IgA nephropathy in association with Crohn's disease

Novel immune cross-talk between inflammatory bowel disease and IgA nephropathy

The mechanisms underlying the complex correlation between immunoglobulin A nephropathy (IgAN) and inflammatory bowel disease (IBD) remain unclear. This study aimed to identify the optimal cross-talk genes, potential pathways, and mutual immune-infiltrating microenvironments between IBD and IgAN to elucidate the linkage between patients with IBD and IgAN. The IgAN and IBD datasets were obtained from the Gene Expression Omnibus (GEO). Three algorithms, CIBERSORTx, ssGSEA, and xCell, were used to evaluate the similarities in the infiltrating microenvironment between the two diseases. Weighted gene co-expression network analysis (WGCNA) was implemented in the IBD dataset to identify the major immune infiltration modules, and the Boruta algorithm, RFE algorithm, and LASSO regression were applied to filter the cross-talk genes. Next, multiple machine learning models were applied to confirm the optimal cross-talk genes. Finally, the relevant findings were validated using histology and immunohistochemistry analysis of IBD mice. Immune infiltration analysis showed no significant differences between IBD and IgAN samples in most immune cells. The three algorithms identified 10 diagnostic genes, MAPK3, NFKB1, FDX1, EPHX2, SYNPO, KDF1, METTL7A, RIDA, HSDL2, and RIPK2; FDX1 and NFKB1 were enhanced in the kidney of IBD mice. Kyoto Encyclopedia of Genes and Genomes analysis showed 15 mutual pathways between the two diseases, with lipid metabolism playing a vital role in the cross-talk. Our findings offer insights into the shared immune mechanisms of IgAN and IBD. These common pathways, diagnostic cross-talk genes, and cell-mediated abnormal immunity may inform further experimental studies.

Crohn's Disease Associated With IgA Nephropathy Effectively Treated With the Interleukin-23 Inhibitor Risankizumab

Extraintestinal manifestations (EIMs) are common in inflammatory bowel disease (IBD). Renal EIMs, including immunoglobulin A nephropathy (IgAN), are relatively rare. EIMs are important to consider when developing a treatment plan for IBD. Studies differ on whether IBD disease activity correlates with IgAN disease activity. Published guidance on effective therapies for IBD-associated IgAN is limited. This case report suggests that risankizumab, an effective therapy for Crohn's disease, may also be effective in treating Crohn's disease-associated IgAN.

Crohn's disease-associated IgA nephropathy may prone to better renal outcome

BACKGROUND AND AIM

Renal involvement in Crohn's Disease (CD) was rare in the population. Little was known between IgA nephropathy and CD. This study aimed to investigate the differences in clinical and outcome features of CD-associated IgA nephropathy (CD-IgAN) and primary IgA nephropathy (PIgAN).

METHODS

Clinical data of patients diagnosed with IgAN by kidney biopsy were collected in the Sixth Affiliated Hospital of Sun Yat-sen University from January 1st, 2016 to June 1st, 2023. 17 patients with CD-IgAN and 87 patients with PIgAN were enrolled in this retrospective study.

RESULTS

Compared with PIgAN patients, CD-IgAN patients had lower levels of urinary protein excretion (1.57 g per 24 h vs. 0.33 g per 24 h, p < 0.01), but higher levels of estimated glomerular filtration rate (77.63 ± 40.11 ml per min per 1.73m2 vs. 104.53 ± 32.97 ml per min per 1.73m2, p = 0.008). From the point of renal pathology of PIgAN, patients with CD-IgAN had a less incidence of tubular atrophy or interstitial fibrosis (p = 0.001). CD-IgAN patients had a higher incidence of complete remission of proteinuria (45.8% vs. 81.8%, p = 0.031) or hematuria (10.4% vs. 45.4%, p = 0.019) than PIgAN patients after twelve-month treatments.

CONCLUSIONS

CD-IgAN manifests a milder progression of renal function than those PIgAN. After the treatment, proteinuria or hematuria are more prone to remit in patients with CD-IgAN.

Immunoglobulin A Glycosylation Differs between Crohn's Disease and Ulcerative Colitis

Inflammatory bowel diseases (IBD), such as Crohn's disease (CD) and ulcerative colitis (UC), are chronic and relapsing inflammations of the digestive tract with increasing prevalence, yet they have unknown origins or cure. CD and UC have similar symptoms but respond differently to surgery and medication. Current diagnostic tools often involve invasive procedures, while laboratory markers for patient stratification are lacking. Large glycomic studies of immunoglobulin G and total plasma glycosylation have shown biomarker potential in IBD and could help determine disease mechanisms and therapeutic treatment choice. Hitherto, the glycosylation signatures of plasma immunoglobulin A, an important immunoglobulin secreted into the intestinal mucin, have remained undetermined in the context of IBD. Our study investigated the associations of immunoglobulin A1 and A2 glycosylation with IBD in 442 IBD cases (188 CD and 254 UC) and 120 healthy controls by reversed-phase liquid chromatography electrospray-ionization mass spectrometry of tryptic glycopeptides. Differences of IgA O- and N-glycosylation (including galactosylation, bisection, sialylation, and antennarity) between patient groups were associated with the diseases, and these findings led to the construction of a statistical model to predict the disease group of the patients without the need of invasive procedures. This study expands the current knowledge about CD and UC and could help in the development of noninvasive biomarkers and better patient care.

