Acute tubulointerstitial nephritis associated with antineutrophil cytoplasmic antibody following cimetidine treatment: a case report.

BACKGROUND: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis usually induces rapidly progressive glomerulonephritis, including pauci-immune necrotizing crescentic glomerulonephritis. Acute tubulointerstitial nephritis (ATIN), which is often drug-induced, is a frequent cause of kidney injury. However, ATIN associated with ANCA without any glomerular lesions has been rarely reported, and drug-induced ATIN associated with ANCA is not well recognized. Here we present a case of an older woman with ATIN associated with myeloperoxidase-ANCA (MPO-ANCA) following cimetidine treatment. CASE PRESENTATION: A 70-year-old woman was admitted to our hospital due to acute kidney injury and mild proteinuria. She had a one-year history of chronic thyroiditis and dyslipidemia, for which she was taking levothyroxine sodium and atorvastatin, respectively. Two weeks before admission she had started cimetidine, methylmethionine sulfonium chloride, and itopride hydrochloride for gastric discomfort persistent since a month. She had experienced fatigue for two weeks and later appetite loss. The patient demonstrated a positive titer for MPO-ANCA (192 IU/mL) and a positive drug-induced lymphocyte stimulation test for cimetidine. She underwent two kidney biopsies that revealed ATIN without any glomerular lesions. Despite discontinuation of cimetidine on admission, renal injury continued with the presence of high MPO-ANCA titer. Oral steroid treatment was closely related with the recovery of her renal function and disappearance of MPO-ANCA. CONCLUSIONS: In this case, ATIN presented as sustained renal insufficiency and high MPO-ANCA titer despite withdrawal of cimetidine. Therefore, we reason that the development of ANCA-associated ATIN was caused by cimetidine. Serologic follow-up with measurement of MPO-ANCA titers and renal biopsy are recommended when the clinical history is inconsistent with the relatively benign course of drug-induced ATIN.

Neutropenia related to an azathioprine metabolic disorder induced by an inosine triphosphate pyrophosphohydrolase (ITPA) gene mutation in a patient with PR3-ANCA-positive microscopic polyangiitis
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A 68-year-old Japanese man was monitored for chronic kidney disease (CKD), with unknown primary disease starting in 2014. His serum creatinine (sCr) was stable at ~ 2.5 mg/dL for ~ 2 years. Two weeks before admission, he had bloody sputum, and sCr increased to 4.63 mg/dL. Soon after admission, the patient developed a high fever with pigment spots on the legs. A kidney biopsy was performed. The kidney specimens showed necrotizing and crescentic glomerulonephritis without granuloma formation. An additional blood-sampling test revealed high titers of PR3-ANCA, and we diagnosed PR3-ANCA-positive microscopic polyangiitis (MPA). Treatment with intravenous steroid pulse therapy and intermittent pulse intravenous cyclophosphamide therapy was started for remission induction. With these treatments, sCr improved to ~ 3.0 mg/dL. Azathioprine (AZA) was added for remission-maintenance therapy. Three days later, the dose of AZA was increased from 50 to 100 mg/day, and the number of neutrophils decreased to 30/µL. After withdrawal of AZA, neutrophil levels gradually recovered. We suspected that an abnormal metabolism of AZA was responsible for the neutropenia. Therefore, we analyzed three AZA metabolism-associated genes for mutations: thiopurine S-methyltransferase (TPMT), inosine triphosphate pyrophosphohydrolase (ITPA), and nucleoside diphosphate linked moiety X-type motif 15 (NUDT15), and we identified ITPA 94C>A mutation. This was a rare case of PR3-positive MPA with AZA-induced severe neutropenia that was possibly due to an ITPA gene mutation. This case suggests that ITPA gene mutation is related to the adverse reactions of AZA in Japanese patients. We have to pay attention to severe neutropenia when we use AZA, especially in Asian patients with CKD.
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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.

Subclinical antibody-mediated rejection due to anti-human-leukocyte-antigen-DR53 antibody accompanied by plasma cell-rich acute rejection in a patient with cadaveric kidney transplantation.

