Predominant CD8+ cell infiltration and low accumulation of regulatory T cells in immune checkpoint inhibitor-induced tubulointerstitial nephritis.

Immune checkpoint inhibitors (ICIs) can provide survival benefits to cancer patients; however, they sometimes result in the development of renal immune-related adverse events (irAEs). Tubulointerstitial nephritis (TIN) is the most representative pathological feature of renal irAEs. However, the clinicopathological entity and underlying pathogenesis of ICI-induced TIN are unclear. Therefore, we compared the clinical and histological features of this condition with those of non-ICI drug-induced TIN. Age and C-reactive protein levels were significantly higher in ICI-induced TIN, but there were no significant differences in renal function. Immunophenotyping of ICI-induced TIN showed massive T cell and macrophage infiltration with fewer B cells, plasma cells, neutrophils, and eosinophils. Compared with those in non-ICI drug-induced TIN, CD4+ cell numbers were significantly lower in ICI-induced TIN but CD8+ cell numbers were not significantly different. However, CD8/CD3 and CD8/CD4 ratios were higher in ICI-induced TIN. Moreover, CD25+ and FOXP3+ cells, namely regulatory T cells, were less abundant in ICI-induced TIN. In conclusion, T cell, B cell, plasma cell, neutrophil, and eosinophil numbers proved useful for differentiating ICI-induced and non-ICI drug-induced TIN. Furthermore, the predominant distribution of CD8+ cells and low accumulation of regulatory T cells might be associated with ICI-induced TIN development.

Disulfiram treatment suppresses antibody-producing reactions by inhibiting macrophage activation and B cell pyrimidine metabolism.

Antibody responses, involving B cells, CD4 + T cells, and macrophages, are implicated in autoimmune diseases and organ transplant rejection. We have previously shown that inhibiting FROUNT with disulfiram (DSF) suppresses macrophage activation and migration, effectively treating inflammatory diseases. In this study, we investigated the effectiveness of DSF in antibody-producing reactions. Using a heart transplantation mouse model with antibody-mediated rejection, we administered anti-CD8 antibody to exclude cellular rejection. DSF directly inhibited B cell responses in vitro and significantly reduced plasma donor-specific antibodies and graft antibody deposition in vivo, resulting in prolonged survival of the heart graft. DSF also mediated various effects, including decreased macrophage infiltration and increased Foxp3+ regulatory T-cells in the grafts. Additionally, DSF inhibited pyrimidine metabolism-related gene expression induced by B-cell stimulation. These findings demonstrate that DSF modulates antibody production in the immune response complexity by regulating B-cell and macrophage responses.

Uterine carcinosarcoma showing immature teratoid-like differentiation.

A carcinosarcoma is a rare form of cancer characterised by the presence of both carcinomatous and sarcomatous components. Here, we present our experience with an extremely rare case of an uterine carcinosarcoma with immature teratoid-like differentiation. The patient was a woman in her 60s. She was referred for the evaluation of a uterine tumour. She underwent total abdominal hysterectomy with bilateral adnexectomy and received postoperative treatment with paclitaxel and carboplatin. On microscopic examination, the tumour had a heterogeneous appearance with a combination of carcinomatous and sarcomatous elements, and teratoid features. The tumour included immature squamous epithelial cells and immature epithelial glands, and focal atypical fused glands, which are consistent with endometrioid carcinoma, were identified in the endometrium. Pathological differentiation from extrarenal Wilms' tumour and teratocarcinosarcoma was challenging. The final pathological diagnosis was uterine carcinosarcoma with immature teratoid-like differentiation. At 14 months after the surgery, the patient has not experienced recurrence.

Discontinuing Hemodialysis through Corticosteroid Treatment in a Patient with Cryofibrinogen-associated Glomerulonephritis.

Cryofibrinogen-associated glomerulonephritis (CryoFiGN) is rare, and its diagnosis is difficult while treatment is not established. We herein report an elderly woman with CryoFiGN who experienced recurrent purpura and nephritic features that subsequently progressed to nephrotic syndrome and required hemodialysis during the 18-month clinical course. The patient was treated with corticosteroids, which led to the discontinuation of hemodialysis. The diagnosis of CryoFiGN was based on the clinical presentation, characteristic glomerular deposits, and results of laser microdissection and liquid chromatography-tandem mass spectrometry of the glomeruli. This case highlights the potential utility of corticosteroids as a treatment option for patients with CryoFiGN, even after hemodialysis.

