Case of hereditary kidney disease presenting thin basement membrane with a single heterozygous variant of Intersectin 2.

Objective: Intersectin 2 (ITSN2) is reported to cause hereditary nephrotic syndrome, but the number of cases remains quite small. We observed a case of progressive renal dysfunction and family history for end-stage kidney disease with a known single heterozygous ITSN2 variant. This study aimed to reveal the novel pathological significance of altered ITSN2 expression via a detailed examination. Patient and Methods: A 52-year-old Japanese woman with mild proteinuria and hematuria visited our center. The patient did not opt for a detailed examination but was instead followed up with conservative treatment consisting of low-dose angiotensin receptor blockers. Serum Cr worsened from 1.15 to 1.79 mg/dL after 7 years when precise diagnosis was performed by renal biopsy and genetic testing. Results: Kidney biopsy showed a thin basement membrane (TBM) and global glomerulosclerosis in 37.5% (6 out of 16) glomeruli examined. Comprehensive gene panel testing of 121 genes revealed a known ITSN2 variant, assumed to be involved in pathogenesis. No variants in the Alport syndrome genes, which are typically responsible for TBM, were detected. Conclusion: A possible novel phenotype of the heterozygous ITSN2 variant was identified as a cause of hereditary renal failure. Further investigation of similar cases is required for a better understanding.

Central diabetes insipidus with anti-rabphilin-3A antibody positivity causing hypovolemic shock after resection of tumorous lesions in the pelvic cavity.

A 36-year-old female was pointed out to have liver enzyme elevation by routine health checkup. Subsequent contrast-enhanced CT scan identified gigantic uterine fibroids and retroperitoneal tumor. She was referred to the gynecologist at JA Toride Medical Center and planned to undergo a uterus enucleation and biopsy of the retroperitoneal tumor. The surgery was conducted without any troubles. After the surgery, the patient presented polyuria with urine volume 10-20 L a day and developed hypovolemic shock. Laboratory test revealed hypotonic urine and hypernatremia. Arginine vasopressin (AVP) loading test suggested shortage of endogenous vasopressin. Since the subcutaneous administration of AVP was not sufficient to control the urine volume, continuous intravenous infusion of AVP was initiated. After achieving hemodynamic stability, the treatment was switched to oral desmopressin. MRI finding indicated attenuation of high signal in posterior pituitary in T1 weighted image while neither enlargement of pituitary nor thickening of pituitary stalk was indicated by enhanced MRI. Hypertonic salt solution test indicated no responsive elevation of AVP, confirming the diagnosis of central diabetes insipidus (CDI). Her anterior pituitary function was preserved. Only anti-rabphilin-3A antibody was found positive in the serum of the patient, while other secondary causes for CDI were denied serologically and radiologically. Hence, lymphocytic infundibuloneurohypophysitis　(LINH) was suspected as the final diagnosis. Hormonal replacement therapy by nasal desmopressin was continued and the patient managed to control her urine volume. In cases of CDI considered idiopathic with conventional examinations, anti-rabphilin-3A antibody may be a clue for determining the cause as LINH.

Transition of lymphocyte subsets in peritoneal dialysis effluent and its relationship to peritoneal damage.

Objective: Peritoneal function during peritoneal dialysis (PD) declines over time due to peritoneal inflammation; however, the immunological mechanism has not been fully clarified. Here, we examined changes in each cellular fraction in the peritoneal dialysis effluent by flow cytometry and their relationship to peritoneal damage. Patients and Methods: We enrolled 23 patients who began PD between 2006 and 2017 and had available datasets of the peritoneal equilibration test and flow cytometric analysis for at least three consecutive visits, with an interval of six months from six months after introducing PD. The levels and changes in each cellular fraction, dialysate/plasma (D/P) creatinine ratio, and the forward scatter (FSC) ratio of mesothelial cells to lymphocytes were compared using a simple linear regression analysis. Results: Among the examined variables, only the fraction of CD8+ TCM cells during the first observation was significantly correlated with the change rate in the D/P creatinine ratio (ß=1.47, P=0.001, adjusted R2=0.379). The CD8+ naïve T and CD8+ TCM cell fractions were negatively correlated with the change rate of the D/P creatinine ratio (naïve T cells: ß=-0.058, P=0.022, adjusted R2=0.188; TCM cells: ß=-0.096, P=0.046, adjusted R2=0.137). In addition, the change rates of the D/P creatinine ratio tended to be higher, though not significantly (one way ANOVA; P=0.080), in accordance with the increase in the change rate of the CD8+ effector memory T cells (TEM). Conclusion: The CD8+ naïve T and TCM cells may transition into TEM cells by repeated exposure to the dialysate over time. The TEM cells residing in the peritoneum may play a significant role in the progression of peritoneal damage.

Predominant tubulointerstitial lupus nephritis with preceding pernicious anemia.

