IgA nephropathy

Recurrent gross hematuria with positive family history of IgA nephropathy and an unexpected diagnosis

A 12-year-old girl presented with recurrent gross hematuria over 3 months and regular findings in sonography of the urogenital tract. The first suspected diagnosis of familial IgA glomerulonephritis was excluded by kidney biopsy. After a further episode of gross hematuria leading to vesical tamponade, the patient received magnetic resonance imaging with angiography and urography, which was suspicious for a renal tumor. Consecutively, unilateral nephrectomy was performed and a nephroblastoma was diagnosed. This case demonstrates that even in grossly normal renal ultrasound, relapsing episodes of gross hematuria can be caused by renal tumor, and therefore in unclear situations, further diagnostic is necessary.

Urinary kidney injury molecule-1 in patients with IgA nephropathy is closely associated with disease severity

BACKGROUND

The pathological characteristics of IgA nephropathy (IgAN) are highly variable. Urinary kidney injury molecule-1 (KIM-1) is a sensitive biomarker for proximal tubule injury. The aim of the study is to investigate the value of KIM-1 as a biomarker for assessing the renal injury in IgAN.

METHODS

The levels of urinary KIM-1 in 202 patients with IgAN, 46 patients with other renal diseases as disease controls and 60 healthy blood donors as normal controls were measured. Correlations with clinical and histopathological features of patients with IgAN were evaluated.

RESULTS

The levels of urinary KIM-1 were significantly higher in patients with IgAN than in normal controls (P < 0.001) and in patients with non-IgAN (P = 0.011). Urinary levels of KIM-1 in IgAN positively correlated with levels of serum creatinine and proteinuria and negatively with creatinine clearance. The more severe the tubulointerstitial injury was, the higher the levels of urinary KIM-1. Patients with severe mesangial proliferation, crescents formation or endocapillary proliferation had higher levels of urinary KIM-1 than those without. The levels of tubular KIM-1 expression in immunohistochemistry closely correlated with the levels of urinary KIM-1 (r = 0.553, P = 0.032). Renal survival was significantly worse in patients with elevated urinary KIM-1 (P = 0.020).

CONCLUSION

Urinary KIM-1 may be a useful biomarker to evaluate kidney injury in IgAN.

Low-dose sirolimus combined with angiotensin-converting enzyme inhibitor and statin stabilizes renal function and reduces glomerular proliferation in poor prognosis IgA nephropathy

BACKGROUND

There is a lack of new therapeutic strategies for IgA nephropathy. Low-dose sirolimus inhibits mesangial cell proliferation and renal fibrosis in animal models.

METHODS

We performed a pilot, randomized controlled trial to evaluate the efficacy and safety of low-dose sirolimus in patients with a high-risk IgA nephropathy. Twenty-three patients with a glomerular filtration rate (GFR) within 30-60 mL/min and/or proteinuria >1 g/day were randomly assigned to low-dose sirolimus plus enalapril and atorvastatin (SRL group, n = 14) or enalapril plus atorvastatin (CONTROL group, n = 9). Primary composite end point was variation of haematuria, proteinuria and blood pressure. Secondary end points were isotopic GFR, renal histology evaluated by Oxford classification and safety parameters evaluated at 6 and 12 months.

RESULTS

Primary end point improved significantly in the SRL group at 12 months. Regarding isotopic GFR, patients included in the CONTROL group lost 8 mL/min/1.73 m(2), whereas those in the SRL arm improved 5 mL/min/1.73 m(2) (P = 0.03). Proteinuria decreased similarly in both study groups. At 1 year, SRL treatment was associated with a significant reduction of mesangial and endocapillary proliferation, whereas glomerular sclerosis, tubular atrophy and interstitial fibrosis were similar. Sirolimus was well tolerated; all patients remained on therapy at 12 months.

CONCLUSION

The addition of low-dose sirolimus to enalapril and statin is safe, stabilizes renal function and reduces glomerular proliferative lesions in patients with poor prognosis IgA nephropathy.

Clinical and histopathological spectrum of IgA nephropathy in Kuwait

BACKGROUND

Little is known about the nature and the course of IgA nephropathy (IgAN) in Arab countries. The aim of this work was to study the spectrum of clinical presentation and histopathological findings at our institution.

DESIGN AND SETTING

Retrospective review, all renal biopsies at the Mubarak Al Kabeer Hospital between January 2000 and December 2004.

METHODS

Cases of IgA nephropathy were selected, and their medical records and biopsy findings were reviewed.

RESULTS

Eighty patients (9.2% of all native kidney biopsies) were diagnosed to have IgAN nephropathy. Sixty-nine biopsies were included in the study;11 were excluded. Forty-three (62.3%) patients were male and 26 (37.7) patients were female. Fifty (72.5%) patients were below the age of 40 years. Mean (SD) duration of follow-up was 3.6 (1.3) years. The first presentation included nephritic-range proteinuria (49.3%) and renal impairment (50.7%). During the follow-up period, 56 (81.2%) patients were stable or improved. Hass classification of biopsies showed 36.2% had class I, 27.5% had class II, 13.0% had class III, 5.8% had class IV, and 17.4% had class V IgAN. Females had milder forms of the disease than males. Macroscopic hematuria and renal impairment at presentation were seen more in patients with class IV and V IgAN. The presenting serum creatinine and uric acid values were higher in those with Hass classes III to V. Deterioration of renal function during the follow-up period was more significant in the presence of hypertension, renal impairment, or macroscopic hematuria at the time of biopsy .

CONCLUSION

The prevalence of IgAN in Kuwait is about 9.2%. Renal impairment or macroscopic hematuria at presentation was seen in patients with more aggressive renal lesions and contributed to poor outcome.

Myeloperoxidase-antineutrophil cytoplasmic antibody-negative microscopic polyangiitis with pulmonary haemorrhage and IgA nephropathy

AIM

To report a case of a patient with myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA)-negative microscopic polyangiitis (MPA) and IgA nephropathy associated with severe pulmonary haemorrhage.

