成年人肾小球基底膜厚度及基底膜变薄标准研究

目的 了解成年人肾小球基底膜（GBM）厚度及拟建议薄基底膜肾病（TBMN）的GBM弥漫变薄的标准。 方法 选取肾癌根治性切除患者29例,分析性别、年龄、尿常规、Scr以及既往史、家族史等临床资料。选取远离病灶的肾皮质组织,进行光镜、免疫荧光及透射电镜检查,并进行GBM厚度测量和Ⅳ型胶原α3、α5链免疫荧光检查。 结果 29例中,男15例、女14例,年龄（55.9±14.9）岁（20~80岁）,所有病例均无肾脏病家族史。肾组织GBM厚度为（363.6±46.8） nm。GBM厚度与性别相关,男性为（384.0±41.7） nm,女性为（335.0±39.2） nm,差异有统计学意义（P = 0.008）。建议以均数减去两倍标准差作为GBM变薄的标准,即GBM厚度＜270 nm。 结论 成年人肾组织的GBM厚度为（363.6±46.8） nm。GBM厚度和性别相关,男性GBM厚度大于女性,差异有统计学意义。TBMN的GBM弥漫变薄的诊断标准建议为GBM厚度＜270 nm,也建议今后制定TBMN标准中应考虑男女的差异。     

Pathology of thin basement membrane nephropathy

Thin basement membrane nephropathy (TBMN) is a glomerular disorder characterized clinically by isolated hematuria and pathologically by diffuse thinning of the glomerular basement membrane (GBM) on ultrastructural examination. The pathologic diagnosis of TBMN is problematic, in part because of the wide range of GBM thicknesses in the normal population. GBM thickness varies with age, sex, and the different methods of tissue preparation and measurement. In addition, there are no standardized diagnostic criteria defining the degree or extent of GBM thinning required for the diagnosis of TBMN. GBM thinning is often seen in other glomerulopathies, where it may represent an overlap with TBMN or may be secondary to GBM damage and remodeling. Importantly, TBMN must be differentiated from the GBM thinning seen in some renal biopsy specimens from boys and female heterozygotes with X-linked Alport syndrome because of the very different prognoses of these two conditions.     

一例女性Fabry病并发薄基底膜肾病及其家系调查

目的 了解具有两种遗传性疾病,即Fabry病并发薄基底膜肾病（TBMN）的临床病理和基因突变特点以及家系患病情况。 方法 总结分析本院收治的1例41岁女性Fabry病并发TBMN患者的临床病理特征和基因突变情况,同时对家系成员进行调查及相关检测。 结果 先证者呈现典型的Fabry病的肾外临床表现,包括皮疹、神经痛、眩晕、耳鸣、肥厚型心肌病等,同时亦有蛋白尿、镜下血尿及高血压等肾脏受累表现;肾活检光镜下病理改变为局灶性节段性肾小球硬化（FSGS）,部分足细胞空泡变性;电镜下肾小球脏层上皮细胞胞质内多数髓磷脂小体形成,肾小球基底膜（GBM）弥漫性变薄,厚度为（216±31） nm。家系调查及基因突变检测显示先证者女儿除有典型Fabry病肾外表现外,亦有以血尿为主的肾脏症状。先证者的1个妹妹仅表现为镜下血尿。先证者及其女儿α-半乳糖苷酶 A（α-Gal A）活性分别为33和75活性单位（正常参考值为100~500活性单位）,且2人均携带新发现的GLA基因突变——1208ins21 bp及COL4A3基因多态性——c:3627 G>A（p:M1209I）。仅表现为镜下血尿的先证者的妹妹仅携带COL4A3基因的c:3627 G>A（p:M1209I）多态性,α-Gal A活性正常,无GLA基因突变。 结论 对于Fabry肾病患者呈现血尿,尤其是表现为家族性血尿时,应考虑并认真排除并发TBMN的可能。     