IgA nephropathy associated with Crohn's disease

The relationship between IgA nephropathy (IgAN) and Crohn’s disease was reported. IgAN is the most common primary glomerulonephritis and one of the leading causes of chronic kidney disease and end-stage renal failure, and up to 50% of cases progressed to end-stage renal disease within 25 years after IgAN diagnosis. However, specific and effective therapeutic strategies are still lacking. In this review, we discuss the possibility of the mechanism involved in IgAN associated with Crohn’s disease based on the findings of basic and clinical studies. Although the etiology of IgAN associated with Crohn’s disease is not permanent and various factors are thought to be involved, the stabilization of the disease condition of Crohn’s disease is believed to help treat IgAN.

Secondary IgA Nephropathy and IgA-Associated Nephropathy: A Systematic Review of Case Reports

Primary (pIgAN), secondary IgA nephropathy (sIgAN), and IgA-associated nephropathy can be distinguished. While pIgAN has been thoroughly studied, information about the etiology of sIgAN remains scarce. As concerns sIgAN, several studies suggest that different etiologic factors play a role and ultimately lead to a pathophysiologic process similar to that of pIgAN. In this article, we review a vast number of cases in order to determine the novel putative underlying diseases of sIgAN. Moreover, updates on the common pathophysiology of primary disorders and sIgAN are presented. We identified liver, gastrointestinal, oncological, dermatological, autoimmune, and respiratory diseases, as well as infectious, iatrogenic, and environmental factors, as triggers of sIgAN. As novel biological therapies for listed underlying diseases emerge, we suggest implementing drug-induced sIgAN as a new significant category. Clinicians should acknowledge the possibility of sIgAN progression in patients treated with TNF-α inhibitors, IL-12/IL-23-inhibitors, immune checkpoint inhibitors, CTLA-4, oral anticoagulants, thioureylene derivatives, and anti-vascular endothelial growth factor drugs.

Glomerulonephritis and inflammatory bowel disease: A tale of gut-kidney axis dysfunction

The incidence and prevalence of Inflammatory Bowel Disease (IBD) has increased over the past decades, imposing a growing socioeconomic burden on healthcare systems globally. Most of the morbidity and mortality related to IBD is typically attributed to gut inflammation and its complications; yet the disease is characterized by various extraintestinal manifestations that can be severe. Glomerulonephritis (GN) is of particular interest since a significant proportion of patients evolve into end-stage kidney disease, requiring kidney replacement therapy and associated with high morbidity and mortality. Herein, we review the GN landscape in IBD and define the clinical and pathogenic associations reported to date in the literature. Underlying pathogenic mechanisms suggest either the initiation of antigen-specific immune responses in the inflamed gut that cross react with non-intestinal sites, such as the glomerulus, or that extraintestinal manifestations are gut-independent events that occur due to an interaction between common genetic and environmental risk factors. We present data associating GN with IBD either as a bona fide extraintestinal manifestation or reporting it as an extraneous co-existing entity, involving various histological subtypes, such as focal segmental glomerulosclerosis, proliferative GN, minimal change disease, crescentic GN, but most emphatically IgA nephropathy. Supporting the pathogenic interplay between gut inflammation and intrinsic glomerular processes, enteric targeting the intestinal mucosa with budesonide reduced IgA nephropathy-mediated proteinuria. Elucidating the mechanisms at play would provide insight not only into IBD pathogenesis but also into the gut's role in the development of extraintestinal diseases, such as glomerular diseases.

Seronegative Full-house Nephropathy with Crohn's Disease

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disease. Lupus nephritis (LN) is a major risk factor for mortality in SLE, and glomerular "full-house" immunofluorescence staining is a well-known characteristic of LN. However, some cases of non-lupus glomerulonephritis can also present with a "full-house" immunofluorescence pattern. We recently encountered a patient with full-house nephropathy (FHN) during adalimumab administration for Crohn's disease. IgA nephropathy or idiopathic FHN was diagnosed, and treatment with steroids was started, after which there was improvement in proteinuria. The prognosis of FHN has been reported to be poor; therefore, aggressive treatment is required for such patients.

Renal and Urological Disorders Associated With Inflammatory Bowel Disease

Renal and urinary tract complications related to inflammatory bowel disease (IBD) have been relatively understudied in the literature compared with other extraintestinal manifestations. Presentation of these renal manifestations can be subtle, and their detection is complicated by a lack of clarity regarding the optimal screening and routine monitoring of renal function in IBD patients. Urolithiasis is the most common manifestation. Penetrating Crohn's disease involving the genitourinary system as an extraintestinal complication is rare but associated with considerable morbidity. Some biologic agents used to treat IBD have been implicated in progressive renal impairment, although differentiating between drug-related side effects and deteriorating kidney function due to extraintestinal manifestations can be challenging. The most common findings on renal biopsy of IBD patients with renal injury are tubulointerstitial nephritis and IgA nephropathy, the former also being associated with drug-induced nephrotoxicity related to IBD medication. Amyloidosis, albeit rare, must be diagnosed early to reduce the chance of progression to renal failure. In this review, we evaluate the key literature relating to renal and urological involvement in IBD and emphasize the high index of suspicion required for the prompt diagnosis and treatment of these manifestations and complications, considering the potential severity and implications of acute or chronic loss of renal function. We also provide suggestions for future research priorities.

The pathological and outcome characteristics of renal lesions in Crohn's disease

Background

The inflammatory bowel disease, containing Crohn’s disease and ulcerative colitis, was rare in the population, especially in the complication of kidney disease. A few studies had found proteinuria played a potential indicator of inflammatory bowel disease occurrence and activity. This study aimed to better define the histopathologic spectrum and study the outcome of renal disease in Crohn’s disease.