CASE REPORT

A 59-year-old man presented with ANCA-negative systemic vasculitis accompanied by purpura, nephritis and pulmonary haemorrhage. A skin biopsy specimen revealed pandermal leucocytoclastic vasculitis without IgA deposition and a kidney biopsy showed mesangial nephritis with IgA deposition. Considering these findings, the patient was diagnosed as having MPA with IgA nephropathy.

DISCUSSION

In most cases, MPA presents with rapidly progressive necrotizing glomerulonephritis and sometimes lung haemorrhage, while IgA nephropathy is less common among MPA cases. As recent research suggested that in MPA immunoglobulin deposition in the kidney may be an exacerbating factor for renal dysfunction and poor prognosis, close observation is required in these cases.

Recurrent glomerular disease after kidney transplantation

PURPOSE OF REVIEW

Recurrent glomerulonephritis is the third most common cause of graft failure, ranking only behind immunologic rejection and death with a functioning graft. Knowledge of the rates and timing of recurrent glomerular disease are important in counseling potential transplant recipients and preventive and therapeutic treatment strategies are necessary for those patients at risk.

RECENT FINDINGS

Large observational studies that have analyzed posttransplant biopsies have confirmed the high rates of glomerular disease recurrence in renal allografts. Newer immunosuppressive protocols over the past 10 years have not affected the rate of disease recurrence or graft loss. There is emerging evidence that rituximab may be efficacious in treating recurrent membranous nephropathy and focal segmental glomerulosclerosis; however, larger clinical trials are warranted.

SUMMARY

Recurrent glomerulonephritis is an important determinant of long-term outcomes after transplantation, requiring appropriate counseling to potential transplant recipients. Currently, there are no proven strategies to prevent recurrent glomerulonephritis in renal transplant recipients. Despite the high rates of recurrent disease, long-term graft survival is still very good and transplantation remains the best treatment option for patients with end-stage renal disease from primary glomerulonephritis.

Aberrantly glycosylated IgA1 as a factor in the pathogenesis of IgA nephropathy

Predominant or codominant immunoglobulin (Ig) A deposition in the glomerular mesangium characterizes IgA nephropathy (IgAN). Accumulated glomerular IgA is limited to the IgA1 subclass and usually galactose-deficient. This underglycosylated IgA may play an important role in the pathogenesis of IgAN. Recently, antibodies against galactose-deficient IgA1 were found to be well associated with the development of IgAN. Several therapeutic strategies based on corticosteroids or other immunosuppressive agents have been shown to at least partially suppress the progression of IgAN. On the other hand, several case reports of kidney transplantation or acquired IgA deficiency uncovered a remarkable ability of human kidney to remove mesangial IgA deposition, resulting in the long-term stabilization of kidney function. Continuous exposure to circulating immune complexes containing aberrantly glycosylated IgA1 and sequential immune response seems to be essential in the disease progression of IgAN. Removal of mesangial IgA deposition may be a challenging, but fundamental approach in the treatment of IgAN.

Predicting the risk for dialysis or death in IgA nephropathy

For the individual patient with primary IgA nephropathy (IgAN), it remains a challenge to predict long-term outcomes for patients receiving standard treatment. We studied a prospective cohort of 332 patients with biopsy-proven IgAN patients followed over an average of 13 years. We calculated an absolute renal risk (ARR) of dialysis or death by counting the number of risk factors present at diagnosis: hypertension, proteinuria ≥1 g/d, and severe pathologic lesions (global optical score, ≥8). Overall, the ARR score allowed significant risk stratification (P < 0.0001). The cumulative incidence of death or dialysis at 10 and 20 years was 2 and 4%, respectively, for ARR=0; 2 and 9% for ARR=1; 7 and 18% for ARR=2; and 29 and 64% for ARR=3, in adequately treated patients. When achieved, control of hypertension and reduction of proteinuria reduced the risk for death or dialysis. In conclusion, the absolute renal risk score, determined at diagnosis, associates with risk for dialysis or death.

Polymorphisms in the nonmuscle myosin heavy chain 9 gene (MYH9) are associated with the progression of IgA nephropathy in Chinese

BACKGROUND

IgA nephropathy (IgAN) is the leading cause of end-stage renal disease (ESRD) in China considering different compositions of ESRD causes in different ethnicities. A recent genome-wide association study (GWAS) indicated that the MYH9 gene was significantly associated with non-diabetic ESRD in African-Americans and also influenced kidney function in Europeans. Thus, in the present study, we aim to clarify whether MYH9 confers a shared mechanism among different causes of ESRD and to seek possible further insight into our understanding of IgAN by applying GWAS data from ESRD to IgAN.

METHODS

One thousand one hundred and sixteen Chinese, including 527 patients with renal biopsy-proven IgAN and 589 healthy controls, were enrolled in the present study. Four single neucleotide polymorphisms (SNPs) (rs3752462, rs4821480, rs11089788 and rs2413396) reported to be associated with ESRD with the most significance were genotyped by TaqMan assay or a restriction fragment length polymorphism assay for a further case-control study.

RESULTS

None of the four SNPs was associated with the susceptibility to IgAN or clinical and pathological characters at the time of renal biopsy. However, estimated glomerular filtration rate decline rate was associated with rs11089788 in the dominant model (P = 0.021). Cox regression showed that rs11089788 (hazard ratio, 3.95; 95% confidence interval, 1.23-12.63; P = 2.1 × 10(-2)) was an independent predictive factor for renal survival.

CONCLUSIONS

Based on a large Chinese IgAN cohort, we found an association between rs11089788 and prognosis of IgAN, adding to the mounting evidence of MYH9 as an important gene in IgAN to ESRD.

Antithrombotic drug therapy for IgA nephropathy: a meta analysis of randomized controlled trials

BACKGROUND

Antithrombotic agents, including antiplatelet agents, anticoagulants and thrombolysis agents, have been widely used in the management of immunoglobulin A (IgA) nephropathy in Chinese and Japanese populations. To systematically evaluate the effects of antithrombotic agents for IgA nephropathy.

