Efficacy and safety of low-dose corticosteroids combined with leflunomide for progressive IgA nephropathy: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

The effectiveness of immunosuppressive and corticosteroid treatments for Immunoglobulin A (IgA) nephropathy (IgAN) remains thoroughly evaluated. We undertook a meta-analysis to investigate the efficacy and safety of low-dose corticosteroids plus leflunomide for progressive IgA nephropathy.

METHODS

Eligible studies were obtained from PubMed, Embase, and Cochrane Library databases. We also searched the references of the included studies. Our protocol followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist. Eligibility criteria were defined using a PICOS framework.

RESULTS

Our study included three articles presenting 342 patient cases. Findings revealed that low-dose corticosteroids combined with the leflunomide group were effective in relieving urine protein excretion (UPE) [mean difference (MD) = -0.35, 95% confidence interval (CI): -0.41 to -0.30, P < 0.00001] compared with the full-dose corticosteroids group. Regarding serum creatinine (SCr), estimated glomerular filtration rate (eGFR), complete remission rate, and overall response rate, there was no difference between the groups (p > 0.05). Regarding safety, low-dose corticosteroids combined with leflunomide significantly reduced the risk of serious adverse events [odds ratio (OR): 0.11, 95% CI: 0.01 to 0.91, P = 0.04]. Besides, no significant differences were observed between the two groups in the incidence of respiratory infection, abnormal liver function, diarrhea, herpes zoster, alopecia, pruritus, insomnia, pneumonia, diabetes, and urinary tract infection (P > 0.05).

CONCLUSIONS

Low-dose corticosteroids combined with leflunomide are a safe and effective treatment for progressive IgA nephropathy.

TRIAL REGISTRATION

The PROSPERO registration number is CRD42022361883.

Metal mixture exposure and the risk for immunoglobulin A nephropathy: Evidence from weighted quantile sum regression

Immunoglobulin A nephropathy (IgAN) is the most common type of glomerulonephritis in adults worldwide. Environmental metal exposure has been reported to be involved in the pathogenic mechanisms of kidney diseases, yet no further epidemiological study has been conducted to assess the effects of metal mixture exposure on IgAN risk. In this study, we conducted a matched case‒control design with three controls for each patient to investigate the association between metal mixture exposure and IgAN risk. A total of 160 IgAN patients and 480 healthy controls were matched for age and sex. Plasma levels of arsenic, lead, chromium, manganese, cobalt, copper, zinc, and vanadium were measured using inductively coupled plasma mass spectrometry. We used a conditional logistic regression model to assess the association between individual metals and IgAN risk, and a weighted quantile sum (WQS) regression model to analyze the effects of metal mixtures on IgAN risk. Restricted cubic splines were used to evaluate overall associations between plasma metal concentrations and estimated glomerular filtration rate (eGFR) levels. We observed that except for Cu, all the metals analyzed were nonlinearly associated with decreased eGFR, and higher concentrations of arsenic and lead were associated with elevated IgAN risk in both single-metal [3.29 (1.94, 5.57), 6.10 (3.39, 11.0), respectively] and multiple-metal [3.04 (1.66, 5.57), 4.70 (2.47, 8.97), respectively] models. Elevated manganese [1.76 (1.09, 2.83)] levels were associated with increased IgAN risk in the single-metal model. Copper was inversely related to IgAN risk in both single-metal [0.392 (0.238, 0.645)] and multiple-metal [0.357 (0.200, 0.638)] models. The WQS indices in both positive [2.04 (1.68, 2.47)] and negative [0.717 (0.603, 0.852)] directions were associated with IgAN risk. Lead, arsenic, and vanadium contributed significant weights (0.594, 0.195, and 0.191, respectively) in the positive direction; copper, cobalt, and chromium carried significant weights (0.538, 0.253, and 0.209, respectively). In conclusion, metal exposure was related to IgAN risk. Lead, arsenic, and copper were all significantly weighted factors of IgAN development, which may require further investigation.

Mechanism for the therapeutic effect of Tripterygium wilfordii Hook. f. preparations on IgA nephropathy

Tripterygium wilfordii Hook. f. is a traditional Chinese herbal medicine. The bioactive compounds from Tripterygium wilfordii Hook. f. have unique immunosuppressive and anti-inflammatory effects, and can exert their pharmacological effects through multi-target and multi-channel. Tripterygium wilfordii Hook. f. preparations have been used in IgA nephropathy (IgAN) for many years and are well accepted for good curative effects. However, the underlying mechanisms are still unclear. It is valuable to summarize the current progress in clinical application of Tripterygium wilfordii Hook. f. preparations in IgAN and other kidney diseases. We discussed the component characteristics, efficacies in reducing urinary protein levels and protecting renal function, as well as the side effects. As for the mechanisms, we should focus on all links of IgAN pathogenesis, including reducing the production of pathogenic IgA, decreasing renal inflammation and fibrosis, and protecting podocytes. As a representative drugs with clear efficacy and potential toxicity, Tripterygium wilfordii Hook. f. preparations need more in-depth basic and clinical research to improve their efficacy and safety.

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.

Minimal change disease following the Moderna COVID-19 vaccine: first case report

BACKGROUND

There have been cases of minimal change disease (MCD) reported following previous vaccines. During the COVID-19 era, only 3 cases of new-onset MCD and a case of MCD relapse were reported following the Pfizer-BioNTech COVID-19 vaccine. We herein report the first case of MCD after receiving the Moderna COVID-19 vaccine.

CASE PRESENTATION

A 43-year-old man presented to hospital 3 weeks after receiving the first dose of the Moderna vaccine, with both bilateral lower extremities and scrotal edema. He initially developed a sudden-onset bilateral lower extremities swelling on day 7 post-vaccine. He, then, developed dyspnea and scrotal swelling over a time span of 2 weeks. On physical examination, his blood pressure was 150/92 mmHg. There was a decreased air entry at lung bases, bilateral lower extremities and scrotal edema. Labs revealed hypoalbuminemia, hyperlipidemia and 15 g of proteinuria. His immunologic and serologic work up was negative. Renal biopsy showed concomitant MCD and IgA nephropathy. Patient was treated with oral steroids and had a good response; his edema resolved, serum albumin improved, and proteinuria decreased to 1 g within 2 weeks of treatment.

CONCLUSIONS

To the best of our knowledge, MCD has not been previously reported after receiving the Moderna COVID-19 vaccine. It remains unclear whether the COVID-19 mRNA vaccines are associated with the development of MCD, or it coincided with the mass vaccination. Further studies are needed to determine the incidence of MCD post COVID-19 vaccines and the underlying pathophysiology of glomerular injury post vaccination.

