IgA nephropathy

Gene expression analysis in tubule interstitial compartments reveals candidate agents for IgA nephropathy

BACKGROUND/AIMS

Our aim was to explore the molecular mechanism underlying development of IgA nephropathy and discover candidate agents for IgA nephropathy.

METHODS

The differentially expressed genes (DEGs) between patients with IgA nephropathy and normal controls were identified by the data of GSE35488 downloaded from GEO (Gene Expression Omnibus) database. The co-expressed gene pairs among DEGs were screened to construct the gene-gene interaction network. Gene Ontology (GO) enrichment analysis was performed to analyze the functions of DEGs. The biologically active small molecules capable of targeting IgA nephropathy were identified using the Connectivity Map (cMap) database.

RESULTS

A total of 55 genes involved in response to organic substance, transcription factor activity and response to steroid hormone stimulus were identified to be differentially expressed in IgA nephropathy patients compared to healthy individuals. A network with 45 co-expressed gene pairs was constructed. DEGs in the network were significantly enriched in response to organic substance. Additionally, a group of small molecules were identified, such as doxorubicin and thapsigargin.

CONCLUSION

Our work provided a systematic insight in understanding the mechanism of IgA nephropathy. Small molecules such as thapsigargin might be potential candidate agents for the treatment of IgA nephropathy.

Clinicopathological role of kidney injury molecule-1 in immunoglobulin A nephropathy

BACKGROUND

Urinary kidney injury molecule-1 (KIM-1) is an early and sensitive biomarker of acute kidney injury, but it is unclear if it is a biomarker of chronic glomerulonephritis. We evaluated whether urinary KIM-1 levels in patients with immunoglobulin A (IgA) nephropathy can be a marker to reflect clinicopathological severity and predict the prognosis.

METHODS

We measured urinary KIM-1 levels in 40 patients (15 males; mean age 36.6±12.9 years) with IgA nephropathy and 10 healthy people (5 males; mean age 37.3±9.6 years) as controls. The correlation of urinary KIM-1 levels with patients' clinical parameters, histological grades, and follow-up data were analyzed using the modified H. S. Lee grading system and tubulointerstitial change scores.

RESULTS

Urinary KIM-1 levels were higher in patients with IgA nephropathy than healthy controls (P=0.001). Univariate and multivariate regression analyses showed that urinary KIM-1 levels had a direct correlation with H. S. Lee grade and tubulointerstitial inflammation (P=0.004 and P=0.011, respectively).

CONCLUSION

In patients with IgA nephropathy, urinary KIM-1 has a significant correlation with histopathologic severity.

Time-averaged albumin predicts the long-term prognosis of IgA nephropathy patients who achieved remission

Background

Primary IgA nephropathy (IgAN) is the most common form of idiopathic glomerulonephritis worldwide. Although most patients are able to achieve remission with the current therapy, a large number of patients will still progress to end-stage renal disease. This study aimed to evaluate kidney disease progression and the risk factors for progression in IgAN patients who achieved remission.

Methods

Patients from a prospective database with IgAN were included in this study. All the subjects had achieved a complete remission (CR) or partial remission (PR) following 6 months of therapy. Renal survival and the relationship between the clinical parameters and composite renal outcomes were assessed.

Results

The study comprised 878 IgAN patients recruited between January 2005 and December 2010. Overall, 632 patients were enrolled in this study. The data from the 369 patients who achieved remission were analyzed; the mean follow-up time was 49 months. The median serum creatinine (SCr) concentration at baseline was 91.3 μmol/L, and the time-averaged creatinine (TA-SCr) was 91.8 μmol/L. The mean serum albumin (ALB) level at baseline was 39.4 g/L, and the time-averaged serum albumin (TA-ALB) was 42.1 g/L. Multivariate Cox regression analyses revealed that the TA-ALB and TA-SCr levels were independently associated with the composite renal outcome. The patients with a TA-SCr value > 120 μmol/L and a TA-ALB level < 38 g/L were less likely to recover from renal progression.

Conclusion

The strong predictive relationship of low TA-ALB and high TA-SCr levels with progression observed in this study suggests that TA-ALB may serve as a marker of the long-term renal prognosis of IgAN patients who have achieved remission.