A 56-year-old man who had undergone cadaveric kidney transplantation 21 months earlier was admitted to our hospital for a protocol biopsy; he had a serum creatinine level of 1.2 mg/dL and no proteinuria. Histological features showed two distinct entities: (i) inflammatory cell infiltration, in the glomerular and peritubular capillaries and (ii) focal, aggressive tubulointerstitial inflammatory cell infiltration, predominantly plasma cells, with mild tubulitis (Banff 13 classification: i2, t1, g2, ptc2, v0, ci1, ct1, cg0, cv0). Immunohistological studies showed mildly positive C4d immunoreactivity in the peritubular capillaries. The patient had donor specific antibody to human-leucocyte-antigen-DR53. We diagnosed him with subclinical antibody-mediated rejection accompanied by plasma cell-rich acute rejection. Both antibody-mediated rejection due to anti- human-leucocyte-antigen -DR53 antibodies and plasma cell-rich acute rejection are known to be refractory and have a poor prognosis. Thus, we started plasma exchange with intravenous immunoglobulin and rituximab for the former and 3 days of consecutive steroid pulse therapy for the latter. Three months after treatment, a follow-up allograft biopsy showed excellent responses to treatment for both histological features. This case report considers the importance of an early diagnosis and appropriate intervention for subclinical antibody-mediated rejection due to donor specific antibody to human-leucocyte-antigen-DR53 and plasma cell-rich acute rejection.

Rare case of nephrocalcinosis in the distal tubules caused by hereditary renal hypouricaemia 3 months after kidney transplantation.

We report a rare case of nephrocalcinosis caused by hereditary renal hypouricaemia 3 months after kidney transplantation. A 41-year-old man who underwent living-related kidney transplantation from his father was admitted to our hospital for a protocol biopsy; he had a serum creatinine (S-Cr) of 1.37 mg/dL and no proteinuria. Histologically, there was no evidence of rejection or calcineurin inhibitor toxicity, although scattered nephrocalcinosis was observed in the distal tubules. Perioperatively, the patient had a serum uric acid (S-UA) of 1.9 mg/dL with a fractional excretion of uric acid (FEUA) of 29% (normal, <10%) and UA clearance of 26.8 mL/min (normal, 7.3-14.7 mL/min) 3 days after kidney transplantation. The donor also had a relatively low S-UA of 2.4 mg/dL and high FEUA of 10.3%. Subsequent DNA direct sequencing followed by restriction fragment length polymorphism revealed that both the recipient's and donor's urate transporter 1 (URAT1) gene had a heterozygous nonsense mutation in exon 5 (C889T). Further, the immunoreactivity of antibodies for the C terminus of URAT1 revealed a partial deletion. De Galantha and von Kossa staining revealed that the nephrocalcinosis was due to urate crystals and calcium stones. Therefore, we diagnosed hereditary renal hypouricaemia. We directed the patient to avoid hard exercise, drink plenty of water, and alkalize the urine. The 1-year follow-up allograft biopsy showed no evidence of nephrocalcinosis in the distal tubules. This is the first report of nephrocalcinosis in the distal tubules as a diagnostic clue to hereditary renal hypouricaemia. We also review the related literature.

Probable C4d-negative accelerated acute antibody-mediated rejection due to non-HLA antibodies.

We report a case of probable C4d-negative accelerated acute antibody-mediated rejection due to non-HLA antibodies. A 44 year-old male was admitted to our hospital for a kidney transplant. The donor, his wife, was an ABO minor mismatch (blood type O to A) and had Gitelman syndrome. Graft function was delayed; his serum creatinine level was 10.1 mg/dL at 3 days after transplantation. Open biopsy was performed immediately; no venous thrombosis was observed during surgery. Histology revealed moderate peritubular capillaritis and mild glomerulitis without C4d immunoreactivity. Flow cytometric crossmatching was positive, but no panel-reactive antibodies against HLA or donor-specific antibodies (DSAbs) to major histocompatibility complex class I-related chain A (MICA) were detected. Taken together, we diagnosed him with probable C4d-negative accelerated antibody-mediated rejection due to non-HLA, non-MICA antibodies, the patient was treated with steroid pulse therapy (methylprednisolone 500 mg/day for 3 days), plasma exchange, intravenous immunoglobulin (40 g/body), and rituximab (200 mg/body) were performed. Biopsy at 58 days after transplantation, at which time S-Cr levels were 1.56 mg/dL, found no evidence of rejection. This case, presented with a review of relevant literature, demonstrates that probable C4d-negative accelerated acute AMR can result from non-HLA antibodies.

