Retinal disease in the C3 glomerulopathies and the risk of impaired vision

Background: Dense deposit disease and atypical hemolytic uremic syndrome are often caused by Complement Factor H (CFH) mutations. This study describes the retinal abnormalities in dense deposit disease and, for the first time, atypical haemolytic uremic syndrome. It also reviews our understanding of drusen pathogenesis and their relevance for glomerular disease. Methods: Six individuals with dense deposit disease and one with atypical haemolytic uremic syndrome were studied from 2 to 40 years after presentation. Five had renal transplants. All four who had genetic testing had CFH mutations. Individuals underwent ophthalmological review and retinal photography, and in some cases, optical coherence tomography, and further tests of retinal function. Results: All subjects with dense deposit disease had impaired night vision and retinal drusen or whitish-yellow deposits. Retinal atrophy, pigmentation, and hemorrhage were common. In late disease, peripheral vision was restricted, central vision was distorted, and there were scotoma from sub-retinal choroidal neovascular membranes and atypical serous retinopathy. Drusen were present but less prominent in the young person with atypical uremic syndrome due to a heterozygous CFH mutation. Conclusions: Drusen are common in forms of C3 glomerulopathy caused by compound heterozygous or heterozygous CFH mutations. They are useful diagnostically but also impair vision. Drusen have an identical composition to glomerular deposits. They are also identical to the drusen of age-related macular degeneration, and may respond to the same treatments. Individuals with a C3 glomerulopathy should be assessed ophthalmologically at diagnosis, and monitored regularly for vision-threatening complications.     

Rheumatoid arthritis and membranoproliferative glomerulonephritis: an unusual case

SUMMARY: Renal involvement is not uncommon in rheumatoid arthritis (RA). Many RA patients have renal dysfunction either secondary to the drugs used to treat arthritis or because of the chronic inflammation. Renal pathologies have often included amyloidosis, drug-related renal disease and mesangial glomerulonephritis. However, membranoproliferative glomerulonephritis has only been rarely reported. We report a case of rheumatoid arthritis associated with membranoproliferative glomerulonephritis that rapidly progressed to end-stage renal disease.     

原发性增殖性肾炎β2整合素及L-选择素表达的研究

目的探讨原发增殖性肾小球肾炎(PGN)患者外周血β2整合素(CD11 a、CD11b)、L-选择素(CD62L)的表达,了解它们在PGN发病中的作用机制。方法采用流式细胞技术检测32例PGN患者外周血及肾组织CD11 a、CD11b、CD62L的表达情况,同时观察血胆固醇、低密度脂蛋白、纤维蛋白原、血粘度、血清白蛋白的变化。结果PGN患者外周血CD11 a、CD11b明显低于正常,而CD62L显著升高。CD11b降低程度与CD11 a相一致,且CD11b降低程度与CD62L呈负相关关系。肾组织CD11 a、CD11b表达明显增加,CD11 a增加水平与CD11b呈正相关关系,CD62L波动较大。结论PGN患者外周血及肾组织的β2整合素,L-选择素存在异常,提示CD11 a、CD11b、CD62L在PGN的发病中可能具有一定的作用。     

Characterization of a Factor H Mutation That Perturbs the Alternative Pathway of Complement in a Family with Membranoproliferative GN

Complement C3 activation is a characteristic finding in membranoproliferative GN (MPGN). This activation can be caused by immune complex deposition or an acquired or inherited defect in complement regulation. Deficiency of complement factor H has long been associated with MPGN. More recently, heterozygous genetic variants have been reported in sporadic cases of MPGN, although their functional significance has not been assessed. We describe a family with MPGN and acquired partial lipodystrophy. Although C3 nephritic factor was shown in family members with acquired partial lipodystrophy, it did not segregate with the renal phenotype. Genetic analysis revealed a novel heterozygous mutation in complement factor H (R83S) in addition to known risk polymorphisms carried by individuals with MPGN. Patients with MPGN had normal levels of factor H, and structural analysis of the mutant revealed only subtle alterations. However, functional analysis revealed profoundly reduced C3b binding, cofactor activity, and decay accelerating activity leading to loss of regulation of the alternative pathway. In summary, this family showed a confluence of common and rare functionally significant genetic risk factors causing disease. Data from our analysis of these factors highlight the role of the alternative pathway of complement in MPGN.     

