Histiocytic Glomerulopathy With Noncrystalline Inclusion Associated With IgG-Kappa Plasma Cell Dyscrasia.

The kidney pathology of monoclonal gammopathy of renal significance varies greatly. In this report, we present a woman in her 20s with nephrotic syndrome and monoclonal immunoglobulin G kappa (serum and urine) without diabetes. She had a family history of nephrotic syndrome as well as hematologic and connective tissue disorders. A kidney biopsy showed nodular glomerulosclerosis, with the glomerular capillary full of histiocytes, which were strongly positive for kappa, not lambda. Immunoelectron microscopy revealed that histiocytes had infiltrated the glomerular subendothelial space, and enlarged lysosomes of histiocytes contained kappa light chains, without apparent crystalline formation. Bone marrow examination was negative for malignancy; thus, we diagnosed this case as histiocytic glomerulopathy with noncrystalline inclusion associated with immunoglobulin G-kappa plasma cell dyscrasia. Hematologic treatment with bortezomib and daratumumab decreased her level of serum kappa chain and proteinuria. Two years after diagnosis, her kidney function remained normal, urinary protein level decreased to 1 g/d, and free light-chain ratio decreased to 3.1.

Possible Use of Non-purine Selective Xanthine Oxidoreductase Inhibitors for Prevention of Exercise-induced Acute Kidney Injury Associated with Renal Hypouricemia.

Exercise-induced acute kidney injury (EIAKI) is frequently complicated with renal hypouricemia (RHUC). In patients with RHUC, limiting anaerobic exercise can prevent EIAKI. However, it is challenging to reduce exercise intensity in athletes. We herein report a 16-year-old Japanese football player with familial RHUC with compound heterozygous mutations in urate transporter 1 (URAT1) who presented with recurrent EIAKI. As prophylaxis (hydration during exercise) could not prevent EIAKI, febuxostat was initiated. EIAKI was not observed for 16 months despite exercising intensively. Hence, non-purine-selective xanthine oxidoreductase inhibitors may decrease the incidence of EIAKI in athletes with RHUC.

Different Clinical Courses of Nephronophthisis in Dizygotic Twins.

Siblings with nephronophthisis occasionally show different clinical courses; however, the reasons for this remain unclear. We herein report cases of nephronophthisis in a pair of dizygotic twins with different clinical courses. The brother developed end-stage kidney disease at 17 years old; however, his sister did not show kidney insufficiency. Kidney biopsies revealed severe tubulointerstitial damage at 14 and 22 years old in the brother and sister, respectively. Both had a homozygous NPHP1 deletion with different heterozygous mutations related to hereditary cystic kidney disease. Since the dizygotic twins were exposed to similar environmental factors, genetic factors may have influenced their clinical course more strongly than environmental factors.

Genetic Background and Clinicopathologic Features of Adult-onset Nephronophthisis.

INTRODUCTION: Recently, nephronophthisis (NPH) has been considered a monogenic cause of end-stage renal disease (ESRD) in adults. However, adult-onset NPH is difficult to accurately diagnose and has not been reported in a cohort study. In this study, we assessed the genetic background and clinicopathologic features of adult NPH. METHODS: We investigated 18 sporadic adult patients who were suspected as having NPH by renal biopsy. We analyzed 69 genes that cause hereditary cystic kidney disease and compared clinicopathologic findings between patients with and without pathogenic mutations in NPH-causing genes. RESULTS: Seven of 18 patients had pathogenic NPH-causing mutations in NPHP1, NPHP3, NPHP4, or CEP164. Compared with patients without pathogenic mutations, those with pathogenic mutations were significantly younger but did not significantly differ in the classic NPH pathologic findings, such as tubular cysts. On the other hand, the number of tubules with thick tubular basement membrane (TBM) duplication, which was defined as >10-µm thickness, was significantly higher in patients with genetically proven adult NPH than in those without pathogenic mutations. α-Smooth muscle actin (α-SMA)-positive myofibroblasts were detected inside thick TBM duplication. CONCLUSIONS: In adult patients with NPH, thick TBM duplication was the specific finding. Our analysis also suggested that older patients tended to have no pathogenic mutations, even when they were suspected to have NPH by renal biopsy. These findings could be the novel clinical clue for the diagnosis of NPH in adult patients.