The risk of recurrent IgA nephropathy in a steroid-free protocol and other modifying immunosuppression

Recurrent glomerulonephritis is an important cause of kidney allograft failure. The effect of immunosuppression on recurrent IgA nephropathy (IgAN) is unclear. We analyzed the impact of steroids and other immunosuppression on the risk of recurrent IgAN post-kidney transplantation. Between June 1989 and November 2008, 3311 kidney transplants were performed at our center. IgAN was the primary disease in 124 patients; of these, 75 (60.5%) patients received steroid-based immunosuppression (15 undergoing late steroid withdrawal), and 49 (39.5%) were maintained on steroid-free immunosuppression. Recurrent IgAN was diagnosed in 27 of 124 (22%) patients in clinically indicated kidney allograft biopsies over a median follow-up of 6.86 ± 5.4 yr. On cox proportional hazards model multivariate analysis, the hazard risk (HR) of IgAN recurrence was significantly higher in patients managed with steroid-free (HR 8.59: 3.03, 24.38, p < 0.001) and sirolimus-based (HR = 3.00:1.16, 7.75, p = 0.024) immunosuppression without antilymphocyte globulin induction (HR = 4.5: 1.77, 11.73, p = 0.002). Mycophenolate use was associated with a lower risk (HR = 0.42: 0.19, 0.95, p = 0.036), whereas cyclosporine did not have a significant impact on the risk of IgAN recurrence (p = 0.61). These results warrant future prospective studies regarding the role of steroids and other immunosuppression drugs in reducing recurrence of IgAN and other glomerulonephritis post-transplant.

Enzymatic sialylation of IgA1 O-glycans: implications for studies of IgA nephropathy

Patients with IgA nephropathy (IgAN) have elevated circulating levels of IgA1 with some O-glycans consisting of galactose (Gal)-deficient N-acetylgalactosamine (GalNAc) with or without N-acetylneuraminic acid (NeuAc). We have analyzed O-glycosylation heterogeneity of naturally asialo-IgA1 (Ale) myeloma protein that mimics Gal-deficient IgA1 (Gd-IgA1) of patients with IgAN, except that IgA1 O-glycans of IgAN patients are frequently sialylated. Specifically, serum IgA1 of healthy controls has more α2,3-sialylated O-glycans (NeuAc attached to Gal) than α2,6-sialylated O-glycans (NeuAc attached to GalNAc). As IgA1-producing cells from IgAN patients have an increased activity of α2,6-sialyltransferase (ST6GalNAc), we hypothesize that such activity may promote premature sialylation of GalNAc and, thus, production of Gd-IgA1, as sialylation of GalNAc prevents subsequent Gal attachment. Distribution of NeuAc in IgA1 O-glycans may play an important role in the pathogenesis of IgAN. To better understand biological functions of NeuAc in IgA1, we established protocols for enzymatic sialylation leading to α2,3- or α2,6-sialylation of IgA1 O-glycans. Sialylation of Gal-deficient asialo-IgA1 (Ale) myeloma protein by an ST6GalNAc enzyme generated sialylated IgA1 that mimics the Gal-deficient IgA1 glycoforms in patients with IgAN, characterized by α2,6-sialylated Gal-deficient GalNAc. In contrast, sialylation of the same myeloma protein by an α2,3-sialyltransferase yielded IgA1 typical for healthy controls, characterized by α2,3-sialylated Gal. The GalNAc-specific lectin from Helix aspersa (HAA) is used to measure levels of Gd-IgA1. We assessed HAA binding to IgA1 sialylated at Gal or GalNAc. As expected, α2,6-sialylation of IgA1 markedly decreased reactivity with HAA. Notably, α2,3-sialylation also decreased reactivity with HAA. Neuraminidase treatment recovered the original HAA reactivity in both instances. These results suggest that binding of a GalNAc-specific lectin is modulated by sialylation of GalNAc as well as Gal in the clustered IgA1 O-glycans. Thus, enzymatic sialylation offers a useful model to test the role of NeuAc in reactivities of the clustered O-glycans with lectins.