A case of rapidly progressive glomerulonephritis with double-positive anti-GBM antibody and MPO-ANCA after SARS-CoV-2 vaccination and relapse during 1 year follow-up.

Although mRNA vaccines for COVID-19 are highly beneficial and are recommended for patients with kidney disease, adverse reactions in some patients after vaccination have been problematic. Various vasculitis and renal disorders have been reported after vaccination; however, a causal relationship has not yet been identified. In this report, we describe a case of rapidly progressive glomerulonephritis that developed after SARS-CoV-2 vaccination, in which both anti-glomerular basement membrane (anti-GBM) and myeloperoxidase antineutrophil cytoplasmic antibodies (MPO-ANCA) were present. The patient's renal biopsy showed that of the 48 glomeruli in total, four showed global sclerosis and none showed segmental sclerosis. The biopsy showed 11 cellular glomerular crescents and 5 fibrocellular glomerular crescents. Renal function improved with steroids, rituximab, and plasma exchange. Approximately 9 months later, MPO-ANCA was again elevated, and the pulmonary lesions worsened, again requiring multidisciplinary treatment. This case suggests that caution should be exercised in the development of double-positive disease after vaccination, and that long-term observation may be necessary because of the possibility of relapse.

A retrospective study describing the effective exchange of total blood plasma for disease control in the exacerbation of serpiginous choroiditis.

INTRODUCTION: Serpiginous choroiditis presents with large yellow-white exudative lesions that occur near the optic nerve papillae, that progresses slowly with repeated relapses and cures. Although infection and autoimmunity have been implicated, the cause is unknown. METHODS: A man was diagnosed with serpiginous choroiditis on clinical and other examinations. He started treatment with oral corticosteroids, cyclophosphamide, adalimumab, azathioprine, rituximab, and mycophenolate mofetil. Only the steroids and cyclophosphamide had a therapeutic effect. Plasma exchange was initiated, and the lesions quickly resolved. RESULTS: Disease control has been maintained by plasma exchange and cyclophosphamide during flare-ups in the fall and winter, suggesting that plasma exchange is effective in the treatment of serpiginous choroiditis. CONCLUSION: The reproducible response with each recurrence suggests a strong association between the disease and autoimmunity. Furthermore, that some, as yet unknown, autoantibodies are involved in the pathogenesis of serpiginous choroiditis.

Urinary liver-type fatty acid-binding protein level as a prognostic indicator of acute kidney injury secondary to severe falciparum malaria.

Acute kidney injury (AKI) secondary to severe falciparum malaria possesses a high mortality rate; however, a prognostic marker of renal dysfunction has not yet been identified. Thus, we reported a case of a patient with AKI secondary to falciparum malaria who underwent hemodialysis and a renal biopsy due to prolonged renal dysfunction. The male patient, in his 50 s, presented to our hospital with vomiting, diarrhea, fever, and decreased level of consciousness. The Giemsa-stained peripheral blood film revealed approximately 5% parasitemia, and a rapid diagnostic test was positive for Plasmodium falciparum. He was diagnosed with severe falciparum malaria and was started on quinine hydrochloride. Hemodialysis was initiated due to the decreased urine output and fluid retention. Subsequently, he was weaned off hemodialysis. The histopathological analysis of a renal biopsy revealed interstitial fibrosis, tubular atrophy, and chronic inflammatory cell infiltration; thus, malarial nephropathy was diagnosed. Thereafter, his renal function stabilized, and he was discharged from the hospital. The urinary liver-type fatty acid-binding protein (L-FABP) level decreased before renal function improved. Our report highlighted that long-term follow-up is essential for severe AKI secondary to malaria. The urinary L-FABP level may be a useful prognostic indicator of AKI secondary to severe falciparum malaria.