Predominant tubulointerstitial nephritis with negligible glomerular lesions is a rare form of lupus nephritis. Although tubulointerstitial changes occur in two-thirds of patients with lupus nephritis, these lesions were mostly accompanied by glomerulonephritis. Predominant tubulointerstitial lupus nephritis has been reported to be only 13 cases in the literature as far as we surveyed. Here, we present a case of a 72-year-old male who had pancytopenia associated with pernicious anemia and later developed a mild proteinuria and renal insufficiency. Although urinary tubulointerstitial markers increased, serological screening tests for tubulointerstitial nephritis were all negative. Three months later, the patient was diagnosed as systemic lupus erythematosus, based on polyarthritis, positive antinuclear antibody, immunological disorder and hematological disorder. Renal biopsy revealed severe infiltration of mononuclear cells in the interstitium with minimal abnormalities in glomeruli. Positive IgG and C1q staining with immunofluorescence antibody method in the tubular basement membrane and dense deposits in the same region with electron microscopy confirmed a diagnosis of predominant tubulointerstitial lupus nephritis. Since the patient's renal function declined rapidly, treatment with intravenous 500 mg methyl prednisolone followed by 40 mg/day of oral prednisolone was initiated. The patient's renal function improved and became stable even after tapering of prednisolone. Although lupus nephritis is generally accompanied by multiple symptoms such as fever, malaise, arthralgia, rashes, this case showed only pernicious anemia and tubulointerstitial nephritis initially.

Cervical cancer of the uterus complicated by renal AA amyloidosis.

Cervical cancer of the uterus rarely develops systemic secondary amyloidosis. We present the case of a 66-year-old female patient who manifested systemic amyloid A (AA) amyloidosis in the kidney, digestive tract, and cervix of the uterus, secondary to cervical cancer. She exhibited nephrotic syndrome, intractable diarrhea, and mild fever 3 months after she underwent an extended hysterectomy with postoperative cisplatin-based chemotherapy and whole pelvic irradiation. Further examinations revealed AA amyloidosis of the kidney and colon and cytomegalovirus infection in the colon. AA amyloid deposition was positive in the resected tissues of uterine cancer. The patient was diagnosed with systemic AA amyloidosis consecutive to cervical cancer. Despite a decrease in urinary protein after antiviral therapy, it increased 14 months later with neither apparent symptoms nor an increase in tumor marker. A second renal biopsy revealed AA amyloidosis of the kidney. Subsequent investigations revealed the recurrence of cervical cancer in the lung, liver, and lymph nodes. This case report indicated that AA amyloidosis would complicate cervical cancer and recur even after resection of neoplasm owing to other stimulation. Moreover, urine protein could be a marker for cancer relapse in known cases of cancer-derived AA amyloidosis.

A Case of COVID-19 Failed in Viral Identification but Showed Consistent Host Responses to Severe Acute Respiratory Syndrome Coronavirus 2.

In a 75-year-old hemodialysis patient, pneumonia manifested with computed tomography (CT) images suggestive of coronavirus disease 2019 (COVID-19). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ribonucleic acid (RNA) was not detected with repeated polymerase chain reaction (PCR) tests, but serum immunoglobulin G (IgG) and IgM antibodies against SARS-CoV-2 turned positive with two different assay kits. The patient was thus treated as a probable COVID-19 case, and then recovered through the intensive care including ciclesonide, favipiravir, and methyl prednisolone. In PCR-negative cases, the diagnosis of COVID-19 cannot be established at present, but such COVID-19 cases certainly exist. To avoid a delay in treatment of COVID-19, available diagnostic tools should be utilized with careful attention for their limitations.

Case of immunotactoid glomerulopathy showing high responsiveness to steroids therapy despite severe pathological features.

A 72-year-old woman presented with nephrotic proteinuria and moderate haematuria. Renal pathology was compatible with immunotactoid glomerulopathy (ITG), for which there is no consensus for appropriate therapy. We, therefore, postponed immunosuppressive therapy. After 4 years, the patient's renal function started to decline and renal pathology was re-evaluated, revealing a pathological change from mesangial proliferative glomerulonephritis to endocapillary proliferative glomerulonephritis. Treatment with oral prednisolone (30 mg/day) was initiated. Within 5 weeks, complete remission of proteinuria was obtained (proteinuria 6.02 g/gCr to 0.12 g/gCr), and the patient's renal function stabilised. Generally, responsiveness to immunosuppressive therapy is poor in patients with ITG, and the present case represented a very rare clinical course. Some previous cases have indicated susceptibility to the therapy, regardless of the severity of renal damage. As a possible distinct entity that determines susceptibility to immunosuppressive therapy, we suggest the presence of a latent lymphoproliferative disease with no significant haematological symptoms.

Risk of Heparin-induced Immediate-type Hypersensitivity during Arteriovenous Fistula Placement.

Heparin is commonly used to prevent clotting; however, severe hypersensitivity reactions during vascular access (VA) placement are rarely but occasionally reported. A 49-year-old man experienced a heparin-induced hypersensitivity reaction during VA placement. Severe side effects may occur even while placing the VA; therefore, we reconsidered the routine use of heparin, as the side effects are unpredictable. Physicians should be aware of the risk of heparin-induced hypersensitivity and be ready to effectively manage it during VA placement.