Significance of levels of circulating IgA-class immune complex in discriminant analysis of patients with IgA nephropathy before renal biopsy

Discriminant analysis of clinical markers including circulating IgA-class immune complex (IgA-CIC) before renal biopsy in patients with IgA nephropathy is described. Fifty-six patients with IgA nephropathy (IgA nephropathy group) and 54 patients with other primary chronic glomerulonephritis (non-IgA nephropathy group) were examined. Discriminant analysis was applied to separate these two groups by using 21 clinical markers including levels of IgA-CIC. The levels of IgA-CIC in sera were measured by a solid-phase anti-C3 Facb enzyme immunoassay (EIA). Among these clinical markers, the levels of serum IgA, IgA-CIC and creatinine, and the degree of microhematuria in the IgA nephropathy group were significantly higher than those in the non-IgA nephropathy group. Contributions of IgA and IgA-CIC to the classification were very high and both had almost the same effect. The correct classification rate was 80.00% using five clinical markers: serum IgA, microhematuria, IgA-CIC, serum creatinine, and blood urea nitrogen. It was shown that the levels of serum IgA and IgA-CIC were major markers for the clinical diagnosis of patients with IgA nephropathy. It was concluded that discriminant analysis before renal biopsy was useful for the diagnosis of IgA nephropathy.     

原发性IgA肾病与非IgA系膜增生性肾小球肾炎的临床病理分析

目的 比较原发性IgA肾病与非IgA系膜增生性肾小球肾炎（non-IgA mesangial proliferative glomerulonephritis,non-IgA MsPGN）的临床及肾脏病理改变特点.方法 选择我科经肾活检确诊的原发性IgA肾病患者（A组）和non-IgA MsPGN患者（B组）进行临床与病理资料对比分析.结果 A、B组的性别、前驱上呼吸道感染诱因、起病时伴发高血压、镜下血尿、血肌酐无统计学差异（P＞0.05）.B组较A组起病年龄小,起病时伴发肉眼血尿比率低,肾病综合征发生率高,血IgG水平低,差异均有统计学意义（P＜0.05）.A组肾小球、肾小管间质、肾小动脉病理改变发生率高于B组（P＜0.05）,IgM、C3沉积、系膜区电子致密物沉积、大块状致密物、足细胞微绒毛化、肾小球基底膜分层发生率均较B组高（P＜0.01）.结论 IgA肾病与non-IgA MsPGN在临床表现、病理改变上存在明显差异,IgA肾病较non-IgA MsPGN病理损伤重.     

IgA nephropathy in a young man with primary hyperparathyroidism

We report the first documented case of IgA nephropathy occurring after treatment of primary hyperparathyroidism. A 29-year-old man with a history of kidney stones and primary hyperparathyroidism underwent kidney biopsy for persistent proteinuria and microhematuria 18 months after resection of an ectopic parathyroid adenoma with subsequent normalization of serum calcium and parathyroid hormone levels. On ultrasound, renal intraparenchymal calcifications were noted. Renal biopsy revealed IgA nephropathy in addition to tubulointerstitial microcalcifications. The development of IgA nephropathy may have been influenced by hyperparathyroidism and/or its treatment. The case highlights the role of renal biopsy in patients with a history of kidney stones and abnormal urinary findings.     

Serum levels of soluble Fas and disease activity in patients with IgA nephropathy

Using a sandwich ELISA, we studied 48 patients with IgA nephropathy and 10 patients with diffuse mesangial proliferative glomerulonephritis without IgA deposition (non-IgA PGN) to determine if levels of serum soluble Fas (s-Fas) might reflect the disease activity. The levels of serum s-Fas in patients with the advanced stage of IgA nephropathy were significantly higher than those in patients with the mild stage of the disease, in non-IgA PGN or in healthy controls. The results showed that advanced stage IgA nephropathy patients who showed heavy proteinuria and the presence of urinary casts revealed high levels of serum s-Fas. It was thus suggested that the measurement of serum s-Fas is useful in evaluating the degree of renal injury in patients with IgA nephropathy.     