148例肾小球轻微病变患者的临床和电镜病理探讨

目的    对肾小球轻微病变（glomerular minor lesion,GML）进行临床及电镜病理的分类总结,进一步明确该病理表现的性质及意义,探讨其与临床表现的相关性。 方法    纳入北京协和医院2003年1月7日至2008年12月2日经光镜及免疫荧光病理诊断为GML、同时电镜病理资料完整的患者148例,回顾性分析其临床及病理资料。 结果    孤立性血尿是患者最常见的临床表现,其次为血尿合并少量蛋白尿及单纯蛋白尿,部分患者可并存高血压、特殊自身免疫表现、肝炎标志物阳性等。经电镜检查明确,GML可最终呈现各种不同的病理表现：薄基底膜肾病（66.2%）、系膜增生性肾小球肾炎（20.3%）、Alport综合征（2.7%）、膜性肾病（3.4%）以及正常组织（4.7%）等。结合临床与病理,表现为孤立性血尿的GML患者,经电镜病理检查诊断为薄基底膜肾病的可能性最大（76.9%）。部分患者存在蛋白尿、高血压等提示不良预后的情况。 结论    GML只是一种对肾脏病理表现的粗泛描述,对应的电镜病理具有较大异质性,临床意义各异,需积极完善电镜病理,结合临床特点,明确最终诊断,指导治疗。
        

Thin basement membrane nephropathy associated with minimal change disease in a 15-year-old boy

Thin basement membrane nephropathy (TBMN) is characterized clinically by persistent hematuria, minimal proteinuria, normal renal function, another family member with hematuria, and a benign course. Especially in childhood TBMN, proteinuria of any degree is reported to be uncommon. We report on a boy with benign familial hematuria found by urinary screening at 3 years of age who presented with nephrotic syndrome (NS) at 15 years of age. His renal histology showed TBMN associated with minimal change disease (MCD). Treatment with corticosteroid resulted in complete remission of NS in a short period of time, while isolated hematuria persisted during the follow-up period despite this therapy. We speculate, therefore, that the nephrotic range proteinuria is not due to TBMN but rather is the manifestation of associated MCD. Several cases of TBMN with NS have been reported in adults, but it has not yet been reported in children in the literature. To our knowledge, this is the first case of childhood TBMN associated with NS resulting from coincidental MCD.     

The clinical features of thin basement membrane nephropathy

Thin basement membrane nephropathy (TBMN) is a common, lifelong condition affecting the kidneys that is characterized by microscopic glomerular hematuria, minimal or no proteinuria, and normal renal function. It often is discovered incidentally, and usually has an excellent prognosis. Many cases are familial and show autosomal-dominant inheritance. The defining characteristic is a glomerular basement membrane (GBM) that is thinned to about half its normal thickness on ultrastructural examination of the renal biopsy specimen. However, occasionally patients with TBMN develop marked proteinuria or renal impairment. It is unclear whether individuals with TBMN and impaired renal function represent part of the spectrum of TBMN associated with heterozygous COL4A3 or COL4A4 mutations, or if their disease is caused by mutations of other genes, or whether it is caused by a second coexistent renal lesion or is misdiagnosed Alport syndrome.     

IgA Nephropathy Associated with Thin Basement Membrane with or without Inflammatory Disease: Getting a Different Prognosis?

Background. Thin basement membrane nephropathy (TBMN) patients with additional inflammatory diseases and IgA nephropathy (IgAN) have not been reported before. It was unclear that if the prognosis of these patients is better or worse than patients with IgAN and TBMN, or IgAN patients with normal glomerular basement membrane (GBM). Methods. We first reported five TBMN patients with additional inflammatory diseases and IgAN: three were with rheumatoid arthritis, and two had Crohn's disease. Clinical and laboratory features were analyzed between this group (group 3), IgAN patients with normal GBM (group 1), and patients with TBMN and IgAN (group 2). Results. Significant differences were observed in serum levels of IgG, IgA, and IgM between groups 1 and 3, p < 0.001, and between groups 2 and 3, p < 0.001. Glomerular filtration rate (GFR) in group 3 was significantly lower than that of groups 1 and 2, p < 0.01, respectively. Conclusion. The prognosis of these patients is worse than patients with IgAN and TBMN or IgAN patients with normal GBM. Serum immunoglobulin levels and GFR in these patients were different from patients with IgAN and TBMN, or IgAN patients with normal GBM.     

