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.

GATA-3 is upregulated in peripheral blood mononuclear cells from patients with minimal change nephrotic syndrome.

BACKGROUND: An imbalance of Th1 and Th2 cytokines has been reported in MCNS. Interleukin-13 (IL-13: Th2 cytokine) has been implicated in the pathogenesis of MCNS, but Th1/Th2 regulators such as T-bet (Th1-specific transcription factor) and GATA-3 (Th2-specific transcription factor) have not been examined. METHODS: We isolated PBMC from 25 patients with MCNS during nephrosis and remission phases, from 17 nephrotic patients with membranous nephropathy (MN), and from 25 healthy subjects. We measured mRNA expression levels of T-bet, GATA-3, Stat5A (regulator of Th2 priming), IFN-gamma (Th1 cytokine), IL-2 (Th1 cytokine and activator of Stat5), IL-4 (Th2 cytokine), and IL-13 in PBMC, using real-time RT-PCR. RESULTS: GATA-3, Stat5A, and IL-13 mRNA expression levels were higher in the nephrotic MCNS group compared to the others. IL-2 mRNA expression levels were higher in nephrotic patients with MCNS and MN than in MCNS patients in remission and healthy controls. There were no differences in mRNA expression levels of T-bet, IFN-gamma, and IL-4 between MCNS and MN patients and healthy controls. CONCLUSIONS: This study is the first to reveal increased mRNA expression levels of GATA-3 and Stat5A in PBMC from MCNS patients in nephrosis. This study also supports recent findings suggesting the role of IL-13 in the development of MCNS. A predominant Th2 type of T cell activation may be involved in the pathogenesis of MCNS.

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.

Renal amyloidosis associated with extracapillary glomerulonephritis and vasculitis in a patient with inflammatory bowel disease treated with infliximab.

A 70-year-old woman with an 11-year history of indeterminate inflammatory bowel disease developed rapidly progressive glomerulonephritis (RPGN) 3 months after the initiation of infliximab therapy. A renal biopsy showed Congo red-positive homogenous deposits in the mesangial area, glomerular capillary walls and arterial walls. Cellular and fibrocellular crescents were observed in 7 of 28 functioning glomeruli. There were findings of active tubulointerstitial nephritis and vasculitis of the small arteries. On electron microscopy, amyloid fibrils were observed in the deposits. Immunohistochemistry showed positive staining for amyloid A (AA) protein. After cessation of infliximab therapy, she was treated with methylprednisolone pulse therapy followed by oral prednisolone therapy. Thereafter, her RPGN was improved. This is a rare case of co-existent focal extracapillary glomerulonephritis with vasculitis and AA renal amyloidosis. Considering the temporal association of drug use with new onset of RPGN in our patient, we suggest a causal link between infliximab and RPGN due to extracapillary glomerulonephritis and vasculitis.

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.

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.