伴有新月体形成的原发性IgA肾病的临床与病理特点及预后分析

目的观察伴有新月体形成的原发性IgA肾病的临床、病理特点,分析其对激素及环磷酰胺治疗的反应。 方法收集包头医学院第一附属医院1997年8月至2015年04月收治的80例经肾活检确诊为原发性IgA肾病并伴新月体形成的患者,并依据新月体累及的肾小球比例进行分组,新月体占受累肾小球比例≥50% (A组) 24例;新月体累及的肾小球比例<50%(B组) 56例。肾小球系膜增生、肾小管间质病变采用R.Katafuchi标准积分量化。对两组的临床及病理特点进行比较。治疗方案：将A、B两组再分为单纯糖皮质激素(激素)治疗组,激素＋环磷酰胺治疗组,分别比较不同治疗方案对各组的疗效。A、B组各有24例患者接受了随访。应用SPSS软件进行统计学分析。 结果①临床方面：32例(40%)患者有镜下血尿＋蛋白尿,76例(95%)患者尿蛋白≥2 g/24 h,32例(40%)患者有肉眼血尿;水肿、高血压、肾功能异常者超过半数。A组尿蛋白量及血清肌酐明显高于B组(t＝1.890,t＝2.570; P<0.05),血清白蛋白及肾小球滤过率明显低于B组(t＝2.681, t＝3.014;P<0.05)。②病理方面：所有受累肾小球的新月体面积百分比为5.92%～88.9%,其中A组为52.6%～88.9%, B组为5.92%～48.9%;与B组比较A组肾小管间质损害更严重,两组比较差异有统计学(P<0.05)。③治疗情况：A组及B组经激素或激素＋环磷酰胺治疗后,尿蛋白定量均明显减少(P<0.05) ;单纯激素治疗后A组血清肌酐较治疗前有明显下降(t＝3.243,P<0.05)。随访2～4年时,A组8例患者出现血清肌酐升高,达透析指征,1例死亡;B组2例患者出现血清肌酐升高(1例原有轻度升高,1例新出现血清肌酐升高)。 结论IgA肾病患者随着新月体占受累肾小球比例的增加,肾小管间质病理损害及临床表现亦逐渐加重且预后不佳;激素治疗可减少伴有大新月体形成的原发性IgA肾病的蛋白尿并有可能改善其肾功能。     

贫血加重IgA肾病患者的临床和病理改变

目的 分析IgA肾病合并贫血患者的临床病理特征.方法 收集经肾活检确诊的IgA肾病患者临床资料409例,按照贫血与否分为非贫血组和贫血组,回顾性分析两组患者的临床和病理资料.结果 与非贫血组比较,贫血组患者的肾小球损伤和肾小管间质萎缩程度较重、24 h尿蛋白增多和eGFR降低.Spearman相关分析结果显示,血红蛋白、eGFR与肾脏病理损伤呈负相关(P＜0.05),血尿酸、24h尿蛋白与肾脏病理损伤呈正相关(P＜0.05).多因素Logistic回归分析发现贫血是肾小管间质萎缩的独立危险因素.结论 IgA肾病合并贫血患者的临床和病理损伤重于IgA肾病非贫血的患者,贫血参与IgA肾病的进展.     