Perirenal fat stranding as a predictor of disease progression after radical nephroureterectomy for renal pelvic urothelial carcinoma: a retrospective study.

BACKGROUND: To investigate the impact of Perirenal fat stranding (PRFS) on progression after radical nephroureterectomy (RNU) for renal pelvic urothelial carcinoma (RPUC) without hydronephrosis and to reveal the pathological findings of PRFS. METHODS: Clinicopathological data, including computed tomography (CT) findings of the ipsilateral PRFS, were collected from the medical records of 56 patients treated with RNU for RPUC without hydronephrosis between 2011 and 2021 at our institution. PRFS on CT was classified as either low or high PRFS. The impact of PRFS on progression-free survival (PFS) after RNU was analyzed using the Kaplan-Meier method and log-rank test. In addition, specimens including sufficient perirenal fat from patients with low and with high PRFS were pathologically analyzed. Immunohistochemical analysis of CD68, CD163, CD3, and CD20 was also performed. RESULTS: Of the 56 patients, 31(55.4%) and 25 (44.6%) patients were classified as having low and high PRFS, respectively. Within a median follow-up of 40.6 months postoperatively, 11 (19.6%) patients showed disease progression. The Kaplan-Meier method and log-rank test revealed that patients with high PRFS had significantly lower PFS rates than those with low PRFS (3-year PFS 69.8% vs 93.3%; p = 0.0393). Pathological analysis revealed that high PRFS specimens (n = 3 patients) contained more fibrous strictures in perirenal fat than low PRFS specimens (n = 3 patients). In addition, M2 macrophages (CD163 +) infiltrating fibrous tissue in perirenal area were observed in all patients with high PRFS group. CONCLUSIONS: PRFS of RPUC without hydronephrosis consists of collagenous fibers with M2 macrophages. The presence of ipsilateral high PRFS might be a preoperative risk factor for progression after RNU for RPUC patients without hydronephrosis. Prospective studies with large cohorts are required in the future.

Development of angiogenic periglomerular microvessels after acute glomerular lesions in IgA nephropathy.

AIM: To clarify the clinicopathological characteristics and role of periglomerular angiogenesis in IgA nephropathy. METHODS AND RESULTS: The renal biopsy specimens of 114 patients with IgA nephropathy were examined. Among them, 46 (40%) showed periglomerular angiogenesis around the glomeruli. CD34 and α-smooth muscle actin (α-SMA) staining in serial sections revealed that these vessels contained CD34+ α-SMA+ microarterioles along with CD34+ α-SMA- capillaries. We termed these "periglomerular microvessels (PGMVs)". Patients with PGMVs (PGMV group) had clinically and histologically more severe disease than those without PGMVs (non-PGMV group) at the time of biopsy. Even after adjusting for age, there were significant differences in the degree of proteinuria and estimated glomerular filtration rate reduction between the PGMV and non-PGMV groups. The PGMV group showed a higher incidence of segmental and global glomerulosclerosis and crescentic lesions than the non-PGMV group (P < 0.01). Here, PGMVs were undetectable in the acute and active inflammation phase, but were observed in the acute to chronic or chronic glomerular remodelling phase. PGMVs mainly developed around glomerular adherent lesions to the Bowman's capsule with small or minimal glomerular sclerotic lesions. Conversely, they were rarely observed in segmental sclerosis areas. CONCLUSION: The PGMV group is clinically and pathologically more severe than the non-PGMV group; however, they were undetectable in segmental sclerosis with mesangial matrix accumulation. PGMVs might occur after acute/active glomerular lesions, suggesting that PGMVs may inhibit segmental glomerulosclerosis progression and could be a marker for good repair response after acute/active glomerular injury in severe IgA nephropathy cases.