METHODS

Data sources consisted of MEDLINE, EMBASE, the Cochrane Library, Chinese Biomedical Literature Database (CBM), Chinese Science and Technology Periodicals Databases (CNKI) and Japana Centra Revuo Medicina (http://www.jamas.gr.jp) up to April 5, 2011. The quality of the studies was evaluated from the intention to treat analysis and allocation concealment, as well as by the Jadad method. Meta-analyses were performed on the outcomes of proteinuria and renal function.

RESULTS

Six articles met the predetermined inclusion criteria. Antithrombotic agents showed statistically significant effects on proteinuria (p<0.0001) but not on the protection of renal function (p=0.07). The pooled risk ratio for proteinuria was 0.53, [95% confidence intervals (CI): 0.41-0.68; I(2)=0%] and for renal function it was 0.42 (95% CI 0.17-1.06; I(2)=72%). Subgroup analysis showed that dipyridamole was beneficial for proteinuria (p=0.0003) but had no significant effects on protecting renal function. Urokinase had statistically significant effects both on the reduction of proteinuria (p=0.0005) and protecting renal function (p<0.00001) when compared with the control group.

CONCLUSION

Antithrombotic agents had statistically significant effects on the reduction of proteinuria but not on the protection of renal function in patients with IgAN. Urokinase had statistically significant effects both on the reduction of proteinuria and on protecting renal function. Urokinase was shown to be a promising medication and should be investigated further.

[Renal biopsy in patients aged 65 years or older: are there differences in the indication and histopathology compared to other patients?]

BACKGROUND

Renal biopsy (RB) represents the gold standard for diagnosis of kidney diseases. In this paper we analyse whether the indication of RB and histopathology in patients 65 years or older is different from the other patients.

MATERIAL AND METHODS

Retrospective study of 93 native renal biopsies performed in the General Hospital of Segovia in the period 2004-2008. The RB was performed percutaneously under ultrasound guidance in real time, using a 16G automatic needle.

RESULTS

Mean age of biopsied patients was 56.89 ± 19 (range 14-89) , and 57% were males. A total of 39RB were performed on people aged 65 years or older. Overall, nephrotic syndrome (NS) is the most common indication of RB, and IgA glomerulonephritis the most common histology. In people ≥ 65 years, acute renal failure (ARF) is the most common indication for RB, and rapidly progressing (crescentic) glomerulonephritis/vasculitis the most detected the diagnosis. When taking age into account, no significant differences in the number of glomeruli obtained by RB or in the number of RB performed on the same patient.

CONCLUSIONS

In people 65 years or older, ARF is the main indication of RB and crescentic glomerulonephritis/vasculitis the most frequent diagnosis.

A meta-analysis of the clinical remission rate and long-term efficacy of tonsillectomy in patients with IgA nephropathy

BACKGROUND

We wished to evaluate the clinical remission rate and long-term efficacy of tonsillectomy for patients with IgA nephropathy.

METHODS

We searched a number of databases, including PubMed, CNKI, Wanfang and others, for clinical case-control studies of tonsillectomy in patients with IgA nephropathy. We then performed a meta-analysis of these studies. After evaluating total clinical remission rates, we compared the remission rates for specific treatments: tonsillectomy plus steroid pulse, tonsillectomy plus normal-dose steroid, and general treatment using neither tonsillectomy nor steroids. We also compared the rates of end-stage renal failure (ESRF) at last follow-up to estimate the long-term renal survival rate associated with each treatment.

RESULTS

Seven retrospective studies met the inclusion criteria and were included. These included a total of 858 patients, in which 534 underwent tonsillectomy and 324 did not. The total clinical remission rate was higher in the operative group, while the ESRF rate was higher in the non-operative group. The clinical remission rate in patients who underwent tonsillectomy remained higher than in the non-operative group at both 5- and 10-year follow-up. The clinical remission rate in patients who underwent tonsillectomy plus steroid pulse was higher than in those treated with steroid pulse alone, normal-dose steroids or general treatment alone (P < 0.05). However, the clinical remission rate of simple tonsillectomy was not higher than that of general treatment (P > 0.05).

CONCLUSIONS

Whereas neither tonsillectomy nor steroid treatment alone increased remission rates in patients with IgA nephropathy, tonsillectomy combined with either normal steroid or steroid pulse treatment resulted in higher remission rates with favourable long-term efficacy.

Genetic studies of IgA nephropathy: past, present, and future

Immunoglobulin A nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide and an important cause of kidney disease in young adults. Highly variable clinical presentation and outcome of IgAN suggest that this diagnosis may encompass multiple subsets of disease that are not distinguishable by currently available clinical tools. Marked differences in disease prevalence between individuals of European, Asian, and African ancestry suggest the existence of susceptibility genes that are present at variable frequencies in these populations. Familial forms of IgAN have also been reported throughout the world but are probably underrecognized because associated urinary abnormalities are often intermittent in affected family members. Of the many pathogenic mechanisms reported, defects in IgA1 glycosylation that lead to formation of immune complexes have been consistently demonstrated. Recent data indicates that these IgA1 glycosylation defects are inherited and constitute a heritable risk factor for IgAN. Because of the complex genetic architecture of IgAN, the efforts to map disease susceptibility genes have been difficult, and no causative mutations have yet been identified. Linkage-based approaches have been hindered by disease heterogeneity and lack of a reliable noninvasive diagnostic test for screening family members at risk of IgAN. Many candidate-gene association studies have been published, but most suffer from small sample size and methodological problems, and none of the results have been convincingly validated. New genomic approaches, including genome-wide association studies currently under way, offer promising tools for elucidating the genetic basis of IgAN.

Tonsillectomy for the treatment of tonsillitis-induced immunoglobulin A nephropathy

Tubular occlusion from red blood cell casts secondary to immunoglobulin A nephropathy (IgAN) is a rare, serious complication of tonsillitis that can cause acute renal failure, also referred to as acute kidney injury. IgAN is the most common primary glomerulonephritis with up to 20% of cases resulting in renal failure worldwide. Tonsillectomy is an effective treatment option for patients suffering from IgAN secondary to recurrent acute tonsillitis. Tonsillectomy alone or in combination with additional medical modalities improves renal function and can have a positive effect on long-term renal survival.