Apoptotic cells in six patients with IgA nephropathy in repeat biopsies

SUMMARY: Programmed cell death is a selective process of physiological cell deletion and is known as apoptosis. The purpose of the present study was to determine the relationship between the existence of apoptotic cells in glomeruli and the clinical or histopathological findings obtained in repeat renal biopsies of patients with IgA nephropathy. Repeat renal biopsy specimens were obtained from six patients with IgA nephropathy. The nick end labelling method (TUNEL) was used for the detection of apoptotic cells. Clinical laboratory data, i.e. urinary protein excretion, creatinine clearance (Ccr), blood urea nitrogen (BUN) and serum creatinine, (s‐Cr) were obtained from these patients. At the first renal biopsy, apoptotic cells in the glomeruli were observed in three out of six patients using TUNEL. These patients were classified as the severe glomerular damage group. The other three patients without apoptotic cells were in the mild glomerular damage group. Mean levels of urinary protein excretion at the first renal biopsy in the patients with apoptotic cells were slightly higher than those in patients without apoptotic cells. Levels of Ccr in patients with apoptotic cells were lower than those in patients without apoptotic cells. There were no significant differences in the levels of BUN and s‐Cr in patients with or without apoptotic cells. Two patients with apoptotic cells in glomeruli at the first renal biopsy did not show apoptotic cells at the second renal biopsy. These two patients showed improvement not only in clinical laboratory findings but also in histological findings at the second biopsy. Only one patient with apoptotic cells at the first and second biopsies exhibited deterioration at the second biopsy. All three patients without apoptotic cells at the first renal biopsy also showed deterioration of the clinical laboratory and histopathological findings. It is postulated that various factors other than apoptosis might induce progression of renal injuries in such patients. It appears that the clinical laboratory data, i.e. proteinuria, renal function and histopathological findings, might be influenced by apoptosis in patients with IgA nephropathy. It is postulated that apoptosis may induce reduction of excess proliferative glomerular mesangial cells and/or infiltrating cells and tissue repair.     

银屑病合并IgA或非IgA系膜增生性肾小球肾炎六例临床病理分析

目的分析银屑病合并肾损害的临床病理特点。方法回顾性分析北京协和医院1983年至2004年有肾活检结果的银屑病并肾损害患者6例，分析其临床及病理特点。结果男性2例，女性4例，平均年龄38岁。肾损害在银屑病发病后平均16年(7—30年)被发现。2例表现为无症状性镜下血尿和蛋白尿；3例表现为慢性肾炎综合征；1例为肾病综合征。6例均有中大量镜下血尿，其中2例有发作性肉眼血尿：蛋白尿平均为2．05g／24h(0．01—5．42g／24h)；血压4例正常，2例升高；Scr均正常。肾组织免疫荧光检查发现系膜区IgA沉积4例，系膜区IgG沉积1例，免疫荧光阴性1例。光镜表现均不严重，轻度系膜增生3例，中度系膜增生3例；均无新月体形成；慢性肾小管间质病变不明显；2例肾内动脉内膜增生、管腔狭窄。结论在银屑病合并肾损害中，系膜增生性。肾小球肾炎并不少见。可能与银屑病存在一定关系。     

Specificity of IgA antibodies in sera from patients with IgA nephropathy.

A study was undertaken on the specificity of circulating IgA antibodies in patients with IgA nephropathy detected by immunofluorescence using avidin-biotin complexes. Renal biopsy specimens and serum samples were obtained from 33 patients with IgA nephropathy, 14 other glomerular diseases and 3 normal renal tissues. These renal specimens were treated with citrate buffer (pH 3.2), and then incubated with serum samples obtained from the same and other patients with IgA nephropathy, other glomerular diseases or healthy adults at 37 degrees C for 30 min. The specimens were incubated with biotin conjugated gout F(ab')2 anti-human IgA antiserum at 37 degrees C for 30 min, and then with fluorescein-labeled avidin at 37 degrees C for 30 min. It was found that IgA antibodies in the sera from patients with IgA nephropathy specifically combined with the autologous glomerular mesangial areas, but only 25.7% of them combined with allogeneic renal tissues of IgA nephropathy patients. Confirmatory findings were obtained using an automatic image analyzer. However, these IgA antibodies did not combine with the renal tissues from patients with other glomerular diseases or normal renal tissues. In parallel studies, in order to distinguish IgA nephropathy from other glomerular diseases before renal biopsy, the renal specimens from patients with IgA nephropathy were also incubated with serum samples obtained from 42 patients with proteinuria and/or hematuria before renal biopsy. It was demonstrated that the incidence of IgA binding in IgA nephropathy was significantly higher than that in other glomerular diseases prior to renal biopsy.(ABSTRACT TRUNCATED AT 250 WORDS)     

IgA nephropathy: prognostic significance of proteinuria and histological alterations

