Secondary IgA nephropathy presenting as nephrotic syndrome with glomerular crescentic changes and acute renal failure in a patient with autoimmune hepatitis

Patients with end-stage liver disease are prone to hemodynamic and immunologic renal injury, the latter at times manifesting as glomerulonephritis. Elevated serum immunoglobulin A (IgA) levels and mesangial IgG-IgA deposits are common in these patients, but are often clinically silent. We report a patient with autoimmune hepatitis and secondary IgA nephropathy (IgAN) who presented with nephrotic syndrome, acute renal failure (ARF), with 30% of the renal glomeruli having undergone crescentic change, and with IgA2 deposits in the glomerular mesangium. This article discusses secondary IgAN pathogenesis and its therapeutic management.     

Genetic Polymorphism of C3 and Bf in IgA Nephropathy

C3 and Bf alleles were examined in the general population, in67 patients with biopsy-confirmed mesangial IgA nephropathyand 81 patients with other types of glomerulonephritis, fromthe Heidelberg and Leiden renal programmes respectively. In both populations, a significant excess of homozygous phenotypeC3FF (3.4% in controls; 10.4% in IgA nephropathy) and a deficitof C3FS heterozygous phenotype (35.8% in controls; 19.4% inIgA nephropathy) were observed in patients with IgA nephropathy,but not in other types of glomerulonephritis. No differenceof C3 gene frequencies was found. C3FF was associated with anadverse clinical outcome (a higher prevalence of renal failureand hypertension). A significant excess of Bf-F gene frequency was noted (0.20in controls; 0.33 in IgA nephropathy). In addition, an excessof phenotype BfFF was found (none in controls; 10.4% in IgAnephropathy). BfFF homozygotes also carried a higher risk ofan adverse outcome (renal failure and hypertension). The data suggest a role for genetically coded (presumably) immunologicalfactors in the genesis and course of IgA nephropathy.     

Alpha-1-antitrypsin deficiency and hepatocellular carcinoma. Determination of Pi phenotypes using iso-electric focusing

Alpha-1-antitrypsin (AAT) deficiency resulting from the homozygous protease inhibitor (Pi) ZZ and the heterozygous Pi Z states has been reported to be aetiologically associated with hepatocellular carcinoma (HCC). We studied the phenotype distribution of AAT variants (Pi) by iso-electric focusing on polyacrylamide gel and measured serum AAT concentrations by rocket immuno-electrophoresis in 80 unselected southern African Black patients with HCC and 103 age-, sex- and tribally matched control subjects. Aberrant (non-MM) phenotypes were present in 7 HCC patients (8,7%) and 13 controls (12,6%), an insignificant difference. None of the patients or controls had the Pi ZZ phenotype, while 4 HCC patients (5,0%) and 2 controls (1,9%) (P greater than 0,05) were found to be heterozygous carriers of the Z gene. No HCC patient had a subnormal serum AAT value, and the values in the patients were not lower than those in the controls. We conclude that AAT deficiency does not play an aetiological role in HCC in southern African Blacks. The 4 patients with the heterozygous Z phenotype did not have fibrolamellar carcinomas.     

IgA nephropathy in blacks: studies of IgA2 allotypes and clinical course.

The prevalence of IgA nephropathy (IgAN) varies among racial groups, being most common among Caucasians and Orientals and rare in Blacks. Other investigators have hypothesized that the risk for IgAN may be influenced by the IgA2 allotype. It has been suggested that the rare Black patients with IgAN may be homozygous for the A2m(1) allele which predominates in Whites, but is less common in Blacks. In a multicenter study, 27 Black IgAN patients were enrolled to investigate this hypothesis and analyze the clinical course of disease in Blacks. The IgA2 allotypes of 18 Black patients and 14 controls were determined using restriction fragment length polymorphism analysis. Three patients were homozygous for the A2m(1) allele, four were homozygous for A2m(2) and 11 were heterozygous. The respective allelic frequencies of A2m(1) and A2m(2) were 0.47 and 0.53 and did not differ significantly from Black controls. Most clinical manifestations of disease did not significantly differ with respect to distribution of the two alleles, although the gender ratio differed between the homozygous A2m(1) and heterozygous patients. The presence of the A2m(1) allele did not increase the risk for IgAN, and the presence of the A2m(2) allele or homozygosity for this allele did not protect Blacks from the development of IgAN.     