Cyclosporine A combined with medium/low dose prednisone in progressive IgA nephropathy

The aim of the present study was to evaluate the efficacy of cyclosporine A (CsA) combined with medium/low dose prednisone in the treatment of progressive immunoglobulin A nephropathy (IgAN). Ninety-six patients who satisfied the inclusion criteria were enrolled in a prospective controlled clinical study. They were assigned into two groups and initially given either 0.6-0.8 mg/kg/day prednisone (maximum 40 mg/day) plus 3 mg/kg/day CsA (CsA group), or 1 mg/kg/day prednisone (maximum 60 mg/day) alone (steroid group). During therapy, the dose of prednisone was reduced in both groups and the dose of CsA was gradually tailed off over the first 3 months and maintained at 2 mg/kg/day in the CsA group. Urinary protein excretion, serum biochemical indexes, clinical efficacy and side effects of CsA were assayed. A significant decline in mean 24-hour urinary protein excretion (p < 0.05) was observed 1 month after treatment in patients in the CsA group, which was observed 2 months after treatment in the steroid group. The decline in mean 24-hour urinary protein excretion in the CsA group was more significant than in the steroid group. Serum albumin level increased significantly in the CsA group 2 months after therapy (p < 0.05). Moreover, at the end of the course, a higher remission rate was observed in patients with Lee's Grade III IgAN after combined treatment with prednisone and CsA (p < 0.05). No significant difference in clinical efficacy was observed in patients with Lee's Grade IV and Grade V IgAN between the two groups (p > 0.05). CsA at a dose of 2-3 mg/kg/day in combination with medium/low dose prednisone was effective in inducing remission of IgAN, especially for patients with Lee's Grade III IgAN, and is a safe and effective choice for short-term treatment of patients with progressive IgAN.

The combined role of galactose-deficient IgA1 and streptococcal IgA-binding M Protein in inducing IL-6 and C3 secretion from human mesangial cells: implications for IgA nephropathy

IgA nephropathy (IgAN) is characterized by mesangial cell proliferation and extracellular matrix expansion associated with immune deposits consisting of galactose-deficient polymeric IgA1 and C3. We have previously shown that IgA-binding regions of streptococcal M proteins colocalize with IgA in mesangial immune deposits in patients with IgAN. In the present study, the IgA-binding M4 protein from group A Streptococcus was found to bind to galactose-deficient polymeric IgA1 with higher affinity than to other forms of IgA1, as shown by surface plasmon resonance and solid-phase immunoassay. The M4 protein was demonstrated to bind to mesangial cells not via the IgA-binding region but rather via the C-terminal region, as demonstrated by flow cytometry. IgA1 enhanced binding of M4 to mesangial cells, but not vice versa. Costimulation of human mesangial cells with M4 and galactose-deficient polymeric IgA1 resulted in a significant increase in IL-6 secretion compared with each stimulant alone. Galactose-deficient polymeric IgA1 alone, but not M4, induced C3 secretion from the cells, and costimulation enhanced this effect. Additionally, costimulation enhanced mesangial cell proliferation compared with each stimulant alone. These results indicate that IgA-binding M4 protein binds preferentially to galactose-deficient polymeric IgA1 and that these proteins together induce excessive proinflammatory responses and proliferation of human mesangial cells. Thus, tissue deposition of streptococcal IgA-binding M proteins may contribute to the pathogenesis of IgAN.

Lack of serologic evidence to link IgA nephropathy with celiac disease or immune reactivity to gluten

IgA nephropathy is the most common form of primary glomerulonephritis worldwide. Mucosal infections and food antigens, including wheat gluten, have been proposed as potential contributing environmental factors. Increased immune reactivity to gluten and/or association with celiac disease, an autoimmune disorder triggered by ingestion of gluten, have been reported in IgA nephropathy. However, studies are inconsistent about this association. We aimed to evaluate the proposed link between IgA nephropathy and celiac disease or immune reactivity to gluten by conducting a comprehensive analysis of associated serologic markers in cohorts of well-characterized patients and controls. Study participants included patients with biopsy-proven IgA nephropathy (n = 99), unaffected controls of similar age, gender, and race (n = 96), and patients with biopsy-proven celiac disease (n = 30). All serum specimens were tested for IgG and IgA antibodies to native gliadin and deamidated gliadin, as well as IgA antibody to transglutaminase 2 (TG2). Anti-TG2 antibody-positive nephropathy patients and unaffected controls were subsequently tested for IgA anti-endomysial antibody and genotyped for celiac disease-associated HLA-DQ2 and -DQ8 alleles. In comparison to unaffected controls, there was not a statistically significant increase in IgA or IgG antibody reactivity to gliadin in individuals with IgA nephropathy. In addition, the levels of celiac disease-specific serologic markers, i.e., antibodies to deamidated gliadin and TG2, did not differ between IgA nephropathy patients and unaffected controls. Results of the additional anti-endomysial antibody testing and HLA genotyping were corroborative. The data from this case-control study do not reveal any evidence to suggest a significant role for celiac disease or immune reactivity to gluten in IgA nephropathy.