Methods

A retrospective study of 3557 Crohn's disease from January 1^st, 2016 to July 1^st, 2021 in the Sixth Affiliated Hospital of Sun Yat-sen University identified 20 (0.56% [20/3557]) patients who underwent kidney biopsy. All biopsy specimens were examined by standard procedures containing light microscopy, immunofluorescence, and electron microscopy.

Results

Twenty cases were shown in this review study. Subnephrotic proteinuria (30% [6 of 20]), persistent hematuria and proteinuria (25% [5 of 20]), and isolated hematuria with acanthocytes (25% [5 of 20]) were the main indications for kidney biopsy. The most common diagnosis was IgA nephropathy (70% [14/20]), followed by minimal change disease (10% [2/20]), acute interstitial nephritis (5% [1/20]), granulomatous interstitial nephritis (5% [1/20]), non-IgA mesangial proliferative nephritis (5% [1/20]) and thin basement membrane nephropathy (5% [1/20]). The Lee classification of IgA nephropathy was mostly II or III level. Glomerular mesangial hyperplasia was the most common pathologic manifestation according to the MEST-C Sore. After twelve-month treatment, the majority of patients turned to complete remission of renal disease by measuring proteinuria, while 3 patients still stayed in the relapse stage and 6 patients turned to partial remission by measuring hematuria.

Conclusions

IgA nephropathy is the most common kidney biopsy diagnosis in Crohn's disease. Renal damage in Crohn's disease mainly involves the glomerulus, especially the mesangial matrix. After the treatment, proteinuria might be in remission, but hematuria remains.

Differentiation of T Helper 17 Cells May Mediate the Abnormal Humoral Immunity in IgA Nephropathy and Inflammatory Bowel Disease Based on Shared Genetic Effects

Background

IgA nephropathy (IgAN) is the most frequent glomerulonephritis in inflammatory bowel disease (IBD). However, the inter-relational mechanisms between them are still unclear. This study aimed to explore the shared gene effects and potential immune mechanisms in IgAN and IBD.

Methods

The microarray data of IgAN and IBD in the Gene Expression Omnibus (GEO) database were downloaded. The differential expression analysis was used to identify the shared differentially expressed genes (SDEGs). Besides, the shared transcription factors (TFs) and microRNAs (miRNAs) in IgAN and IBD were screened using humanTFDB, HMDD, ENCODE, JASPAR, and ChEA databases. Moreover, weighted gene co-expression network analysis (WGCNA) was used to identify the shared immune-related genes (SIRGs) related to IgAN and IBD, and R software package org.hs.eg.db (Version3.1.0) were used to identify common immune pathways in IgAN and IBD.

Results

In this study, 64 SDEGs and 28 SIRGs were identified, and the area under the receiver operating characteristic curve (ROC) of 64 SDEGs was calculated and two genes (MVP, PDXK) with high area under the curve (AUC) in both IgAN and IBD were screened out as potential diagnostic biomarkers. We then screened 3 shared TFs (SRY, MEF2D and SREBF1) and 3 miRNAs (hsa-miR-146, hsa-miR-21 and hsa-miR-320), and further found that the immune pathways of 64SDEGs, 28SIRGs and 3miRNAs were mainly including B cell receptor signaling pathway, FcγR-mediated phagocytosis, IL-17 signaling pathway, toll-like receptor signaling pathway, TNF signaling pathway, TRP channels, T cell receptor signaling pathway, Th17 cell differentiation, and cytokine-cytokine receptor interaction.

Conclusion

Our work revealed the differentiation of Th17 cells may mediate the abnormal humoral immunity in IgAN and IBD patients and identified novel gene candidates that could be used as biomarkers or potential therapeutic targets.

IgA nephropathy in a child: Crohn's disease-associated or adalimumab induced?

In pediatric patients with Inflammatory Bowel Disease renal parenchymal disease is infrequent. There are only two reports about the association between IgA Nephropathy and Pediatric Crohn Disease. IgA Nephropathy is a rather uncommon complication of Tumor Necrosis Factor-alpha (TNF-α) inhibition. We describe a case of IgA Nephropathy which has arisen in a 11-year-old child 2 years after Crohn disease diagnosis, during therapy with anti-TNF-α. An ileal e jejunal Crohn disease was diagnosed at 9 years old, initially treated with prednisone, followed by biological therapy with anti-TNF-α (Adalimumab) due to severe disease activity, with gradual improvement of clinical conditions until clinical remission is achieved. Two years after the diagnosis, the child suddenly presented macroscopic hematuria. Subsequent laboratory examinations showed acute renal failure. So kidney biopsy was performed and IgA Nephropathy diagnosis was made. Adalimumab was discontinued and the child has been treated with steroids for sixth months associated with angiotensin-converting enzyme inhibitor resulted in clinical improvement over the following year and remission was maintained. To our knowledge the association of IgA Nephropathy and pediatric IBD during therapy with anti-TNF-α has never been reported. Careful monitoring of renal function, proteinuria, and autoantibodies is advised in patients treated with anti-TNF-α agents.