Ulcerative IgA vasculitis in the setting of warfarin therapy

Henoch-Schönlein purpura (HSP) is a small vessel vasculitis characterized by the presence of vascular immunoglobulin A deposition that usually presents as non-thrombocytopenic palpable purpura. It primarily affects children and is less common in adults. The incidence of hemorrhagic necrotic skin lesions increases with age, similarly to renal involvement. Warfarin is a widely used oral anticoagulant drug that has rarely been associated with leukocytoclastic vasculitis and allergic interstitial nephritis. We report a patient with HSP who presented with cutaneous ulcerative plaques and proteinuria in the setting of warfarin therapy. We would like to raise the awareness of this potential adverse effect of warfarin for prompt diagnosis.

Renal Effects after Pembrolizumab Treatment for Non-small Cell Lung Carcinoma

Immune checkpoint inhibitors (CPIs), including pembrolizumab, are becoming common oncological treatments. CPIs have been associated with a significant risk of developing immune-related adverse events (irAEs), such as nephritis and interstitial nephritis. However, the occurrence of glomerulonephritis has only rarely been reported. We herein present the case of a 75-year-old woman with non-small cell lung carcinoma (NSCLC) who developed proteinuria and microscopic hematuria during treatment with pembrolizumab. Renal biopsy revealed tubulointerstitial nephritis and IgA nephropathy. Considering that a urinalysis showed no abnormality before treatment, the condition might have been induced by pembrolizumab. In this report, we focus on the correct diagnosis and management of renal irAEs, which remain controversial.

Bevacizumab-induced immunoglobulin A vasculitis with nephritis: A case report

RATIONALE

Bevacizumab-an inhibitor of vascular endothelial growth factor-is effective against various advanced cancers. However, it is associated with the development of hypertension and high-grade proteinuria during thrombotic microangiopathy of the kidney. In addition, there are several reports of immunoglobulin A deposition in the glomeruli, but the etiology is unclear.

PATIENT CONCERNS

A 67-year-old Japanese man with metastatic rectal cancer underwent low anterior rectal resection, followed by treatment with bevacizumab and SOX (S-1 plus oxaliplatin). Six months later, the patient developed hematuria, nephrotic syndrome, and purpura.

DIAGNOSES

Renal biopsy revealed endocapillary proliferative glomerulonephritis. Immunofluorescence analyses showed granular mesangial deposition of galactose-deficient immunoglobulin A1. Skin biopsy revealed leukocytoclastic vasculitis.

INTERVENTIONS

We ceased bevacizumab treatment, while continuing the remaining chemotherapy regimen, as we suspected bevacizumab-induced nephropathy.

OUTCOMES

Proteinuria and purpura improved immediately after cessation of bevacizumab. We identified this as a case of bevacizumab-induced immunoglobulin A vasculitis with nephritis.

LESSONS

To our knowledge, this is the first case of bevacizumab-related immunoglobulin A vasculitis with nephritis, as evidenced by galactose-deficient immunoglobulin A1. When a patient's urine tests are abnormal during bevacizumab treatment, clinicians should consider not only thrombotic microangiopathy but also vasculitis.

IgA Nephropathy after Nivolumab Therapy for Postoperative Recurrence of Lung Squamous Cell Carcinoma

Immune checkpoint inhibitors (ICIs) are becoming a common and important cancer therapy. ICIs are associated with a unique category of side effects, termed immune-related adverse events (irAEs). We herein report the case of a 72-year-old man with postoperative recurrence of lung squamous cell carcinoma who was treated with nivolumab and who developed proteinuria and a worsening kidney function. A kidney biopsy revealed IgA nephropathy. After drug withdrawal, the proteinuria improved and the deterioration of the patient's renal function was halted. Although renal irAEs are considered to be rare and glomerulonephritis is not typical presentation, physicians need to pay more attention to renal irAEs and glomerular injury.

[Development of mesangial immunoglobulin IgA glomerulonephritis and p-ANCA positivity in a patient with psoriatic arthritis]

Tumor necrosis factor (TNF) inhibitors are widely used for the treatment of various rheumatic diseases. These agents may lead to development of systemic autoimmune diseases and renal complications. We report a patient with psoriatic arthritis and renal failure treated with two TNF inhibitors (Etanercept and then Adalimumab). After this treatment he developed proteinuria with nephrotic syndrome. A renal biopsy was performed highlighting GN with mesangial IgA deposits. Then he developed p-ANCA positivity. Following that, etanercept and adalimumab were stopped and a treatment by corticosteroids was initiated, but renal function decreased. Currently the patient is treated by haemodialysis. In our patient, the pathogenic role for anti-TNF therapy is suggested by the close temporal relationship with development of glomerular disease and by the improvement in proteinuria after drug withdrawal. However, the patient was treated once more with TNF agents, so he developed end stage renal disease.

[A case of acute kidney injury during warfarin therapy]

The patient was an 82-year-old female. She had been treated with warfarin for atrial fibrillation that developed after a heart valve replacement operation. She was admitted because of a progressive loss of renal function together with persistent microscopic hematuria and proteinuria. Although the renal biopsy showed only focal mononuclear cell infiltration and mild mesangial expansion in the glomeruli, the occlusive red blood cell casts were remarkable in the tubules and were accompanied by inflammatory and edematous changes in the surrounding interstitial area. After the adjustment of an excessively extended prothrombin time, her renal function gradually improved in parallel with the marked decrease in the microhematuria. It was assumed that an acute kidney injury observed in this case was caused by the occlusive red blood cell casts as a result of abnormal hemorrhage in the glomeruli due to focal glomerulonephritis and a warfarin overdose. The present case, therefore, suggests that a warfarin overdose is a potential risk factor for acute kidney injury in the presence of coexisting glomerular injury.

[Comparison of two rat models of IgA nephropathy]

OBJECTIVE

To study the methods for rapid establishment of rat models of IgA nephropathy.

METHODS

Forty female SD rats weighing 160-200 g were randomized into 3 groups. In group A, the rats received intravenous injection of staphylococcal enterotoxin B (SEB) and oral bovine serum albumin (BSA), and in group B, CCl4 was injected subcutaneously in addition to the above treatments; the rats in group C received no treatments to serve as the normal control group. The rats were sacrificed 10 and 14 weeks after the treatment for biochemical testing of the arterial blood and histopathological and IgA immunofluorescence examination of the renal tissues. The twenty-four-hour urine was collected at 10, 12, and 14 weeks after the treatments for detecting the urine proteins.

RESULTS

Compared with the control group, the rats in groups A and B showed significantly increased serum creatinine, urine nitrogen and protein levels. Pathological examination of the renal tissue showed mild to moderate mesangial expansion and mesangial cell proliferation in groups A and B, without obvious difference between the two groups; but hematuria and proteinuria occurred earlier in group B with stronger IgA immunofluorescence than in group A.

CONCLUSION

Both of the methods used in group A and group B can successfully induce IgA nephropathy in rats, but in group B, hematuria and urineprotein occurs earlier and IgA immunofluorescence is more stronger. Therefore intravenous SEB injection combined with oral BSA and subcutaneous CCl4 administration is a better method for time-efficient establishment of rat models of IgA nephropathy.