Comparison of the Haas and the Oxford classifications for prediction of renal outcome in patients with IgA nephropathy

Pathologic features can provide valuable information for determining prognosis in IgA nephropathy (IgAN). However, it is uncertain whether the Oxford classification, a new classification of IgAN, can predict renal outcome better than previous ones. We conducted a retrospective cohort study in 500 patients with biopsy-proven IgAN between January 2002 and December 2010 to compare the ability of the Haas and the Oxford classifications to predict renal outcome. Primary outcome was a doubling of the baseline serum creatinine concentration (D-SCr). During a mean follow-up of 68 months, 52 (10.4%) and 35 (7.0%) developed D-SCr and end-stage renal disease, respectively. There were graded increases in the development of D-SCr in the higher Haas classes. In addition, the primary endpoint of D-SCr occurred more in patients with the Oxford M and T lesions than those without such lesions. In multivariate Cox regression analyses, the Haas class V (HR, 12.19; P=.002) and the Oxford T1 (hazard ratio [HR], 6.68; P<.001) and T2 (HR, 12.16; P<.001) lesions were independently associated with an increased risk of reaching D-SCr. Harrell's C index of each multivariate model with the Haas and the Oxford classification was 0.867 (P=.015) and 0.881 (P=.004), respectively. This was significantly higher than that of model with clinical factors only (C=0.819). However, there was no difference in C-statistics between the 2 models with the Haas and the Oxford classifications (P=.348). This study suggests that the Haas and the Oxford classifications are comparable in predicting progression of IgAN.

Rapamycin slows IgA nephropathy progression in the rat

BACKGROUND

IgA nephropathy (IgAN) is the most frequent glomerulonephritis worldwide. Different therapeutic approaches have been tested against IgAN. The present study was designed to explore the renoprotective potential of low-dose mammalian target of rapamycin (mTOR) inhibitor rapamycin in an IgAN rat model and the possible mechanism of action.

METHODS

After establishing an IgAN model, the rats were randomly divided into four groups: control, control with rapamycin treatment, IgAN model, and IgAN model with rapamycin treatment. Coomassie Brilliant Blue was utilized to measure 24-hour urinary protein levels. Hepatic and renal function was determined with an autoanalyzer. Proliferation was assayed via 5-bromo-2'-deoxyuridine incorporation. Real-time PCR and immunohistochemistry were utilized to detect the expression of α-SMA, collagen I, collagen III, TGF-β1 and platelet-derived growth factor. Western blotting and immunohistochemistry were performed to determine p-S6 protein levels.

RESULTS

Low-dose mTOR inhibitor rapamycin prevented an additional increase in proteinuria and protected kidney function in a model of IgAN. Rapamycin directly or indirectly interfered with multiple key pathways in the progression of IgAN to end-stage renal disease: (1) reduced the deposition of IgA and inhibited cell proliferation; (2) decreased the expression of fibrosis markers α-SMA and type III collagen, and (3) downregulated the expression of the profibrotic growth factors platelet-derived growth factor and TGF-β1. The expression of p-S6 was significantly elevated in IgAN rats.

CONCLUSIONS

The mTOR pathway was activated in IgAN rats and the early application of low-dose mTOR inhibitor rapamycin may slow the renal injury of IgAN in rats.