Aberrantly Glycosylated IgA1 in IgA Nephropathy: What We Know and What We Don't Know

IgA nephropathy (IgAN), the most common primary glomerular disease worldwide, is characterized by glomerular deposition of IgA1-containing immune complexes. The IgA1 hinge region (HR) has up to six clustered O-glycans consisting of Ser/Thr-linked N-acetylgalactosamine usually with β1,3-linked galactose and variable sialylation. Circulating levels of IgA1 with abnormally O-glycosylated HR, termed galactose-deficient IgA1 (Gd-IgA1), are increased in patients with IgAN. Current evidence suggests that IgAN is induced by multiple sequential pathogenic steps, and production of aberrantly glycosylated IgA1 is considered the initial step. Thus, the mechanisms of biosynthesis of aberrantly glycosylated IgA1 and the involvement of aberrant glycoforms of IgA1 in disease development have been studied. Furthermore, Gd-IgA1 represents an attractive biomarker for IgAN, and its clinical significance is still being evaluated. To elucidate the pathogenesis of IgAN, it is important to deconvolute the biosynthetic origins of Gd-IgA1 and characterize the pathogenic IgA1 HR O-glycoform(s), including the glycan structures and their sites of attachment. These efforts will likely lead to development of new biomarkers. Here, we review the IgA1 HR O-glycosylation in general and the role of aberrantly glycosylated IgA1 in the pathogenesis of IgAN in particular.

IgA nephropathy in association with inflammatory bowel diseases: results from a national study and systematic literature review

BACKGROUND

Little is known about clinical characteristics and kidney outcome in patients with biopsy-proven immunoglobulin A nephropathy (IgAN) in a context of inflammatory bowel disease (IBD).

METHODS

We conducted a retrospective multicenter study with centralized histological review, to analyze the presentation, therapeutic management and outcome of 24 patients suffering from IBD associated IgAN relative to a cohort of 134 patients with primary IgAN without IBD.

RESULTS

Crohn's disease and ulcerative colitis accounted for 75% and 25% of IBD-associated IgAN cases, respectively. IBD was diagnosed before IgAN in 23 cases (a mean of 9 years previously) and was considered active at IgAN onset in 23.6% of patients. Hypertension was present in 41.7% of patients. Urinary protein-to-creatinine ratio exceeded 100 mg/mmol in 70.8% of patients (mean: 254 mg/mmol). Estimated glomerular filtration rate (eGFR) exceeded 60 ml/min/1.73m2 in 13/24 patients and only one patient required dialysis. In the Oxford MEST-C classification of renal biopsies, 57% were M1, 48% E1, 76% S1, 57% T1+T2 and 38% C1+C2. Steroids were administered in 50% of cases. After a mean follow-up of 7.2 years, four patients (16.7%) had a poor kidney outcome: end-stage renal disease (n = 3) or a > 50% decrease in eGFR from initial values (n = 1). A similar evolution was observed in patients with primitive IgAN.

CONCLUSIONS

This first case series suggests that IBD-associated IgAN have frequent inflammatory lesions at onset and variable long-term outcome.

Prevalence of Inflammatory Bowel Disease and Celiac Disease in Patients with IgA Nephropathy over Time

INTRODUCTION

IgA nephropathy (IgAN) has been connected with increased intestinal permeability and subclinical intestinal mucosal inflammation as well as with inflammatory bowel disease (IBD) and celiac disease - nevertheless, the results are controversial. The prevalence of bowel diseases has increased over time in Western populations. Whether similar trend is seen among IgAN patients remains obscure. Our aim was to study the prevalence of IBD and celiac disease in IgAN patients over time.

METHODS

The study cohort consisted of altogether 629 patients with newly diagnosed IgAN during years 1976-2012. Data on diagnosis of IBD and celiac disease were retrospectively collected from medical records. Further, to detect unrecognized celiac disease, IgA-class tissue transglutaminase antibodies (tTGA) were measured from serum samples taken at the time of kidney biopsy during years 1980-2012 (defined as screen-detected celiac disease autoimmunity).

RESULTS

The prevalence of IBD among IgAN patients increased over time from 0 to 4.4%, while the prevalence of clinically diagnosed celiac disease decreased from 2.6 to 0.6%. Moreover, the number of screen-detected tTGA-positive cases decreased from the 1980s to the 21st century (2.8-0.7%).

CONCLUSION

The prevalence of IBD increased over time in IgAN patients, which exceeds the prevalence of 0.6% in Finnish general population. In parallel, the prevalence of celiac disease and screen-detected celiac disease autoimmunity decreased over time. The coexistence of IBD and IgAN is not negligible. Whether this finding is caused by the increase in the prevalence of IBD in the population or shared pathophysiology between IgAN and IBD remains a matter of further studies.

Clinical characteristics of inflammatory bowel disease patients with immunoglobulin A nephropathy

Background/Aims

Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract. Some patients with this condition have been reported to present with immunoglobulin A nephropathy (IgAN), a renal complication that can cause end-stage renal failure, but the frequency of this comorbidity has not been described. Thus, the aim of this study was to investigate the frequency of IgAN in patients with IBD.

Methods

This study included 620 patients with IBD (338 with ulcerative colitis [UC] and 282 with Crohn’s disease [CD]) from the Hiroshima University Hospital outpatient department. IgAN cases were identified from medical interviews, blood examinations (serum immunoglobulin A), and urinalyses (occult blood, proteinuria). Definitive IgAN cases were diagnosed by renal biopsies, while those detected through the clinical course and test results, but not clinically recommended for renal biopsy, were defined as suspected IgAN.

Results

We analyzed 427 cases meeting the inclusion criteria (220 with UC and 207 with CD). The incidence of IgAN across all patients with IBD was 3.0%. The frequency of IgAN was significantly higher in patients with CD (11/207, 5.3%) than in those with UC (2/220, 0.9%) (P< 0.01). Moreover, a significant correlation was found between CD patients with ileostomy or colostomy and a diagnosis of IgAN.

Conclusions

Patients with IBD present a high incidence of IgAN, especially those with CD who have undergone ileostomy or colostomy.

