Immunoglobulin A nephropathy complicating pulmonary tuberculosis.

A 31-year-old man who presented with smear- and culture-negative pulmonary tuberculosis had associated macroscopic hematuria, elevation of serum creatinine and immunoglobulin A (IgA) levels, overt proteinuria, and peripheral edema. Renal biopsy revealed focal mesangial proliferation with IgA deposits, and a diagnosis of IgA nephropathy was made. The patient received treatment with isoniazide and rifampin. After 4 months, pulmonary lesions were almost completely healed, and a significant improvement of creatinine clearance with normalization of serum creatinine and IgA levels and disappearance of proteinuria were observed. Treatment with isoniazide and rifampin was discontinued after 6 months, without reappearance of either pulmonary or renal symptoms. Two years after the diagnosis of IgA nephropathy, the patient is in good general condition. Serum creatinine and IgA levels are normal, proteinuria is absent, and there is neither macrohematuria nor microhematuria. These findings suggest that IgA nephropathy may be a consequence of tuberculosis, possibly due to an abnormal IgA-mediated immune response against Mycobacterium tuberculosis with formation of nephrotoxic immune complexes.     

Thin basement membrane nephropathy as a cause of recurrent haematuria in childhood

A survey of 69 children presenting with recurrent or persistent haematuria and submitted to percutaneous renal biopsy at this hospital over a 17-year period, was performed to establish the incidence of thin basement membrane nephropathy (TBMN). A diagnosis of primary glomerular disease was established in 44 (IgA nephropathy in 16, Alport's syndrome in 13 and other varieties of glomerulonephritis in 15). Of the remaining 25 patients in whom light microscopical and immunochemical examination revealed no abnormalities, material for electron microscopy was available in 11. In eight of these (five of whom had a family history), TBMN was diagnosed on the basis of ultrastructural morphometric evaluation of glomerular basement membrane thickness. Assuming a similar proportion of the remaining 14 patients with renal biopsy specimens normal by light microscopy had TBMN, the probable frequency of this abnormality in the whole series would be 26%, very similar to that of IgA nephropathy. In the eight TBMN patients the mean glomerular basement membrane thickness ranged between 181 and 236 nm, whilst in 'control' biopsies from children with 'minimal change' nephrotic syndrome or IgA nephropathy, the mean thickness ranged between 242 and 333 nm.     

Immunoglobulin A nephropathy associated with Plasmodium falciparum malaria

Glomerulonephritis occurs as a rare form of renal manifestation in Plasmodium falciparum malaria. Herein, we report a case of falciparum malaria-associated IgA nephropathy for the first time. A 49-yr old male who had been to East Africa was diagnosed with Plasmodium falciparum malaria. Microhematuria and proteinuria along with acute kidney injury developed during the course of the disease. Kidney biopsy showed mesangial proliferation and IgA deposits with tubulointerstitial inflammation. Laboratory tests after recovery from malaria showed disappearance of urinary abnormalities and normalization of kidney function. Our findings suggest that malaria infection might be associated with IgA nephropathy.     

A case of sporadic medullary cystic kidney disease type 1 (MCKD1) with kidney enlargement complicated by IgA nephropathy

Medullary cystic kidney disease (MCKD) is a progressive tubulointerstitial nephropathy, and it leads to end‐stage kidney disease (ESKD). It is an autosomal dominant inherited disease, and is categorized into two types according to the localizing chromosome and timing of ESKD onset. Its pathogenesis has not been revealed clearly, thus accumulation of the cases is very valuable. We report here the first reported case of MCKD with kidney enlargement complicated by IgA nephropathy. A 70‐year‐old male was admitted to our hospital because of renal dysfunction and bilateral kidney enlargement. He was diagnosed as having MCKD complicated by IgA nephropathy (IgA‐N) by renal biopsy. We speculated that he had MCKD type 1 on the basis of the late onset of renal failure and no significant evidence of mutation in the UMOD gene that is associated with MCKD type 2. Thereafter, his kidney function decreased progressively and he started to receive hemodialysis. This is an interesting case of MCKD1 in terms of its sporadic nature, kidney enlargement, and complication of IgA‐N.     

