, treatment of different subgroups of AAV (based on the age, renal function, clinical presentation and type of autoantibody), long-term outcome of patients with AAV, adverse events of treatment and treatment of end-stage renal disease in AAV.

EXPERT OPINION

Our analysis demonstrates that although the introduction of rituximab modified the approach to both the induction and maintenance treatment of AAV, more conventional induction and maintenance treatment with standard immunosuppressive drugs still retains its importance as we need more data on long-term efficacy and safety of biologic treatment, and also its cost-effectiveness still remains an open issue.