膜性肾病合并薄基底膜肾病患者临床病理分析

目的探讨膜性肾病（MN）合并薄基底膜肾病（TBMN）的临床病理特点。方法选择我院经肾脏活体组织检查（简称：肾活检）确诊为I期MN合并TBMN（I期MN-TBMN）患者7例,分析其临床病理特点,并与同期的I期MN及单纯的TBMN进行比较。结果7例I期MN—TBMN患者占同期所有I期MN的1．49％（7／471例）,均表现为持续性变形性镜下血尿、轻中度蛋白尿[（2．09±0．78）g／24h]和正常肾功能[SCr（65．30±14．09）／2mol／L];电镜超微结构显示肾小球基底膜（GBM）弥漫性变薄[GBM厚度（205．96±45．94）nm]伴上皮下块状电子致密物沉积,免疫荧光显示Ⅳ型胶原a3、a5链呈线条样沿GBM分布与正常肾组织相同。与同期原发性I期MN组相比,I期MN-TBMN组血尿发生率显著升高（P=0．015）,蛋白尿程度显著降低（P=0．019）。随访时间（22．3±16．4）个月,I期MN—TBMN组较I期MN组血白蛋白水平显著增高（P=0．045）,尿蛋白阴性患者比例显著增高（P＝0．017）。结论少数原发性I期MN可与TBMN同时存在,I期MN-TBMN与原发性I期MN相比较血尿发生率升高,蛋白尿程度降低,临床相对较轻,预后相对较好。     

Morphometric study of glomerular basement membrane and proximal tubular basement membrane in adult thin basement membrane disease

Background. Thin basement membrane disease (TBMD) is a benign hereditary glomerulopathy with a diffuse attenuation of glomerular basement membrane (GBM). Whether the development of renal basement membranes other than GBM is normal in TBMD has not yet been resolved. Methods. We performed a morphometric study to measure the thickness of GBM and proximal tubular basement membrane (P-TBM) in 44 adult patients with TBMD and in 10 adult diseased controls confirmed to have minor glomerular abnormalities. Results. There was a significant difference between the patients with TBMD and the diseased controls in the thickness of the GBM; however, there was no significant difference between the two groups in the thickness of the P-TBM. In the patients with TBMD, the thickness of the GBM was unchanged with age, but the thickness of the P-TBM increased with age, as did that in the diseased controls. Conclusion. Our morphometric study clarified that the development of P-TBM was normal in the patients with TBMD. Received: October 7, 1998 / Accepted: May 27, 1999     

Thin basement membrane nephropathy

Thin basement membrane nephropathy. Thin basement membrane nephropathy (TBMN) is the most common cause of persistent glomerular bleeding in children and adults, and occurs in at least 1% of the population. Most affected individuals have, in addition to the hematuria, minimal proteinuria, normal renal function, a uniformly thinned glomerular basement membrane (GBM) and a family history of hematuria. Their clinical course is usually benign. However, some adults with TBMN have proteinuria >500 mg/day or renal impairment. This is more likely in hospital-based series of biopsied patients than in the uninvestigated, but affected, family members. The cause of renal impairment in TBMN is usually not known, but may be due to secondary focal segmental glomerulosclerosis (FSGS) or immunoglobulin A (IgA) glomerulonephritis, to misdiagnosed IgA disease or X-linked Alport syndrome, or because of coincidental disease. About 40% families with TBMN have hematuria that segregates with the COL4A3/COL4A4 locus, and many COL4A3 and COL4A4 mutations have now been described. These genes are also affected in autosomal-recessive Alport syndrome, and at least some cases of TBMN represent the carrier state for this condition. Families with TBMN in whom hematuria does not segregate with the COL4A3/COL4A4 locus can be explained by de novo mutations, incomplete penetrance of hematuria, coincidental hematuria in family members without COL4A3 or COL4A4 mutations, and by a novel gene locus for TBMN. A renal biopsy is warranted in TBMN only if there are atypical features, or if IgA disease or X-linked Alport syndrome cannot be excluded clinically. In IgA disease, there is usually no family history of hematuria. X-linked Alport syndrome is much less common than TBMN and can often be identified in family members by its typical clinical features (including retinopathy), a lamellated GBM without the collagen alpha3(IV), alpha4(IV), and alpha5(IV) chains, and by gene linkage studies or the demonstration of a COL4A5 mutation. Technical difficulties in the demonstration and interpretation of COL4A3 and COL4A4 mutations mean that mutation detection is not used routinely in the diagnosis of TBMN.     

