Evaluation of a newly proposed renal risk score for Japanese patients with ANCA-associated glomerulonephritis

BACKGROUND

We determined the usefulness and prognostic ability of the renal risk score (RRS), proposed in Europe, for Japanese patients with antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (AAGN) and high myeloperoxidase (MPO)-ANCA positivity; these aspects remain to be verified.

METHODS

This retrospective study was conducted on 86 Japanese patients with new, biopsy-confirmed AAGN. We calculated the RRS and analyzed the relationship between this classification, and clinicopathological features and prognosis. We also compared the predictive values between RRS for endpoints including renal death and conventional prognostic tools for patients with AAGN.

RESULTS

There were 33, 37, and 16 patients in the low-, medium-, and high-risk groups, respectively. All patients were MPO-ANCA positive. The median follow-up period was 33 months; 16 (18.6%) patients progressed to end-stage renal disease (ESRD). In the high-risk group, 9/16 (56.3%) patients progressed to ESRD, and renal prognosis was significantly poorer than that in other groups (low-risk group, P < 0.001; medium-risk group, P = 0.004). In Cox multivariate regression analysis, RRS was an independent, poor renal prognostic factor (hazard ratio 5.22; 95% confidence interval 2.20-12.40; P < 0.001). The receiver-operating characteristic curves of the RRS for each endpoint were comparable with those of the 2010 histological classification and those of the severity classification of Japanese rapidly progressive glomerulonephritis.

CONCLUSIONS

This is the first study to report the usefulness of the RRS for predicting renal outcomes among Japanese patients with AAGN. Our predictive value of the RRS was comparable with that of conventional prognostic tools.

Discrete renal deposition of IgM heavy chain and κ light chain in Waldenström macroglobulinemia (IgM-κ)

We report previously undescribed renal lesions associated with monoclonal gammopathy in a 59-year-old man with Waldenström macroglobulinemia (IgM-κ). Light microscopy showed mesangial proliferation and thickening of glomerular basement membranes (GBMs) and tubular basement membranes (TBMs). Neither intraglomerular thrombi nor nodular glomerulosclerosis was observed. Immunofluorescence studies disclosed essentially discrete localization of IgM heavy chain within the mesangial area and κ light chain along GBMs and TBMs. Electron microscopy showed continuous linear deposits of finely granular electron-dense material along the inner aspect of GBMs and TBMs. Repeated rituximab treatment and chemotherapy (melphalan and prednisolone) led to the improvement of proteinuria.

Thrombotic thrombocytopenic purpura with severe ADAMTS-13 deficiency in a patient with antiphospholipid antibodies and Charcot-Marie-Tooth disease

A 26-year-old woman with a history of mild mental retardation, Charcot-Marie-Tooth disease (CMT) and idiopathic thrombocytopenic purpura developed severe thrombocytopenia with Coombs-negative hemolytic anemia. Magnetic resonance imaging revealed a fresh cerebral infarction in the left precentral gyrus. ADAMTS-13 deficiency caused by an inhibitor and anti-cardiolipin antibodies were detected in the blood. After treatment with prednisolone and fresh frozen plasma, ADAMTS-13 activity was normalized, the ADAMTS-13 inhibitor had disappeared and the thrombocytopenia with a bleeding tendency was improved. To our knowledge, this is the first case of thrombotic thrombocytopenic purpura caused by ADAMTS-13 deficiency associated with antiphospholipid antibodies and CMT.

Tubulointerstitial nephritis and renal tubular acidosis of different types are rare but important complications of primary biliary cirrhosis

BACKGROUND

A very few cases of biopsy-proven tubulointerstitial nephritis (TIN) in patients with primary biliary cirrhosis (PBC) have been reported. Although the clinical importance of this association has been suggested, information on its clinicopathological features and prognosis is limited.

METHODS

We reviewed 5955 renal biopsies processed at our department, and identified four patients with TIN associated with asymptomatic PBC. We evaluated clinicopathological features and outcomes in these patients, and reviewed the previously reported cases of TIN associated with PBC.

RESULTS

Our four patients were female. The patients' age at the time of renal biopsy ranged from 36 to 77. Three patients had been treated with ursodeoxycholic acid. All patients had urinary abnormalities such as proteinuria and elevated levels of urinary β(2)-microglobulin, and three patients had renal insufficiency. All patients had distal renal tubular acidosis (RTA), and two patients also had Fanconi syndrome. Renal biopsy showed severe lymphocyte infiltration in the tubules and interstitium with mild-to-moderate tubular atrophy and fibrosis. All patients responded well to steroid therapy. On review of the previously reported five cases, all patients were female. The patients' age ranged from 42 to 68. Apparent symptoms linked to PBC were not described. All patients had renal insufficiency. Three patients suffering from bone pains or bone fractures also had Fanconi syndrome. Marked or transient improvements were observed after steroid therapy in three patients.

CONCLUSIONS

TIN and RTA of different types are extremely rare but one of the important extrahepatic complications of PBC. Steroid therapy can be beneficial in treating PBC patients with these renal complications.