A retrospective study of 166 patients with IgA nephropathy was undertaken to clarify possible correlations between clinical and histological features, and the severity and prognosis of the disease. At the time of biopsy, impaired renal function, with creatinine clearance (Ccr) below 90 ml/min was found in 61 cases. At the final examination, after a mean follow-up period of 34 months, 82 patients had impaired renal function, 12 of these patients went into terminal renal failure requiring hemodialysis treatment. The presence of proteinuria of more than 1.0 g/day was closely correlated with impairment of renal function both at the time of biopsy and at the final observation. An unfavorable outcome was also anticipated in the presence of hypertension. In contrast, microhematuria, macrohematuria or high serum IgA levels did not appear to be related to the outcome. Histologically, sclerotic lesions such as mesangial or global sclerosis, interstitial fibrosis and tubular atrophy, and some active changes such as mesangial hypercellularity and tuft adhesion were more frequent and severe in patients with impaired renal function. Impressive localization of IgA and C3 in the mesangium as well as in capillary loops was observed more often in these patients. These results clearly indicate that IgA nephropathy may follow a slowly progressive course in about half of the patients, and that marked proteinuria and severe histological changes appear to correlate closely with an unfavorable course.     

Clinical and pathological features of IgA nephropathy with macrohematuria in history

Objective To investigate the clinical and pathological characteristics of IgA nephropathy (IgAN) with macrohematuria (MH). Method 1512 consecutive patients with biopsy-proven IgAN diagnosed from January 2006 to December 2011 were enrolled, and divided into MH group and control group respectively, according to whether there existed episodes of MH before renal biopsy. The clinical and pathological characteristics were compared between two groups. Patients in MH group were then divided into three groups according to the interval from the last episode of MH to renal biopsy to clarify the concomitant clinicopathological changes associated with occurrence of MH. Results The rate of MH in history was 22.1%. MH group patients had significantly lower serum creatinine, slighter proteinuria, lower prevalence of hypertension and heavier microhematuria than control group (all P＜0.001). The prebiopsy durations were similar in two groups (P=0.627). In MH group, chronic pathological indicators, including global/segmental sclerosis, tubule atrophy/interstitial fibrosis were all slighter (all P＜0.001), whereas activity indicators, including necrosis lesions, crescents and mesangial proliferation were all more severe compared with control group (all P＜0.05). Those who underwent renal biopsy within 30 days of the last episode of MH had more severe proteinuria and microhematuria, higher prevalence of necrosis lesions, more severe crescents formation, and endothelial proliferation (all P＜0.05). Conclusions IgAN patients with MH in history have relatively milder clinical and chronic pathological manifestations, however more active pathological changes especially in those who suffer episode of MH recently.     

IgA肾病患者高血压的相关因素分析

目的探讨IgA肾病患者高血压的相关因素。方法经肾脏活体组织检查确诊的IgA肾病患者120例,采用单因素和多因素Logistic回归分析IgA肾病患者高血压发生的相关因素。结果120例IgA肾病患者中伴有高血压患者39例（占32．5％）。单因素分析发现,24h尿蛋白定量≥2．0g、尿素氮（BUN）≥8mmol／L、血肌酐（SCr）≥133μmol／L、肾小球率过滤（GFR）〈60ml·min^-1·（1．73m^2）^-1、高尿酸血症、贫血、肾小球慢性病变指数≥4分、肾间质炎症细胞侵润〉25％、肾小管萎缩和问质纤维化〉25％、肾小动脉管壁增厚、Lee分级Ⅳ～Ⅴ级与IgA肾病患者高血压相关。多因素Logistic回归结果显示,蛋白尿程度、GFR水平为IgA肾病高血压发生的独立危险因素。结论32．5％的IgA肾病患者伴有高血压,蛋白尿程度、GFR水平是高血压的独立危险因素。     