Glycosylation of IgA1 and pathogenesis of IgA nephropathy

IgA nephropathy, described in 1968 as IgA-IgG immune-complex disease, is an autoimmune disease. Galactose-deficient IgA1 is recognized by unique autoantibodies, resulting in the formation of pathogenic immune complexes that ultimately induce glomerular injury. Thus, formation of the galactose-deficient IgA1-containing immune complexes is a critical factor in the pathogenesis of IgA nephropathy. Studies of molecular defects of IgA1 can define new biomarkers specific for IgA nephropathy that can be developed into clinical assays to aid in the diagnosis, assessment of prognosis, and monitoring of disease progression.     

The Value of Electron Microscopy in the Diagnosis of IgA Nephropathy

Electron microscopy plays a fundamental role in the evaluation of renal diseases in general. IgA nephropathy represents a heterogeneous disease clinically and morphologically. There are a number of conditions that need to be considered in the differential diagnosis of IgA nephropathy. The renal pathologist must wisely integrate the light microscopic, immunofluorescence, and ultrastructural data when evaluating cases in which IgA nephropathy is a consideration. Electron microscopy can be crucial in providing information either to support a diagnosis of IgA nephropathy or to aid in the diagnosis of one of its mimics.     

The value of electron microscopy in the diagnosis of IgA nephropathy

Electron microscopy plays a fundamental role in the evaluation of renal diseases in general. IgA nephropathy represents a heterogeneous disease clinically and morphologically. There are a number of conditions that need to be considered in the differential diagnosis of IgA nephropathy. The renal pathologist must wisely integrate the light microscopic, immunofluorescence, and ultrastructural data when evaluating cases in which IgA nephropathy is a consideration. Electron microscopy can be crucial in providing information either to support a diagnosis of IgA nephropathy or to aid in the diagnosis of one of its mimics.     

IgA nephropathy. Correlation of clinical and histologic features

The clinical and histologic features of 81 patients with IgA nephropathy were analyzed. Azotemia was present in 32 per cent of the patients, proteinuria was present in 88 per cent, and gross or microscopic hematuria was present in all of the patients tested. The median age of histologic diagnosis was 27 years. The median age at onset of clinical signs was 20 years. There was no increased incidence in any HLA-A or -B antigen within the patient population over our control population. All patients had glomerular mesangial IgA deposition (by definition) greater than or equal to IgG or IgM. Histologic changes were quantitated and ranged from normal to necrotizing and/or crescentic glomerulonephritis. Many patients (48 per cent) had mild or moderate generalized glomerlular hypercellularity. Nonparametric statistical analysis showed strong correlations among patient age at histologic diagnosis, creatinine, proteinuria, global glomerular sclerosis, and interstital fibrosis. Our analysis suggests that IgA nephropathy is an indolent disease generally beginning in childhood. It is a cause of renal insufficiency in a significant number of patients. Interpretation of this series and other reported studies suggests that most cases of IgA nephropathy in the United States are best considered idiopathic but that hereditary and secondary forms may exist.     

IgA nephropathy in children and adults

Conclusions Knowledge concerning IgA nephropathy has expanded greatly in the last 10 years, and its importance as the major form of glomerulonephritis and major contributor to the endstage renal disease is becoming apparent in children and adults. IgA nephropathy is a slowly progressive glomerular disease. Once renal function impairment develops, eventual progression to uremia is inevitable, and so a prophylactic approach to the progression of IgA nephropathy, based on an arbitrary period of therapy early in the course of disease, warrants serious consideration and investigation. A program of urinalysis screening in schools and an appropriate renal biopsy policy make an early diagnosis of IgA nephropathy possible. The development of successful therapy during childhood will offer a great potential for reducing the high morbidity and mortality associated with this disease in adults.     