Interstitial fibroblasts in donor kidneys predict late posttransplant anemia.

BACKGROUND: Posttransplant anemia (PTA) is associated with the progression of kidney disease and mortality in kidney transplant recipients. Although the main causes of PTA are recipient factors, donor factors have not been fully investigated. In this study we investigated the association of donor pathological findings with the incidence of PTA in kidney transplant recipients after 3 years of transplantation. METHODS: We conducted a retrospective cohort study at a single university hospital. A total of 50 consecutive adult recipients and donors were enrolled. To assess the structure of interstitial lesions, immunohistochemical staining of interstitial fibrosis and fibroblasts were assessed in 0-h biopsies for quantitative analysis. RESULTS: The incidence of PTA in this cohort was 30%. The mean hemoglobin (Hb) was 11.6 ± 0.8 g/dL in patients with PTA and 14.3 ± 1.5 g/dL in patients without PTA. An inverse association was observed in biopsies between interstitial fibrosis area and interstitial fibroblast area (P < 0.01) and each pathological finding was examined for its association with PTA incidence after multivariate adjustment. For the interstitial fibrosis area, the odds ratio (OR) was 1.94 [95% confidence interval (CI) 1.26-2.99; P < 0.01]. For the interstitial fibroblast area, the OR was 0.01 (95% CI 0.00-0.16; P < 0.01). Receiver operating characteristics curve analysis indicated that the interstitial fibroblast area had high predictive power for the incidence of PTA. CONCLUSIONS: The presence of interstitial fibroblasts in donor kidneys may play an important role in predicting the incidence of PTA.

A Case of Transplant Nephrectomy due to Chronic Graft Intolerance Syndrome.

We report a case of graft intolerance syndrome in which transplant nephrectomy was performed 11 years after kidney transplantation. A 46-year-old man was admitted to our hospital in February 2018 with a mild fever, left lower abdominal pain, and gross hematuria with enlargement of the transplanted kidney. Urinary tract infection was ruled out. Because the symptoms developed after the immunosuppressants had been stopped after kidney graft loss, graft intolerance syndrome was suspected. He had lost his graft in 2016 and had stopped all immunosuppressants since January of 2017. Immunosuppressive therapy was intensified, and steroid half-pulse therapy was added for 3 days. After the steroid pulse therapy, the C-reactive protein (CRP) decreased from 6.47 mg/dL to 0.76 mg/dL, but there was little improvement in the symptoms, and the CRP then increased to 4.44 mg/dL. Transplant nephrectomy was performed in March 2018. Postoperatively, the symptoms disappeared without the administration of immunosuppressants, and the CRP decreased. Pathologically, the resected kidney graft showed persistent active allograft rejection with severe endarteritis, transplant glomerulopathy, and diffuse interstitial fibrosis. Massive thrombi occluded the large arteries, and there was extensive hemorrhagic cortical necrosis. Transplant nephrectomy is uncommon in patients >6 months after transplantation. However, even if more time has passed since transplantation, as in this case, transplant nephrectomy may be a valid option in some cases of severe graft intolerance syndrome.

Association Between Galactose-Deficient IgA1 Derived From the Tonsils and Recurrence of IgA Nephropathy in Patients Who Underwent Kidney Transplantation.

Background: Recurrence of IgA nephropathy (IgAN) in the transplanted kidney is associated with graft survival, but no specific treatment is available. Tonsillectomy (TE) reportedly arrests the progression of IgAN in the native kidney. Thus, we conducted a single-center retrospective cohort study to evaluate the effect of TE prior to IgAN recurrence. Methods: Of the 36 patients with biopsy-proven IgAN who underwent kidney transplantation, 27 were included in this study. Nine patients underwent TE at 1 year after kidney transplantation (group 1), and the remaining 18 did not undergo TE (group 2). Results: The rate of histological IgAN recurrence was significantly lower in group 1 than in group 2 (11.1 vs. 55.6%, log-rank p = 0.046). In addition, half of the recurrent patients in group 2 exhibited active lesions, compared to none in group 1. Serum Gd-IgA1 levels decreased after TE in group 1, whereas they remained stable or increased slightly in group 2. In the recurrent cases, IgA and Gd-IgA1 were found in the germinal center in addition to the mantle zone of tonsils. Finally, mesangial IgA and Gd-IgA1 immunoreactivity was reduced after TE in some cases. Conclusion: Our data suggest that TE at 1 year after kidney transplantation might be associated with the reduced rate of histological IgAN recurrence. TE arrested or reduced serum Gd-IgA1 and mesangial Gd-IgA1 immunoreactivity. Therefore, we generated a hypothesis that serum Gd-IgA1 derived from the tonsils may play a pivotal role in the pathogenesis of IgAN. Based on these findings, we need to conduct verification in a prospective randomized controlled trial.

