Introduction: Far-infrared radiation therapy (FIRT), which utilizes an invisible electromagnetic wave, has demonstrated its ability to improve vascular access flow for hemodialysis (HD) patients. Although previous overseas studies revealed the beneficial effects of FIRT on HD patients by improving vascular function, no study in Japan has examined the clinical efficacy of FIRT for such patients. Therefore, we aimed to evaluate the usefulness of FIRT for HD patients. We paid particular attention on secondary vascular access (VA) patency of HD patients. Methods: Eighteen patients who had undergone vasodilation of VA vessels or vascularization more than once were selected from approximately 70 outpatients receiving HD in the Dialysis Unit of the Juntendo University Hospital. FIRT was administered for 40 min during HD three times per week for 1 year to the not frequent VA treatment (nf-VAT) group, for which VA intervention had been performed no more than two times during the 1 year, and to the frequent VA treatment (f-VAT) group, for which VA intervention had been performed three times or more over the 1 year. Variables including VA treatment interval were compared between those groups. Results: The nf-VAT group did not require VA re-treatment during the study period. The VA treatment interval was significantly prolonged in the f-VAT group. The fistula diameter expanded, and intimal thickening improved significantly in the nf-VAT group. Oxidized low-density lipoprotein cholesterol levels decreased slightly. Conclusion: This study suggested that FIRT is effective for improving secondary VA patency. Trial registration: UMIN, UMIN000011965.

A 45-year-old man suffering from dermal blistering disease with proteinuria and hematuria underwent renal biopsy. The renal biopsy specimen suggested proliferative glomerulonephritis with monoclonal IgG deposits under routine light, immunofluorescence and electron microscopy. The staining for IgG subclasses (IgG1 and IgG2) and κ/λ light chain indicated secondary immune complex type MPGN type 3. The patient had been diagnosed as having dermatitis herpetiformis (DH), a phenotype of gluten hypersensitivity prior to the appearance of the renal abnormality. Although common autoantibodies might be related to the pathogenesis of disorders in the skin and kidney, DH is mainly driven by IgA autoantibody, while MPGN is induced by IgG immune complexes. IgA was not observed in the glomeruli by immunofluorescence. Neither the examination for DH specific autoantibodies nor HLA-DQB1 genotype supported the diagnosis of DH. Reassessment of the skin biopsy record revealed that the blister was localized in the epidermis, suggesting pemphigus herpetiformis by IgG class anti-epidermal autoantibody, which also affected the renal disorder.

Recently, as the number of case reports of IgG4-related kidney disease (IgG4-RKD) has increased, the histopathological features and clinical approach have been clarified. IgG4-RKD generally has a benign prognosis due to the efficacy of steroid therapy and rarely requires dialysis. Herein, we report a case of IgG4-RKD that presented with a subacute onset, advanced to end-stage kidney disease, and finally required maintenance hemodialysis despite steroid therapy. A 75-year-old man was admitted to our hospital for further evaluation of subacute renal failure. Diffuse enlargement of the kidney on computed tomography and increased urinary N-acetyl-β-D-glucosaminidase and α1-microglobulin levels led us to suspect IgG4-RKD. Upon admission, the laboratory serological findings were as follows: creatinine 3.3 mg/dL, urea nitrogen 46.9 mg/dL, and IgG4 235 mg/dL. Urinalysis showed slight proteinuria without hematuria. Percutaneous renal needle biopsy showed diffuse infiltration of abundant lymphocytes and IgG4-positive plasma cells and storiform fibrosis, which is specific to IgG4-RKD, in the interstitium on light microscopy. Slight linear deposition of C3 was also observed in the tubules on immunofluorescence microscopy, with no electron-dense deposits. He was definitively diagnosed as having IgG4-RKD and started on prednisolone 0.6 mg/kg/day. However, the renal insufficiency continued to progress and hemodialysis was necessary. As the prednisolone was tapered, renal function did not improve and maintenance hemodialysis was started. In conclusion, this case indicates that the prognosis of IgG4-RKD is not necessarily benign and that further studies involving more patients are needed.