Immune checkpoint inhibitors associated granulomatous small vessel vasculitis accompanied with tubulointerstitial nephritis: a case report.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have provided significant benefits in cancer treatment, but they could develop immune-related adverse events (irAE). ICI-associated renal adverse effects are rare and tubulointerstitial nephritis (TIN) is the most common in the renal irAE. However, only a few case reports of renal vasculitis associated with ICI have been reported. In addition, the characteristics of infiltrating inflammatory cells of ICI-associated TIN and renal vasculitis have been uncertain. CASE PRESENTATION: A 65-year-old man received immune checkpoint inhibitors (ICIs), anti-CTLA-4 (cytotoxic T-lymphocyte-associated protein 4) and anti-PD-1 (programmed cell death 1) antibodies for aggravated metastatic malignant melanoma. About 1 week after the second administration of nivolumab and ipilimumab, acute kidney injury developed. A renal biopsy was performed that showed TIN and non-necrotizing granulomatous vasculitis in interlobular arteries. Massive CD3+ T cells and CD163+ macrophages infiltrated both tubulointerstitium and interlobular arteries. Many infiltrating cells tested positive for Ki-67 and PD-1 ligand (PD-L1), but negative for PD-1. In CD3+ T cells, CD8+ T cells were predominantly infiltrated, and these cells were positive for Granzyme B (GrB) and cytotoxic granule TIA-1, but negative for CD25, indicating antigen-independent activated CD8+ T cells. Infiltration of CD4+ T cells was noted without obvious CD4+ CD25+ regulatory T (Treg) cells. His renal dysfunction recovered within 2 months of treatment with prednisolone in addition to discontinuation of nivolumab and ipilimumab. CONCLUSIONS: We herein reported a case of ICI-related TIN and renal granulomatous vasculitis with infiltration of massive antigen-independent activated CD8+ T cells and CD163+ macrophages, and none or few CD4+ CD25+ Treg cells. These infiltrating cells might be a characteristic of the development of renal irAE.

The reduced number of nephrons with shortening renal tubules in mouse postnatal adverse environment.

BACKGROUND: The intrauterine adverse environment during nephrogenesis reduces the nephron number, probably associates with impaired ureteric bud (UB) branching. METHODS: The kidneys in C57/BL6 mice were irradiated with a single dose of 10 gray (10 Gy) as adverse environment on postnatal day 3 (irradiated PND3 kidneys) after UB branching ceased. The renal functions and pathological findings of irradiated PND3 kidneys were compared with those of non-irradiated control and 10 Gy irradiation on PND14 (irradiated PND14 kidney) from 1 to 18 months. RESULTS: The number and density of glomeruli in irradiated PND3 kidneys were reduced by 1 month with renal dysfunction at 6 months. The morphologically incomplete glomeruli with insufficient capillaries were involuted by 1 month in the superficial cortex. Reduced tubular numbers and developmental disability with shortening renal tubules occurred in irradiated PND3 kidneys with impaired urine concentration at 6 months. Hypertrophy of glomeruli developed, and occasional sclerotic glomeruli appeared in the juxtamedullary cortex with hypertension and albuminuria at 12 to 18 months. CONCLUSIONS: The reduced number of nephrons with shortening renal tubules occurred with impaired renal functions in a postnatal adverse environment after cessation of UB branching, and glomerular hypertrophy with occasional glomerulosclerosis developed accompanied with hypertension and albuminuria in the adulthood. IMPACT: The reduced number of nephrons with shortening renal tubules occurred with impaired renal functions in a postnatal adverse environment after cessation of ureteric bud branching. The reduced number of glomeruli were associated with not only the impaired formation of glomeruli but also involution of morphologically small incomplete glomeruli after an adverse environment. The insufficiently developed nephrons were characterized by the shortening renal tubules with impaired urine concentration. In addition, glomerular hypertrophy and occasional glomerulosclerosis developed with hypertension and albuminuria in adulthood. The present study can help to understand the risk of alternations of premature nephrons in preterm neonates.

A Case of Metastatic Submandibular Salivary Duct Carcinoma that Completely Responded to Pembrolizumab Monotherapy.