Effects of eicosapentaenoic acid supplementation on immunoglobulin A nephropathy

Eicosapentaenoic acid (EPA), which is purified from fish oil, attenuates inflammatory responses by decreasing eicosanoid and cytokine production. EPA reportedly improves renal survival in patients with immunoglobulin (Ig)A nephropathy; however, this is unconfirmed. We studied the effects of EPA on IgA nephropathy patients. Eighteen biopsy-confirmed IgA nephropathy patients (aged 31 +/- 3 years) were enrolled. The prognoses based on glomerular findings were good (N = 5), relatively poor (N = 12), and poor (N = 1). EPA was administered at 1.8 g/day for 12 months. Five biopsy-confirmed IgA nephropathy patients were enrolled as control subjects. Administration of other drugs used to treat IgA nephropathy was not changed. The estimated creatinine clearance (eCCr), serum creatinine (Cr) concentration, urinary protein creatinine ratio (U/P), and other clinical parameters were checked. In the EPA group, the Cr went from 0.8 +/- 0.2 mg/dL to 0.7 +/- 0.2 mg/dL after 12 months of EPA treatment, and the U/P went from 550 +/- 580 mg/g Cr to 330 +/- 920 mg/g Cr. The values did not differ significantly; however, Cr and U/P tended to improve, with no adverse effects from the EPA. The eCCr improved significantly (99 +/- 7-110 +/- 8 mL/min, P = 0.001) in the EPA group, but not in the control group (126 +/- 12-120 +/- 13, P > 0.05). The effect of EPA in patients with IgA nephropathy is not pronounced, but these results suggest that EPA is a safe and worthwhile supplement to the drugs used to treat this disease.

Spontaneous remission of nephrotic syndrome in patients with IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN) can be complicated by nephrotic syndrome. Because the spontaneous resolution of heavy proteinuria is rare, corticosteroid therapy should be considered in such cases, particularly when IgAN is combined with minimal-change disease. Here, we report our experience of spontaneous remission of nephrotic syndrome in patients with IgAN and the long-term outcomes of these patients.

METHODS

Two hundred and thirty-three patients with biopsy-proven IgAN were enrolled between January 2001 and March 2009. Demographic, clinical and laboratory data were collected retrospectively based on medical records. In addition, pathologic findings were reviewed for glomerular and tubulointerstitial lesions. Outcome data for complete or partial remission, spontaneous remission, relapse, deterioration of renal function, and end-stage renal disease were recorded.

RESULTS

Twenty-four patients (10.3%) presented nephrotic syndrome. Among them, five patients underwent spontaneous remission within 6 months after the presentation of nephrotic syndrome. Interestingly, spontaneous remission occurred even in two patients who had elevated serum creatinine levels and advanced renal damage. During follow-up, neither recurrence nor relapse occurred, and no patients showed progressive deterioration of kidney function. Conclusions. This study suggests that spontaneous remission of nephrotic syndrome may occur in any stage of IgAN and carries a favourable long-term outcome without relapse. Given the possibility of under-reported cases, large-scale studies are required, and careful attention should be paid to such complicated cases.

Clinical remission of Henoch-Schönlein purpura nephritis after a monotherapeutic tonsillectomy

We herein describe an adult male patient who presented with tonsillitis, purpura, hematuria, and proteinuria. The serological analyses revealed elevated serum antistreptolysin, and the throat culture yielded Lancefield group A β-hemolytic streptococci. A renal biopsy revealed mild mesangial proliferation associated with granular mesangial depositions of IgA and C3, consistent with Henoch-Schönlein purpura nephritis (HSPN). Initially, the patient was treated with dipyridamole, which was followed by limited improvements in the proteinuria and hematuria. Nine months later, the tonsillitis relapsed due to GAS infection and deteriorated urinary abnormalities were noticed, which finally disappeared after monotherapeutic tonsillectomy. Although the impact of tonsillectomy on the treatment of HSPN remains to be characterized, our observations suggest that tonsillectomy in the present patient played a pivotal role in facilitating the recovery of the renal injuries. Because the arbitrary application of a tonsillectomy appears to be accompanied by ethical concerns, the evaluation of the clinical benefits of this procedure should be addressed more directly in the future.

Addition of azathioprine to corticosteroids does not benefit patients with IgA nephropathy

The optimal treatment for IgA nephropathy (IgAN) remains unknown. Some patients respond to corticosteroids, suggesting that more aggressive treatment may provide additional benefit. We performed a randomized, multicenter, controlled trial to determine whether adding azathioprine to steroids improves renal outcome. We randomly assigned 207 IgAN patients with creatinine ≤2.0 mg/dl and proteinuria ≥1.0 g/d to either (1) a 3-day pulse of methylprednisolone in months 1, 3, and 5 in addition to both oral prednisone 0.5 mg/kg every other day and azathioprine 1.5 mg/kg per day for 6 months (n = 101, group 1) or (2) steroids alone on the same schedule (n = 106, group 2). The primary outcome was renal survival (time to 50% increase in plasma creatinine from baseline); secondary outcomes were changes in proteinuria over time and safety. After a median follow-up of 4.9 years, the primary endpoint occurred in 13 patients in group 1 (12.9%, 95% CI 7.5 to 20.9%) and 12 patients in group 2 (11.3%, CI 6.5 to 18.9%) (P = 0.83). Five-year cumulative renal survival was similar between groups (88 versus 89%; P = 0.83). Multivariate Cox regression analysis revealed that female gender, systolic BP, number of antihypertensive drugs, ACE inhibitor use, and proteinuria during follow-up predicted the risk of reaching the primary endpoint. Treatment significantly decreased proteinuria from 2.00 to 1.07 g/d during follow-up (P < 0.001) on average, with no difference between groups. Treatment-related adverse events were more frequent among those receiving azathioprine. In summary, adding low-dose azathioprine to corticosteroids for 6 months does not provide additional benefit to patients with IgAN and may increase the risk for adverse events.