Henoch-Schönlein purpura associated with acetaminophen and codeine

We report a case of a relapse of Henoch-Schönlein Purpura (HSP) associated with intake of paracetamol (also known as acetaminophene) and codeine. A 69-year-old man presented with fever, gross hematuria, acute renal failure, palpable purpuric skin rash over the legs, feet and arms, arthralgias and abdominal discomfort. 1 week before he had started therapy with co-efferalgan (association of paracetamol and codeine) for cervical arthrosis. Blood test revealed increase in serum creatinine levels (2.6 mg/dl), CRP (375 mg/dl), with no thrombocytopenia or hypocomplementemia. Co-efferalgan was discontinued. Gross hematuria resolved in 2 days, purpuric rash disappeared in 10 days, renal function returned to normal after 2 weeks and abdominal pain and arthralgias improved on the following 2 - 3 weeks. An objective causality assessment in accordance with the Naranjo algorithm, revealed that the adverse drug reaction was probable between paracetamol/codeine and Henoch-Schönlein purpura. To our knowledge, and based on a medline search (up to 2005), we believe that this could be considered the first case of Henoch-Schönlein purpura, associated with intake of paracetamol and codein. Although this event could be considered rare, clinicians should to be aware of possible associations between HUS and the intake of paracetamol and/or codeine to provide an early therapeutic intervention and a close monitoring.

Cholestatic jaundice and IgA nephropathy induced by OTC muscle building agent superdrol

Over the counter (OTC) medicines are commonly used in the United States despite a lack of scientific evidence for clinical utility and toxicity associated with their use. A case of jaundice and IgA nephropathy as a consequence of use of a muscle enhancing OTC supplement that was advertised as innocuous with no hormonal activity is described. IgA nephropathy has not been described previously in association with the use of testosterone. The case highlights that, besides adulteration, the misrepresentation of chemicals present in OTC medications and supplements can create confusion and a false sense of security with their use.

Attenuation of mycotoxin-induced IgA nephropathy by eicosapentaenoic acid in the mouse: dose response and relation to IL-6 expression

Clinical trials have revealed that progression of immunoglobulin A nephropathy (IgAN), the most common form of human glomerulonephritis, is inhibited by dietary (n-3) polyunsaturated fatty acid (PUFA) supplementation. The early stages of IgAN can be mimicked by feeding mice the mycotoxin deoxynivalenol (DON). Here, the effects of consuming the (n-3) PUFA eicosapentaenoic acid (EPA) on DON-induced IgAN were assessed relative to dose dependency and to expression of interleukin (IL-6). In the dose-response study, weight gain and feed intake did not differ among mice consuming 20 ppm DON supplemented with 0%, 0.1%, 0.5% and 3% EPA for 16 weeks. Mice fed the two highest EPA concentrations exhibited markedly increased splenic EPA, docosapentaenoic acid and docosahexaenoic acid, whereas arachidonic acid was decreased in all three EPA fed groups. Deoxynivalenol consumption significantly increased serum IgA and IgA immune complexes as well as kidney mesangial IgA deposition. All three IgAN markers were attenuated in mice fed 3% EPA diet but not in those fed 0.1% or 0.5% EPA. Elevated IgA production was observed in spleen and Peyer's patch (PP) cell cultures derived from mice fed DON in control diets, but this was reduced in cultures from mice fed 0.1%, 0.5% and 3% EPA. Acute DON exposure increased serum levels of IL-6, a cytokine that drives differentiation of IgA-committed B cells to IgA secretion. Relatedly, expression of IL-6 mRNA and IL-6 heteronuclear RNA, a marker of IL-6 transcription, was increased in spleen and PP. All three indicators of IL-6 expression were suppressed in mice consuming 3% EPA. Suppressed IL-6 corresponded to decreased binding activity of two factors that regulate transcription of this cytokine, cyclic AMP response element-binding protein and activator protein-1. The results indicate that a threshold existed for EPA relative to suppression of experimental IgAN and that the threshold dose was effective at inhibiting IL-6 transcription.

Effect of PA-MSHA vaccine on plasma phospholipids metabolic profiling and the ratio of Th2/Th1 cells within immune organ of mouse IgA nephropathy

Phospholipids as a class of important constituents in the biomembranes have been paid increasing attention in many fields. IgA nephropathy is now generally known to be the most common form of primary glomerulonephritis in the world. However, phospholipids metabolism in IgA nephropathy was not clear. Until recently, there was no effective treatment available for patients with IgA nephropathy. In this paper, effect of PA-MSHA vaccine on plasma phospholipid metabolic profile of mouse IgA nephropathy was investigated using high performance liquid chromatography/mass spectrometry (HPLC/MS) and principal components analysis (PCA). Female Balb/c mice were divided into four groups: model group, control group, PA-MSHA treatment group and medicine control group (dipyridamole+common threewingnut root). The experimental IgA nephropathy model was established by the immunity combination method of oral BSA and injection of SEB. It was found that combination of LC/MS technology with PCA can be successfully applied to phospholipids profile analysis, clearly classify the model group and normal group, and PA-MSHA treatment group is closer to the normal control group than medicine control group. The result showed that Th(2)/Th(1) (=CD(4)(+)CD(30)(+)/CD(4)(+)CD(30)(-)) of the model group is 20.70+/-3.57, which is significantly higher than that of the control group (1.34+/-0.14) (P<0.001). The Th(2)/Th(1) ratio of the PA-MSHA treatment group and the medicine control group are lower than that of the model group (P<0.01). It is suggested that mouse IgA nephropathy has the phospholipids metabolic abnormality, PA-MSHA vaccine cannot only regulate the abnormal phospholipids metabolism mouse with the IgA nephropathy, but also correct the over unbalance of Th(2)/Th(1) proportion.

Role of cyclooxygenase-2 in deoxynivalenol-induced immunoglobulin a nephropathy

Ingestion of the trichothecene mycotoxin deoxynivalenol (DON) induces serum IgA elevation and kidney mesangial IgA deposition in a manner that mimics the early stages of IgA nephropathy (IgAN), the most common human glomerulonephritis. Previous studies indicate that elevated interleukin-6 (IL-6) expression is crucial for this model and that DON induction of cyclooxygenase-2 (COX-2) might drive IL-6 upregulation. We hypothesized that COX-2 and its metabolites are essential for DON-induced IgAN and thus might be a suitable target for prophylaxis against aberrant IgA upregulation. DON feeding studies using COX-2 knockout mice or the COX-2 specific inhibitor, rofecoxib (Vioxx), were employed to test the hypothesis. Study 1 results demonstrated that DON consumption induced serum IgA and IgA-immune complex (IC) accumulation, IgA kidney deposition and splenic IgA secretion in wild-type mice. COX-2 deficiency did not affect upregulation of these parameters but rather, promoted DON-induced serum IgA elevation. Study 2 demonstrated that rofecoxib could not block DON-induced serum IgA, serum IgA-IC and mesangial IgA accumulation but instead increased enhanced serum IgA upregulation. These corroborating results suggest that COX-2 is not a requisite for DON-induced IgAN and furthermore, that COX-2 inhibitors such as rofecoxib would be contraindicated for the prevention of early stages of IgAN.