Plasma exchange combined with bortezomib-based chemotherapy is effective for early renal recovery in a patient with IgD-λ type multiple myeloma.

The immunoglobulin (Ig) D type is a rare variant of multiple myeloma (MM), that accounts for 1-2% of all cases. Compared to the more common types of MM, IgD MM is known to have more severe symptoms at presentation, and a poorer prognosis. A woman was admitted to our hospital for severe acute kidney disease and disorder (AKD) and back pain, and was started on hemodialysis. The renal biopsy revealed light chain cast nephropathy. She was diagnosed with IgD-λ MM based on Bence-Jones protein expression and high IgD serum levels, and started bortezomib therapy with plasma exchange (PE). After three sessions of PE, the serum free light chain levels decreased by 92%, and she was withdrawn from dialysis. The patient underwent autologous transplantation and is still in remission, demonstrating the benefits of a bortezomib-based regimen in combination with PE for IgD MM with AKD.

Long-term survival in Japanese renal transplant recipients with Alport syndrome: a retrospective study.

BACKGROUND: Patients with Alport syndrome (AS) develop progressive kidney dysfunction due to a hereditary type IV collagen deficiency. Survival of the kidney allograft in patients with AS is reportedly excellent because AS does not recur. However, several studies have implied that the type IV collagen in the GBM originates from podocytes recruited from the recipient's bone marrow-derived cells, suggesting the possibility of AS recurrence. Limited data are available regarding AS recurrence and graft survival in the Japanese population; the vast majority were obtained from living related kidney transplantation (LRKTx). METHODS: In this retrospective study, twenty-one patients with AS were compared with 41 matched patients without AS from 1984 to 2015 at two centers using propensity scores. Nineteen of the 21 patients with AS underwent LRKTx. The mean post-transplant follow-up period was 83 months in the AS group and 110 months in the control group. Histopathological AS recurrence was assessed by immunoreactivity of α5 (type IV collagen) antibody and electron microscopy. RESULTS: The graft survival rate was equivalent between patients with and without AS (86.7% vs. 77.1% and 69.3% vs. 64.2% at 5 and 10 years; p = 0.16, log-rank test). Immunoreactivity to α5 antibody showed strong linear positivity with no focal defect in six patients. Electron microscopy showed no GBM abnormalities in two patients who were exhibiting long-term kidney allograft survival. CONCLUSIONS: We confirmed that α5 and the GBM structure were histopathologically maintained in the long term after kidney transplantation. The patient and graft survival rates were equivalent between Japanese patients with and without AS.

Antibody-mediated rejection due to anti-HLA-DQ antibody after pregnancy and delivery in a female kidney transplant recipient.

Herein, we report a case of antibody-mediated rejection (ABMR) due to anti-HLA-DQ antibody after pregnancy and delivery in a female kidney transplant recipient. A 34-year-old female recipient was admitted at 2 years after delivery for an examination of an elevated serum creatinine (S-Cr) level. The patient had received a living kidney transplantation from her mother at 22 years of age, and her kidney graft function was almost stable. The episode biopsy showed peritubular capillaritis and transplant capillaropathy with C4d immunoreactivity in the peritubular capillaries. Additional examination revealed expression of a donor-specific antibody (DSA) against HLA-DQ5, leading to the diagnosis of chronic active ABMR. Intravenous immunoglobulin, plasma exchange, and rituximab were administered, and her S-Cr level was maintained stable. This case demonstrates a possible relationship between pregnancy/delivery and development of ABMR due to a de novo DSA in a female kidney transplant recipient.