Lack of association between NPHS2 gene polymorphisms and sporadic IgA nephropathy

AIM: IgA nephropathy (IgAN) is the most common primary form of glomerulonephritis worldwide. In the present study, the genetic structure of the NPHS2 gene was studied to verify if podocin plays a role in the pathogenesis of IgAN. METHODS: Clinical characteristics and DNA samples were collected from 26 Chinese children with sporadic IgAN. A direct sequencing was performed after polymerase chain reaction amplification to all the eight exons of the NPHS2 gene. RESULTS: Three synonymous variants as known polymorphisms (954T-->C homozygous, 1038A-->G heterozygous and homozygous) were found in 3, 4 and 1 patients, respectively. There was no significant difference in the genotypic and allelic frequencies of 954T > C and 1038A > G polymorphisms between the patients and normal controls. CONCLUSION: No significant difference in the genotypic and allelic frequencies of the identified 954T > C and 1038A > G polymorphisms between the patients and normal controls was found.     

Complexes of IgA with FcalphaRI/CD89 are not specific for primary IgA nephropathy

BACKGROUND: The presence of IgA together with the myeloid IgA-receptor FcalphaRI/CD89 in the circulation of patients with IgA nephropathy (IgAN) has been suggested as a specific pathogenic factor for mesangial deposition. However, in a recent study we found these complexes also in serum samples from healthy subjects. To investigate whether these circulating complexes are specific for IgAN, the levels and characteristics of IgA-CD89 complexes were analyzed in patients with IgAN and healthy controls. METHODS: Specific ELISAs with different poly- and monoclonal antibodies and a sensitive dot-blot method were used to measure IgA-CD89 levels in serum and purified IgA samples obtained from healthy volunteers (N = 30) and patients with IgAN (N = 35). Fractionated samples of purified IgA were used to compare the size characteristics of the IgA-CD89 complexes. RESULTS: Almost all CD89 in serum of patients with IgAN and controls was associated with high molecular weight IgA. Quantitative analysis of IgA-CD89 complexes in purified IgA revealed no significant difference between patients with IgAN and controls. No correlation was found between levels of IgA-CD89 complexes and clinical parameters associated with progressive IgAN. CONCLUSIONS: CD89 in the circulation is found mainly linked to high molecular weight IgA. The presence of these complexes is not specific for IgAN. Therefore, if IgA-CD89 complexes are involved in the pathogenesis of primary IgA nephropathy, additional factors are required to explain the IgA-CD89 complex-mediated renal inflammation.     

Immunoglobulin A nephropathy complicating ulcerative colitis

Ulcerative colitis is rarely associated with immunoglobulin A nephropathy (IgAN). The development of IgA nephropathy complicates further the clinical course of patients with ulcerative colitis. A 72-year old man with a 30-year history of ulcerative colitis requiring colectomy and modest renal insufficiency secondary to complications of nephrolithiasis and renal artery stenosis developed glomerular hematuria, proteinuria and progressive renal failure. Percutaneous kidney biopsy revealed IgAN with extensive glomerular and interstitial sclerotic changes. After resection of a chronically infected ileo-rectal pouch, renal function improved, while hematuria and proteinuria gradually disappeared without specific treatment of the IgAN. The manifestations of IgAN complicating ulcerative colitis can be improved with effective treatment of the bowel disease even when there are extensive sclerotic changes in the kidneys.     

