Nobuki Maki

Up‐regulated expression of Toll‐like receptors mRNAs in peripheral blood mononuclear cells from patients with systemic lupus erythematosus

Recent studies in animal models for systemic lupus erythematosus (SLE) have shown that Toll‐like receptors (TLR‐7 and TLR‐9) and interferon (IFN)‐α are involved in the pathogenesis of murine lupus. Recent studies using flow cytometry have also shown increased expression of TLR‐9 in peripheral blood mononuclear cells (PBMCs) from SLE patients. In this study, we performed quantitative real‐time reverse transcription–polymerase chain reaction analyses of PBMCs from 21 SLE patients and 21 healthy subjects, to estimate TLR2, TLR3, TLR4, TLR5, TLR7, TLR8, TLR9, IFN‐α and LY6E (a type I IFN‐inducible gene) mRNA expression levels. Expression levels of TLR2, TLR7, TLR9, IFN‐α and LY6E mRNAs in SLE patients were significantly higher than those in healthy controls. Expression levels of TLR7 and TLR9 mRNAs correlated with that of IFN‐α mRNA in SLE patients. These results suggest that up‐regulated expression of TLR7 and TLR9 mRNAs together with increased expression of IFN‐α mRNA in PBMCs may also contribute to the pathogenesis of human lupus.

Monoclonal immunoglobulin deposition disease associated with membranous features

BACKGROUND Very few cases of non-organized and non-Randall-type monoclonal immunoglobulin deposition disease (MIDD) associated with membranous features have been reported. Information on clinicopathological features and prognosis in this entity is limited. METHODS We reviewed 5443 renal biopsies processed at our department, and identified three patients with MIDD associated with membranous features. We evaluated clinicopathological features and outcomes in these patients. RESULTS All patients had proteinuria, and one patient developed nephrotic syndrome. Renal insufficiency was not observed. Cryoglobulin or monoclonal protein in serum and urine was not detected. A renal biopsy showed thickening of the glomerular capillary walls and spike formation. Tubulointerstitial and vascular alterations were mild or absent. Immunofluorescence studies revealed granular IgG3-kappa deposits in two patients and IgG1-kappa deposits in one patient, along the glomerular capillary walls. Immunofluorescence studies using antibodies specific for gamma-heavy chain Fab containing C(H)1 domain, C(H)2 domain and C(H)3 domain did not show any apparent deletion. On confocal microscopy, glomerular colocalization of light and heavy chains was observed. Electron microscopy showed predominant subepithelial granular deposits without distinct ultrastructural organization. All patients were treated with steroids, and good effects were observed. A follow-up renal biopsy performed in one patient showed histological improvements. No patient developed myeloma or other haematological malignancy during the course of follow-up (mean 44 months). CONCLUSIONS MIDD associated with membranous features is an extremely rare but distinctive entity. Our study suggests glomerular deposition of a nondeleted whole immunoglobulin molecule. Patients with this entity appear to respond well to steroid therapy.

The HLA-DRB1 * 1501 allele is prevalent among Japanese patients with anti-glomerular basement membrane antibody-mediated disease

BACKGROUND We aimed to clarify the relationship between HLA-DRB1(*)1501 and anti-glomerular basement membrane (GBM) antibody-mediated disease in Japanese patients. MATERIALS Samples were collected from 16 anti-GBM antibody-positive patients who were admitted to our department or related hospitals from December 1990 to October 2005. We analysed clinical and laboratory data, kidney biopsy findings, and the HLA-DR phenotypes and HLA-DRB1 alleles of the patients. RESULTS Among the 16 patients, 15 had HLA-DR15 [the phenotype frequency (PF) was 93.8%], 7 were positive for DR4 (the PF was 43.8%) and 5 were positive for DR9 (the PF was 31.3%). The allele frequency of HLA-DRB1(*)1501 was 46.4% (13/28), which was significantly different from Japanese controls (11.6%) (P < 0.001). In contrast, the frequency of HLA-DRB1(*)1502 was not different from controls (0/28). The odds ratio of HLA-DRB1(*)1501 in these patients was 6.4 (95% CI: 2.4-16.5). CONCLUSION The present study demonstrated that Japanese patients with anti-GBM antibody-mediated disease are very likely to carry the HLA-DRB1(*)1501 but not the HLA-DRB1(*)1502 allele.

Clinicopathological features and prognosis in immunoglobulin light and heavy chain deposition disease.