Clinicopathological study of de novo membranous nephropathy of 'stage 0' after kidney transplantation.

AIM: De novo membranous nephropathy (dnMN) contributes to graft failure, but the pathophysiology of the disease remains poorly understood. We defined cases exhibiting granular Immunoglobulin G (IgG) immunofluorescence staining but lacking dense deposits on electron microscopy as being of 'dnMN stage 0'; we studied the associated clinicopathological features. METHODS: We studied 4653 allograft biopsy specimens (from 1747 cases treated in the Department of Urology, Tokyo Women's Medical University) and found 42 cases of allograft membranous nephropathy, of which 28 (1.6%) were diagnosed as dnMN. Of these, five cases (0.06%) fulfilled the criteria for dnMN stage 0. RESULTS: All five cases were diagnosed based on biopsies indicating increased serum levels of creatinine. Proteinuria status varied from negative to 2+. The median period from transplantation to allograft biopsy was 4068 days. Four of the five cases exhibited suspicious antibody-mediated rejection together with dnMN. The glomerular capillaries of all cases were C4d-positive, as were the peritubular capillaries of three of the four ABO-compatible transplants. In terms of IgG subclass, IgG1 and IgG3 predominated in all cases, and phospholipase A2 receptor status (evaluated via immunoreactivity) was negative in all cases. We examined two cases by immunoelectron microscopy using anti-IgG and anti-C4d antibodies. We found subendothelial and intramembranous deposits expressing both IgG and C4d, corresponding to positivity in immunofluorescence analysis. CONCLUSION: We confirmed the existence of dnMN stage 0 by focusing on granular IgG immunofluorescence positivity.

Recurrence of native kidney disease after kidney transplantation.

The extent of recurrence of original kidney disease after kidney transplantation has been underestimated for several reasons. First, the duration of observation varies among studies. Second, the criteria used to schedule protocol and episode biopsies differ among institutions. And third, diagnostic modalities used for early detection of recurrent original kidney disease also vary. Thus, rates of graft loss attributable to a recurrence of original kidney disease vary among institutions and are often underestimated. However, the recurrence of original disease is often thought to be less important than chronic rejection followed by loss of a functioning allograft. It is important to note that recent data have shown that in patients with certain limited primary kidney diseases (e.g., membranous proliferative glomerulonephritis [MPGN], IgA nephritis [IgAN], focal segmental glomerulonephritis [FSGS], and membranous nephropathy [MN]), the predominant (60%) cause of graft loss is the recurrence of original kidney disease. In addition, the rate of 5-year graft survival in patients with recurrent original kidney disease averages 45%. Thus, research must address the recurrence of original kidney disease. Here we focus on this recurrence and discuss diagnoses, preventive strategies, treatments, and future research directions.

Clinicopathological features and outcomes of kidney allografts in plasma cell-rich acute rejection: A case series.

Plasma cell-rich acute rejection (PCAR) is a rare type of acute rejection in renal transplantation. Despite aggressive immunotherapy, approximately 40-60% of patients develop graft loss within 1 year after an episode of PCAR. However, the reason for this outcome remains obscure. This study retrospectively identified six patients with PCAR diagnosed between 2009 and 2015 at a single university hospital. Clinicopathological data were collected. Five of the six patients were male, and mean age at the onset of PCAR was 49.0 ±14.5 years. None of the patients showed overall poor adherence to medication. Mean time to diagnosis was 302 ±234 days post-transplantation. All patients had preceding or concurrent viral infection. Four patients developed PCAR alone and two patients developed PCAR with antibody-mediated rejection. One of the six patients showed both severe tubulointerstitial and microvascular inflammation (total of Banff tubulitis 't' + interstitial inflammation 'i' + glomerulitis 'g' + peritubular capillaritis 'ptc' scores >10). This patient had progressive worsening of graft function and re-initiated dialysis at 74 months after a PCAR episode. In addition, three of the six patients had long-term recurrence of PCAR. With the recurrence of PCAR, patients with both moderate tubulointerstitial and microvascular inflammation (total of Banff 't' + 'i' + 'g' + 'ptc' scores >6) had progressive worsening of graft function. In summary, the present results suggest that concurrent moderate to severe tubulointerstitial and microvascular inflammation may lead to poor outcomes of graft function after a PCAR episode.