Adjuvant diagnosis of tuberculosis in hemodialysis patients using fourth generation interferon γ releasing assay.

INTRODUCTION: Dialysis patients have a 10-25 times higher risk of reactivation of tuberculosis (TB). In this study, we investigated the diagnostic ability of QuantiFERON (QFT)-plus for TB in hemodialysis patients. QFT-plus, an interferon gamma release assay, is characterized by its use of CD4 and CD8 T cell signals. METHODS: Hemodialysis patients aged 20 years or older who underwent QFT-plus measurement in our hospital were included, inclusion criteria being fever above 37°C, high inflammatory response, and infiltrative pulmonary shadows. RESULTS: Forty-six patients were enrolled. Of these, 15% were QFT positive, 4% were diagnosed with active TB, 76% were QFT negative, 8% had inconclusive results. Sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 87.5%, 28%, and 100%, respectively. CONCLUSIONS: QFT-plus may be useful for the diagnosis of active TB in dialysis patients. Further studies in cohorts with larger sample sizes are expected.

Long-term changes in anemia-related parameters among Japanese dialyzed patients assessed by newly developed web-based system.

Anemia treatment is crucial in the management of dialyzed patients. Although Hb and serum ferritin levels are commonly used as indicators for treatment, these values change over time due to changes in policy, drugs for treating anemia, and target levels suggested by clinical guidelines. To clarify long-term changes in anemia-related parameters in Japan, we extracted annual patient data from a newly developed web-based system by the Japanese Society for Dialysis Therapy, the Web-based Analysis of Dialysis Data Archives system. Hb levels gradually increased from 2008 to 2019. Serum ferritin levels and transferrin saturation tended to increase between 2012 and 2019. Although these changes were found in all dialyzed patients, these were more pronounced in patients on peritoneal dialysis. We believe that our results can contribute to a better understanding of the results of clinical studies assessing the effects of treatment for anemia on clinical outcomes among dialyzed patients.

Near-sudden unexpected death in a patient with epilepsy undergoing hemodialysis: a case report.

Sudden unexpected death in epilepsy (SUDEP) has been defined as a sudden/unexpected, witnessed/unwitnessed, nontraumatic, and nondrowning death in epileptic patients with/without seizure evidence and documented status epilepticus. Identified as the leading cause of epilepsy-related deaths, SUDEP cases are highly unrecognized and underreported due to diagnostic difficulty. We report a case of a successfully revived hemodialysis patient who developed cardiopulmonary arrest after a witnessed convulsive seizure. Electroencephalogram revealed epileptic abnormalities. Therefore, this case could be seizure-induced cardiopulmonary arrest and near-SUDEP. Hence, the possibility of SUDEP should be considered even in hemodialysis patients having conventional coronary risk factors for sudden cardiac death.

Hepcidin/Ferritin Ratios Differ Among Non-Dialyzed Chronic Kidney Disease Patients, and Patients on Hemodialysis and Peritoneal Dialysis.

The serum levels of hepcidin generally increase in patients with chronic kidney disease (CKD) due to inflammation or a decline in the glomerular filtration rate. However, the differences in the ferrokinetics among dialysis modalities are unclear. We investigated the relationship between serum levels of hepcidin and ferritin among non-dialyzed CKD (ND), hemodialysis (HD), and peritoneal dialysis (PD) patients. We recruited 285 CKD patients (117 ND, 80 HD, and 88 PD patients) and measured the serum levels of hepcidin-25, ferritin, hemoglobin, iron, transferrin saturation (TSAT), albumin, and high sensitivity C-reactive protein (hs-CRP). Hepcidin-25 levels were elevated in all CKD patients and were significantly higher in PD than in ND and HD patients. The hepcidin/ferritin ratio was significantly higher in PD patients independent of TSAT, hemoglobin, hs-CRP, and serum albumin. Hepcidin/ferritin ratio, associated with both dialysis modality and inflammation, is expected to be a useful indicator of anemia in CKD.