Chronic renal failure and shortened lifespan in COL4A3+/- mice: an animal model for thin basement membrane nephropathy

A heterozygous mutation in autosomal Alport genes COL4A3 and COL4A4 can be found in 20 to 50% of individuals with familial benign hematuria and diffuse glomerular basement membrane thinning (thin basement membrane nephropathy [TBMN]). Approximately 1% of humans are heterozygous carriers of mutations in the autosomal Alport genes and at risk for developing renal failure as a result of TBMN. The incidence and pathogenesis of renal failure in heterozygous COL4A3/4 mutation carriers is still unclear and was examined further in this study using COL4A3 knockout mice. In heterozygous COL4A3(+/-) mice lifespan, hematuria and renal function (serum urea and proteinuria) were monitored during a period of 3 yr, and renal tissue was examined by light and electron microscopy, immunohistochemistry, and Western blot. Lifespan of COL4A3(+/-) mice was found to be significantly shorter than in healthy controls (21.7 versus 30.3 mo). Persistent glomerular hematuria was detected starting in week 9; proteinuria of > 0.1 g/L started after 3 mo of life and increased to > 3 g/L after 24 mo. The glomerular basement membrane was significantly thinned (167 versus 200 nm in wild type) in 30-wk-old mice, coinciding with focal glomerulosclerosis, tubulointerstitial fibrosis, and increased levels of TGF-beta and connective tissue growth factor. The renal phenotype in COL4A3(+/-) mice resembled the clinical and histopathologic phenotype of human cases of TBMN with concomitant progression to chronic renal failure. Therefore, the COL4A3(+/-) mouse model will help in the understanding of the pathogenesis of TBMN in humans and in the evaluation of potential therapies.     

Thin basement membrane nephropathy and IgA glomerulonephritis: Can they be distinguished without renal biopsy?

BACKGROUND: Thin basement membrane nephropathy (TBMN) and IgA glomerulonephritis (IgA gn) are the most common primary glomerular conditions diagnosed on renal biopsy, performed for microscopic haematuria or microscopic haematuria with proteinuria. While up to 50% of patients with IgA gn will develop chronic renal failure, most patients with TBMN enjoy an excellent prognosis. Because TBMN is estimated to occur in up to 1% of the general population, differentiation between the two conditions without resort to renal biopsy is desirable. METHODS: This retrospective analysis of 248 patients diagnosed on renal biopsy as having either TBMN or IgA gn, sought to identify clinical or biochemical factors which would have enabled confident differentiation between the two conditions to be made without resort to renal biopsy. RESULTS: No single clinical or pathological variable adequately discriminated between the two conditions. Impaired renal function and heavy proteinuria were highly specific for IgA gn but lacked sensitivity in differentiating from TBMN. Isolated microscopic haematuria (IMH) was a more common finding in patients diagnosed with TBMN but, as a discriminator between TBMN and IgA gn, lacked sufficient specificity. However, if assumptions were made based on the differing incidence of a positive family history between IgA gn and TBMN, then specificity of >99% could be achieved. CONCLUSION: TBMN and IgA gn cannot be distinguished on the basis of clinical or pathological variables alone. However, in patients with IMH and a positive family history of either IMH or biopsy-proven TBMN, there is usually no need for renal biopsy.     

Thin glomerular basement membrane disease: clinical significance of a morphological diagnosis--a collaborative study of the Italian Renal Immunopathology Group.

BACKGROUND: Thin glomerular basement membrane disease (TBMD) is a nephropathy defined by diffuse thinning of the glomerular basement membrane (GBM) at electron microscopy examination, without the alterations of Alport's syndrome (ATS). It is known that many patients with TBMD have a type IV collagen disorder and that the disease occasionally may be progressive. This study investigated 51 patients with the morphological diagnosis of TBMD lacking any sign of ATS, with the aim of defining the prevalence of type IV collagen mutations and the course of the disease. METHODS: Patients were investigated as follows: (a) clinical picture and family investigation; (b) renal biopsy findings; (c) immunohistochemical study of renal tissue for collagen IV alpha-chains; (d) pedigree reconstruction and molecular investigations in genes encoding type IV collagen chains, when DNA samples were available; and (e) follow-up data. RESULTS: Renal biopsy analysis revealed no light microscopy changes in 27 patients and minimal abnormalities in the remainder. Global glomerular sclerosis was found in seven cases and superimposed mesangial immunoglobulin-A deposits in four. Normal staining of GBM for alpha(IV) chains was observed in all but one patient, where alpha5(IV) was absent and molecular investigation revealed a COL4A5 mutation. Five out of 25 cases had a mutation in the COL4A3/COL4A4 genes. Eight out of 38 patients followed up for 12-240 months (21%) showed signs of disease progression or hypertension. CONCLUSIONS: This study confirms that a considerable proportion of patients with TBMD have a type IV collagen disorder and that this lesion is not always benign. Thus, families should be investigated carefully whenever possible and patients and affected relatives should be examined periodically for signs of disease progression.     