BACKGROUND There are three subtypes of monoclonal immunoglobulin deposition disease: light chain deposition disease (LCDD), light and heavy chain deposition disease (LHCDD), and heavy chain deposition disease (HCDD). Although it has been considered that LHCDD is a variant of LCDD, information on clinicopathological features and prognosis in LHCDD is presently limited. METHODS We reviewed 5,443 renal biopsies, and evaluated clinicopathological features and outcomes in patients with LHCDD, in comparison with those in patients with LCDD and previously reported patients with HCDD. We also characterized paraprotein deposits in patients with LHCDD. RESULTS We identified 6 patients with LHCDD, 6 patients with LCDD, and 1 patient with HCDD. The most common clinicopathological findings in patients with LHCDD were proteinuria, renal insufficiency, and nodular sclerosing glomerulopathy. Three patients had IgG-k deposits and 3 patients had IgG-l deposits. Heavy chain subclass analysis performed in 4 patients showed IgG3 deposits in all patients. Dual immunostaining revealed glomerular colocalization of light and heavy chains. In contrast with LCDD, glomerular C3 and C1q deposits were common findings in LHCDD and HCDD. All patients with LHCDD were treated with steroids and cytotoxic agents, but no effect on proteinuria was observed. Three patients developed end-stage renal disease requiring hemodialysis. The underlying hematological disorders in LHCDD and HCDD were milder than in LCDD. Early renal survival and overall patient survival in our patients appeared to be better in LHCDD than in LCDD. CONCLUSIONS There are apparent differences in clinicopathological features and prognosis between LHCDD and LCDD. LHCDD is probably more similar to HCDD.

Successful treatment of post-MRSA infection glomerulonephritis with steroid therapy

A 48-year-old man without underlying disease developed mediastinitis and was treated by mediastinal drainage. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in a culture of the abscess material. He was treated with anti-MRSA antibiotics and the MRSA infection improved. Four weeks after the onset of MRSA infection, he developed rapidly progressive glomerulonephritis (RPGN) with nephrotic syndrome (NS). A renal biopsy showed endocapillary proliferative glomerulonephritis with IgA-predominant glomerular deposition. These clinicopathological findings were consistent with those in glomerulonephritis following MRSA infection (post-MRSA infection glomerulonephritis). The level of serum creatinine increased to 6.3 mg/dl, 7 weeks after the onset of RPGN. At that time, the eradication of MRSA infection was considered. He was given middle-dose steroid therapy. Thereafter, his RPGN with NS improved. MRSA infection did not recur. If the disease activity of post-MRSA infection glomerulonephritis persists after the disappearance of MRSA infection, the application of immunosuppressive therapy with steroids may be useful.

Characteristics of proliferative glomerulo-nephritis with monoclonal IgG deposits associated with membranoproliferative features.

BACKGROUND Proliferative glomerulonephritis with monoclonal IgG deposits (PGNMID) associated with membranoproliferative features is an extremely rare entity. Information on clinicopathological features and prognosis in this entity is limited. METHODS We reviewed 5,443 renal biopsies processed at our department, and identified 4 patients with PGNMID associated with membranoproliferative features. We evaluated clinicopathological features and outcomes in these patients, and characterized paraprotein deposits by immunofluorescence studies. RESULTS Three out of 4 patients had nephrotic syndrome with renal insufficiency at presentation. Cryoglobulin or monoclonal protein in serum and urine was not detected. Renal biopsy showed membranoproliferative features with or without nodular formation. Tubulointerstitial and vascular alterations were mild in three patients. All patients had glomerular IgG-kappa deposits. Heavy chain subclass analysis performed in 3 patients showed IgG3 deposits. Immunofluorescence studies using antibodies specific for gamma-heavy chain C(H)1, C(H)2, and C(H)3 domains and gamma3 hinge did not show any apparent deletion. Confocal microscopy revealed glomerular colocalization of light and heavy chains. On electron microscopy, granular deposits were predominantly mesangial and subendothelial. All patients were treated with steroids and cytotoxic agents, but no effect on proteinuria was observed. The renal outcome was progressive in all patients. Early death was observed in two elder patients. No patient had overt myeloma or lymphoma at presentation or over the course of follow-up (mean 43 months). CONCLUSIONS Our study suggests a predominance of IgG3-kappa glomerular deposits of nondeleted whole immunoglobulin molecules in PGNMID associated with membranoproliferative features. The clinical outcome in patients with this entity appears to be poor.