HLA polymorphism and susceptibility to end-stage renal disease in Cantonese patients awaiting kidney transplantation

Background

End-Stage Renal Disease (ESRD) is a worldwide public health problem. Currently, many genome-wide association studies have suggested a potential association between human leukocyte antigen (HLA) and ESRD by uncovering a causal relationship between HLA and glomerulonephritis. However, previous studies, which investigated the HLA polymorphism and its association with ESRD, were performed with the modest data sets and thus might be limited. On the other hand, few researches were conducted to tackle the Chinese population with ESRD. Therefore, this study aims to detect the susceptibilities of HLA polymorphism to ESRD within the Cantonese community, a representative southern population of China.

Methods

From the same region, 4541 ESRD patients who were waiting for kidney transplantation and 3744 healthy volunteer bone marrow donors (controls) were randomly chosen for this study. Polymerase chain reaction-sequence specific primer method was used to analyze the HLA polymorphisms (including HLA-A, HLA-B and HLA-DRB1 loci) in both ESRD patients and controls. The frequencies of alleles at these loci and haplotypes were compared between ESRD patients and controls.

Results

A total of 88 distinct HLA alleles and 1361 HLA A-B-DRB1 haplotypes were detected. The frequencies of five alleles, HLA-A*24, HLA-B*55, HLA-B*54, HLA-B*40(60), HLA-DRB1*04, and one haplotype (HLA-A*11-B*27-DRB1*04) in ESRD patients are significantly higher than those in the controls, respectively.

Conclusions

Five HLA alleles and one haplotype at the HLA-A, HLA-B and HLA-DRB1 loci appear to be associated with ESRD within the Cantonese population.

Association of C4d deposition with clinical outcomes in IgA nephropathy

BACKGROUND AND OBJECTIVES

Several studies have suggested that activation of the complement system is a contributing pathogenic mechanism in IgA nephropathy (IgAN). C4d staining is an inexpensive and easy-to-perform method for the analysis of renal biopsies. This study aimed to assess the clinical and prognostic implications of C4d staining in IgAN.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective cohort study included 283 patients with IgAN in 11 hospitals in Spain who underwent a renal biopsy between 1979 and 2010. The primary predictor was mesangial C4d staining. Secondary predictors included demographic, clinical, and laboratory characteristics, and Oxford pathologic classification criteria. The primary end point was the cumulative percentage of patients who developed ESRD, defined as onset of chronic dialysis or renal transplantation. C4d was analyzed by immunohistochemical staining using a polyclonal antibody. Kaplan-Meier and Cox proportional hazards analyses were performed to evaluate the effect of C4d staining on renal survival.

RESULTS

There were 109 patients (38.5%) and 174 patients (61.5%) who were classified as C4d positive and C4d negative, respectively. Renal survival at 20 years was 28% in C4d-positive patients versus 85% in C4d-negative patients (P<0.001). Independent risk factors associated with ESRD were as follows: proteinuria (hazard ratio [HR] per every 1 g/d increase. 1.16; 95% confidence interval [95% CI], 1.03 to 1.31; P=0.01), eGFR (HR per every 1 ml/min per 1.73 m(2) increase, 0.96; 95% CI, 0.94 to 0.97; P<0.001), T2 Oxford classification (tubular atrophy/interstitial fibrosis, >50%; HR, 4.42; 95% CI, 1.40 to 13.88; P=0.01), and C4d-positive staining (HR, 2.45; 95% CI, 1.30 to 4.64; P=0.01).

CONCLUSIONS

C4d-positive staining is an independent risk factor for the development of ESRD in IgAN. This finding is consistent with the possibility that complement activation is involved in the pathogenesis of this disease.

O-linked glycosylation determines the nephritogenic potential of IgA rheumatoid factor

Deficient glycosylation of O-linked glycans in the IgA1 hinge region is associated with IgA nephropathy in humans, but the pathogenic contribution of the underlying structural aberrations remains incompletely understood. We previously showed that mice implanted with cells secreting the class-switch variant 6-19 IgA anti-IgG2a rheumatoid factor, but not 46-42 IgA anti-IgG2a rheumatoid factor, develop glomerular lesions resembling IgA nephropathy. Because the levels of O-linked glycosylation in the hinge region and the structures of N-linked glycans in the CH1 domain differ in 6-19 IgA and 46-42 IgA, we determined the respective contributions of O- and N-linked glycans to the nephritogenic potential of the 6-19 IgA rheumatoid factor in mice. Wild-type 6-19 IgA secreted by implanted cells induced significant formation of glomerular lesions, whereas poorly O-glycosylated 6-19 IgA glycovariants or a 6-19 IgA hinge mutant lacking O-linked glycans did not. However, we observed no apparent heterogeneity in the structure of N-linked glycans attached to three different sites of the Fc regions of nephritogenic and non-nephritogenic 6-19 IgAs. Collectively, our data suggest a critical role of O-linked glycans attached to the hinge region in the development of IgA nephropathy-like GN induced by 6-19 IgA rheumatoid factor in mice.