Autoantibodies targeting galactose-deficient IgA1 associate with progression of IgA nephropathy

Mesangial and circulating IgA1 with aberrantly glycosylated hinge region O-glycans characterize IgA nephropathy (IgAN). Unlike healthy individuals, some IgA1 is galactose deficient in patients with IgAN, leaving terminal N-acetylgalactosamine residues in the hinge region exposed. Circulating autoantibodies that recognize such galactose-deficient IgA1 as an autoantigen, or the levels of the autoantigen itself, may allow prediction of disease progression. Here, we analyzed serum samples obtained at diagnosis for autoantigen and autoantibodies from 97 patients with IgAN selected from our prospective cohort according to their absolute renal risk for progression to dialysis or death (0, very low; 1, low; 2, high; 3, very high). We also analyzed samples from controls comprising 30 healthy volunteers and 30 patients with non-IgAN disease. The mean follow-up was 13.8 years. We found that mean serum levels of total autoantigen, normalized IgG autoantibody, and total IgA autoantibody were significantly higher in patients than in the combined controls (all P≤0.01). Furthermore, increasing levels correlated with worse clinical outcomes. In Cox regression and Kaplan-Meier analyses, IgG autoantibody levels ≥1.33 predicted dialysis or death (both P≤0.01). In conclusion, these data suggest that serum levels of IgG and IgA autoantibodies strongly associate with the progression of IgAN nephropathy.     

Selective elevation of monomeric IgA1 in IgA nephropathy patients with normal renal function

The molecular form of the pathognomonic IgA in IgA nephropathy (IgAN) remains controversial. Because characterization of the molecular form of IgA molecules can lend insight into their origin (systemic v mucosal), we developed immunoassays to measure both total and J chain-containing (polymeric) IgA1 and IgA2. These assays were used to measure IgA in sera from two groups of IgAN patients (with normal or decreased renal function), as well as from a group of normal individuals. IgA1 levels were higher in both groups of patients with IgAN when compared with the controls. The elevation appeared to be restricted to non-J chain-containing (monomeric) IgA1 in patients with normal renal function, whereas polymeric IgA1 was also slightly elevated in patients whose renal function was diminished. While there were no significant differences between the groups in terms of the levels of total IgA2, the patient group with normal kidney function appeared to have lower levels of polymeric IgA2. The observation that the elevation in serum IgA appears to be restricted to the monomeric form of IgA1, at least when renal function is normal, implies a systemic origin of the pathognomonic IgA in IgAN and further suggests an abnormality in the regulation of IgA secretion by immunoglobulin-producing cells in bone marrow, the site of systemic IgA synthesis.     

Sequential occurrence of IgA nephropathy and Henoch-Schönlein purpura: support for common pathogenesis

We report a patient who developed Henoch-Schönlein purpura (HSP) 13 years after he presented with IgA nephropathy (IgAN). In both HSP and IgAN renal biopsy most commonly reveals focal proliferative glomerulonephritis on light microscopy and immunofluorescence displays mesangial IgA deposits. In addition, patients with HSP or IgAN have elevated serum IgA levels, circulating IgA immune complexes, IgA-bearing lymphocytes, immunoglobulin-producing cells, and binding of IgG to glomerular components of similar molecular weight. The occurrence of both diseases in the same patient or the same families and the presence of immune abnormalities compatible with HSP or IgAN in relatives of patients with these diseases suggest a common pathogenesis.     

Clinicopathological features and outcomes of primary IgA nephropathy patients with chronic tonsillitis

Objective To explore the clinicopathological features and renal outcomes of primary IgA nephropathy (IgAN) patients with chronic tonsillitis. Methods Patients with biopsy-proven primary IgAN admitted to The First Affiliated Hospital, Sun Yat-sen University from January 2006 to December 2011 were enrolled. The clinicopathological features and renal outcomes of patients with and without chronic tonsillitis were retrospectively compared. The primary outcome was progression to end stage renal diseases and/or doubling of serum creatinine. Results A total of 981 primary IgAN patients were enrolled and 98 patients (9.99%) had a history of chronic tonsillitis. Compared with patients without chronic tonsillitis, IgAN patients with chronic tonsillitis exhibited significantly higher prevalence of acute episodes of tonsillitis as a predisposition (P＜0.001), higher serum IgA levels (P=0.012), and higher prevalence of macrohematuria (P=0.006). No significant difference in renal pathological features was observed in patients with and without chronic tonsillitis. Moreover, the renal outcomes were similar as regards IgAN patients with and without chronic tonsillitis. Conclusion IgAN patients with chronic tonsillitis had higher prevalence of acute episodes of tonsillitis and macrohematuria as well as higher serum IgA levels. However, IgAN patients with and without chronic tonsillitis showed no significant difference in renal pathological features and renal outcomes.     