Analysis of mutations in alpha-actinin 4 and podocin genes of patients with chronic renal failure due to sporadic focal, segmental glomerulosclerosis

Although the pathogenesis of idiopathic focal segmental glomerulosclerosis (FSGS) may be heterogeneous, autosomal dominant and recessive forms of FSGS are recognized. Recently, mutations in alpha-actinin 4 (ACTN4) and podocin genes were reported in patients with such familial FSGS. However, whether mutations in ACTN4 and podocin genes are associated with sporadic FSGS has not been determined. In the present study, we clarified the relation between mutations in ACTN4 and podocin genes and sporadic FSGS. We analyzed these reported mutations in ACTN4 and podocin in five patients with chronic renal failure due to therapy-resistant FSGS by direct sequencing of polymerase chain reaction products of ACTN4 and podocin. We found a C to T transition at nucleotide 465 in the ACTN4 gene in all of patients, and a T to C transition at nucleotide 954 in exon eight of podocin gene in two of five patients, resulting in no amino acid substitutions. Other mutations were not found in ACTN4 and podocin genes. Our findings suggest that sporadic FSGS is a heterogeneous disease, since ACTN4 and podocin genes are not found in our patients with sporadic FSGS.

Interaction of the spectrin-like repeats of alpha-actinin-4 with humanin peptide

BackgroundPodocyte alpha-actinin-4 (actinin-4) is an essential component of the glomerular filtration barrier. We recently reported that the central rod spectrin-like repeats (R1–R4) of actinin-4 have a high affinity to puromycin aminonucleoside (PAN), which can induce nephro-sis in animals. The aim of this study was to identify endogenous molecules that interact with the actinin-4 R1–R4 domain.MethodsTo identify such molecules, we performed a bacterial two-hybrid screening of a human kidney cDNA library using as a bait human actinin-4 R1–R4. We further verified the identified interactions by in vitro affinity assays and immunofluorescent studies of cultured human embryonic kidney HEK293 cells. To investigate the expression of the identified molecules in podocytes, in situ hybridization, and immunohistochemical studies were performed.ResultsOne isolated cDNA from the library encoded humanin, a recently identified antiapoptotic peptide. In vitro affinity assays showed specific interactions of recombinant actinin-4 R1–R4, R1, R2, R3, and R4 proteins with humanin-Sepharose. PAN had no effect on these interactions. Green fluorescent protein-fused humanin and endogenous actinin colocalized mainly in the perinuclear cytoplasm of HEK293 cells. Altered colocalization was not observed by the addition of PAN. In situ hybridization and immunohistochemistry showed the expression of humanin in podocytes.ConclusionsOur results suggest that humanin is a novel binding partner of the actinin-4 R1–R4 domain in podocytes. Humanin and PAN are unlikely to compete for the same binding surface in actinin-4.

Cutaneous polyarteritis nodosa in a patient with Crohn's disease

A 19-year-old Japanese woman with a 4-year history of Crohn’s disease (CD) developed high fever, polyarthralgia, and painful subcutaneous nodules of the legs. A skin biopsy showed panarteritis with fibrinoid necrosis in the deep dermis. Endoscopic examination showed aphthous lesions in the entire colon. She was diagnosed with cutaneous polyarteritis nodosa (PAN) associated with CD. Steroid therapy improved her symptoms. To our knowledge, this is the first Japanese case of cutaneous PAN associated with CD.

Increased serum levels of S100A12 in patients with MPO-ANCA-associated glomerulonephritis

BACKGROUND Increased serum levels of S100A12, a proinflammatory protein secreted by activated neutrophils, have recently been shown in patients with active inflammatory diseases, such as rheumatoid arthritis and Kawasaki disease. In this study, we investigated serum levels of S100A 12 in patients with small-vessel vasculitis, myeloperoxidase anti-neutrophil cytoplasmic antibodies- (MPO-ANCA) associated pauci-immune glomerulonephritis. METHODS Serum S100A12 concentrations were measured by a sandwich enzyme-linked immunosorbent assay (ELISA) in 46 patients with MPO-ANCA-associated glomerulonephritis and 29 healthy controls. We analyzed correlations between serum S100A12 levels and a clinical index of vasculitis activity, the Birmingham Vasculitis Activity Score (BVAS), various laboratory parameters, and pathological activity scores in the patients. We also analyzed changes of serum S100A12 levels in 10 patients after treatment. RESULTS ELISA showed about 4-fold higher levels of serum S100A12 in patients with MPO-ANCA-associated glomerulonephritis than healthy controls. Serum S100A12 levels correlated with the BVAS scores, the peripheral white blood cell count, levels of serum C-reactive protein and creatinine, and pathological activity scores in the patients, but did not correlate with serum MPO-ANCA titers. Serum S100A12 levels after treatment decreased in all the 10 patients examined. CONCLUSION We demonstrated that increased serum S100A12 levels correlate with clinical, laboratory and pathological parameters of disease activity in patients with MPO-ANCA-associated glomerulonephritis. Serum S100A12 level may be one of the useful markers of disease activity in MPO-ANCA-associated glomerulonephritis.