The accumulated experience with the use of mycophenolate mofetil in primary glomerulonephritis

IMPORTANCE OF THE FIELD

The use of mycophenolate mofetil (MMF) has been extended from renal transplantation to the treatment of glomerulonephritis. MMF has been used in patients with steroid- and ciclosporin A (CsA)-dependent or -resistant idiopathic nephrotic syndrome and in patients with deteriorating renal function or adverse reactions to other drugs. MMF has been also used in patients with membranous and IgA nephropathy after failure of other regimens as well as initial treatment.

AREAS COVERED IN THIS REVIEW

The rationale of MMF treatment in primary glomerulonephritis is based in its antifibrotic and antiproteinuric effects. The mechanism of action is described; the results of cohort and randomized trials in minimal change disease, focal segmental glomerulosclerosis, idiopathic membranous nephropathy and IgA nephropathy are presented along with the adverse reactions profile and the expert opinion.

WHAT THE READER WILL GAIN

This is an up-to-date review providing insight on this novel agent that is increasingly used in the therapeutics of primary glomerulonephritis.

TAKE HOME MESSAGE

Although the results are conflicting, MMF seems to be effective at least in some patients, who do not respond to corticosteroids, ciclosporin or cytotoxic drugs. However, the experience with MMF in primary glomerulonephritis is limited and further research is required in order to establish MMF in the treatment of patients with glomerular disease.

Antibody response to IgA-binding streptococcal M proteins in children with IgA nephropathy

BACKGROUND

IgA nephropathy (IgAN), the most common glomerulonephritis worldwide, is characterized by mesangial deposits containing predominantly IgA. IgAN commonly occurs or exacerbates after upper respiratory tract infections such as streptococcal pharyngitis. Certain group A streptococci express M proteins with IgA-binding regions (IgA-BRs). We have previously shown that these IgA-BRs co-localize with mesangial IgA in IgAN.

METHODS

Blood samples from patients with IgAN (n = 21) and age-matched controls (n = 83) were assayed by ELISA to detect an IgG antibody response to the IgA-BRs of the M4, M22 and M60 proteins. Antibodies were assayed for each IgA-BR separately and the results were combined.

RESULTS

Antibody levels to the IgA-BRs were significantly higher in IgAN patients than controls (P = 0.016), particularly in patients with recent streptococcal infection (P = 0.008). Conclusions. The results suggest that children with IgAN had a previous infection with a streptococcal strain expressing an IgA-binding M protein.

IgA nephropathy associated with Castleman disease with cutaneous involvement

A 35-year-old Japanese man developed systemic lymphadenopathy during the course of immunosuppressive therapy for IgA nephropathy associated with cutaneous nodules, polyclonal hypergammaglobulinemia, and persistent increased serum C-reactive protein of unknown cause. Lymph node examination showed the plasmacytic type of Castleman disease (CD). A skin biopsy showed specific pathologic findings of CD cutaneous involvement. Considering the involvement of interleukin-6 in CD, we treated the patient with humanized anti-interleukin-6 receptor antibody. Thereafter, his symptoms and abnormal laboratory findings were improved. Cutaneous CD has rarely been described in Asian population, and renal complications in CD are uncommon and heterogeneous. To our knowledge, this is the first case of IgA nephropathy associated with multicentric CD with cutaneous involvement.

Cigarette smoking and progression of IgA nephropathy

BACKGROUND

Multiple community-based cohort studies of mainly middle-aged and elderly populations have shown that cigarette smoking is a risk factor for chronic kidney disease. However, little information is available about an effect of cigarette smoking on progression of primary kidney diseases, including immunoglobulin A (IgA) nephropathy.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

971 of 1,001 patients with a diagnosis of IgA nephropathy in 3 major nephrology centers in Osaka, Japan, between 1992 and 2005 who enrolled in the Study of Outcome and Practice Pattern of IgA Nephropathy (STOP-IgAN).

PREDICTORS

Smoking status and number of cigarettes smoked at the time of diagnosis using kidney biopsy. Dose-dependent associations between cigarette smoking and outcomes were assessed in multivariate Cox proportional hazards models. Significantly different clinical characteristics between non-/past and current smokers were controlled for using propensity score-based adjustment, stratification, and matching.

OUTCOMES

50% increase in serum creatinine level as primary outcome. A composite outcome of a 100% increase in serum creatinine level or end-stage renal disease (ESRD) and ESRD alone as secondary outcomes.

RESULTS

During the median 5.8 years (interquartile range, 2.6-10.2) of the observational period, 117 participants progressed to a 50% increase in serum creatinine level and 47 advanced to ESRD. Multivariate Cox proportional hazards models identified current smokers (HR, 2.03 [95% CI, 1.33-3.10] for primary outcome) and number of cigarettes at kidney biopsy (HR, 1.21 [95% CI, 1.06-1.39] per 10 cigarettes per day) as significant predictors of outcomes. Propensity score-based models confirmed these results. Tests for interaction showed that the association of current smoking with adverse outcomes was stronger in those with lower compared with higher estimated glomerular filtration rates.

LIMITATION

Baseline smoking status was not verified using biochemical tests. Smoking status during the observational period was unavailable.

CONCLUSIONS

Cigarette smoking, in a dose-dependent manner, was identified as a key prognostic factor in IgA nephropathy. Smoking cessation should be encouraged as part of the treatment for IgA nephropathy.

Effects of cyclosporin A therapy combined with steroids and angiotensin converting enzyme inhibitors on childhood IgA nephropathy

To evaluate the effects of cyclosporin A (CyA) on clinical outcome and pathologic changes in children with IgA nephropathy (IgAN), we retrospectively evaluated 14 children (mean age 8.9+/-2.9 yr; eight males, six females) who were treated with CyA and steroids. The starting dose of CyA was 5 mg/kg per day, and the drug level was maintained at 100-200 ng/mL. The mean CyA level was 183.8+/-48.3 ng/mL (range 120.7-276.0 ng/mL) and the mean duration of CyA therapy was 10.9+/-1.9 months (range 8-12 months). After CyA therapy the mean 24 hr urinary protein excretion declined from 107.1+/-35.1 mg/m(2)/hr to 7.4+/-2.4 mg/m(2)/hr (P<0.001) and serum albumin increased from 3.3+/-0.6 g/dL to 4.3+/-0.3 g/dL (P<0.001). At a follow-up biopsy the histological grade of IgAN was improved in seven (50%) of the 14 patients, remained the same in three (21%), and was aggravated in four (29%). Serum creatinine, creatinine clearance, and blood pressure did not differ before and after CyA therapy. Two patients (14%) showed CyA-induced nephrotoxicity at the second biopsy. Our findings indicate that CyA therapy may be effective in reducing proteinuria and regressing renal pathology in a subset of children with IgAN.