Docosahexaenoic acid attenuates mycotoxin-induced immunoglobulin a nephropathy, interleukin-6 transcription, and mitogen-activated protein kinase phosphorylation in mice

The purpose of this investigation was to evaluate the dose-dependent effects of docosahexaenoic acid (DHA) on deoxynivalenol (DON)-induced IgA nephropathy in mice and their relation to proinflammatory gene expression and mitogen-activated protein kinase (MAPK) activation. Consumption of a modified AIN-93G diet containing 1, 5, and 30 g/kg DHA resulted in dose-dependent increases of DHA in liver phospholipids with concomitant decreases in arachidonic acid compared with control diets. DHA dose dependently inhibited increases in serum IgA and IgA immune complexes (IC) as well as IgA deposition in the kidney in DON-fed mice; the 30 g/kg DHA diet had the earliest detectable effects and maximal efficacy. Both splenic interleukin-6 (IL-6) mRNA and heterogeneous nuclear RNA (hnRNA), an indicator of IL-6 transcription, were significantly reduced in DON-fed mice that consumed 5 and 30 g/kg DHA; a similar reduction was observed for cyclooxygenase (COX-2) mRNA. In a subsequent study, acute DON exposure (25 mg/kg body weight) induced splenic IL-6 mRNA and hnRNA as well as COX-2 mRNA in mice fed the control diet, whereas induction of both RNA species was significantly inhibited in mice fed 30 g/kg DHA. These latter inhibitory effects corresponded to a reduction in DON-induced phosphorylation of p38, extracellular-signal related kinase 1/2, and c-Jun N-terminal kinase 1/2 MAPKs in the spleen. Taken together, the results indicate that DHA dose-dependently inhibited DON-induced IgA dysregulation and nephropathy, and that impairment of MAPK activation and expression of COX-2 and IL-6 are potential critical upstream mechanisms.

Deoxynivalenol-induced mitogen-activated protein kinase phosphorylation and IL-6 expression in mice suppressed by fish oil

The trichothecene mycotoxin deoxynivalenol (DON) induces IgA hyperelevation and mesangial IgA deposition in mice that mimics the early stages of human IgA nephropathy (IgAN). Among potential mediators of this disease, interleukin-6 (IL-6) is likely to play a particularly critical role in IgA elevation and disease exacerbation. Based on previous findings that dietary fish oil (FO) suppresses DON-induced IgAN, we hypothesized that FO inhibits the induction of IL-6 expression by this mycotoxin in vivo and in vitro. Mice were fed modified AIN 93G diet amended with 7% corn oil (CO) or with 1% corn oil plus 6% menhaden fish oil (FO) for up to 8 weeks and then exposed acutely to DON by oral gavage. DON-induced plasma IL-6 and splenic mRNA elevation in FO-fed mice were significantly suppressed after 8 weeks when compared to the CO-fed group. The effects of FO on phosphorylation of mitogen-activated protein kinases (MAPKs), critical upstream transducers of IL-6 up-regulation, were also assessed. DON-induced phosphorylation of extracellular signal regulated protein kinases 1 and 2 (ERK1/2) and c-Jun N-terminal kinases 1 and 2 (JNK1/2) was significantly suppressed in spleens of mice fed with FO, whereas p38 was not. Splenic COX-2 mRNA expression, which has been previously shown to enhance DON-induced IL-6, was also significantly decreased by FO, whereas plasma levels of the COX-2 metabolite, prostaglandin E2, were not affected. To confirm in vivo findings, the effects of pretreatment with the two primary n-3 PUFAs in FO, eicosapentaenoic acid (20:5[n-3]; EPA) and docosahexaenoic acid, (22:6[n-3]; DHA), on DON-induced IL-6 expression were assessed in LPS-treated RAW 264.7 macrophage cells. Consistent with the in vivo findings, both EPA and DHA significantly suppressed IL-6 superinduction by DON, as well as impaired DON-induced ERK1/2 and JNK1/2 phosphorylation. In contrast, the n-6 PUFA arachidonic acid (20:4[n-3]) had markedly less effects on these MAPKs. Taken together, the capacity of FO and its component n-3 PUFAs to suppress IL-6 expression as well as ERK 1/2 and JNK 1/2 activation might explain, in part, the reported suppressive effects of these lipids on DON-induced IgA nephropathy.

Docosahexaenoic acid and eicosapentaenoic acid, but not alpha-linolenic acid, suppress deoxynivalenol-induced experimental IgA nephropathy in mice

Diets enriched in the (n-3) PUFAs, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and their precursor alpha-linolenic acid (ALA), were evaluated for efficacy in ameliorating the development of IgA nephropathy (IgAN) induced in mice by the mycotoxin deoxynivalenol (DON). The effects of DON were compared in mice that were fed for 18 wk with AIN-93G diets containing 1) 10 g/kg corn oil plus 60 g/kg oleic acid (control); 2) 10 g/kg corn oil plus 35 g/kg oleic acid and 25 g/kg DHA-enriched fish oil (DHA); 3) 10 g/kg corn oil plus 33 g/kg oleic acid and 27 g/kg EPA-enriched fish oil (EPA); and 4) 10 g/kg corn oil plus 37 g/kg oleic acid and 23 g/kg DHA + EPA (1:1) enriched fish oil (DHA + EPA). The DHA, EPA and DHA + EPA diets attenuated induction by dietary DON (10 mg/kg) of serum IgA and IgA immune complexes, kidney mesangial IgA deposition, and ex vivo IgA secretion by spleen cells. Consumption of the DHA + EPA diet for 8 wk significantly abrogated the DON-induced gene expression of interleukin (IL)-6, a requisite cytokine for DON-induced IgA nephropathy, in spleen and Peyer's patches. Finally, incorporation of ALA-containing flaxseed oil up to 60 g/kg in the AIN-93G diet did not affect DON-induced IgA dysregulation in mice. Taken together, both DHA and EPA, but not ALA, ameliorated the early stages of IgAN, and these effects might be related to a reduced capacity for IL-6 production.

Henoch-Schönlein IgA glomerulonephritis complicating myeloma kidneys: case report

Myeloma kidney is the principal pathological substrate of rapidly progressive renal failure in multiple myeloma. We report the unusual case of a 72-year-old male diagnosed with kappa Bence Jones myeloma with renal failure which needed dialysis. After treatment with vincristine, doxorubicin (Adriamycin), dexamethasone (VAD), and plasmapheresis, the renal function was recovered until serum creatinine level was <2 mg/dl. Six months later, the pathological counterpart of rapidly progressive renal failure was crescentic IgA proliferative glomerulonephritis as a manifestation of Henoch-Schönlein syndrome associated with sepsis caused by coagulase-negative staphylococci. This case suggests that mesangial IgA deposition should be considered within the spectrum of consequent glomerular lesion-associated chemotherapy occurring in multiple myeloma.