强直性脊柱炎相关IgA肾病临床病理分析

目的了解强直性脊柱炎（AS）相关IgA肾病的临床病理特点。方法自1997年1月至2006年12月10年间在北京协和医院接受肾活检确诊为IgA肾病的AS患者10例，回顾性分析其临床及病理特点。结果男性9例，女性l例，平均年龄（28．6＋6．8）岁（16～53岁）。4例患者表现为无症状镜下血尿；6例表现反复血尿合并蛋白尿，其中2例有发作性肉眼血尿。平均尿蛋白量（24h）为（1．56±1．53）g（0．02-5．26g）。2例患者有血压升高。所有患者的血肌酐水平均在正常范围。光镜下，8例患者呈轻度系膜细胞增生，IgA肾病Lee氏分级均为Ⅰ或Ⅱ级；另外2例呈中重度系膜增生性改变，IgA肾病Lee氏分级分别为Ⅲ级和Ⅵ级。结论AS相关IgA肾病临床表现为隐匿性肾炎或慢性肾小球肾炎，病理改变以轻度系膜增生为主。     

Histological grading of IgA nephropathy predicting renal outcome: revisiting H. S. Lee's glomerular grading system.

BACKGROUND: The glomerular grading system is useful to compare biopsy specimens and to predict the natural course of disease in IgA nephropathy (IgAN), although no grading system can be perfect. METHODS: H. S. Lee's grading system for IgAN was refined as follows: grade I, normal or focal mesangial cell proliferation; grade II, diffuse mesangial cell proliferation, or <25% of glomeruli with crescent (Cr)/segmental sclerosis (SS)/global sclerosis (GS); grade III, 25-49% of glomeruli with Cr/SS/GS; grade IV, 50-75% of glomeruli with Cr/SS/GS; grade V, >75% of glomeruli with Cr/SS/GS. This refined H. S. Lee grading system was then tested for clinical relevance on 187 patients with IgAN followed up for an average of 6.5 years (minimum, 3 years). In the survival analysis, a modified primary end-point (progressive renal disease) was used. RESULTS: The glomerular grades were significantly related to hypertension, serum creatinine levels and the amounts of proteinuria at time of biopsy. By univariate analysis, glomerular grades, hypertension, renal insufficiency and significant proteinuria (> or =1 g/day) were significantly associated with progressive renal disease. By multivariate analysis using the Cox regression model, glomerular grades, renal insufficiency and significant proteinuria were independent prognostic factors for progressive renal disease. At the end of follow-up, glomerular grades were significantly related to serum creatinine levels, amounts of proteinuria, hypertension and progressive renal disease. CONCLUSIONS: These findings indicate that the refined H. S. Lee grading system for IgAN is useful in assessing the patients' clinical outcome and is sufficiently simple and easy to reproduce as to be universally applicable in prognostic work.     

The spectrum of acute renal failure in IgA nephropathy

Background: Acute renal failure rarely complicates the course of IgA nephropathy. In this study, we have tried to define the mode of presentation, the spectrum of morphology, and the prognostic factors for renal outcome. Methods: Twenty patients with biopsy-proven IgA nephropathy who developed acute renal failure were identified from 2000 to 2009 at a medical center in Taiwan. The patients' records were retrospectively reviewed with respect to clinical presentation, morphology of renal biopsy, and outcomes. Results: On histology, glomerular crescents were present in 11 patients (55%), acute tubular necrosis was identified in 11 patients (55%), acute interstitial nephritis was seen in 4 patients (20%), and extensive tubular red blood cell casts were present in 4 patients (20%). At the end of follow-up, 2 patients (10%) had died, 11 patients (55%) were in remission, and 7 patients (35%) developed end-stage renal disease. The prognostic factors for renal outcome were peak serum creatinine, dialysis support requirement, morphology (prominent glomerular/tubular injury), percentage of glomeruli affected by crescents, and interstitial infiltration (p = 0.04, <0.001, 0.013, 0.05, 0.02, respectively). Conclusions: Our findings suggested that there were four pathogenic mechanisms involved in IgA nephropathy with acute renal failure including (1) crescentic IgA nephropathy; (2) acute tubular necrosis associated with microhematuria and red blood cell casts occluding tubules; (3) acute tubular necrosis not related to microhematuria; and (4) acute interstitial nephritis, apparently induced by drugs. In general, patients with prominent tubular injury had a much higher remission rate than patients with prominent glomerular injury.     