IgA nephropathy in a patient with polycythemia vera. Clinical manifestation of chronic renal failure and heavy proteinuria

IgA nephropathy (IgAN) is one of the most frequent forms of glomerulonephritis (GN). However, its association with polycythemia vera (PV) has rarely been described. We report a case of IgAN combined with PV. The patient was a 46-year-old male with chronic renal failure, heavy proteinuria and erythrocytosis. He also presented hypertension and hematuria as well as splenomegaly, high arterial oxygen saturation and elevated leukocyte alkaline phosphatase activity. Possible causes of secondary erythrocytosis were ruled out. The renal biopsy revealed mesangial proliferative GN with predominant IgA deposition in mesangium. He was diagnosed as having IgAN and PV concomitantly. After administration of hydroxyurea, enalapril and felodipine, blood cell count and blood pressure normalized, while azotemia persisted. There was also a partial remission of the heavy proteinuria. We describe a case of IgAN associated with PV, and possible pathophysiologic relationships between two diseases are discussed with review of the literature.     

Henoch-Schönlein syndrome and IgA nephropathy: A case report suggesting a common pathogenesis

An 8-year-old Caucasian male presented with two episodes of gross hematuria but was otherwise asymptomatic. Serum IgA levels were markedly elevated and a renal biopsy showed mesangial proliferative glomerulonephritis with immunofluorescent and electron microscopy findings consistent with IgA nephropathy (IgAN). Two years later he developed abdominal pain, rectal bleeding, gross hematuria and a classic purpuric rash of Henoch-Schönlein syndrome (HSS). Serum IgA levels continued to be elevated and 3 years later in follow-up he is clinically well. These observations support the concept that HSS and IgAN are variants of the same process. The reverse situation has been reported in a 15-year-old female who developed HSS at 4 years of age and IgAN at age 15 years.     

Analysis of 4931 renal biopsy data in central China from 1994 to 2014

The purpose of this study is to investigate the changing spectrum and clinicopathologic correlation of biopsy-proven renal diseases in central China. We retrospectively analyzed data of 4931 patients who underwent renal biopsy in ten hospitals between September 1994 and December 2014. Among them, 81.55% were primary glomerular diseases (GD), and 13.02% were secondary GD. IgA nephropathy (IgAN) was the most common primary GD (43.45%), followed by focal glomerulonephritis (16.79%), mesangial proliferative glomerulonephritis (MsPGN, 14.35%), and membranous nephropathy (MN, 13.28%). IgAN was leading primary GD in patients under 60 years old, while MN was the leading one over 60 years old. The most frequent secondary GD was lupus nephritis (LN) (47.35%). The prevalence of IgAN, MN and minimal change disease was found to increase significantly (p?<?0.001, p?<?0.001, and p?<?0.01, respectively), while that of MsPGN, membranoproliferative glomerulonephritis and LN decreased significantly (p?<?0.001, p?<?0.001, and p?<?0.05, respectively). The main indication for renal biopsy was proteinuria and hematuria (49.03%), followed by nephrotic syndrome (NS, 20.36%). IgAN was the most common cause in patients with proteinuria and hematuria, chronic-progressive kidney injury, hematuria and acute kidney injury; and MN was the leading cause of NS. Primary GD remained the predominant renal disease in central China. IgAN and LN were the most prevalent histopathologic lesions of primary and secondary GD, respectively. The spectrum of biopsy-proven renal disease had a great change in the past two decades. Proteinuria and hematuria was the main indication for renal biopsy.     