Deoxynivalenol-induced IgA production and IgA nephropathy-aberrant mucosal immune response with systemic repercussions

Dietary exposure to the common foodborne mycotoxin deoxynivalenol (DON) selectively upregulates serum immunoglobulin A (IgA) in the mouse, most of which is polymeric, thus suggesting that the mucosal immune system is a primary target. When ingested, DON has no adjuvant or antigen properties but, rather, induces polyclonal IgA synthesis and serum elevation in an isotype-specific fashion. Resultant hyperelevated IgA is polyspecific, autoreactive and is likely to be involved in immune complex formation as well as kidney mesangial deposition. These latter effects mimic IgA nephropathy, the most common human glomerulonephritis. At the cellular level, DON upregulates production of T helper cytokines and enhances T cell help for IgA secretion. Analogous effects are observed in the macrophage with IL-6 being of particular importance based on ex vivo reconstitution and antibody ablation studies as well as experiments with IL-6 deficient mice. Upregulation of cytokines by DON involves both increased transcriptional activation and mRNA stability which are mediated by activation of mitogen-activated protein kinases. Interestingly, dietary omega-3 fatty acids can downregulate these processes and ameliorate DON-induced IgA nephropathy. From the perspective of gut mucosal immunotoxicology, these studies demonstrate that the capacity of a chemical to affect mucosal immune response can have systemic repercussions and, further, that these effects can be modulated by an appropriate nutritional intervention.

[The effect of the extract from Radix Paeoniae alba on IgA Glomerulonephritis in mice]

OBJECTIVE

To observe the effect of the extract from Radix Paeoniae Alba on IgA glomerulonephritis in mice.

METHODS

IgA glomerulonephritis was induced by injection of dextran and sephadex-150. After administrating the extract, the contents of urinary protein, BUN and Cr in serum were determined.

RESULTS

The extract could inhibit the decline of mouse weight, and decrease urinary protein content and BUN content in serum. While, the extract had no effect on Cr in serum.

CONCLUSION

The extract from Radix Paeoniae Alba had therapeutical effect on IgA glomerulonephritis.

ANCA-positive glomerulonephritis and IgA nephropathy in a patient on propylthiouracil

A 14-year-old girl developed acute renal failure after 3 years therapy with propylthiouracil (PTU) for Grave's disease. Serologic evaluation showed antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 and myeloperoxidase. Renal biopsy showed a crescentic glomerulonephritis (GN) as well as evidence of IgA nephropathy (IgAN). PTU was discontinued and the patient was treated with prednisone and cyclophosphamide. ANCA became negative and renal function improved, but did not normalize. A second biopsy showed evidence of IgA nephropathy only. Propylthiouracil use has been associated with ANCA positive pauci-immune glomerulonephritis, but not with IgA nephropathy. An overlap syndrome between IgAN and ANCA-positive GN, however, has been described. This patient may have had a preexisting IgAN, with acute pauci-immune GN secondary to PTU, or this may be the first description of an overlap syndrome of IgAN and ANCA vasculitis all caused by PTU therapy.

Dietary fish oil suppresses experimental immunoglobulin a nephropathy in mice

Dietary fish oil (FO) supplementation reportedly retards the progression of renal disease in patients with immunoglobulin (Ig)A nephropathy (IgAN), the most common glomerulonephritis worldwide. Using an experimental mouse model in which early immunopathological hallmarks of IgAN are induced by the mycotoxin vomitoxin (VT), the ameliorative effects of FO ingestion on this disease were evaluated in two studies. In Study 1, the capacity of VT to induce IgAN was evaluated in mice fed for 12 wk AIN-76A diets containing 50 g/kg corn oil (CO), 50 g/kg CO plus 9 mg/kg tert butylhydroquinone (TBHQ), or 5 g/kg CO plus 45 g/kg menhaden FO that contained 200 mg/kg TBHQ. Serum IgA, serum IgA immune complexes and kidney mesangial IgA deposition were greater in mice fed VT + CO compared with the CO control group, whereas all three variables were significantly attenuated in mice fed VT + FO. Although TBHQ also had attenuating effects, these were significantly less than those for the VT + FO group. In Study 2, the effects of feeding modified AIN 93G diets containing either 70 g/kg CO or 10 g/kg CO plus 60 g/kg FO for 20 wk on VT-induced IgAN were compared. Again, consumption of FO attenuated all three immunopathological variables. In addition, spleen cell cultures from the VT + FO group produced markedly less IgA than those cultures from mice fed VT + CO. Taken together, the results suggested that diets containing FO may impair early immunopathogenesis in VT-induced IgAN and that this was not totally dependent on the presence of the antioxidant TBHQ.

Effects of vomitoxin ingestion on murine models for systemic lupus erythematosus

Dietary exposure to the trichothecene vomitoxin (VT) results in reduced body weight gain, elevated serum IgA, terminal differentiation of Peyer's patch B cells to IgA secreting plasma cells haematuria, and increased kidney mesangial IgA accumulation in B6C3F1 mice and other inbred strains. These effects closely mimic a human autoimmune-like kidney disease known as IgA nephropathy. Using NZBW/F1, MRL/lpr, and BXSB mouse strains as models of systemic lupus erythematosus, we assessed whether consumption of diet containing 5 ppm or 10 ppm VT will similarly affect mice genetically prone to autoimmunity. Reduced weight gains were seen in NZBW/F1 and MRL/lpr mice fed both doses of VT within 2-3 weeks. In contrast, VT had little effect on weight gain by BXSB mice. Serum Ig levels in all three strains generally did not differ from control mice. Haematuria was significantly increased when all three strains were fed VT. In NZBW/F1 Peyer's patch cultures stimulated with lipopolysaccharide (LPS), prior VT exposure significantly increased the IgG and IgM secretion but had no effect on IgA. In MRL/lpr Peyer's patch cultures stimulated with LPS, VT exposure increased IgA secretion but not IgM or IgG. BXSB Peyer's patch cultures prepared from VT treatment groups produced significantly more IgA than controls when cultured with LPS or Concanavalin A. Whereas mesangial deposition of IgA and IgG was significantly lower in the treatment groups of NZBW/F1 and MRL/lpr mice compared with control, BXSB mice had significantly higher IgA, IgG, and complement (C3) deposition when fed VT. The results suggest that although dietary VT differentially affected mice with aberrant immune systems, these strains did not appear to be any more sensitive to the mycotoxin than were more immunologically robust inbred strains.