Clinicopathological correlation of young onset chronic glomerulonephritis

In a retrospective analytical study involving 98 children with primary glomerulonephritis who were seen by us at our hospital during a 2-year period from 1984 through 1985 and who had renal biopsy performed previously, attempts were made to correlate pathological findings with both clinical findings and prognosis. The results are summarized as follows: 1) Of 87 patients with asymptomatic chronic glomerulonephritis, glomerular findings were those of minimal change lesion, mesangial proliferative nephritis, MPGN, membranous nephropathy and FGS or sclerosing nephritis in 29.9%, 51.7%, 13.8%, 1.1% and 3.5%, respectively. Among the other 11 patients in whom the diagnosis was made after manifesting the nephritic symptoms, minimal change was noted less frequently and MPGN was detected more frequently than in the aforementioned asymptomatic group. IgA nephropathy was estimated to account for 44.2% of cases of asymptomatic chronic nephritis. 2) Mild mesangial proliferation was observed relatively frequently and severe mesangial proliferation or MPGN rather infrequently in hematuria cases without proteinuria while in those with severe proteinuria minimal change lesion was uncommon and severe mesangial proliferative changes, MPGN or FGS were relatively frequent. 3) In 22 patients with IgA nephropathy and 11 with non-IgA nephritis the severity of glomerular changes was related to the intensity of proteinuria at the time of renal biopsy. 4) A 3 to 5 years' follow-up study of patients with mesangial proliferative nephritis inclusive of IgA nephropathy disclosed that 26-28% of patients became free from urinary abnormalities, 27-37% had persistent hematuria without proteinuria and 24-32% still had proteinuria of 2 plus or above. Patients with milder glomerular changes had a definitely better prognosis than those with severe glomerular lesions.     

Clinical remission and pathological progression after tonsillectomy in a renal transplant patient with recurrent IgA nephropathy

Abstract:  We discuss a renal transplant patient with recurrent IgA nephropathy (IgAN) before and after tonsillectomy. A 36-year-old man started on hemodialysis support in 1996 due to biopsy-proven IgAN, living related renal transplantation was then performed in 1997. Six years after transplantation, the patient presented with microhematuria and proteinuria. Graft biopsy for these urinary abnormalities showed recurrent IgAN. Tonsillectomy was subsequently performed in December 2003, proteinuria remitted 6 months after the tonsillectomy and microhematuria disappeared three years later. Protocol graft biopsy was subsequently performed twice, at 2 yr after the tonsillectomy (2005) and 4 yr after (2008). Comparing the findings of the pre-tonsillectomy biopsy and the two post-tonsillectomy biopsies, an increase in mesangial cells and matrix in 2005, and an expansion of the mesangial matrix and proliferation of mesangial interposition in 2008. In addition, global sclerosis of glomeruli increased over time, the area of tubulointerstitial damage has extended as well. While the tonsillectomy led to clinical remission of recurrent IgAN, the chronicity progressed on these protocol biopsies. This is the first report of the efficacy and the limitations of tonsillectomy in a case of recurrent IgAN in a transplant patient.     

Development and validation of a noninvasive diagnostic model for IgA nephropathy

Objective To explore the development and clinical application value of Nomogram model, a noninvasive early diagnosis model, in IgA nephropathy. Methods The clinical data of 712 patients with primary glomerular disease diagnosed by renal histopathological examination in Affiliated Hospital of Qingdao University during October 1, 2010 to August 31, 2019 were collected retrospectively, including 241 cases of IgA nephropathy and 471 cases of non-IgA nephropathy. According to the time of case inclusion, the patients were divided into the training set (n=426, 156 cases of IgA nephropathy and 270 cases of non-IgA nephropathy) and the validation set (n=286, 85 cases of IgA nephropathy and 201 cases of non-IgA nephropathy). Univariate and multivariate logistic regression equations were used to analyze the risk factors for diagnosing IgA nephropathy in patients of training set. Nomogram model for noninvasive diagnosis of IgA nephropathy was established according to the akichi information criteria (AIC) and applied to the validation set for validation. The discriminant degree, calibration degree and clinical practicability of the model were verified and evaluated by receiver operating characteristic curve (ROC), calibration curve and decision curve analysis (DCA), respectively. Results Multivariate logistic regression results showed that the age (OR=0.966, 95%CI 0.947-0.985, P=0.001), IgA/C3 ratio (OR=1.889, 95%CI 1.468-2.432, P＜0.001), serum albumin (OR=1.091, 95%CI 1.047-1.136, P＜0.001), total cholesterol (OR=0.810, 95%CI 0.694-0.946, P=0.008), and gross hematuria (OR=6.858, 95%CI 1.867-25.189, P=0.004) of patients with primary glomerular disease were independent factors for the diagnosis of IgA nephropathy. Nomogram diagnostic model was constructed based on the above indicators, and the areas under ROC curve were 0.880 and 0.887 respectively in the training set and the validation set. The calibration curve showed that the predicted probability of the model was in good agreement with the actual probability. DCA showed that the safety and clinical net benefit of the model were higher. Conclusions The Nomogram model has high accuracy and clinical practicality in diagnosing IgA nephropathy, and can be used for noninvasive and early diagnosis of IgA nephropathy to enable patients to receive early treatment.     