Immunoglobulin a nephropathy: Pathological markers of renal survival in paediatric patients

IgA nephropathy (IgAN) is one of the leading causes of glomerulonephritis characterized by the findings of IgA and IgG immune deposits in the mesangium of kidney biopsies from patients with persistent microscopic haematuria. IgAN is frequently detected among adolescents and young adults. IgAN presents a highly variable course that includes a spectrum from a very mild disease to end‐stage renal disease (ESRD). There are several clinical and histological factors that strongly determined the final outcome of patients with IgAN. Pathological variables associated with unfavorable outcomes are mesangial hypercellularity, segmental glomerulosclerosis, endocapillary hypercellularity and interstitial fibrosis/tubular atrophy, according to the Oxford classification. Moreover, some studies also suggest a role for complement activation in the pathogenesis of IgAN. In this regard, staining for C4d may be an independent risk factor for the development of ESRD in IgAN. Despite the growing number of studies assessing IgAN risk factors, this kind of investigation in paediatric patients is still very limited. The aim of this article is to revise pathological markers related to deterioration of renal function in paediatric patients with IgAN, particularly those that can independently affect renal survival.     

Increased immunoglobulin-secreting cells in the blood of patients with active idiopathic IgA nephropathy

Peripheral blood lymphocytes from 33 patients with idiopathic IgA nephropathy (IgAN) and 15 healthy controls were stimulated in vitro by Protein A from Staphylococcus Cowan I; immunoglobulin (Ig) production was measured by a reverse hemolytic plaque assay to evaluate the quantity of cells secreting Ig. In addition, serum Ig levels, circulating IgG, IgA and IgM immune complexes (ICs) and the Fc and C3b receptor mediated phagocytosis of peripheral monocytes were measured. The laboratory findings in different phases of the disease were compared. The mean level of IgA-plaque forming cells (IgA PFC) in IgAN patients with normal renal function was significantly higher (p less than 0.001) than the mean control value. In contrast, they were reduced significantly in those patients who were subjected to periodic hemodialysis (p less than 0.001). Disease activity produced a significant increase in IgG PFC and IgA PFC, high IgG and IgM serum levels, high circulating IgG ICs, and low C3b-mediated phagocytic function of the peripheral macrophages. These findings demonstrate that IgAN is associated with an increased number of IgG and IgA-secreting cells in the peripheral blood of patients during the active phase of the disease and that the concurrent presence of high levels of circulating Ig ICs may be responsible for the gross hematuria, as their deposition in the glomeruli could activate the complement system.     

Downregulation of Bcl-2 by podocytes is associated with progressive glomerular injury and clinical indices of poor renal prognosis in human IgA nephropathy

Bcl-2 defines a new class of proto-oncogenes that block cell death without promoting cell proliferation. To elucidate the role of Bcl-2 in the development of glomerular lesions in human IgA nephropathy (IgAN), we applied immunohistochemistry coupled with in situ hybridization to detect the expression of Bcl-2 products and their association with Bax, p27(kip1), and p57(kip2) in modulating the apoptotic, proliferative, and sclerotic events in progressive glomerular injury. Glomerular cell apoptosis was examined by TdT-mediated dUTP-biotin nick-end labeling (TUNEL) staining. A total of 51 IgAN cases were categorized into four subgroups (A to D) according to the severity of their histopathological lesions. Creatinine levels, creatinine clearance, and magnitude of proteinuria based on 24-h urine collections at the time of diagnostic renal biopsy were available for the majority of subjects. Bcl-2 expression was observed predominantly in podocytes in IgAN. Podocyte expression of Bcl-2 was found to be upregulated in early-stage disease and downregulated in late-stage disease. Bcl-2 downregulation in progressive IgAN was associated with an increased Bax/Bcl-2 ratio in glomerular epithelial cells and correlated with the downregulation of high endogenous podocyte p27(kip1) and p57(kip2) expression. Bax/Bcl-2 ratios positively correlated with glomerular cell apoptosis and the degree of glomerulosclerosis, whereas p27(kip1) and p57(kip2) expression levels were inversely correlated with mesangial hypercellularity and glomerulosclerosis. Clinicopathologic correlations demonstrated that downregulation of Bcl-2 protein expression was associated with indices of poor renal prognosis in human IgAN. The results suggest that Bcl-2 expression by podocytes may exert modulatory effects on cellular processes that contribute to progressive glomerular injury and play an important role in determining renal outcome in human IgA nephropathy.     