Glomerular changes in microscopic haematuria, studied by quantitative immunoelectron microscopy and in situ zymography.

BACKGROUND:Haematuria of glomerular origin, even if mild, implies the development of defects in the glomerular basement membrane (GBM). In diseases where there is no infiltration of leukocytes into the glomerulus-such as thin basement membrane disease (TBMD) and histologically mild cases of IgA nephropathy (IgAN)-the mechanism by which such defects form is unclear. METHODS:Frozen renal tissue from 18 cases of TBMD, 18 of mild IgAN and 18 cases with no detectable abnormality were studied: (i) by quantitative in situ zymography, to estimate the activity of glomerular collagenases; and (ii) by quantitative immunoelectron microscopy to estimate the amount of major basement membrane proteins per unit length and per unit area of glomerular basement membrane. RESULTS:Cases of IgAN showed considerably more glomerular collagenase activity than normal (P=0.001). Thin basement membrane disease showed no difference in collagenase activity. A count of LCA-positive cells in glomeruli confirmed that the IgAN cases did not show glomerular leukocyte infiltration. Conversely, cases of IgAN showed no difference in GBM composition from normal, nor was any difference in GBM thickness detected in this group. However, cases of TBMD showed considerably less laminin (P=0.0008), fibronectin (P=0.002) and type VI collagen (P=0.0005) per unit length of basement membrane. Collagen IV showed a smaller reduction per unit length (P=0.01), but unlike the other protein studies it appeared to be present in higher concentration per unit area (P=0.03), suggesting that it is more 'compact' in TBMD disease. CONCLUSIONS:Two distinct mechanisms of haematuria seem to be involved in these two conditions. In IgAN there is increased activity of enzymes that can degrade GBM, probably reflecting mesangial cell activation. In TBMD an abnormal composition of the thinned GBM is confirmed. When considered with published reports of genetic abnormalities in TBMD, these results raise the possibility of an abnormal interaction between collagen IV and laminin.     

COL4A5基因多态性与汉族人薄基底膜肾病的关系

目的探讨薄基底膜肾病COL4A5基因突变情况,为其诊断及遗传咨询提供理论基 础。方法使用聚合酶链反应-单链构象多态性分析(PCR-SSCP)的方法,对39例薄基底膜肾病(TBMN)患者COL4A5基因的51个外显子进行分析,对SSCP发现异常者测序。结果8例患者同时发现3个同义突变和1个错义突变,即1297G-C(365Gly-Gly)、1533T-G(444Ile-Ser)、3715A-G(1171Gln-Gln)及4477C-T(1425Asp-Asp)。该4个突变构成一个单体型,在本组TBMN患者中的基因频率为11％(8/70),而正常对照中该单体型的发现率为9％(9/100)。其中1例患者还合并2417C-G(739Pro-Ala)。结论我们研究发现的单体型为正常汉族人COL4A5基因的多态性;该多态性合并其他的基因突变可能与薄基底膜肾病发病有关。     

Unique microstructures and podocytic infolding in glomerular basement membrane associated with collagen diseases: a report of three cases

Unique renal histopathological appearances, consisting of podocytic infolding and microstructures in the glomerular basement membrane (GBM) were identified in the renal biopsies from three patients with collagen diseases such as systemic lupus erythematosus (lupus nephritis, class II) and Sjögren's syndrome. In each case, the GBM contained microstructures, including microspheres and microtubular structures, accompanied by podocytic infolding into the GBM when examined by electron microscope. The size of the microstructures in the GBM ranged from 40 to 160 nm. Glomerular endothelial cells also seemed to be infolded in the GBM in a case with lupus nephritis. The response to glucocorticoid therapy was favorable in two cases. The cause of these morphological changes in the GBM might be associated with autoimmune disorders.     