Inhibition of activated human mesangial cell proliferation by the natural product of Cordyceps sinensis (H1-A): an implication for treatment of IgA mesangial nephropathy

Cordyceps sinensis (CS) is a parasitic fungus that has been used as a Chinese medicine for a long time in the treatment of nephritis. Today, the hypothesis about the pathogenesis of immunoglobulin A nephropathy (IgAN) is that nephritogenic IgA immune complexes (IgAIC) go to the kidney to stimulate resting mesangial cells to release cytokines and growth factors. These cytokines and growth factors cause mesangial cell proliferation and release matrix, chemical mediators that lead to the glomerular injury. However, nephritogenic IgAIC in humans is still unknown. To solve this problem previously, we established an in vitro model that showed that cultured human mesangial cells (HMC) stimulated with interleukin-1 (IL-1) plus IL-6 can cause mesangial cell proliferation, increasing production of chemical mediators and superoxide anion. An in vivo model also proved that this culture medium may lead to renal injury with hematuria and proteinuria. Therefore, to fractionate the crude components that can be used in the treatment of patients with IgAN, we cultured HMC, and then an HMC activating model with HMC incubated with IL-1 and IL-6 was established. We fractionated the crude methanolic extracts from fruiting bodies of CS with the use of this in vitro inhibition of HMC activation model as our assay method. In brief, the fruiting bodies were extracted by silica gel column chromatography. One out of 6 column fractions, F-2, significantly inhibited the HMC activation by IL-1 plus IL-6. The acute toxicity test with male Institute of Cancer Research mice showed no liver toxicity or mutagenicity. Then we established an IgAN animal model with R36A (Pneumococcal C-polysaccharide purified from Streptococcus pneumoniae) as antigen and anti-R36A IgA monoclonal antibody to form nephritogenic IgA-IC, which can induce hematuria and proteinuria in mice with IgA deposition in the mesangial area. The mice in the IgAN model fed with 1% F-2 in diet had significant reduction of hematuria and proteinuria together with histopathologic improvement. Therefore this fraction was then purified by silica gel column chromatography and high-performance liquid chromatography, which got a purified compound H1-A, which can suppress the activated HMC and alleviate IgAN (Berger's disease) with clinical and histologic improvement. These results give us a new regimen for the treatment of patients with IgAN in the future.

Experimental IgA nephropathy induced by a low-dose environmental mycotoxin, nivalenol

Based on the hypothesis that IgA nephropathy (IgAN) is triggered by some exogenous antigen(s) which induces dysregulation of the mucosal immune system, we developed an experimental model of orally induced IgAN by an environmental mycotoxin, nivalenol (NIV), which often contaminates agricultural products in Southeast Asia and Japan. In the present study, low doses of oral NIV reproducibly induced significant IgA deposits in the glomerular mesangium and elevated serum IgA levels in mice irrespective of the strain; the degree of immunopathological changes analogous to human IgAN was associated with the dose and duration of NIV treatment. Furthermore, a competitive enzyme-linked immunosorbent assay with an NIV analogue-protein conjugate disclosed that the IgA antibody in the sera from the NIV model mice had a higher affinity to the mycotoxin. Conclusively, these findings suggest that NIV induces some pathological changes in mice which resemble those in human IgAN, and that this mycotoxin is associated with pathogenesis in some types of glomerulonephritis.

Effects of dihydrotestosterone and estradiol on experimental IgA nephropathy induced by vomitoxin

Ingestion of the trichothecene vomitoxin (VT) by mice induces effects that mimic the common human glomerulonephritis, IgA nephropathy (IgAN). These include elevation of serum IgA, IgA immune complexes, and mesangial IgA deposition. Based on previous observations that male mice are more prone to VT-induced IgAN, the effects of castration of male and female B6C3F1 mice and sex hormone supplementation on several immunopathologic indicators of the disease were compared. In the first study, castrated and intact male and female mice were fed control AIN-76A diet or the same diet containing 10 ppm VT for 12 weeks. At Week 12, all but the intact female group fed VT exhibited increased serum IgA, with castrated female mice having greater levels than intact females. When microscopic hematuria was used as an indicator of disease severity in intact VT-fed mice, erythrocyte counts for males exceeded those for females at weeks 4 and 12. VT-fed, castrated females exhibited greater hematuria than intact counterparts, whereas VT-fed, castrated males had lower urinary erythrocyte counts than intact counterparts. In a second study, castrated male and female mice were implanted with controlled release pellets of placebo, 5 alpha-dihydrotestosterone (DHT), or 17 beta-estradiol (E2) and then were fed either control diet or a 10 ppm VT diet for 8 weeks. Castrated male and female mice treated with VT and DHT pellet exhibited more severe hematuria, higher IgA levels, and greater mesangial IgA deposition than mice exposed to the same diet with placebo or E2 pellet at Week 8. While VT-fed animals with an E2 pellet exhibited greater hematuria and mesangial IgA deposition at Week 8 than the placebo groups, their IgA levels were not significantly elevated over those for VT-fed mice with a placebo pellet. Relative to two other pathologic markers for IgAN, the aforementioned effects in both studies were generally consistent with mesangial deposition of complement component C3 but not IgG. The results suggest that (1) enhanced male susceptibility to VT-induced IgAN may be related to modulation by the biologically active androgen DHT and (2) while castration of females increased severity of VT-induced IgAN, supplementation of castrated male or female mice with E2 did not reverse this effect but rather increased disease severity.

Organic solvent exposure may increase the risk of glomerular nephropathies with chronic renal failure

BACKGROUND

Several studies have suggested that exposure to organic solvents is associated with glomerular nephropathies (GN), but this relationship remains controversial.

METHODS

A case-control study of 298 biopsy-proven cases and 298 hospital controls, matched for year of birth, sex, origin, and place of residence, was conducted between 1989 and 1991 in five hospitals in the Paris area: 82 cases of membranous glomerulopathy were included; 100, nephrotic syndrome with either minimal change nephropathy or focal and segmental hyalinosis (MCN/FSH); and 116, IgA nephropathy (IgA N). Subjects were interviewed about their lifelong occupational and non-occupational activities. A 'blind' assessment of type, level, and duration of solvent exposure was carried out by two industrial hygienists. Human leucocyte antigen (HLA) phenotypes were determined.

RESULTS

Among males, a clear association, which was not explained by social class, was observed between chronic renal failure and high exposure to solvents for both MCN/FSH (OR = 7.7, 95% CI: 1.4-41.6) and IgA N (OR = 3.5, 95% CI: 1.0-11.8). The odds ratios increased with duration of exposure. No relationship was observed between such exposure and GN cases with normal renal function. No evidence was found that the HLA phenotype plays a role in the association between solvent exposure and the disease.

CONCLUSIONS

These results support the hypothesis of a causal relationship between high solvent exposure, which concerned 15% of the males in this study, and the development of GN with chronic renal failure.