Serum levels of galactose-deficient immunoglobulin (Ig) A1 and related immune complex are associated with disease activity of IgA nephropathy

Background

The primary abnormal manifestation in immunoglobulin A nephropathy (IgAN) is recurring bouts of hematuria with or without proteinuria. Although immunohistochemical analysis of renal biopsy tissue remains the gold standard not only for diagnosis but also for evaluating the activity of IgAN, new sensitive and reasonably specific noninvasive tests are emerging to guide therapeutic strategy applicable to all stages of IgAN. The present study examined serum levels of galactose-deficient IgA1 (Gd-IgA1) and its immune complex (IgA/IgG-IC) as noninvasive markers for the disease activity.

Methods

We enrolled 50 IgAN patients (male 40 %, median age 37 years) showing complete or partial clinical remission after steroid pulse therapy with tonsillectomy (TSP) whose clinical data and serum could be followed up for 3–5 years.

Results

Cross-sectional analysis revealed that the degree of hematuria and proteinuria were significantly associated with levels of Gd-IgA1 and levels of IgA/IgG-IC. Longitudinal analysis further showed that from the group of 44 patients with heavy hematuria before TSP, 31 patients showed complete disappearance of hematuria (group A), but the remaining patients did not (group B). Although the levels of Gd-IgA1 and IgA/IgG-IC in the two groups before TSP were similar, percentage decrease of Gd-IgA1 and IgA/IgG-IC levels in group A was significantly higher than in group B.

Conclusion

Disease activity of IgAN assessed by hematuria and proteinuria correlated with serum levels and changes of Gd-IgA1 and IgA/IgG-IC. These new noninvasive disease activity markers can be useful for future activity scoring system and guiding therapeutic approaches.

Periodontal disease bacteria specific to tonsil in IgA nephropathy patients predicts the remission by the treatment

Background

Immunoglobulin (Ig)A nephropathy (IgAN) is the most common form of primary glomerulonephritis in the world. Some bacteria were reported to be the candidate of the antigen or the pathogenesis of IgAN, but systematic analysis of bacterial flora in tonsil with IgAN has not been reported. Moreover, these bacteria specific to IgAN might be candidate for the indicator which can predict the remission of IgAN treated by the combination of tonsillectomy and steroid pulse.

Methods and Findings

We made a comprehensive analysis of tonsil flora in 68 IgAN patients and 28 control patients using Denaturing gradient gel electrophoresis methods. We also analyzed the relationship between several bacteria specific to the IgAN and the prognosis of the IgAN. Treponema sp. were identified in 24% IgAN patients, while in 7% control patients (P = 0.062). Haemophilus segnis were detected in 53% IgAN patients, while in 25% control patients (P = 0.012). Campylobacter rectus were identified in 49% IgAN patients, while in 14% control patients (P = 0.002). Multiple Cox proportional-hazards model revealed that Treponema sp. or Campylobactor rectus are significant for the remission of proteinuria (Hazard ratio 2.35, p = 0.019). There was significant difference in remission rates between IgAN patients with Treponema sp. and those without the bacterium (p = 0.046), and in remission rates between IgAN patients with Campylobacter rectus and those without the bacterium (p = 0.037) by Kaplan-Meier analysis. Those bacteria are well known to be related with the periodontal disease. Periodontal bacteria has known to cause immune reaction and many diseases, and also might cause IgA nephropathy.

Conclusion

This insight into IgAN might be useful for diagnosis of the IgAN patients and the decision of treatment of IgAN.

Combined immune thrombocytopenic purpura and immunoglobulin A nephropathy: a similar pathophysiologic process?