The spectrum of renal lesions in patients with cirrhosis: a clinicopathological study

BACKGROUND/OBJECTIVE

Little is known on the morphological changes in the kidneys of cirrhotic patients with abnormal urinalysis and/or high serum creatinine levels. This retrospective, one-point-in-time study aimed to report the results of the analysis of renal biopsy specimens obtained in patients with cirrhosis.

METHODS

We retrieved information on 65 patients who underwent transvenous renal biopsy for proteinuria >0.5 g/day and/or microscopic haematuria and/or unexplained renal impairment (defined by serum creatinine levels >1.5 mg/dl).

RESULTS

Fifty-one per cent of the patients had proteinuria >0.5 g/day, 58% had haematuria and 83% had renal impairment. Renal biopsy disclosed injury to glomeruli in 77% of the patients, to vessels in 69% and to the tubulointerstitium system in 94% (chronic in 77%; acute in 75%). Fibrous endarteritis was the most common renal vascular lesion. Injuries to different structures were frequently combined. Isolated glomerular alterations were found in only two patients. Acute tubular necrosis was significantly more common in patients with fibrous endarteritis than in those without. Among 18 patients with renal impairment, proteinuria <0.5 mg/day and no haematuria, 10 had glomerular lesions, 13 had chronic tubulointerstitial lesions and 12 acute tubulointerstitial lesions.

CONCLUSION

In patients with cirrhosis, various types of renal injuries are frequently combined. Chronic lesions (vascular or tubulointerstitial) may influence the outcome, in particular in patients who subsequently undergo liver transplantation and receive anticalcineurins. Renal vascular lesions may increase the risk of acute tubular necrosis. In patients with renal impairment, the absence of significant proteinuria and haematuria do not rule out the presence of renal lesions.

[Glomerulonephritis with IgA mesangial deposits]

IgA nephropathy is the primitive glomerulonephritis the most frequently encountered worldwide. In about one case out of three, it is responsible for the progression from progressive renal failure to end-stage renal failure. The pathophysiological mechanisms of this disease which is mediated by immune complexes remain unclear. The presentation, clinical progression and optical microscope aspect of the renal biopsy may widely vary, making any histological classification very difficult. Most therapeutic studies include the patients only on clinical criteria of severity. The only consensual management is that of patients with a nephropathy and mild glomerular lesions and a nephritic syndrome, or with an extracapillar glomerulonephritis and a rapidly progressive renal failure; corticoids are indicated in former cases while corticoids must be combined with immunosuppressive agents in the latter ones. Corticotherapy may be considered in patients with a proteinuria higher than 1g/day without renal failure. In any patient with primitive IgA nephropathy, the overall management used for chronic glomerulopathy must be initiated, including, in case of arterial hypertension or proteinuria, the renin-angiotensin system blockade.

Omega-3 and renal function in older adults

Chronic kidney disease (CKD) is a major public health problem and can result in end-stage renal disease with need for dialysis or transplantation. In Europe up to 12% of the adult population had some renal impairment, while in the United States the end stage of CKD has increased dramatically from 209.000 in 1991 to 472.000 in 2004. Diabetes and hypertension are major causes of kidney pathology. Infection, particularly ascending infection, is more common with increasing age, as both immune function declines and associated pathology predisposing to infection, such as obstructive uropathy, becomes more common. Most pathological changes in the kidney appear to be initiated by oxidative stress, followed by an inflammatory reaction. Oxidative stress results from an imbalance between free radicals and their detoxification by endogenous and exogenous scavengers, including polyunsaturated fatty acids (PUFA). Recent studies showed that PUFA supplementation slowed the rate of loss of renal function in patients with IgA nephropathy. Then, studies of omega-3 supplementation in dialysis patients describe salutary effects on triglyceride levels and dialysis access patency. We examined the relationship between total plasma PUFA levels and change in creatinine clearance over a three-year follow-up in the older persons enrolled in the InCHIANTI study, a population-based epidemiology study conducted in Tuscany, Italy. This study showed that older adults with low total plasma PUFA levels have a greater decline in creatinine clearance over three years of follow-up. These findings suggest that a higher dietary intake of PUFA may be protective against progression to chronic kidney disease.

Tissue deposits of IgA-binding streptococcal M proteins in IgA nephropathy and Henoch-Schonlein purpura

IgA nephropathy (IgAN) and Henoch-Schönlein purpura (HSP) are diseases characterized by IgA deposits in the kidney and/or skin. Both may arise after upper respiratory tract infections, but the pathogenic mechanisms governing these diseases remain unclear. Patients with IgAN (n = 16) and HSP (n = 17) were included in this study aimed at examining whether IgA-binding M proteins of group A streptococci could be involved. As M proteins vary in sequence, the study focused on the IgA-binding-region (IgA-BR) of three different M proteins: M4, M22, and M60. Renal tissue from IgAN and HSP patients and skin from HSP patients were examined for deposits of streptococcal IgA-BR by immunohistochemistry and electron microscopy using specific antibodies, and a skin sample from a HSP patient was examined by mass spectrometry. IgA-BR deposits were detected in 10/16 IgAN kidneys and 7/13 HSP kidneys. Electron microscopy demonstrated deposits of IgA-BRs in the mesangial matrix and glomerular basement membrane, which colocalized with IgA. Skin samples exhibited IgA-BR deposits in 4/5 biopsies, a result confirmed by mass spectrometry in one patient. IgA-BR deposits were not detected in normal kidney and skin samples. Taken together, these results demonstrate IgA-BR from streptococcal M proteins in patient tissues. IgA-BR, would on gaining access to the circulation, encounter circulatory IgA and form a complex with IgA-Fc that could deposit in tissues and contribute to the pathogenesis of IgAN and HSP.