Salivary gland carcinoma is a rare cancer and has more than 20 histopathological types. Although chemotherapy has been the mainstay of treatment for unresectable carcinomas such as multiple recurrence and distant metastasis, no standard regimen is available. In this article, we report a case of poorly differentiated salivary duct carcinoma of the submandibular gland with distant metastases that was successfully treated with pembrolizumab monotherapy. A 66-year-old man became aware of a left submandibular mass 2 months before his first visit to our department. A needle biopsy at a previous hospital revealed carcinoma, not otherwise specified. The combined positive score on a programmed death ligand-1 immunohistochemistry test was 1-10%. The patient was referred to our department for further treatment. Computed tomography revealed left level II and IV neck lymphadenopathy, bilateral lung shadowing, and osteolytic changes in the 12th thoracic vertebra. Needle biopsy showed poorly differentiated carcinoma, positive human epidermal growth factor receptor 2, and positive androgen receptor, which suggested salivary duct carcinoma. These findings indicated a diagnosis of submandibular carcinoma T4aN2bM1 stage IVC. Pembrolizumab monotherapy was started, and tumor shrinkage was observed after three courses of treatment. At 1 year, complete response was achieved without adverse events, and treatment is ongoing. Despite a lack of evidence for the efficacy of immune checkpoint inhibitors in salivary gland carcinoma, the present case suggests that some patients might respond to this treatment. Hence, clinical trials are warranted.

Inhibition of the chemokine signal regulator FROUNT by disulfiram ameliorates crescentic glomerulonephritis.

Activated monocytes/macrophages promote glomerular injury, including crescent formation, in anti-glomerular basement membrane (GBM) glomerulonephritis. Disulfiram, an alcohol-aversion drug, inhibits monocyte/macrophage migration by inhibiting FROUNT, a cytosolic protein that enhances chemokine receptor signaling. Our study found that disulfiram at a human equivalent dose successfully blocked albuminuria and crescent formation with podocyte loss, and later stage kidney fibrotic lesions, in a rat model of anti-GBM glomerulonephritis. A disulfiram derivative, DSF-41, with more potent FROUNT inhibition activity, inhibited glomerulonephritis at a lower dose than disulfiram. Disulfiram markedly reduced the number of monocytes or macrophages at the early stage of glomerulonephritis and that of CD3+ and CD8+ lymphocytes at the established stage. Impaired pseudopodia formation was observed in the glomerular monocytes/macrophages of the disulfiram group; consistent with the in vitro observation that disulfiram blocked chemokine-dependent pseudopodia formation and chemotaxis of bone marrow-derived monocytes/macrophages. Furthermore, disulfiram suppressed macrophage activation as revealed by reduced expression of inflammatory cytokines and chemokines (TNF-α, CCL2, and CXCL9) and reduced CD86 and MHC class II expressions in monocytes/macrophages during glomerulonephritis. The dramatic reduction in monocyte/macrophage number might have resulted from disulfiram suppression of both the chemotactic response of monocytes/macrophages and their subsequent activation to produce cytokines and chemokines, which further recruit monocytes. Additionally, FROUNT was expressed in CD68+ monocytes/macrophages infiltrating the crescentic glomeruli in human anti-GBM glomerulonephritis. Thus, disulfiram can be a highly effective and safe drug for the treatment of glomerulonephritis by blocking the chemotactic responses of monocytes/macrophages and their activation status in the glomerulus.

Heavy Metal Enhancement Technique for Diaminobenzidine in Immunohistochemistry Enables Ultrastructural Observation by Low-vacuum Scanning Electron Microscopy.

Low-vacuum scanning electron microscopy (LV-SEM) is a powerful tool that allows to observe light microscopic specimens with periodic acid-silver methenamine (PAM) staining at a higher magnification, simply by removing the coverslip. However, it is not suitable for observation of immunohistochemistry (IHC) using 3,3'-diaminobenzidine (DAB) due to insufficient backscattered electron image. Traditional heavy metal enhancement techniques for DAB in IHC, (1) osmium tetroxide and iron, (2) cobalt, (3) methenamine silver (Ag), (4) gold chloride (Gold), and (5) both Ag and Gold (Ag + Gold), were examined by LV-SEM. Tissue specimens from Thy1.1 glomerulonephritis rat kidney stained with α-smooth muscle actin and visualized with DAB were enhanced by each of these enhancement methods. We found, in light microscopic and LV-SEM, that the enhancement with Ag, Gold, or Ag + Gold had better intensity and contrast than others. At a higher magnification, Ag + Gold enhancement showed high intensity and low background, although only Ag or Gold enhancement had nonspecific background. Even after observation by LV-SEM, the quality of specimens was maintained after remounting the coverslip. It was also confirmed that Ag + Gold enhancement could be useful for IHC using clinical human renal biopsy. These findings indicate that Ag + Gold provided an adequate enhancement in IHC for both LM and LV SEM observation.