IgA nephropathy is one of the most common forms of glomerulopathies. It is an immune complex-mediated glomerulonephritis diagnosed by the presence of mesangial IgA deposits that are often associated with mesangial cell proliferation. The IgG, C3, IgM, or other immunoglobulin light chains may be co-existed with IgA. Its pathogenesis suggested that it is responsible for enhancing the production of proinflammatory cytokines, chemokines, and growth factors. Platelet-derived growth factor (PDGF) has also been implicated as a modulator of disease activity. Immune thrombocytopenic purpura (ITP) is a bleeding disorder caused by thrombocytopenia that is not associated with a systemic disease. Its pathogenesis suggested an autoimmune disease in which IgG is thought to damage megakaryocytes, which are the precursors of platelet cells. Several studies reported that PDGF levels were higher in normal subjects than in patients with ITP. Moreover, ITP is a disease related to the antibody. Thus, our aim is to examine whether a similar pathophysiological relationship exist between ITP and IgAN that may be mediated by PDGF and/or IgG.

IgA nephropathy with early kidney disease is associated with increased arterial stiffness and renin-angiotensin system activity

BACKGROUND

IgA nephropathy is associated with increased cardiovascular risk, though whether this is due to loss of kidney function or proteinuria is unclear.

METHODS

For this study 10 normotensive IgA nephropathy subjects with early kidney disease (41±5 yrs, glomerular filtration rate (GFR) 87±9 ml/min, proteinuria 720±300 mg/d) and 10 gender- and blood pressure-matched healthy controls (36±1 yrs, estimated GFR 102±5 ml/min, proteinuria 70±6 mg/d) were studied in high-salt balance. Blood pressure and arterial stiffness, expressed as pulse wave velocity and aortic augmentation index, were measured at baseline and in response to 60 min of angiotensin II (AngII) infusion.

RESULTS

At baseline, IgA nephropathy subjects demonstrated similar pulse wave velocity (8.6±0.7 vs. 8.0±0.4 m/s, p=0.5) but increased aortic augmentation index (12.6±3.1 vs. 1.8±4%, p=0.04) and a trend towards increased circulating renin-angiotensin system (RAS) components (plasma renin activity, 0.55±0.18 vs. 0.21±0.05 ng/l/s, p=0.08; angiotensin II, 25±5 vs. 16±1 ng/l, p=0.08) compared with controls. However, despite similar baseline blood pressure values (p=0.8), IgA nephropathy was associated with reduced arterial sensitivity to AngII challenge (Δmean arterial pressure: 19±4 vs. 29±1 mm Hg, p=0.05; Δpulse wave velocity: -0.06±0.6 vs. 1.5±0.3 m/s, p=0.07) compared with controls, even after multivariate analysis.

CONCLUSION

Even in the setting of early kidney disease, IgA nephropathy is associated with increased arterial stiffness and decreased angiotensin II responsiveness, a marker of increased RAS activity.

Progression of IgA nephropathy under current therapy regimen in a Chinese population

BACKGROUND AND OBJECTIVES

Current therapy for IgA nephropathy mainly includes renin-angiotensin system inhibitors and adding steroids for patients with persistent proteinuria. This study aimed to evaluate kidney disease progression and its risk factors in a Chinese cohort under current therapy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with IgA nephropathy followed up for at least 12 months from a prospective database were involved. Renal survival and the relationship between clinical parameters and composite kidney failure events (defined as end stage kidney failure or eGFR halving) were assessed.

RESULTS

Overall, 703 patients between 2003 and 2011 were enrolled in this study, with a mean follow-up time of 45 months. Mean eGFR was 84.0 ml/min per 1.73 m(2), systolic BP was 124 mmHg, and time-averaged mean arterial pressure was 90.0 mmHg. Median proteinuria at baseline was 1.60 g/d, and time-averaged proteinuria was 0.80 g/d. The mean rate of eGFR decline was -3.12 ml/min per 1.73 m(2) per year (95% confidence interval, -19.07 to 11.80), and annual end stage kidney failure rate was 2.3%. Multivariate Cox regression analyses revealed that baseline eGFR (hazard ratio, 0.76 per 10 ml/min per 1.73 m(2); 95% confidence interval, 0.66 to 0.91), proteinuria at 6 months (hazard ratio, 1.53 per g/d; 95% confidence interval, 1.27 to 1.84), and systolic BP control at 6 months (hazard ratio, 1.36 per 10 mmHg; 95% confidence interval, 1.05 to 1.77) were associated with composite kidney failure events. Baseline eGFR (regression coefficient, -0.06; 95% confidence interval, -0.07 to -0.04), time-averaged proteinuria (regression coefficient, -0.21; 95% confidence interval, -0.25 to -0.16), and time-averaged mean arterial pressure (regression coefficient, -0.15; 95% confidence interval, -0.21 to -0.09) were independent predictors of the slope of eGFR by linear regression.