Intrarenal expression of microRNAs in patients with IgA nephropathy

MicroRNAs (miRNAs) are noncoding, single-stranded RNA molecules that have important roles in a number of physiological and pathological processes. Previous studies have proved that miRNAs targeting ZEB1 and ZEB2 may repress epithelial-to-mesenchymal transition. In this work, we studied the intrarenal expression of miR-200 family, miR-205 and miR-192 in patients with immunoglobulin A (IgA) nephropathy. We studied 43 patients with biopsy-proven IgA nephropathy (IgA group). The intrarenal expression of miRNAs was quantified and compared with that of 15 patients with noninflammatory glomerulosclerosis (GS group) and 20 patients with nephrectomy for kidney cancer as controls (CTL group). The level of intrarenal miR-200c was downregulated, whereas the levels of intrarenal miR-141, miR-205 and miR-192 were upregulated in IgA but not GS group. Proteinuria significantly correlated with the intrarenal expression of miR-200c (r=-0.324, P=0.011) and glomerular filtration rate (GFR) significantly correlated with the intrarenal expression of miR-205 (r=-0.280, P=0.030). The degree of tubulointerstitial scarring correlated with miR-205 expression (r=0.389, P=0.021), whereas glomerulosclerosis correlated with miR-192 expression (r=-0.311, P=0.045). The rate of GFR decline significantly correlated with the intrarenal expression of miR-192 (r=0.373, P=0.015). The intrarenal expression of E-cadherin significantly correlated with the intrarenal expression of miR-200c (r=0.392, P=0.002). The results show that intrarenal expression of miR-200c, miR-141, miR-205 and miR-192 was diversely regulated and correlated with disease severity and progression in patients with IgA nephropathy. These miRNA species may be important in the pathogenesis and progression of IgA nephropathy.

Meta-analysis of Tripterygium wilfordii Hook F in the immunosuppressive treatment of IgA nephropathy

OBJECTIVE

Numerous Chinese patients with IgA nephropathy (IgAN) have benefited from Tripterygium wilfordii Hook F (TwHF) from two decades ago. However, to date there is no systematic evaluation of this remedy for IgAN.

METHODS

We conducted a meta-analysis of all eligible randomized clinical trials (RCTs) to assess the effect of TwHF on IgAN for the first time. In August 2009 a systematic search was performed among eight electronic databases. Review Manager (RevMan) version 5.0 was used.

RESULTS

(i) Four eligible RCTs with 188 participants were included; (ii) The validities of included RCTs were generally acceptable; (iii) TwHF brought about a favorable increase in complete remission (CR) (RR 1.53, 95%CI 1.09 to 2.16, I(2)=12%) and total remission (TR) (RR 1.27, 95%CI 1.08 to 1.48, I(2)=0%) compared with non-TwHF treatment; and this result was further confirmed by intention-to-treat analysis; (iv) Exploiting subgroup meta-analysis, TwHF led to significantly greater improvements of IgAN with non-nephrotic proteinuria with regard to the increase of CR (RR 1.80, 95%CI 1.21 to 2.68, I(2)=0%) and TR (RR 1.32, 95%CI 1.11 to 1.57, I(2)=0%), and decrease of urinary proteinuria excretion (UPE) (MD -467.41 mg/24h, 95%CI -633.99 to -300.82, I(2)=0%). Meanwhile, the renal function was well preserved (MD -2.66 µmol/L, 95%CI -9.26 to 3.94, I(2)=0%). Conclusion Although the results of this meta-analysis should be interpreted with caution and warrant further investigation, TwHF was certainly a valuable and promising immunosuppressive remedy for IgAN, which was in accordance with the accruing evidence from numerous large clinical and experimental studies.

Long-term study of mycophenolate mofetil treatment in IgA nephropathy

Since the efficacy of mycophenolate mofetil (MMF) to treat immunoglobulin A (IgA) nephropathy is controversial, we extended our original study by following 40 Chinese patients with established IgA nephropathy for 6 years. All patients were maintained on their angiotensin blockade medication and half were randomized to receive MMF for 6 months. After 6 years, 11 patients required dialysis (2 from the MMF and 9 from the control group). Significantly, only 3 treated (as compared to 10 control) patients reached the composite end point of serum creatinine doubling or end-stage renal disease. Linear regression showed the annualized decline in the estimated glomerular filtration rate was significantly less in the MMF-treated group. Urinary protein excretion and the albumin-to-creatinine ratio were lower with MMF treatment during the first 24 months, beyond which there was no difference between groups. Multivariable Cox regression analysis showed that the baseline estimated glomerular filtration rate and proteinuria, and change in the urine albumin-to-creatinine ratio at 1 year to be important predictors of progression to end-stage renal disease. We found that among Chinese patients with IgA nephropathy who had mild histologic lesions and persistent proteinuria despite maximal angiotensin blockade, MMF treatment may result in transient and partial remission of proteinuria in the short-term and renoprotection in the long-term.

Natural history and renal pathology in patients with isolated microscopic hematuria

BACKGROUND/AIMS

No definite conclusions have been reached about the natural history of patients with isolated microscopic hematuria (IMH). In this study, we observed the natural history of patients with IMH and examined factors related to a pathologic diagnosis and subsequent prognosis.

METHODS

We retrospectively evaluated 156 subjects with IMH who had a renal biopsy performed. Of the 156 subjects, 33.3% were diagnosed with IgA nephropathy, 23.7% with mesangial proliferative glomerulonephritis, 15.4% with glomerular minor lesion, and 12.8% with thin basement membrane nephropathy; 6.4% had normal biopsies.

RESULTS

We followed up with 100 subjects for about 31 months. During this follow-up period, two subjects who had received a pathologic diagnosis of IgA nephropathy developed chronic kidney disease. During the course of the study, one of these subjects presented with proteinuria and hypertension and the other with proteinuria. The overall incidences of proteinuria and hypertension were 6% and 5% respectively.