血清HBsAg阳性IgA肾病肾组织HBV抗原蛋白及血清和肾组织HBV-DNA检测分析

目的探讨乙型肝炎病毒（HBV）感染与IgA肾病发病的关系。方法32例肾活检冰冻切片组织HBsAg和HBcAg蛋白和42例HBsAg阳性的肾活检石蜡切片组织及其部分血清HBV-DNA的检测。结果HBsAg和HBcAg在IgA肾病肾活检组织的总阳性率为59．1％，在非IgA肾病中的总阳性率为63．6％，二者差异无统计学意义。42例肾活检组织中，仅发现有5例（11．9％）在肾活检组织中有HBV-DNA的存在。且5例均为大三阳患者，其病理诊断为系膜增生性肾小球肾炎2例，轻微肾小球病变1例，基底膜病变1例，IgA肾病仅1例。血清HBsAg阳性的患者，同时进行了42例肾活检组织的血清HBV-DNA检测，其中大三阳患者为12例，其血清HBV-DNA均为阳性，而这12例血清阳性的肾活检组织中仅有5例HBV-DNA为阳性，其余30例血清及肾活检组织中HBV-DNA为阴性。结论HBsAg和HBcAg蛋白在IgA肾病肾活检组织和非IgA肾病肾活检组织表达差异无统计学意义，表明HBV感染与IgA肾病并无直接关系。     

Familial IgA nephropathy. Evidence of an inherited mechanism of disease

The evaluation of familial glomerulonephritis in patients with IgA nephropathy who were from central and eastern Kentucky resulted in the discovery of potentially related pedigrees containing 14 patients. An additional 17 members of the pedigrees had clinical glomerulonephritis, and 6 had "chronic nephritis" noted on their death certificates. Six patients with IgA nephropathy had a common ancestor. In addition, both parents of six patients with the disease came from families with other cases of IgA nephropathy. No single HLA haplotype or antigen was found in all the patients with IgA nephropathy. Our data on these pedigrees strongly support an inherited mechanism in the pathogenesis of IgA nephropathy in some patients.     

The Natural Course of Biopsy-Proven Isolated Microscopic Hematuria: a Single Center Experience of 350 Patients

The increasing interest in healthcare and health screening events is revealing additional cases of asymptomatic isolated microscopic hematuria (IMH). However, a consensus of the evaluation and explanation of the IMH prognosis is controversial among physicians. Here, we present the natural course of IMH together with the pathological diagnosis and features to provide supportive data when approaching patients with IMH. We retrospectively evaluated 350 patients with IMH who underwent a renal biopsy between 2002 and 2011, and the pathological diagnosis and chronic histopathological features (glomerulosclerosis, interstitial fibrosis, and tubular atrophy) were reviewed. Deterioration of renal function was examined during follow up. The patients with IMH were evaluated for a mean of 86 months. IgA nephropathy was the most common diagnosis in 164 patients (46.9%). Chronic histopathological changes were observed in 166 (47.4%) but was not correlated with proteinuria or a decline in renal function. Ten patients developed proteinuria, and all of them had IgA nephropathy. Three patients progressed to chronic kidney disease with an estimated glomerular filtration rate < 60 mL/min/1.73 m² but none progressed to end stage renal disease. In conclusion, IMH had a generally benign course during 7-years of observation, although IgA nephropathy should be monitored if it progresses to proteinuria. Future prospective randomized studies may help conclude the long-term prognosis and lead to a consensus for managing IMH.     

Immunological studies in a familial IgA nephropathy.