Successful treatment of recurrent immunoglobulin a nephropathy using steroid pulse therapy plus tonsillectomy 10 years after kidney transplantation: a case presentation.

BACKGROUND: Both prevention and treatment of recurrent immunoglobulin A nephropathy (IgAN) in kidney transplant recipients are important since recurrent IgAN seems to affect long-term graft survival. We present here a case of recurrent IgAN that was successfully treated using steroid pulse therapy plus tonsillectomy 10 years after kidney transplantation. CASE PRESENTATION: A 46-year-old male was admitted for an episode biopsy with a serum creatinine level of 1.8 mg/dl and proteinuria (0.7 g/day). Histological features showed recurrent IgAN (only focal segmental mesangial proliferation) and severe arteriolar hyalinosis partly associated with calcineurin inhibitor toxicity, with limited interstitial fibrosis and tubular atrophy (5%) (IF/TA) 8 years after transplantation. Sodium restriction and conversion from cyclosporine to tacrolimus successfully reduced his proteinuria to the level of 0.15 g/day. However, 2 years later, his proteinuria increased again (1.0 g/day) and a second episode biopsy showed global mesangial proliferation with glomerular endocapillary and extracapillary proliferation accompanied by progressive IF/TA (20%). The steroid pulse therapy plus tonsillectomy successfully decreased his proteinuria and he achieved clinical remission 3 years after this treatment. CONCLUSION: This case, presented with a review of relevant literature, demonstrates the difficulty and importance of the treatment of recurrent IgAN and calcineurin inhibitor arteriolopathy, especially in long-term kidney allograft management.

Successful Treatment of Plasma Cell-Rich Acute Rejection Using Pulse Steroid Therapy Alone: A Case Report.

Despite the recent development of immunosuppressive agents, plasma cell-rich acute rejection (PCAR) has remained refractory to treatment. Herein, we report an unusual case of PCAR that responded well to pulse steroid therapy alone. A 47-year-old man was admitted for a protocol biopsy three months after kidney transplantation, with a stable serum creatinine level of 1.6 mg/dL. Histological examination showed focal aggressive tubulointerstitial inflammatory cell infiltration of predominantly polyclonal mature plasma cells, leading to our diagnosis of PCAR. Three months following three consecutive days of high-dose methylprednisolone (mPSL) therapy, an allograft biopsy performed for therapy evaluation showed persistent PCAR. We readministered mPSL therapy and successfully resolved the PCAR. Although PCAR generally develops more than six months after transplantation, we diagnosed this case early, at three months after transplantation, with focally infiltrated PCAR. This case demonstrates the importance of early diagnosis and prompt treatment of PCAR to manage the development and severity of allograft rejection.

Helicobacter cinaedi bacteremia with cellulitis in a living-donor kidney transplant recipient identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry: a case report.

BACKGROUND: Helicobacter cinaedi causes bacteremia and cellulitis, mainly in immunocompromised patients. We report a rare case of H. cinaedi bacteremia with cellulitis in a living-donor kidney transplant recipient identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). A 54-year-old Asian man with IgA nephropathy underwent living-donor kidney transplantation 14 years previously. He was admitted to our hospital for evaluation of fever and multifocal cellulitis. H. cinaedi was isolated and identified from the patient's blood using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and gyrase subunit B-targeted polymerase chain reaction assays. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry has proven over the years to be a rapid and accurate universal method for the identification of microorganisms. CONCLUSIONS: The combined use of these detection methods enabled the appropriate administration of 6 weeks of antibiotic therapy. The patient recovered completely, with no recurrence.

Recurrence and graft loss after renal transplantation in adults with IgA vasculitis.