Vomitoxin (deoxynivalenol)-induced IgA nephropathy in the B6C3F1 mouse: dose response and male predilection

Oral exposure to the trichothecene vomitoxin (VT or deoxynivalenol) in mice induces marked elevation of total and autoreactive IgA, IgA immune complexes, and mesangial IgA deposition in a manner that is highly analogous to human IgA nephropathy. In this study, immunopathologic markers indicative of IgA nephropathy were compared in male and female B6C3F1 mice fed semipurified AIN-76A diet containing 0, 2, 10 or 25 ppm VT for 12 weeks. Males fed 10 and 25 ppm VT and females fed 25 ppm VT had increased serum IgA at 4 weeks. At week 8, male mice fed the minimal dose of 2 ppm VT and female mice fed 10 ppm also exhibited elevated serum IgA. IgA levels were consistently higher in treatment males than females with significant differences being observed in the 10-ppm dose group at 4 and 12 weeks. IgA coproantibodies were marginally increased (maximum of 2-fold) in mice of both genders fed 10 and 25 VT. At 8 and 12 weeks, serum IgM was depressed in male and female mice eating 10 and 25 ppm VT, whereas consistent effects on serum IgG or IgE were not observed. In similar fashion, male mice in the 2, 10 and 25 ppm VT groups exhibited microscopic hematuria as early as 4 weeks, whereas this occurred in females fed 10 and 25 ppm VT only at week 10 with urinary erythrocyte counts being lower than male counterparts. Mesangial deposition of IgA and C3 was significantly increased in males exposed to 2, 10 and 25 ppm VT and in females exposed to 10 and 25 ppm VT, with males exhibiting a greater deposition than corresponding females. Based on these immunological parameters, males appeared more susceptible than female mice to VT-induced IgA dysregulation and IgA nephropathy in terms of latency, threshold dose, and severity.

Role of gender and strain in vomitoxin-induced dysregulation of IgA production and IgA nephropathy in the mouse

Prolonged dietary exposure of female B6C3F1 mice to the trichothecene vomitoxin results in hyperproduction of immunoglobulin A (IgA) with a concurrent immunopathology that mimics human IgA nephropathy. To assess the role of gender and strain in the mouse model, semipurified AIN-76A diet containing 25 ppm vomitoxin was fed to B6C3F1 male mice and to B6C3F1, BALB/c, C3H/HeN, C3H/HeJ, and C57BL/6 female mice for 8 wk, and immunopathologic indicators of IgA nephropathy were compared to mice fed clean diet. At the cessation of the experiment, all treatment groups weighed less than respective controls. Serum IgA was increased in male and female B6C3F1 mice as well as in C3H/HeJ, C57BL/6, and BALB/c female mice compared to corresponding controls. Serum IgA levels were two- to sixfold higher in B6C3F1 male treatment animals compared to female treatment groups from all strains. In contrast, at wk 8 serum IgG levels were unaffected or decreased, and serum IgM was decreased in all groups at wk 8. There was a trend toward increased IgA production by Peyer's patch (PP) lymphocytes isolated from treatment mice as compared to controls in all groups except the C3H/HeJ mice. Notably, IgA levels were 18-fold higher in B6C3F1 male treatment PP cultures than in B6C3F1 female treatment cultures. Hematuria was significantly greater in treatment mice than respective controls at both wk 4 and 8. Increased mesangial IgA deposition was also detectable in all treatment groups except the C57BL/6 mouse. The results suggested that the male B6C3F1 mouse and the five strains of female mice exhibited many of the immunopathologic effects found in IgA nephropathy and that IgA elevation was more marked in male B6C3F1 than female B6C3F1 mice.

Polyclonal autoreactive IgA increase and mesangial deposition during vomitoxin-induced IgA nephropathy in the BALB/c mouse

To establish the relationship between autoreactive antibodies and vomitoxin-induced immunoglobulin A (IgA) nephropathy, the effects of dietary vomitoxin exposure on the antigen specificity of serum IgA, IgA-producing cells and accumulated mesangial IgA in BALB/c mice were assessed. Exposure to dietary vomitoxin for 8 wk caused a significant increase in total serum IgA. There was a concurrent significant increase in serum IgA specific for trinitrophenol (TNP), phosphorylcholine, cardiolipin and sphingomyelin compared with controls, suggesting an elevation of autoreactive IgA. Casein, a protein found in the AIN-76A diet, could inhibit binding of serum IgA to sphingomyelin and cardiolipin, indicating that these antibodies may be polyspecific. When enzyme-linked immunospot assay was used to monitor autoreactive IgA production, trends were observed towards increased IgA-secreting cells specific for TNP, cardiolipin and sphingomyelin in Peyer's patches from vomitoxin-fed mice compared with control mice. IgA-producing cells reactive with TNP were increased in the spleen of vomitoxin-fed mice whereas effects on IgA-secreting cells for the other antigens were marginal. Marked deposition of mesangial IgA was also observed in vomitoxin-fed mice compared with controls. When IgA was eluted from the kidney sections of treated mice and tested by enzyme-linked immunosorbent assay, it exhibited a strong binding to the above antigen panel as well as inulin, DNA and casein. These data suggest that dietary vomitoxin induced the polyclonal activation of IgA-producing cells and that resultant autoreactive IgA was subsequently deposited in the kidney mesangium.

Pathogenesis of IgA nephropathy in ethanol consumption: animal model and cell culture studies

Using the intragastric ethanol infusion model of IgA nephropathy, we investigated the hypothesis that in this model mesangial changes commence prior to the deposition of IgA. We studied the two cellular components of the glomerular mesangium: the mononuclear phagocyte and the contractile mesangial cell. In the in vivo model, we observed a mononuclear phagocyte influx in the mesangium of alcoholic rats before the deposition of IgA. Using molecular techniques on cultured contractile mesangial cells, we demonstrated a threefold increase in interleukin-6 mRNA expression in contractile cells incubated with ethanol. These mesangial changes in the cellular composition, and in the autocrine cytokine system, suggest a direct role for ethanol in the pathogenesis of IgA nephropathy.

Persistent dysregulation of IgA production and IgA nephropathy in the B6C3F1 mouse following withdrawal of dietary vomitoxin (deoxynivalenol)

To assess whether vomitoxin-induced dysregulation of IgA production and IgA nephropathy are reversible, relevant immunologic parameters were compared among experimental groups of B6C3F1 mice that were fed: (1) 25 ppm vomitoxin in AIN-76A semipurified diet for 24 weeks (treatment group), (2) 25 ppm vomitoxin for 8 weeks and then control diet for 16 weeks (withdrawal group), and (3) control diet for 24 weeks (control group). Levels of serum IgA and microhematuria index in the treatment group were elevated after 4 to 8 weeks and continued to increase with further vomitoxin exposure. IgA immune complexes and mesangial IgA deposition, as quantitated by interactive laser cytometer image analysis, were also increased with toxin exposure at Weeks 8, 16, and 24, whereas IgM, IgG, and complement component C3 deposition were unaffected or depressed. Serum IgA, microhematuria index, and mesangial IgA deposition in withdrawal mice remained elevated over those of the controls at Weeks 16 and 24 but were less than those of the treatment group. Cell recovery from Peyer's patches (PP) as well as the percentages of IgA+ and CD4+ cells in PP and spleen at Weeks 16 and 24 were greater in treatment mice than in controls, but only the percentage of IgA+ cells in PP was elevated in the withdrawal mice at these the same time points. When IgA secretion by unstimulated and LPS-stimulated splenic lymphocytes was used as the measure of systemic production, it was elevated in both treatment and withdrawal mice at Weeks 16 and 24. The results indicated that experimental dysregulation of IgA production and IgA nephropathy persisted up to 4 months after a discrete period of dietary vomitoxin exposure, but that the severity of these effects did not increase in a progressive fashion.