Inflammatory bowel disease in patients undergoing renal biopsies

BACKGROUND

There are no good data in the literature on the prevalence of inflammatory bowel disease (IBD) in patients with kidney disease and we do not know whether IBD affects the course of kidney disease or if the type of IBD is an influential factor. The aim of this study was to evaluate the prevalence of IBD among patients who have undergone renal biopsies due to clinical indications and to elucidate whether the presence of IBD influences renal and patient outcomes.

METHODS

We collected retrospective data on concomitant diseases, especially IBD, from adult patients undergoing renal biopsy for any clinical indication between 2000 and 2012 at Tampere University Hospital, Tampere, Finland. Information was systematically collected on the activity of IBD, medication for IBD, surgery performed for IBD and markers of kidney function.

RESULTS

Of the 819 patients biopsied, 35 (4.3%) had IBD. The prevalence of IBD was 13.3 and 4.6% in patients with tubulointerstitial nephritis (TIN) and immunoglobulin A nephropathy (IgAN), respectively. In comparison, the prevalence of IBD in the Finnish population is 0.6%. Ulcerative colitis and Crohn's disease were equally represented. The presence of IBD showed no impact on renal and patient outcomes.

CONCLUSIONS

IBD should not be overlooked in patients undergoing renal biopsies, especially those diagnosed with TIN or IgAN. The renal findings did not associate with the activity of intestinal inflammation. Whether a concomitant IBD truly affects the course of chronic kidney disease should be examined in further studies.

[Renal and Urinary Manifestations of Inflammatory Bowel Disease]

The incidence of inflammatory bowel disease (IBD) is increasing rapidly and extra-intestinal manifestations in IBD are also increasing. The prevalence of renal and urinary involvement in IBD ranges from 4-23%. Nephrolithiasis is the most common urinary complication in IBD patients. Parenchymal renal disease is rare but has been well documented and presents most commonly as glomerulonephritis or tubulointerstitial nephritis. The overall morbidity of IBD-related renal manifestations is significant. Therefore, a high index of clinical suspicion and optimal monitoring of the renal function are needed for the early diagnosis and prevention of IBD-related renal manifestations and complications.

Adalimumab-induced IgA nephropathy

Immunoglobulin A nephropathy (IgAN) is the most commonly diagnosed glomerulonephritis worldwide. It is usually idiopathic and may be associated with many other diseases. Recently, biological agents including tumour necrosis factor alpha (TNFα) inhibitors have been identified as a potential cause for IgAN. We report the case of a 39-year-old woman who presented with renal dysfunction and visible haematuria. She had a background of Crohn's disease (CD) and had been on adalimumab for 4 years following a right hemicolectomy. Subsequently, she underwent a renal biopsy that demonstrated IgAN and adalimumab was ceased. Following a flare in her CD, she was commenced on infliximab, which led to remission of the IgAN and CD. This is the first case to demonstrate the occurrence of IgAN as a complication of a TNFα inhibitor (adalimumab) that remained in remission despite the commencement of a second TNFα inhibitor (infliximab).

Renal involvement in children and adolescents with inflammatory bowel disease

Purpose

The incidence of inflammatory bowel disease (IBD) is rapidly increasing, and several reports have described the renal complications of IBD. We sought to evaluate the clinical manifestations of renal complications in children with IBD in order to enable early detection and prompt treatment of the complications.

Methods

We retrospectively reviewed the medical records of 456 children and adolescents aged <20 years who had been diagnosed with IBD since 2000. We analyzed patient age, sex, medication use, IBD disease activity, and clinical manifestations of renal symptoms.

Results

Our study comprising 456 children with IBD included 299 boys (65.6%) and 157 girls (34.4%). The study included 346 children with Crohn disease and 110 children with ulcerative colitis. The incidence of kidney-related symptoms was 14.7%, which was significantly higher than that in normal children. We observed 26 children (38.8%) with isolated hematuria, 30 children (44.8%) with isolated proteinuria, and 11 children (16.4%) with hematuria and concomitant proteinuria. A renal biopsy was performed in 7 children. Histopathological examination revealed immunoglobulin A nephropathy in 5 children (71.4%). All children presented with mild disease and well-controlled disease activity of IBD.

Conclusion

Children with IBD are more likely to show kidney-related symptoms than healthy children and adolescents are. Therefore, regular screening of urine and evaluation of renal function in such children are necessary for early detection of renal complications.

Paraneoplastic immunoglobulin A nephropathy and associated focal segmental glomerulosclerosis in asymptomatic low volume B-cell lymphoma - a case report

Background

Paraneoplastic glomerulonephritis is rare in haematological malignancies and tends to manifest as minimal change disease, membranous glomerulonephritis or membranoproliferative glomerulonephritis. We present the first report of immunoglobulin A nephropathy and associated focal segmental glomerulosclerosis in a patient with asymptomatic low grade B-cell lymphoma.

Case presentation

A 53 year old gentleman presented with nephrotic range proteinuria (urine protein creatinine ratio of 662 mg/mmol) on a background of type 2 diabetes mellitus (glycosylated haemoglobin: < 6%), hypertension, obesity (body mass index: 47.6 kg/m²) and degenerative spine disease. Bone marrow biopsy diagnosed a low grade B-cell lymphoma and renal biopsy was consistent with immunoglobulin A nephropathy. Lymphoma treatment with six cycles of cyclophosphamide/ rituximab/ prednisolone led to normalisation of urinary protein excretion (urine protein creatinine ratio: 14 mg/mmol at 26 months post-chemotherapy).