Simultaneous herpes simplex virus esophagitis and lupus enteritis in a patient with systemic lupus erythematosus

A 52-year-old woman with a 6-year history of systemic lupus erythematosus (SLE) developed acute abdominal pain, nausea, vomiting, and diarrhea accompanied by hypocomplementemia. Herpes simplex virus (HSV) esophagitis and lupus enteritis were diagnosed on the basis of the results of endoscopic and histological examinations and abdominal computed tomography (CT) findings. Treatment with acyclovir followed by high-dose intravenous steroids improved her symptoms. To our knowledge, this is the first case of simultaneous HSV esophagitis and lupus enteritis.

Differences between Myeloperoxidase-Specific and -Nonspecific P-ANCA-Associated Renal Disease

BACKGROUND

Anti-neutrophil cytoplasmic antibodies (ANCA) are classified into perinuclear (P)-ANCA and cytoplasmic-ANCA by an indirect immunofluorescence (IIF) test with ethanol-fixed neutrophils. Circulating P-ANCA with specificity for myeloperoxidase (MPO) are frequently found in patients with pauci-immune necrotizing glomerulonephritis. P-ANCA without a specificity for MPO are also found in a minority of patients with this form of glomerulonephritis, but their clinicopathological features remain poorly delineated.

METHODS

The clinical data, the renal pathology, and the outcome were compared between 48 patients with MPO-specific P-ANCA-associated glomerulonephritis (MPO-specific group) and five patients with MPO-nonspecific P-ANCA-associated glomerulonephritis (MPO-nonspecific group). In the MPO-nonspecific group, antibodies against bactericidal/permeability-increasing protein were detected in one patient, but the other known antibodies that can produce a P-ANCA pattern on the IIF test were not detected in the remaining patients. All patients in the two groups were treated with steroids with or without cyclophosphamide.

RESULTS

There were no remarkable differences in the degree of hematuria and serum levels of C-reactive protein and creatinine between the two groups. In contrast, proteinuria levels and the rate of glomerular crescent formation were higher in the MPO-nonspecific group than in the MPO-specific group. While the patient survival rate was similar between the two groups, the renal survival rate was lower in the MPO-nonspecific group.

CONCLUSIONS

This pilot analysis suggests that there are clinicopathological differences between patients with MPO-specific and -nonspecific P-ANCA-associated pauci-immune necrotizing glomerulonephritis. Renal lesions appear to be more active in patients with MPO-nonspecific P-ANCA than in patients with MPO-specific P-ANCA.

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.

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.

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)-alpha 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-alpha and LY6E (a type I IFN-inducible gene) mRNA expression levels. Expression levels of TLR2, TLR7, TLR9, IFN-alpha 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-alpha mRNA in SLE patients. These results suggest that up-regulated expression of TLR7 and TLR9 mRNAs together with increased expression of IFN-alpha mRNA in PBMCs may also contribute to the pathogenesis of human lupus.

Up-regulation of TRAIL mRNA expression in peripheral blood mononuclear cells from patients with active systemic lupus erythematosus

It is recently suggested that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is involved in the pathogenesis of systemic lupus erythematosus (SLE). In this study, we examined whether expression levels of TRAIL depend on SLE activity. To estimate TRAIL mRNA expression levels in peripheral blood mononuclear cells (PBMC), we performed quantitative real-time reverse transcription-polymerase chain reaction analyses of PBMC from 18 SLE patients and 20 healthy subjects. Serum soluble TRAIL (sTRAIL) concentrations were measured by an enzyme-linked immunosorbent assay. The mean TRAIL mRNA expression level and serum sTRAIL concentration in SLE patients were significantly higher than those in healthy controls. Expression levels of TRAIL mRNA correlated with the SLE disease activity index and circulating immune complexes levels, while serum sTRAIL concentrations did not. These results indicate that increased expression of TRAIL mRNA in PBMC closely correlates with SLE activity and suggest an important role for TRAIL in the pathogenesis of SLE.

Nodular mesangial lesions, marked mesangiolysis, and fingerprint deposits of unknown origin in a patient with nephrotic syndrome: a unique combination of glomerular lesions

A 46-year-old woman developed nephrotic syndrome at the age of 16 in 1973. On the basis of the histological findings of the first renal biopsy, she was diagnosed as having minimal change nephrotic syndrome. Initial treatment with steroid was effective, but she had several relapses during tapering of the daily dose of steroid. The second renal biopsy, performed in 1997, disclosed glomerular lobulation, mesangial proliferation, nodular mesangial lesions, and mesangiolysis. From 2001, the degree of proteinuria increased, with urinary protein being 5 g/day in January 2003, when a third renal biopsy was performed. On light microscopy, the glomerular lesions were similar to those observed in 1997. Immunofluorescence microscopy revealed coarse granular stainings for IgG, IgA, IgM, kappa, lambda, and C3 in the mesangial area and along the capillary walls. On electron microscopy, fingerprint structures were observed in the mesangial and subendothelial deposits. There were no characteristic fibers in the nodular lesions. On the basis of clinical and laboratory findings in this patient, we excluded disease entities in which nodular mesangial lesions, mesangiolysis, and fingerprint deposits had been reported. To our knowledge, such a unique combination of glomerular lesions has not been described previously in the literature.