A case of endocapillary proliferative glomerulonephritis with macrophages phagocytosing monoclonal immunoglobulin lambda light chain

Multiple myeloma (MM) is a plasma‐cell neoplasm that can cause renal disorders. Renal lesions in MM can present with a very rare pathological manifestation involving a specific monoclonal immunoglobulin (Ig). We report the case of a 33‐year‐old woman who had edema, fatigue, elevated serum creatinine levels, hypoalbuminemia, and hypercholesterolemia. She had persistent hematuria and proteinuria lasting 3 years. Serum protein electrophoresis showed an M‐spike, and serum immunofixation demonstrated the presence of monoclonal IgG λ. She had proteinuria in the nephrotic range, and a monoclonal λ fragment was present on urine immunofixation. Renal biopsy showed proliferative glomerulonephritis with λ light chain and C3c deposition and inflammatory cell infiltration with CD68. Macrophage lysosomes contained λ light chains, suggesting their partial phagocytosis. She was diagnosed with symptomatic MM and was treated with bortezomib and dexamethasone and an autologous peripheral stem cell transplant conditioned with intravenous melphalan. She achieved a partial response with decreased serum monoclonal protein and improved renal function. This case may be categorized as a monoclonal gammopathy‐associated proliferative glomerulonephritis. The biopsy finding of partially phagocytosed Ig λ light chains by macrophages is very rare; this pathological condition is similar to crystal‐storing histiocytosis.     

Cell Interposition in Glomerular Capillary Walls in Cryoglobulinemic Glomerulonephritis (CRYGN). Ultrastructural Investigation of 23 Cases

The present report describes ultrastructural findings on twenty-three cases of CRYGN showing membranoproliferative pattern under light microscopy. Attention was paid to the presence of double contoured peripheral basement membranes and to the characteristics of the interposed cells. The latter, according to the well known characteristics of membranoproliferative GN, are thought to be mesangial in nature. In fact, mesangial cells were found in 8 cases only, always associated with monocytes. Only monocytes were recorded in 12 cases, whereas in other 3 cases double contours were not connected to cell interposition.

Despite similarities under light microscopy, CRYGN is therefore rather different from idiopathic membranoproliferative GN because of the prevalence of exudative changes, mainly due to monocyte infiltration, over proliferative lesions.     

A Case of Kaposi's Sarcoma Following Treatment of Membranoproliferative Glomerulonephritis and a Review of the Literature

Kaposi's sarcoma (KS) is an unusual tumor principally affecting the skin of the lower extremities. Although the association between KS and renal transplant has been well documented, there are a few KS cases in the literature associated with membranoproliferative glomerulonephritis or other glomerular diseases. This report presents a patient with membranoproliferative glomerulonephritis (MPGN) who developed KS following treatment with long-term medium dose glucocorticoid and short-term additional immunosuppressives. The KS cases associated with glomerulonephritis are also reviewed. KS is a rare complication in glomerular diseases that may (or may not) be related to immunosuppression. Hence, immunosuppression treatment should be carefully planned in glomerulonephritis treatment and avoided if they are not essentially necessary.     

脂多糖诱导大鼠肾小球系膜细胞增殖和分泌细胞外基质的研究

目的观察脂多糖（LPS）对大鼠肾小球系膜细胞（GMC）增殖及分泌细胞外基质（ECM）的作用。方法建立体外培养的大鼠GMC,鉴定后用于实验。实验分为两组：对照组和LPS诱导组。甲基噻唑基四唑（MTT）比色法测定24h和48h两个时点两组系膜细胞的增殖情况;ELISA法测定6h、12h和24h系膜细胞培养上清液中ECM蛋白含量;荧光半定量反转录PCR（RT-PCR）法检测ECM中层黏连蛋白（LN）β2 mRNA表达的变化。结果（1）LPS组和对照组GMC增殖情况间差别有显著性意义（P〈0.05）;（2）正常培养的大鼠GMC可分泌一定量的ECM,LPS组在各时点分泌ECM量与对照组间差别有显著性意义（P〈0.01）;（3）正常培养的大鼠GMC有微量LNβ2 mRNA表达,LPS组在各时点LNβ2 mRNA表达量与对照组间差别均有显著性意义（P〈0.01）。结论从蛋白和mRNA两个水平同时观察到ECM成分（如FN、LN和ColⅣ）的增加,说明在系膜增殖性肾炎中ECM明显增加并起主要作用。