Conclusion

Paraneoplastic immunoglobulin A nephropathy can occur with a broad range of haematological malignancies regardless of stage. This case illustrates the importance of meticulous haematological system work-up for patients presenting with immunoglobulin A nephropathy. Recognition of paraneoplastic immunoglobulin A nephropathy and early diagnosis of associated malignancy can be life-saving.

Renal Manifestations of Inflammatory Bowel Disease

Renal and urinary involvement has been reported to occur in 4% to 23% of inflammatory bowel disease (IBD) patients. Parenchymal renal disease is rare and most commonly affects glomerular and tubulointerstitial compartments. The most common findings on renal biopsy of IBD patients are IgA nephropathy and tubulointerstitial nephritis. Overall morbidity of IBD-related renal manifestations is significant, and there is often only a short window of injury reversibility. This, along with subtle clinical presentation, requires a high index of suspicion and routine monitoring of renal function. There are no established guidelines for the optimal screening and monitoring of renal function in IBD patients.

Iatrogenic Kaposi's Sarcoma in an HIV-Negative Young Male With Crohn's Disease and IgA Nephropathy: A Case Report and Brief Review of the Literature

BACKGROUND

Kaposi's sarcoma (KS) is a vascular tumor arising in association with human herpesvirus-8 (HHV-8) infection, and different variants show different clinical presentations. Isolated intestinal KS in the background of Crohn's disease (CD) is exceedingly rare with only 3 cases reported in the English literature (from 1966 to 2016).

CASE PRESENTATION

Herein, we report a case of intestinal KS in a 21-year-old HIV-negative Ethiopian male with a long-standing history of steroid therapy for his underlying IgA nephropathy. Recent gastrointestinal biopsies confirmed an additional diagnosis of CD. Despite the addition of Infliximab to his therapy, his CD remained refractory, and a laparoscopic-assisted ileocolectomy was performed to alleviate a partial small bowel obstruction. Examination of his terminal ileum demonstrated a polypoid mass with adjacent incidental ileal submucosal nodules. These nodules were composed of plump spindle cells with scattered mitoses and vascular channels with extravasated red blood cells. Intratumoral hyaline globules were also noted. Immunohistochemistry revealed HHV-8 positivity, confirming the histologic impression of KS.

CONCLUSIONS

Here we report the fourth case of KS in CD in an HIV-negative patient and only the third case of isolated intestinal KS in the setting of CD. A review of the literature suggests that attenuation of immunosuppressive therapy may be adequate management of iatrogenic KS in the absence of a systemic HHV-8 infection.

The possible involvement of intestine-derived IgA1: a case of IgA nephropathy associated with Crohn's disease

Background

A link between IgA nephropathy and Crohn’s disease has recently been reported. Other researchers hypothesize that intestine-derived IgA complexes deposit in glomerular mesangial cells, eliciting IgA nephropathy. Intestinal mucosal plasma cells mainly secrete IgA₂. Nevertheless, IgA₁ deposition is strongly implicated as being the primary cause of IgA nephropathy.

Case presentation

A 46-year-old Japanese man developed IgA nephropathy 29 years ago, following tonsillectomy. As a result, a normal urinalysis was obtained. The patient previously suffered Crohn’s disease followed by urinary occult blood and proteinuria six years ago. Exacerbation of IgA nephropathy was highly suspected. Therefore a renal biopsy was performed. A diagnosis of exacerbation of IgA nephropathy with mesangial cell proliferation and fibrotic cellular crescent was based upon the pathological findings. The patient exhibited a positive clinical course and eventually achieved a remission with immunosuppressive therapy including prednisolone treatment. Immunostaining for the detection of IgA subtypes was performed on both of his kidney and excised ileum. The results revealed IgA₁ and IgA₂ deposition by submucosal cells in intestine. Furthermore, IgA₁ deposition of mesangial areas in the patient’s kidney, indicated an association of IgA₁ with the exacerbation of IgA nephropathy.

Conclusion

This case represents the possibility that the intestine-derived IgA₁ can be the origin of galactose-deficient IgA which is known to cause IgA nephropathy exacerbation.

Renal Involvement in Inflammatory Bowel Diseases

The prevalence of extraintestinal manifestations in inflammatory bowel diseases varies from 6% to 46%. The aetiology of extraintestinal manifestations remains unclear. There are theories based on an immunological response influenced by genetic factors. Extraintestinal manifestations can involve almost every organ system. They may originate from the same pathophysiological mechanism of intestinal disease, or as secondary complications of inflammatory bowel diseases, or autoimmune diseases susceptibility. The most frequently involved organs are the joints, skin, eyes, liver and biliary tract. Renal involvement has been considered as an extraintestinal manifestation and has been described in both Crohn's disease and ulcerative colitis. The most frequent renal involvements in patients with inflammatory bowel disease are nephrolithiasis, tubulointerstitial nephritis, glomerulonephritis and amyloidosis. The aim of this review is to evaluate and report the most important data in the literature on renal involvement in patients with inflammatory bowel disease. Bibliographical searches were performed of the MEDLINE electronic database from January 1998 to January 2015 with the following key words (all fields): (inflammatory bowel disease OR Crohn's disease OR ulcerative colitis) AND (kidney OR renal OR nephrotoxicity OR renal function OR kidney disease OR renal disease OR glomerulonephritis OR interstitial nephritis OR amyloidosis OR kidney failure OR renal failure) AND (5-aminosalicylic acid OR aminosalicylate OR mesalazine OR TNF-α inhibitors OR cyclosporine OR azathioprine OR drugs OR pediatric).