Malignant granular cell tumors: Combining cytological and pathological findings for a definitive diagnosis.

Malignant granular cell tumors (GCTs) account for less than 2% of all GCTs and mainly occur in the deep soft tissue of the thigh or trunk. Malignant GCTs are highly aggressive tumors with high rates of recurrence and metastasis. In this brief report, we describe a rare case of malignant GCT in a 64-year-old Japanese man who presented with a 14 × 20 cm mass in the left inguinal region. The cytologic findings of fine-needle aspiration (FNA) revealed atypical epithelial-like granular cells with granular substance in the background, which was difficult to differentiate from apocrine carcinoma or melanoma. The immunohistochemistry (IHC) findings of the needle biopsy revealed that the tumor cells were positive for S-100 and lysosomal marker CD68 which was suggestive of a GCT. However, the presence of crush artifacts made it challenging to identify cellular atypia, which is a characteristic of malignant tumor. Taken together, the FNA and needle biopsy results were suggestive of malignant GCT. The importance of preoperative diagnosis of malignant GCT is well known, but few reports have described its cytological findings. In our brief report, we show that combining cytological FNA and biopsy findings with IHC findings achieves an accurate diagnosis of malignant GCT.

A case of juvenile-onset fibrillary glomerulonephritis diagnosed by mass spectrometry and immunohistochemistry of DNAJB9.

Fibrillary glomerulonephritis (FGN) is a rare glomerular disease. FGN is characterized by the deposition of randomly arranged, nonbranching microfibrils in the mesangium and glomerular basement membrane. The discovery of DNAJ homolog subfamily B member 9 (DNAJB9) in 2017 was a breakthrough, and DNAJB9 has been proven to be extremely useful for the definitive diagnosis of FGN. While FGN often occurs in middle-aged individuals, this case was diagnosed at a relatively young age of 17. We performed renal biopsy, and light microscopic study revealed mesangial proliferation with expansion and subepithelial deposits. Electron microscopic study showed glomerular deposition of randomly oriented nonbranching fibrils with a mean of 20 nm. However, direct first scarlet stain for amyloidosis was weakly positive. Therefore, we confirmed the diagnosis of FGN and eliminated the presence of amyloidosis with mass spectrometry. This is the first case in Japan in which the complication of amyloidosis was ruled out with mass spectrometry and FGN was diagnosed using immunostaining and mass spectrometry of DNAJB9. We began treatment with cyclosporine A. One and a half years after the start of the treatment, kidney function continues to be normal.

A case of pathologically confirmed streptococcal infection-related IgA vasculitis with associated glomerulonephritis and leukocytoclastic cutaneous vasculitis.

We report the case of an 80 year-old woman who developed bilateral lower extremity purpura and renal impairment with proteinuria a few days after a transient fever (day 0). High levels of both anti-streptolysin-O antibody (ASO) and anti-streptokinase antibody (ASK), as well as low levels of coagulation factor XIII in serum were noted. Skin biopsy was performed and showed a leukocytoclastic vasculitis with deposition of IgA and C3 in the cutaneous small vessels, indicating IgA vasculitis in the skin. After initiation of oral prednisolone, the skin lesions showed significant improvement. However, renal function and proteinuria gradually worsened from day 12. Kidney biopsy was performed on day 29, which demonstrated a necrotizing and crescentic glomerulonephritis with mesangial deposition of IgA and C3. In addition, the deposition of galactose-deficient IgA1 (Gd-IgA1) was positive on glomeruli and cutaneous small vessels, indicating that the purpura and glomerulonephritis both shared the same Gd-IgA1-related pathogenesis. In addition, the association between the acute streptococcal infection and the IgA vasculitis was confirmed by the deposition of nephritis-associated plasmin receptor (NAPlr) in glomeruli. The patient was treated with steroid pulse and intravenous cyclophosphamide, in addition to the oral prednisolone treatment. Renal function and proteinuria gradually improved, but did not completely recover, as is typically seen with courses of IgA vasculitis in the elderly. In this case, the streptococcal infectionrelated IgA vasculitis was confirmed pathologically by the deposition of both NAPlr and Gd-IgA1 in glomeruli, as well as Gd-IgA1 in the cutaneous small vessels.