The risks of thin basement membrane nephropathy

Most individuals with thin basement membrane nephropathy (TBMN) have an excellent prognosis. For these patients, the only hazards are the anxiety related to misconceptions about the diagnosis and the inconvenience, expense, and wastefulness of unnecessary investigations. However, there also are specific genetic implications for individuals with TBMN because, on average, half their offspring inherit the causative mutations and most of these have hematuria. In addition, despite the generally excellent outcome, some individuals with TBMN develop hypertension, proteinuria, or renal impairment. In some cases, renal failure is caused by apparently progressive but otherwise uncomplicated TBMN, and in others it results from a secondary or coincidental glomerular or tubulointerstitial renal lesion. In particular, TBMN appears to predispose to immunoglobulin (Ig)A glomerulonephritis, and the outcome for these patients is worse than for those with TBMN alone. The risks for patients with TBMN in relation to pregnancy and transplantation have not been well-studied but are described elsewhere in this issue.     

Reactivity of monoclonal antibody P1 with glomerular basement membrane in thin-membrane nephropathy

A monoclonal antibody, P1, possessing antiglomerular basement membrane specificity similar to that of naturally-occurring Goodpasture antibody, was used to study renal biopsy material from patients with thin-membrane nephropathy. Immunofluorescence and immunoperoxidase techniques were employed to detect tissue localisation after sections had been incubated with P1. Staining of glomerular and tubular basement membranes in the 14 patients with thin-membrane nephropathy was similar to that in 10 subjects with various other renal diseases, whereas three patients with Alport's syndrome all gave diminished or absent staining, as has been reported previously. These observations confirm that Goodpasture antigen is present in the basement membranes in thin-membrane nephropathy and that it reacts normally with P1 antibody. They also add to the evidence that the lesions of thin-membrane nephropathy and Alport's syndrome are fundamentally different. The staining method may be used as a differential diagnostic test.     

The clinical and immunological features of the post-extracorporeal shock wave lithotripsy anti-glomerular basement membrane disease

IntroductionExtracorporeal shock wave lithotripsy (ESWL) is a noninvasive modality to treat urolithiasis, with complications including tissue damage and hematoma of kidney parenchyma. Anti-glomerular basement membrane (GBM) disease is suggested to be a rare complication of ESWL since it was reported in several cases to occur after ESWL. However, the clinical and immunological features of the ESWL-associated anti-GBM disease have not been fully investigated so far.Case PresentationHere, we present the clinical, pathological, and immunological characteristics of three patients with the post-ESWL anti-GBM disease in our hospital. Anti-GBM disease occurred within a median of 22 months after ESWL treatment. It presented with similar clinical features to the classic anti-GBM disease, including fever, gross hematuria, and rapidly progressive glomerulonephritis (RPGN) with poor renal prognosis. Sera from all patients recognized the α3(IV)NC1 in GBM, but with IgG2 and IgG4 as the dominant IgG subclasses.ConclusionAlthough further exploration is required to prove the causal relationship in this rare condition, our study reminds physicians that patients developing acute renal insufficiency after ESWL should lead to the suspicion of anti-GBM disease and in-time diagnosis and treatment.     

Immunofluorescence on pronase-digested paraffin sections: a valuable salvage technique for renal biopsies

Direct immunofluorescence (IF) on frozen tissue is the method of choice for the study of medical renal diseases. When no glomeruli are available, IF can be performed on the formalin-fixed paraffin-embedded tissue allocated for light microscopy after antigen retrieval with proteases. In this study, the results of IF on frozen tissue (IF-F) and on deparaffinized, pronase-treated tissue (IF-P) were compared in 71 renal biopsies representing 12 major renal diseases. Using IF-P, diagnostic findings were obtained in 100% of cases of lupus nephritis, acute post-infectious glomerulonephritis, cryoglobulinemic glomerulonephritis, fibrillary glomerulonephritis, primary amyloidosis, myeloma cast nephropathy, and light-chain Fanconi syndrome (LCFS), 88% of cases of immunoglobulin (Ig)A nephropathy, 80% of cases of light-chain deposition disease, 60% of cases of membranoproliferative glomerulonephritis type 1, 50% of cases of idiopathic membranous glomerulopathy (MGN) and 20% of cases of anti-glomerular basement membrane (GBM) disease. IF-P was less sensitive than IF-F for the detection of C3 in all disease categories and for the detection of IgG in cases of MGN and anti-GBM disease. The diagnostic kappa light-chain staining was demonstrated in 100% of cases of LCFS by IF-P versus 40% by IF-F. We conclude that IF-P is a valuable salvage immunohistochemical technique for renal biopsies lacking adequate cortical sampling for IF-F, and is superior to IF-F for the diagnosis of LCFS.