The hypothesis that abnormalities of immune function might occur in healthy first degree relatives of two patients with a familial IgA nephropathy was tested. After 7 days of culture, pokeweed mitogen stimulated peripheral blood mononuclear cells from the two affected members with IgA nephropathy (father and older son), as well as two other healthy sons, produced significantly more polymeric IgA than the controls. The fact that only the two patients with IgA nephropathy presented high serum levels of polymeric IgA favours the idea that a defect in the clearance of this immunoglobulin might be an important step in the appearance of this nephropathy. All the healthy members of the family had a normal OKT4+/OKT8+ cell ratio and a normal concanavalin A generated IgA suppressor cell function in contrast with the abnormalities observed in the two affected members and the previous results in a large number of patients with IgA nephropathy. These data suggest that the primary cellular abnormality might reside in B cells, being the T cell alterations observed in patients a secondary or subsequent phenomenon. These results further support the existence of genetic bases for the susceptibility to this disease.     

Detection and characterization of circulating and glomerular immune complexes in experimental IgA nephropathy.

The different models of experimental IgA nephropathy described so far have provided insight into pathogenesis; however, the evidence for a role of IgA immune complexes (IC) has only been gained in passive systems. In an active model of IgA nephropathy, induced in mice by repeated injections of dextran, some of the mechanisms that could explain the formation of glomerular IgA deposits are studied in this report. Serum total IgA and anti-dextran IgA antibody levels increased significantly over the period of immunization. Only 13-30% of mice had total and/or specific IgA IC, determined by Raji cell and PEG assay in ELISA. Analytical ultracentrifugation showed that IgA IC were of small (7-13 S) or intermediate (13-17 S) size. There was a close correlation between total serum IgA levels and the presence of IC-containing IgA anti-dextran antibodies, with the existence of IgA in the mesangium. The percentage of animals (n = 76) with IgA mesangial deposits increased over the immunization period (88% at 10 weeks). Forty-three per cent of mice had polymeric IgA in the mesangium; by contrast, only 12% had dextran deposits. On the whole, these data suggest that in the dextran-induced IgA nephropathy, the glomerular IgA could be the result of circulating IgA complexes and/or IgA polymers deposition.     

Cold reacting anti-nuclear factor (ANF) in families of patients with IgA nephropathy.

The emergence of cold reacting anti-nuclear factor (ANF) in families of patients with IgA nephropathy was examined to determine whether some immunological alterations among family members affect the development of this disease. The procedure for the detection of the cold reacting ANF was reported previously. Fifty-five per cent of sera from 66 relatives of IgA nephropathy 24 patients was found to have the IgM cold reacting antibody. The incidence of ANF in healthy adults was 3%. Both household and non-household consanguineous relatives showed antibody in their sera. Sixty-five per cent of consanguineous relatives who had close household contacts with IgA nephropathy patients showed cold reacting ANF, whereas only 10% of non-consanguineous relatives who had close household contact had this antibody. It is suggested that familial susceptibility or genetic factors, in addition to environmental factors, may be responsible in the development of IgA nephropathy.     

Vogt-Koyanagi-Harada syndrome in two patients with immunoglobulin A nephropathy

We describe herein 2 patients who developed Vogt-Koyanagi-Harada syndrome in the course of renal biopsy-proven immunoglobulin A (IgA) nephropathy. A 61-year-old man with an 11-year history of IgA nephropathy and a 16-year history of thyroiditis, and a 56-year-old man with a 5-year history of IgA nephropathy developed Vogt-Koyanagi-Harada syndrome. At the time of the eye disease presentation, IgA nephropathy was stable without corticosteroids in both patients. Vogt-Koyanagi-Harada syndrome was successfully treated with intravenous administration of prednisolone tapered from 200 mg daily. Vogt-Koyanagi-Harada syndrome is associated with IgA nephropathy, suggesting a similar autoimmune mechanism for both diseases.     

Detection of polymeric IgA in glomeruli from patients with IgA nephropathy.