A case of proliferative glomerulonephritis with monoclonal IgG3κ deposits accompanied by glomerular capillary microaneurysms.

Glomerular capillary aneurysms are distinctly rare and specific glomerular lesions characterized by aneurysmal dilatation of the glomerular capillaries. This formation is associated with glomerular capillary injuries with focal mesangiolysis. Here, we report a case of proliferative glomerulonephritis with monoclonal immunoglobulin G deposits (PGNMID) presenting with multiple glomerular capillary microaneurysms. A 53-year-old woman presented with persistent proteinuria and microhematuria. She had no underlying diseases, such as hematopoietic or lymphoproliferative disorders. A renal biopsy showed diffuse membranoproliferative lesions with foam cell infiltration and multiple microaneurysms of the glomerular capillary on light microscopy. Immunofluorescence analysis showed granular deposits of monoclonal immunoglobulin G3 kappa (IgG3κ), C1q, C3, and C4 in the glomeruli. Electron microscopy revealed different sizes of non-organized electron-dense deposits in the mesangial, subendothelial, and subepithelial areas. In addition, glomerular endothelial cells showed swelling and loss of fenestra or diffuse formation of fenestrated diaphragms, accompanied by irregular thinning of the glomerular basement membrane. Furthermore, immunostaining for CD31 (a marker for endothelial cell) and low-vacuum scanning electron microscopy study identified loss of endothelial cells in microaneurysm, suggesting severe glomerular endothelial cell injury. After a renal biopsy, only the medication for dyslipidemia was continued because there were no physical symptoms, such as edema, and urinary abnormalities continued with stable renal function. Further studies are needed to elucidate the pathogenesis of glomerular capillary injury in PGNMID and clarify the clinical and pathological characteristics of PGNMID with glomerular capillary microaneurysms.

Evaluation of ultrastructural alterations of glomerular basement membrane and podocytes in glomeruli by low-vacuum scanning electron microscopy.

BACKGROUND: Low-vacuum scanning electron microscopy (LV-SEM) is applied to diagnostic renal pathology. METHODS: To demonstrate the usefulness of LV-SEM and to clarify the optimal conditions of pathology samples, we investigated the alterations of glomerular basement membrane (GBM) and podocytes in control and experimental active Heymann nephritis (AHN) rats by LV-SEM. RESULTS: On week 15 following induction of AHN, spike formation on GBM with diffuse deposition of IgG and C3 developed. Using LV-SEM, diffuse crater-like protrusions were clearly noted three-dimensionally (3D) on surface of GBM in the same specimens of light microscopy (LM) and immunofluorescence (IF) studies only after removal coverslips or further adding periodic acid-silver methenamine (PAM) staining. These 3D ultrastructural findings of GBM surface could be detected in PAM-stained specimens by LV-SEM, although true GBM surface findings could not be obtained in acellular glomeruli, because some subepithelial deposits remained on surface of GBM. Adequate thickness was 1.5-5 µm for 10% formalin-fixed paraffin-embedded (FFPE) and 5-10 µm for the unfixed frozen sections. The foot processes and their effacement of podocytes could be observed by LV-SEM using 10%FFPE specimens with platinum blue (Pt-blue) staining or double staining of PAM and Pt-blue. These findings were obtained more large areas in 2.5% glutaraldehyde-fixed paraffin-embedded (2.5%GFPE) specimens. CONCLUSION: Our findings suggest that LV-SEM is a useful assessment tool for evaluating the alterations of GBM and podocytes in renal pathology using routine LM and IF specimens, as well as 2.5%GFPE specimens.

Renal Biopsy-induced Hematoma and Infection in a Patient with Asymptomatic May-Hegglin Anomaly.