Recurrent IgA nephropathy complicated with Crohn's disease after renal transplantation

A 27-year-old man was diagnosed with IgA nephropathy and Crohn's disease. He had been diagnosed with proteinuria and hematuria since he was 20 years old. Diarrhea had been a continuing problem during the past 5 months. Neither corticosteroid therapy nor tonsillectomy was performed. Hemodialysis was required at age of 30, while the symptoms of Crohn's disease were ameliorated by an elemental diet. He received a renal transplant from his mother 4 months after starting dialysis therapy. The initial immunosuppression therapy consisted of methylprednisolone, mycofenolate mofetil, cyclosporine, and basiliximab. Eight months after transplantation, proteinuria and hematuria appeared and serum creatinine was 1.4 mg/dL. Relapse of IgA nephropathy was confirmed by the one-year protocol biopsy. He had suffered from tonsillitis at 32 months after the transplantation. Urinary protein increased to 3 g/day and serum creatinine was elevated to 2.04 mg/dL. Renal biopsy was performed 2 weeks after the urinary findings were aggravated. The cellular crescents constituted 36 % of the glomeruli. The findings of rejection were not confirmed in both biopsies. Tonsillectomy was performed thereafter. No additional immunosuppressive therapy was added. Proteinuria and hematuria disappeared at 4 and 20 months, respectively, after tonsillectomy, even when the symptoms of Crohn's disease worsened 69 months and 89 months after transplantation. A renal biopsy was performed 101 months after transplantation. Although IgA in the mesangium area was confirmed by immunohistochemical staining, no active lesion was seen. Tonsillectomy along with immunosuppressants for the graft might be an effective treatment for some patients with active recurrent IgA nephropathy.

The histopathologic spectrum of kidney biopsies in patients with inflammatory bowel disease

BACKGROUND AND OBJECTIVES

Kidney disease as a complication of inflammatory bowel disease (IBD), including Crohn disease (CD) and ulcerative colitis (UC), has been the subject of case reports. However, no cases series examining IBD and kidney disease has been published to date. This study aimed to evaluate a large series of kidney biopsy specimens from patients with IBD to better define the spectrum and relative frequencies of IBD-associated kidney pathology.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective review of native kidney biopsy specimens obtained from March 2001 to June 2012 identified 83 patients with IBD. Standard processing of all biopsy specimens included light microscopy, immunofluorescence, and electron microscopy.

RESULTS

There were 45 cases of CD and 38 cases of UC represented. The most common indication for kidney biopsy was acute or chronic kidney failure (63% [52 of 83]) and nephrotic-range proteinuria (16% [13 of 83]). IgA nephropathy was the most common diagnosis (24% [20 of 83]), followed by interstitial nephritis (19% [16 of 83]), arterionephrosclerosis (12% [10 of 83]), acute tubular injury (8% [7 of 83]), proliferative GN (7% [6 of 83]), and minimal-change disease (5% [4 of 83]). When compared, the frequency of IgA nephropathy in IBD was significantly higher than in all other native renal biopsy specimens from the same time period (24% [20 of 83] versus 8% [2734 of 33,630]; P<0.001). Of the 16 cases of interstitial nephritis, 9 (56%) had current or recent past exposure to aminosalicylates, including all cases of granulomatous interstitial nephritis.

CONCLUSIONS

IBD is associated with a spectrum of kidney diseases most commonly affecting the glomerular and tubulointerstitial compartments. IgA nephropathy is the most frequent kidney biopsy diagnosis in IBD and has a significantly higher diagnostic prevalence compared with all non-IBD kidney biopsy specimens. This may reflect a common pathogenic mechanism. Although many cases of tubulointerstitial nephritis are related to aminosalicylate exposure, the possibility of a direct relationship with IBD cannot be ruled out.

Isaac Albeniz (1860-1909): Spanish musician who died of chronic renal disease

Isaac Albéniz was a Spanish musician and pianist who was best known in France and England. One of his last works for piano, the suite Iberia, is well-known and identifies his country of origin. He died with terminal uraemia following longstanding chronic intestinal and kidney symptoms. Suggestions as to pathology include amyloidosis complicated by kidney stones and hypertension that sometimes manifested itself in the form of hypertensive crisis, accompanied by obesity.

Deficiency of N-acetylgalactosamine in O-linked oligosaccharides of IgA is a novel biologic marker for Crohn's disease

BACKGROUND

Ideal biomarkers are required to be developed for the diagnosis and prediction of the treatment of inflammatory bowel disease (IBD). We have reported that alteration of N-linked oligosaccharides of immunoglobulin (Ig) G is a novel diagnostic marker of IBD. Oligosaccharide alterations of IgA, however, have not been investigated in IBD patients.

METHODS

N- and O-linked oligosaccharides of serum IgA purified from 32 patients with Crohn's disease (CD), 30 patients with ulcerative colitis (UC), and 30 healthy volunteers (HV) were analyzed with high-performance liquid chromatography and mass spectrometry. Enzymes related to oligosaccharide attachment were investigated.

RESULTS

N-linked oligosaccharides of IgA were not different between IBD and HV. In contrast, the number of N-acetylgalactosamines per hinge glycopeptide (GalNAc/HP) in the O-linked oligosaccharides of IgA was significantly decreased in patients with CD compared with UC and HV. GalNAc/HP had high sensitivity and specificity for discriminating between CD and HV based on receiver operating characteristic analysis. Lower GalNAc/HP was associated with more severe disease activity of CD. Changes in GalNAc/HP levels in 6 weeks after treatment with infliximab were associated with the clinical activity of CD at 30 weeks. GalNAc transferase expression of naïve B cells and extent of GalNAc attachment in IgA were significantly decreased by interleukin-21 in vitro.