Chronic glomerulonephritis and exposure to solvents: a case-referent study

To evaluate the risk of chronic glomerulonephritis in subjects exposed to solvent vapours, a case-referent study was carried out. The case group, including 60 patients (44 men and 16 women) with non-systemic chronic glomerulonephritis, established by biopsy, was compared with 120 control subjects (60 patients with traumatic fractures and 60 patients affected by nephrolithiasis) matched by sex and age. Information on occupational and non-occupational exposure to solvent was obtained by questionnaire. The exposure scores drawn from questionnaires were significantly higher in the case group than in the referent groups for both total and occupational solvent exposure. No significant differences in non-occupational exposure were found. The odds ratio of chronic glomerulonephritis for occupationally exposed (score > 0) was 3.9 (95% confidence interval (95% CI) 1.64-8.33). When IgA nephropathy patients (n = 27) were separately evaluated, an increased risk was found for both total and occupational exposure. Using a logistic regression model, a dose-response effect for occupational exposure was seen. The results support the hypothesis that chronic glomerulonephritis may be related to environmental factors such as exposure to hydrocarbons.

[Long-term phenytoin (Diphedan) therapy leading to IgA nephropathy]

A single case of IgA nephropathy with a concomitant tubulointerstitial nephritis, developing during a long-term phenytoin therapy is reported. The prolonged phenytoin therapy did neither prevent the transitional increases of serum IgA level nor ward off deterioration of the histological alterations. This case suggests that acute tubulointerstitial nephritis may have played a role in the mesangial trapping of IgA immunocomplexes.

Effect of thrombocytopenia on the onset of immune complex glomerulonephritis

The effect of platelets on the development of immune complex glomerulonephritis (GN) was examined using bovine serum albumin (BSA) GN with platelet depletion. To clarify the role of platelets in the initial stage of BSA GN, thrombocytopenia was induced before BSA infusion. In 18 New Zealand white rabbits, BSA was intravenously injected twice after the presensitization. Eight of these BSA GN rabbits were injected daily with goat anti-rabbit platelet antiserum to induce thrombocytopenia, and platelet counts were maintained below 5 x 10(4)/microliters throughout the experiment. In the thrombocytopenic group, the degree of proteinuria was significantly decreased compared to the control group. Glomerular polymorphonuclear leukocyte infiltration, mononuclear cell proliferation, exudation and glomerular enlargement were significantly suppressed in the thrombocytopenic group. The results suggest that platelets may be quite important in the initiation and development of immune complex GN.

Platelet-derived growth factor expression in mesangial proliferative glomerulonephritis

Proliferation of mesangial cells and expansion of mesangial matrix are common histologic features of proliferative glomerular disease, a frequent cause of renal failure. Proliferation of glomerular mesangial cells occurs in response to platelet-derived growth factor (PDGF), and these cells release PDGF and express PDGF A and B chain mRNAs. However, all studies relating PDGF to potential changes in glomerular structure and function to date have been performed in vitro. To explore the role of PDGF in proliferative glomerulonephritides, we studied the expression of PDGF in vivo in two animal models of IgA nephropathy with different histologic patterns of glomerular injury: either predominant mesangial proliferation or expansion of mesangial matrix. Increased expression of PDGF and PDGF B-chain mRNA in whole kidneys from diseased mice was demonstrated by immunohistochemical techniques and by solution hybridization assay, respectively. Immunohistochemically, PDGF was localized primarily within the mesangial area of glomeruli and to a much lower extent in interstitium. The increased PDGF expression correlated with the degree of hypercellularity and clinical features of the disease. In addition, PDGF expression was increased in some forms of human glomerulonephritis, characterized by mesangial proliferation. These findings suggest that PDGF may be a major contributor to mesangial cell proliferation seen in proliferative glomerulonephritides.

Quantitative assessment of mesangial immunoglobulin A (IgA) accumulation, elevated circulating IgA immune complexes, and hematuria during vomitoxin-induced IgA nephropathy

Extended dietary exposure to the trichothecene vomitoxin (deoxynivalenol), a naturally occurring fungal contaminant of cereal grains, induces elevated serum IgA and mesangial IgA accumulation in a manner similar to the human glomerulonephritis, IgA nephropathy. A 12-week feeding study was conducted in the B6C3F1 mouse to evaluate the effects of exposure to 25 ppm dietary vomitoxin over time on formation of IgA immune complexes (IgA-IC), hematuria, and mesangial deposition of IgA, IgG, IgM, and complement component C3. Both serum IgA and IgA-IC were significantly elevated in vomitoxin-exposed treatment groups compared to controls at weeks 4, 8, and 12, whereas serum IgG was unaffected. The incidence of hematuria was also significant in vomitoxin-exposed mice at weeks 4, 8, and 12. Quantitative immunofluorescence intensity measurements using interactive laser cytometer image analysis revealed significantly greater mesangial IgA accumulation in vomitoxin-fed mice compared to controls at weeks 4, 8, and 12. Although glomerular IgG and IgM deposition was present in both controls and treated mice, it was significantly lower in treated mice as compared to controls at week 12. Mesangial C3 deposition was not induced by vomitoxin feeding. Elevated IgA-IC, hematuria, and IgA mesangial accumulation occurring during exposure to vomitoxin mimicked human IgA nephropathy, whereas the absence of mesangial C3 represented a major difference between this toxin-induced immune dysregulation and the human disease.

Dysregulation of IgA production and IgA nephropathy induced by the trichothecene vomitoxin

The effect of dietary exposure to vomitoxin on serum immunoglobulin A (IgA) was evaluated in the B6C3F1 mouse. Levels of serum IgA were elevated maximally in mice fed 25 ppm vomitoxin in comparison with levels in mice fed 2, 10 or 50 ppm vomitoxin. Significant increases were detectable after as few as 4 wk in mice fed 25 ppm vomitoxin, and IgA levels were increased more than 17-fold after 24 wk of toxin exposure. Serum IgA also exhibited a marked shift from primarily monomeric IgA to primarily polymeric IgA during vomitoxin treatment. Serum IgG and IgM decreased in treated mice, suggesting that the effect was isotype-specific. Elevated serum IgA was not observed in mice when control diet was fed at levels equivalent to those consumed by vomitoxin-treated mice, which exhibited feed refusal. IgA production was significantly increased in both spontaneous and mitogen-stimulated splenocyte cultures from mice exposed to vomitoxin in comparison with cultures prepared from ad lib. or feed-restricted controls. Immunofluorescence staining revealed marked accumulation of mesangial IgA and electron microscopy showed electron-dense deposits in the glomeruli of vomitoxin-treated mice but not in those of controls. Dysregulation of IgA production and accumulation of glomerular IgA as observed in this study were highly analogous to the characteristics of human IgA nephropathy, the most common form of glomerulonephritis worldwide.