CONCLUSIONS

The prognosis for patients with IMH was relatively favorable, but patients developing proteinuria and/or hypertension require careful observation and management during the follow-up period.

Quali-quantitative analysis of urinary glycosaminoglycans for monitoring glomerular inflammatory activity

OBJECTIVE

A 2-year follow-up study was carried out in patients with IgA nephropathy (IgAN) in order to verify the possible use of quali-quantitative analysis of urinary glycosaminoglycans (GAGs) as a prognostic index of disease and for drug treatment monitoring.

MATERIAL AND METHODS

Ten patients with IgAN were evaluated at four time points: baseline, and 6, 9 and 24 months later. GAGs were isolated from 24-h urine using ion-exchange chromatography on diethylaminoethyl-Sephacel, and concentrations were expressed as milligrams of hexuronate per gram of creatinine. GAG composition was determined by cellulose acetate electrophoresis and expressed as relative percentages by means of densitometric scanning of Alcian Blue-stained strips.

RESULTS

The relative content of total low-sulphated chondroitin sulphate species decreased significantly during the study period compared to baseline, whereas the relative percentages of heparan sulphate and chondroitin sulphate increased significantly. Moreover, a significant correlation was noted between the relative contents of urinary GAGs, renal function and inflammation indexes.

CONCLUSIONS

It is likely that the excretion of various types of GAGs may be related to different glomerular pathophysiological conditions. Therefore, the determination of urinary GAG composition may represent a reliable indicator of disease activity.

Concurrent Antiglomerular Basement Membrane Disease and Immune Complex Glomerulonephritis

Antiglomerular basement membrane (GBM) disease is characteristically described with linear deposition of IgG along GBM. However, the concurrent glomerular immune complex deposition was not rare and might be contributed to the development of anti-GBM disease. In the current series, glomerular immune complexes were identified in 10 of 47 patients who presented with renal-biopsy-proven anti-GBM disease. Six of the 10 patients complicated with a well-documented glomerulonephritis, including two patients with membranous nephropathy, one patient with IgA nephropathy, one patient with membranoproliferative glomerulonephritis, one patient with Schonlein-Henoch nephritis, and one patient with hepatitis B virus associated membranous nephritis. The other four patients had immune complexes with IgG or IgM predominance deposited in glomerular mesangium without a well-documented glomerulonephritis. Clinical and pathological data of patients with immune complex deposition (n = 10) were compared with those of patients with anti-GBM disease alone (n = 37). There was no significant difference in age, gender, clinical and pathological manifestations, and renal outcome between the two groups. In general, the association of glomerular immune complexes did not lead to a benign prognosis. Plasma exchange and extensive immunosuppressive therapy should be carried out as soon as possible. The immune complexes deposited in glomeruli might participate in the initiation of anti-GBM disease.

IgA nephropathy associated with ankylosing spondylitis is not controlled by infliximab therapy

The association between seronegative spondyloarthro- pathies and IgA nephropathy is well documented, mainly in cases of ankylosing spondylitis (AS). However, although these diseases have been associated, the physiopathological links between each other appear unclear. Anti-TNFalpha agents have transformed the outcome of axial forms of AS resistant to conventional anti-inflammatory therapies. Infliximab, a monoclonal anti-TNFalpha antibody, has greatly improved the evolution of AS although several adverse events have been described. On the other hand, infliximab has been demonstrated to reduce renal symptoms associated with chronic inflammatory rheumatological diseases, such as amyloid A (AA) amyloidosis, but few data are available on its efficacy in controlling IgA nephropathy associated with AS [1,2]. We report here a case of IgA nephropathy associated with AS that became symptomatic, whereas infliximab therapy efficiently controlled the rheumatological disease. This suggests that even though infliximab therapy effectively controls rheumatological manifestations, it may not be able to prevent IgA nephropathy associated with AS. Thus, this case report illustrates the complexity of the physiopathology of both diseases.

Pathological predictors of prognosis in immunoglobulin A nephropathy: a review

PURPOSE OF REVIEW

To provide a review and discussion of histological prognostic indicators in immunoglobulin A (IgA) nephropathy (IgAN).

RECENT FINDINGS

A variety of histological parameters and classifications have been used to attempt to predict prognosis in patients with IgAN. Grading systems used thus far do not consistently provide a useful adjunct to clinical prognostic parameters. This may be due to the variety of grading systems used, to inconsistent patient recruitment processes, and to the use of actuarial renal survival as an end point. This has led to the development of a new IgAN classification proposal by the International IgA Nephropathy Network in conjunction with the Renal Pathological Society. Additional potential markers of disease progression currently under investigation include glomerular parameters such as number and size, markers of podocyte function and of complement activation, inflammatory infiltrates and mediators of tubulointerstitial fibrosis.

SUMMARY

There is a need for an internationally accepted, reproducible and clinically meaningful pathological classification of IgAN. Such a classification is currently being developed. By using only reproducible, single parameters and validating them on a large group of cases from all over the world, it is hoped that a useful clinically predictive tool will be developed.

Wegener's granulomatosis: a model of auto-antibodies in mucosal autoimmunity

Wegener's granulomatosis (WG) is an autoimmune condition marked by vasculitis of small and medium sized vessels particularly affecting the upper respiratory tract and kidneys. There is a strong mucosal component similar to other autoimmune conditions such as systemic lupus erythematosus and Behçet's disease. While the pathogenesis of WG is not completely known, auto-antibodies such as IgG ANCAs have been implicated in endovascular damage and modulation of neutrophil/monocyte responses by Fc receptor (FcR) signaling. Due to the substantial mucosal involvement in WG (oral, nasal, and upper respiratory tract involvement), it is probable that IgA antibodies (perhaps IgA ANCAs) play a role in disease. Given discrepancies in associating ANCA levels with disease activity, future work should determine if IgA ANCAs are present in WG patients and examine the biology underlying the ANCAs' signaling partners--the FcRs.