A study on the detection of polymeric IgA in glomeruli from renal biopsy specimens in patients with IgA nephropathy is described. Renal biopsy specimens were obtained from patients with IgA nephropathy. These specimens were stained with FITC-labelled anti-human J chain antisera and then examined with a fluorescent microscope. The J chain was observed in the glomerular mesangium by immunofluorescent staining. In parallel studies, renal biopsy specimens were treated with citrate buffer (pH 3.2) and the 'eluate' was neutralized by sodium hydroxide. The eluate was labelled with iodine-125, and the radiolabelled 'eluate' was fractionated by sucrose density-gradient ultracentrifugation. Polymerized IgA in the 'eluate' obtained from patients with IgA nephropathy was found to sediment predominantly as 9S to 11S using a sucrose density gradient analysis. Polymeric IgA in the fractions of the density gradient analysis was determined by anti-human IgA and anti-human J chain antisera. It was demonstrated that IgA and J chain were eluted from the glomeruli in some patients with IgA nephropathy. It is concluded that IgA deposited in the glomeruli is composed of dimers and/or larger polymers of circulating IgA in some patients with IgA nephropathy.     

Sarcoidosis-associated hepatocellular carcinoma

Sarcoidosis is a systemic granulomatous inflammation of unknown etiology, and seems to involve the liver parenchyma in most cases. However, sarcoidosis-associated hepatocellular carcinoma is rare. We report here a case in which a hepatocellular carcinoma occurred within the liver, which was probably involved as a result of systemic sarcoidosis. A 57-year-old Japanese man had been followed up for 2 years because of diabetic nephropathy and sarcoidosis. On admission for pneumonia, imaging studies revealed an unexpected hepatic tumor. Histology revealed a hepatocellular carcinoma accompanied by T-lymphocytic infiltration and marked granulomatous inflammation, which was surrounding some tumor nodules. The background liver parenchyma exhibited a moderate degree of fibrosis with granulomatous inflammation. The patient had no other apparent liver disease such as viral hepatitis, steatohepatitis, or primary biliary cirrhosis. Therefore, in the present case, sarcoidosis may be considered the probable background etiology for hepatocarcinogenesis.     

Sarcoidosis: association with small bowel disease and folate deficiency.

A 30 year old woman with recurrent anaemia due to folate deficiency had evidence of sarcoid granuloma on small bowel biopsy but was presumed to have Crohn's disease. The diagnosis of small bowel sarcoidosis was not seriously considered until she developed systemic manifestations of sarcoidosis (cutaneous and pulmonary lesions) over the following 20 years. Sarcoidosis of the gastrointestinal tract, particularly the small bowel, is rare and this case is unusual because bowel pathology preceded more generalised lesions. As far as is known it is also the first case to be described presenting with malabsorption of folic acid.     

Experimental IgA nephropathy in mice

Based on a hint from an immunological abnormality found in human IgA nephropathy, we tried to make up an experimental IgA nephropathy in mice by administration of a food antigen for a long term with blockage of the reticuloendothelial system (RES). Mice were divided into three groups: group 1 had oral administration of lactalbumin (Lalb); group 2 was treated with colloidal carbon to block RES in addition to oral administration of lactalbumin; and group 3 was treated only with colloidal carbon for RES blockage. Renal biopsy was performed at 18 weeks after RES blockage and the animals were sacrified at 30 weeks for histopathological observation of renal tissue. The deposits of IgA in the mesangial area were not found in animals of groups 1 and 3 but 17.6% of group 2 at 18 weeks following RES blockage, also in no animal of group 1 but 91.7% of Group 2, and 15.4% of group 3 at 30 weeks. They were highly frequent in group 2 at 30 weeks (p less than 0.001). Observation under electron microscope also revealed a significant increase (p less than 0.001) of mesangial dense deposits in group 2 at 30 weeks, and formation of large dense deposits similar to those seen in human IgA nephropathy. Through observation over a period of time, an increase of mesangial IgA deposition and histopathological aggravation were confirmed. Serologically, serum level of IgA was significantly higher in group 2 (p less than 0.001) and was correlated with the intensity of mesangial IgA deposition. It was concluded that lesions very similar to human IgA nephropathy could be prepared in mice by inducing a dysfunction of RES as continuous oral immunization.