CONCLUSIONS

The number of GalNAc attached in the IgA O-linked glycans of CD patients was significantly decreased, and strongly correlated with the clinical activity. Alterations of GalNAc attachment in IgA could be useful as a novel diagnostic and prognostic marker of CD.

A case of rapidly progressive IgA nephropathy in a patient with exacerbation of Crohn's disease

BACKGROUND

IgA nephropathy has been reported as a renal involvement in Crohn's disease. Crescentic IgA nephropathy, which accounts for fewer than 5% of cases of IgA nephropathy, has a poorer prognosis than other forms of crescentic glomerulonephritis. We recently experienced a case of rapidly progressive IgA nephropathy concurrent with exacerbation of Crohn's disease.

CASE PRESENTATION

An 18-year-old male diagnosed with Crohn's disease underwent a hemicolectomy 2 years prior previously. He had maintained a state of Crohn's disease remission with 5-aminosalicylic acid treatment. Four months prior to referral to the nephrology clinic, he experienced non-bloody diarrhea. He simultaneously developed proteinuria and microscopic hematuria with deterioration of renal function. Based on renal biopsy findings, the patient was diagnosed with crescentic IgA nephropathy. Immunostaining for interleukin-17 in renal tissue and previous exacerbated colonic ulcers was positive. Steroid pulse therapy was administered, followed by high-dose glucocorticoid and oral cyclophosphamide therapy. The patient's renal function recovered and his gastrointestinal symptoms were alleviated.

CONCLUSIONS

We report a case of crescentic IgA nephropathy presenting with exacerbation of Crohn's disease, and present a review of the literature focusing on the pathophysiologic relationship between these two conditions.

Renal manifestations and complications of inflammatory bowel disease

Renal manifestations and complications are not rare in patients with inflammatory bowel disease (IBD) and may present as nephrolithiasis, amyloidosis, tubulointerstitial nephritis, and glomerulonephritis. Symptoms of renal impairment are not always specific and since the underlying bowel disease is preponderant, renal function deterioration may be underestimated. Additionally, medical treatment of patients with IBD such as aminosalicylates, cyclosporine, and tumor necrosis factor-α inhibitors can cause renal complications, although direct correlation to bowel disease is not always clear. The well-documented renal manifestations and complications of IBD, as well as the possible renal side effects of new drugs, emphasize the need for periodic evaluation of renal function. New markers of renal function may facilitate early diagnosis and unravel the complex mechanisms responsible for kidney damage. The purpose of this review is to summarize the renal manifestations and complications as well as the markers of renal function utilized in IBD, attempting to shed more light on the pathophysiology of renal damage in IBD.

Infliximab treatment for Crohn's disease in a patient with IgA nephropathy

We describe herein a case of IgA nephropathy in a 34-year-old woman with Crohn's disease (CD) treated with infliximab. CD first appeared at the age of 15 years. An elemental diet was started for remission maintenance. Ten years later, the patient suffered from a recto-vaginal fistula and subtotal colectomy with stoma formation was performed. At the age of 33 years, the patient was investigated for painless macroscopic hematuria and proteinuria. Renal biopsy revealed IgA nephropathy. Mizoribine was started but proteinuria persisted. Due to diarrhea she was admitted to our hospital, and scheduled maintenance therapy with infliximab was initiated. After the first infliximab infusion, the patient presented significant clinical improvement in both diarrhea and proteinuria with concomitant decrease of C-reactive protein to normal levels and proteinuria ~1 g/day. This represents the first report of infliximab treatment in a patient with IgA nephropathy associated with CD and clarifies the importance of tumor necrosis factor-alpha (TNFα) in immunity to renal disease. Further studies are needed to draw firm conclusions for the safety of infliximab in patients with IgA nephropathy.

Secondary IgA nephropathy

IgA nephropathy (IgAN) is the most common pattern of primary glomerulonephritis seen in the Western world. In the majority of cases the cause remains unknown. Cases of familial IgAN and secondary IgAN have been reported and these have provided insights into underlying genetic and environmental triggers for this common glomerular disease. Secondary IgAN is seen most commonly in patients with liver disease or mucosal inflammation, in particular affecting the gastrointestinal tract. A number of dietary and microbial antigens have been identified in circulating IgA immune complexes and mesangial IgA deposits, suggesting that environmental factors may play a role in the pathogenesis of IgAN. There is an increasing literature reporting associations between IgAN and other diseases. Whether these reports represent chance associations or genuine shared pathophysiology is discussed.

[Secondary IgA-nephropathy in gastroenterological diseases]

IgA-nephropathy is the most common primary chronic glomerulonephritis worldwide. Beside the primary IgA-nephropathy (IgA-nephropathy with an unknown origin), there are more and more cases, which are associated with diseases of other organs. Although the causality is often not obvious, these forms are called secondary IgA-nephropathy. In this study, the authors cover only the secondary forms of IgA-nephropathy with relation to gastroenterology in a broader sense that includes the liver. They would like to draw the attention to the necessity of analyzing also the associate occurrence of gastrointestinal diseases (principally liver diseases, coeliac disease, Crohn's disease, ulcerative colitis) in patients with IgA-nephropathy, as well. They think that it would be expedient to organize a nationwide clinical analysis that would search the frequency of occurrence of IgA-nephropathy in the above mentioned gastrointestinal diseases.