Analysis of the NPHP genes in two Japanese patients with suspected sporadic juvenile or adolescent nephronophthisis

BACKGROUND

Mutations in 3 genes (NPHP1, NPHP3 and NPHP4) have been identified in patients with juvenile or adolescent nephronophthisis (NPHP) without extrarenal involvement, mainly in patients from western countries. In this study, we analyzed mutations in the NPHP genes of 2 Japanese patients with suspected sporadic juvenile or adolescent NPHP without extrarenal involvement.

METHODS

A renal biopsy was performed in the 2 patients. Genomic DNA was prepared from peripheral blood mononuclear cells of the patients and their family members. The above NPHP genes were examined by deletion analysis or direct automated sequencing of polymerase chain reaction-amplified DNA products.

RESULTS

Histological findings in the patients were compatible with those of NPHP. In 1 patient, we identified a novel deletion mutation including about half of exons of the NPHP1 gene. In another patient, there was no mutation in the NPHP genes examined.

CONCLUSIONS

We found a novel NPHP1 deletion in 1 patient. To our knowledge, this is the second Japanese NPHP case in which genetic diagnosis was made.

Development of lupus nephritis in a patient with human T-cell lymphotropic virus type I-associated myelopathy

A 77-year-old Japanese man with a 14-year history of human T-cell lymphotropic virus type I-associated myelopathy developed pancytopenia, proteinuria, renal dysfunction, and hypocomplementemia. Antinuclear antibody and anti-double-stranded DNA antibody test results were positive, and circulating immune complexes were detected. A renal biopsy showed diffuse and global mesangiocapillary proliferation with extensive subendothelial deposits. Immunofluorescence microscopy showed strong granular staining for immunoglobulins and complements in the mesangium and along capillary walls. Electron microscopy showed numerous mesangial and subendothelial electron-dense deposits. From these findings, systemic lupus erythematosus and diffuse global lupus nephritis were diagnosed. This is a rare case of a patient developing lupus nephritis during the long-term course of human T-cell lymphotropic virus type I-associated myelopathy.

49, XXXXY syndrome with unilateral renal aplasia, proteinuria, and venous thromboembolism

A 28-year-old man presented with mental retardation, peculiar facial features, radioulnar synostosis, hypogonadism, aplasia of the right kidney, a moderate degree of proteinuria, and peripheral cyanosis. The activated partial thromboplastin time was shortened, and the level of plasma factor VIII was high. A chromosomal analysis revealed a 49, XXXXY karyotype. From the 10th hospital day, he suffered from sudden dyspnea following swelling of the left leg. He was diagnosed as having deep vein thrombosis and pulmonary embolism, and was successfully treated with anticoagulant therapy. This is the first case of the 49, XXXXY syndrome complicated with unilateral renal aplasia, proteinuria, and venous thromboembolism.

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

BACKGROUND

Podocyte 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.

METHODS

To 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.

RESULTS

One 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.

CONCLUSIONS

Our 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.

Distribution of glomerular IgG subclass deposits in malignancy-associated membranous nephropathy

BACKGROUND

Several studies have shown a predominant glomerular deposition of IgG4 in patients with idiopathic membranous nephropathy (MN), whereas significant depositions of other IgG subclasses have been shown in patients with lupus-associated MN and bucillamine-induced MN.

METHODS

We examined the distribution patterns of glomerular IgG subclass deposits in 10 patients with malignancy-associated MN (M-MN) and in 15 patients with idiopathic MN by immunofluorescence (IF) microscopy.

RESULTS

The glomerular IF intensities of IgG1 and IgG2 were significantly stronger in the malignancy group than in the idiopathic group (P<0.05). In contrast, there were no differences in glomerular IF intensities of IgG3 and IgG4 between the two groups.

CONCLUSION

Our findings suggest that the distribution patterns of glomerular IgG subclass deposits are different in idiopathic MN and M-MN. The strong IF intensity of glomerular IgG1 and IgG2 in M-MN may provide a possible predictor for this condition.

Immune complex-type glomerulonephritis with unusual giant deposits in a patient with active rheumatoid arthritis

A 61-year-old woman with rheumatoid arthritis (RA) developed small digital ulcers, proteinuria, and hematuria. Serological studies disclosed high titers of antinuclear antibody and rheumatoid factors (RF; IgM-RF and IgG-RF), and an increased level of circulating immune complexes. These findings suggested an active immunological state of RA. A renal biopsy showed periodic acid-Schiff-positive giant deposits in the mesangial area and subepithelial space. Immunofluorescence microscopy revealed strong stainings for IgG, IgA, IgM, Kappa, Lambda, C3, C1q, and fibrinogen in a granular pattern. Electron microscopy showed giant granular deposits (diameter, up to 4.6 micro m) without specific fibrillary structure in the mesangial area and subepithelial space, and partially in the subendothelial space. There were no findings of vasculitis, such as endothelial proliferation or fibrinoid necrosis of small arteries. This is the first report of immune complex-type glomerulonephritis with unusual giant deposits in a patient with RA in an active immunological state.