BACKGROUND: IgA vasculitis, a rare condition resulting in end-stage renal disease, is a small-vessel vasculitis that affects the kidney in 49-83 % of adults. The reported recurrence rate of IgA vasculitis in renal transplant recipients is 11.5-60 %, leading to graft loss in 0-50 % of these patients. However, limited data are available on recurrence and graft loss after renal transplantation. METHODS: We evaluated renal transplant recipients seen from 1987 to 2015 at the Jikei University School of Medicine and the Department of Urology, Tokyo Women's Medical University. Using a 1:2 match, 21 patients with IgA vasculitis and 42 controls were selected. The mean post-transplant follow-up was 121 ± 69 months for IgA vasculitis and 147 ± 66 months for the controls. RESULTS: The 15-year patient survival was 100 % in IgA vasculitis and 97.6 % in the controls (p = 0.22). The 5-, 10-, and 15-year graft survival rates were 95.2, 90.5, and 81 % in IgA vasculitis and 100, 90.5, and 88.1 % in the controls, respectively (p = 0.63). The recurrence rate was 28.6 % (6 of 21 cases) and half of them (3 of 6 cases) showed histological activity (ISKDC III). We treated them with methylprednisolone pulse therapy and/or tonsillectomy. None of the recurrence cases lost the allograft. CONCLUSION: The long-term patient and graft survival of IgA vasculitis in renal transplantation were comparable with the previous reports. The recurrence rate was 28.6 %, but none of the recurrent cases showed allograft loss in this study. We speculate that methylprednisolone pulse therapy and/or tonsillectomy prevent the progression of recurrent IgA vasculitis.

The prognostic values of caveolin-1 immunoreactivity in peritubular capillaries in patients with kidney transplantation.

The low sensitivity of C4d immunoreactivity in peritubular capillaries (PTCs) hinders its use in the diagnosis of chronic active antibody-mediated rejection (CAAMR). C4d-negative CAAMR was defined in the 2013 Banff classification, which included the expression of endothelial-associated transcripts (ENDATs). We previously showed that the ENDAT caveolin-1 (CAV-1) is a distinct feature of CAAMR. In this study, we investigated the prognostic value of CAV-1 immunoreactivity in PTCs in kidney transplant patients. Ninety-eight kidney transplant recipients were included in this study. The prognostic value of CAV-1 immunoreactivity in PTCs was evaluated by double immunostaining for CAV-1 and pathologische Anatomie Leiden endothelium (PAL-E, a PTC marker) in the PTCs of kidney allograft biopsy samples. The patients were divided into two groups: CAV-1/PAL-E<50% and CAV-1/PAL-E≥50%. Kaplan-Meier curves showed that CAV-1/PAL-E≥50% patients had a significantly worse prognosis than that of CAV-1/PAL-E<50% patients (log-rank; P<.001). C4d staining of PTCs was not associated with the development of graft failure (log-rank; P=.345), whereas in a multivariate Cox regression analysis, CAV-1 immunoreactivity in PTCs was independently associated with graft failure (hazard ratio: 11.1; P=.0324). CAV-1 immunoreactivity in PTCs may serve as a prognostic marker for kidney allograft survival.

Successful treatment of recurrent Henoch-Schönlein purpura nephritis in a renal allograft with tonsillectomy and steroid pulse therapy.

We report a case of recurrent Henoch-Schönlein purpura nephritis (HSPN) treated successfully with a tonsillectomy and steroid pulse therapy in a kidney transplant patient. A 29-year-old woman was admitted to our hospital for an episode biopsy; she had a serum creatinine (S-Cr) of 1.0 mg/dL and 1.34 g/day proteinuria 26 months after kidney transplantation. Histological examination revealed increased amounts of mesangial matrix and mesangial hypercellularity with IgA deposition. Of note, one glomerulus showed focal endocapillary proliferation and tuft necrosis. We diagnosed active recurrent HSPN. Considering both the histological findings and refractory clinical course of the native kidney, she was treated for 3 consecutive days with steroid pulse therapy and a tonsillectomy. The patient's proteinuria decreased gradually to less than 150 mg/day 6 months later. A second biopsy 6 years after kidney transplantation showed an excellent response to treatment and revealed a marked reduction in both the mesangial matrix and mesangial hypercellularity, with trace IgA deposition. We conclude that a tonsillectomy and steroid pulse therapy appeared to be useful in this patient with active recurrent HSPN. This paper is the first to report a tonsillectomy and steroid pulse therapy as a therapeutic option for active recurrent HSPN. Further studies are needed to elucidate the efficacy and mechanisms of tonsillectomy with recurrent HSPN in kidney transplant patients.