The May-Hegglin anomaly is characterized by inherited thrombocytopenia, giant platelets, and leukocyte cytoplasmic inclusion bodies. The Fechtner, Sebastian, and Epstein syndromes are associated with mutations of the MYH9-coding nonmuscle myosin heavy chain IIA, similar to the May-Hegglin anomaly, and are together classified as MYH9 disorders. MYH9 disorders may include symptoms of Alport syndrome, including nephritis and auditory and ocular disorders. A 6-year-old boy was diagnosed with an MYH9 disorder after incidental discovery of hematuria and proteinuria. Focal segmental glomerulosclerosis was detected on renal biopsy. However, despite no prior bleeding diatheses, he developed a large post-biopsy hematoma despite a preprocedural platelet transfusion calculated to increase the platelet count from 54,000/µL to >150,000/µL. Idiopathic thrombocytopenic purpura is a major cause of pediatric thrombocytopenia following acute infection or vaccination, and patients with MYH9 disorders may be misdiagnosed with idiopathic thrombocytopenic purpura and inappropriately treated with corticosteroids. Careful differential diagnosis is important in thrombocytopenic patients with hematuria and proteinuria for the early detection of thrombocytopenia. Patients with MYH9 disorders require close follow-up and treatment with angiotensin II receptor blockers to prevent the onset of progressive nephritis, which may necessitate hemodialysis or renal transplantation. The need for renal biopsy in patients with MYH9 disorders should be carefully considered because there could be adverse outcomes even after platelet transfusion.

Protective Effects of Hydrogen against Irradiation.

Radiation-induced lung injury is characterized by an acute pneumonia phase followed by a fibrotic phase. At the time of irradiation, a rapid, short-lived burst of reactive oxygen species (ROS) such as hydroxyl radicals (•OH) occurs, but chronic radiation-induced lung injury may occur due to excess ROS such as H2O2, O2•-, ONOO-, and •OH. Molecular hydrogen (H2) is an efficient antioxidant that quickly diffuses cell membranes, reduces ROS such as •OH and ONOO-, and suppresses damage caused by oxidative stress in various organs. In 2011, through the evaluation of electron-spin resonance and fluorescent indicator signals, we had reported that H2 can eliminate •OH and can protect against oxidative stress-related apoptotic damage induced by irradiation of cultured lung epithelial cells. We had explored for the first time the radioprotective effects of H2 treatment on acute and chronic radiation-induced lung damage in mice by inhaled H2 gas (for acute) and imbibed H2-enriched water (for chronic). Thus, we had proposed that H2 be considered a potential radioprotective agent. Recent publications have shown that H2 directly neutralizes highly reactive oxidants and indirectly reduces oxidative stress by regulating the expression of various genes. By regulating gene expression, H2 functions as an anti-inflammatory and anti-apoptotic molecule and promotes energy metabolism. The increased evidence obtained from cultured cells or animal experiments reveal a putative place for H2 treatment and its radioprotective effect clinically. This review focuses on major scientific advances in the treatment of H2 as a new class of radioprotective agents.

Uterine leiomyosarcomas with osteoclast-like giant cells associated with high expression of RUNX2 and RANKL.

Uterine leiomyosarcoma (ULMS) with osteoclast-like giant cells (OLGCs) has been reported as a rare phenomenon in ULMS, and its clinico-pathological features and tumorigenesis remain unclear. We recently reported high expression of receptor activator of nuclear factor κB ligand (RANKL) in ULMS with OLGCs. As osteoblasts produce RANKL, in this study, we analyzed the expression of Runt-related transcription factor 2 (RUNX2), a critical transcription factor for osteoblasts, and osteoclast-related proteins in three cases of ULMS with OLGCs as well as five conventional ULMSs and nine leiomyomas. Immunohistochemistry and real-time reverse transcription quantitative polymerase chain reaction analyses showed high expression of RUNX2 and RANKL in ULMS with OLGCs. In these cases, macrophages expressed receptor activator of nuclear factor κB (RANK), and OLGCs expressed osteoclast-related proteins (nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), and cathepsin K). Accumulation sites of cathepsin K-positive OLGCs showed hemorrhagic appearance and degraded type IV collagen. We reviewed reported cases of ULMS with OLGCs, including ours, and found that they presented an aggressive course even at stage I. Furthermore, metastatic lesions showed similar histological features to those of OLGC association in ULMS. Here, we show that tumor cells in ULMS with OLGCs highly express RUNX2 and RANKL and that osteoclastic differentiation of macrophages occurs in the tumor tissue.