Synthesis of immunoglobulins against Haemophilus parainfluenzae by tonsillar lymphocytes from patients with IgA nephropathy.

BACKGROUND: We previously demonstrated glomerular deposition of Haemophilus parainfluenzae (HP) antigens and the presence of IgA antibody against HP antigens in patients with IgA nephropathy (IgAN). In this report we examine the synthesis of immunoglobulins against HP antigens in tonsillar lymphocytes from patients with IgAN. METHODS: We used tonsillar lymphocytes isolated from the palatine tonsils of 15 patients with IgAN and 16 patients with chronic tonsillitis but without renal disease. We examined lymphocyte proliferation and production of IgA, IgG, and IgM antibodies against HP antigens by measuring thymidine uptake and concentrations of these antibodies in culture supernatants after lymphocyte incubation with HP antigens by ELISA. RESULTS: Lymphocytes from patients with IgAN showed a significantly higher stimulation index (SI) on exposure to HP antigens (thymidine incorporation in tonsillar lymphocytes exposed to HP (c.p.m.)/ thymidine incorporation in unstimulated tonsillar lymphocytes (c.p.m.)) than did controls (P=0. 0015). Lymphocytes from patients with IgAN also showed a significantly higher IgA SI (concentrations of IgA against HP antigens in supernatants from HP-stimulated lymphocytes/IgA against HP antigens in supernatants from unstimulated tonsillar lymphocytes) than did controls (P=0.0004). We found positive correlations between concentrations of IgA and IgG antibodies, between IgA and IgM antibodies, and between IgG and IgM antibodies against HP antigens after HP stimulation. CONCLUSIONS: Our results suggest that HP antigens stimulate tonsillar T and B lymphocytes in patients with IgAN and that these patients have polyclonal activation of lymphocytes against HP antigens, with isotype switching of antibody production from IgM to IgA.     

IgA-containing immune complexes in the urine of IgA nephropathy patients.

BACKGROUND: Sera of IgA nephropathy (IgAN) patients contain high levels of circulating immune complexes composed of IgA1 molecules with aberrantly glycosylated hinge-region O-linked oligosaccharides and IgG or IgA1 antibodies with anti-glycan or anti-hinge-region peptide specificities. Due to damaged sieving properties of the glomerular capillary wall in IgAN, these immune complexes may appear in the urine. METHODS: We collected urine samples from 29 patients with biopsy-proven IgAN (Group I), 27 proteinuric patients with non-IgA nephropathies (Group II) and 28 healthy volunteers (Group III). The levels of urinary IgA and IgG and IgA-IgG-containing immune complexes were measured by ELISA and standardized for urinary creatinine concentrations. RESULTS: The urinary IgA and IgG levels were significantly higher in Groups I and II than in Group III. Although the excretion of IgA as a fraction of total urinary protein was not significantly greater in IgAN patients than in patients with other renal diseases, the excretion of aberrantly glycosylated IgA1 was observed by western blot in 68% of the IgAN patients but in none of the healthy controls. The urinary levels of IgA-IgG immune complexes were significantly higher in Group I than in Groups II (P < 0.01) and III (P < 0.05). There was no significant difference in the levels between Groups II and III. These immune complexes had a molecular mass between 650-850 kDa, as shown by size-exclusion chromatography. CONCLUSION: The amounts of urinary IgA-IgG-containing immune complexes were significantly higher in patients with IgAN than in patients with non-IgA nephropathies or healthy controls.