Abnormal IgA glycosylation in Henoch-Schonlein purpura restricted to patients with clinical nephritis

Background: Glomerular deposition of IgA1 is a common feature of Henoch-Schonlein purpura, and is indistinguishable from that seen in IgA nephropathy. Serum IgA1 is abnormally O-glycosylated in IgA nephropathy, and this may contribute to mesangial IgA1 deposition and the development of glomerular injury. This altered O-glycosylation of IgA1 can be detected by its increased binding to the lectin Vicia villosa. Methods: To investigate whether IgA1 is abnormally glycosylated in Henoch-Schonlein purpura, the binding of Vicia villosa lectin to serum IgA1 was studied in the following subject groups: IgA nephropathy; adults and children with Henoch-Schonlein purpura and nephritis; children with clinically diagnosed Henoch-Schonlein purpura but no renal involvement; adults and children with non-IgA associated glomerulonephritis; and matched controls. Results: The abnormality of lectin binding seen in IgA nephropathy was also found in both adults and children with Henoch-Schonlein purpura with nephritis. However the lectin binding of serum IgA1 from children with Henoch-Schonlein purpura lacking renal involvement did not differ from controls, and similarly no abnormality of lectin binding was seen in patients with non-IgA associated glomerulonephritis. Conclusions: These data indicate that the abnormality of IgA1 O-glycosylation seen in IgA nephropathy is also found in Henoch Schonlein purpura, but only in those subjects with renal involvement, while IgA1 O-glycosylation is normal in patients with other forms of renal disease. These findings lend strong support to a role for altered IgA1 O-glycosylation in the pathogenesis of IgA-associated glomerular disease.     

Prognostic indicators in childhood IgA nephropathy.

A number of clinical, laboratory and pathologic parameters were assessed for their prognostic significance in 200 children aged less than 15 years with IgA nephropathy, who had shown normal renal function at the time of initial biopsy and were followed for more than 2 years thereafter. After a mean follow-up period of 5.0 years from the initial biopsy, 93 patients had no demonstrable abnormality, 76 had minor urinary abnormalities, 21 had persistent heavy proteinuria and 10 had developed chronic renal impairment. A poor outcome was found to be correlated with heavy proteinuria at biopsy, diffuse mesangial proliferation, a high proportion of glomeruli showing sclerosis, crescents or capsular adhesions, the presence of moderate or severe tubulointerstitial changes, and the presence of subepithelial electron-dense deposits and lysis of the glomerular basement membrane by electron microscopy. The percentage of glomeruli displaying crescents, sclerosis and adhesions appeared to be the most reliable prognostic indicator. Nine of the 27 patients (33%) in whom greater than or equal to 30% of glomeruli showed crescents, sclerosis and adhesions developed chronic renal impairment, and only 14% of these patients had normal urine at follow-up. In contrast, only 1 of the 173 patients in whom less than 30% of glomeruli showed such lesions developed chronic renal impairment (p less than 0.001) and 51% of these patients showed complete remission at follow-up (p less than 0.001). These results demonstrate that an accurate prediction of the outcome based on the initial renal biopsy findings is possible early in the course of children with IgA nephropathy.