CONCLUSION

Lower proteinuria and lower BP were associated with slower eGFR decline and lower risk of end stage kidney failure in patients currently being treated for IgA nephropathy.

Application of Oxford classification, and overexpression of transforming growth factor-β1 and immunoglobulins in immunoglobulin A nephropathy: correlation with World Health Organization classification of immunoglobulin A nephropathy in a Chinese patient cohort

Immunoglobulin A nephropathy (IgAN) is characterized by the qualitative abnormality of immunoglobulin A (IgA) in circulation and deposits of IgA in the renal mesangium. Transforming growth factor β1 (TGF-β1) plays a key role in fibrogenesis and the progression of renal damage. This study aimed to investigate the clinicopathologic data on IgAN in northeastern China and the presence of TGF-β1, total IgA, and secretory IgA in the glomeruli and sera, as well as changes in galactose-deficient IgA1 in the serum. We investigated the clinicopathologic data of 1050 cases of IgAN diagnosed in a single center over 13 years. We then assessed the concentrations of TGF-β1 and immunoglobulins in the serum of 100 patients with IgAN and 56 healthy control subjects by enzyme-linked immunosorbent assay, and investigated their presence in the glomeruli by immunofluorescence and reverse transcriptase-polymerase chain reaction. From our data, 76.17% of the IgAN cases belonged to classes I and II according to the World Health Organization classification, representing the early stage. Compared with other studies, we found significantly lower frequencies of segmental glomerulosclerosis (27.71%) but higher frequencies of endocapillary proliferation (50.67%), and a similar proportion of mesangial hypercellularity (68.48%) and tubular atrophy/interstitial fibrosis (moderate, 17.81%; severe, 1.52%) in the northeastern Chinese cohort. There was an increased presence of TGF-β1 and immunoglobulins in the serum and glomeruli of IgAN, which correlates with the progression of pathologic classification. The pathologic variables of the Oxford classification correlated significantly with the WHO classifications. TGF-β1 and immunoglobulins could be used as biomarkers of IgAN pathogenic mechanisms, acting as important adjuncts to the original Oxford Classification.

Continuation of immunosuppressive treatment may be necessary in IgA nephropathy patients with remission of proteinuria: Evaluation by repeat renal biopsy

The present study aimed to evaluate the effects of an individualized, low-dose multi-drug immunosuppressive regimen for the treatment of immunoglobulin A nephropathy (IgAN). A preliminary investigation of the course of IgAN following immunosuppressive treatment was conducted based on repeat renal biopsies. Clinical and pathological data of 17 patients with IgAN who received repeat renal biopsies were analyzed retrospectively. In addition to basic treatment, 16 patients regularly received an individualized low-dose immunosuppressive regimen according to their clinical manifestations and pathological patterns following the first biopsy. Clinical parameters, including 24-h urinary protein excretion and levels of serum albumin, uric acid and total cholesterol were collected. Glomerular deposits of IgA and C3, as well as the activity and chronicity indexes of renal lesions were evaluated by semi-quantitative methods. The 24-h urinary protein excretion of the patients decreased significantly from the first biopsy (2.53±2.17 g/day) to the repeated biopsy (0.26±0.55 g/day) (P<0.001). Deposits of IgA and C3 in the glomerulus were persistent, but were reduced in quantity at the second biopsy. Although active renal lesions were observed in the majority of patients, the activity index decreased significantly from 3.18±1.33 prior to therapy to 2.47±0.80 following therapy (P<0.05), while the chronicity index did not change significantly (2.59±2.00 versus 2.76±1.89, respectively). The individualized, low-dose multi-drug immunosuppressive regimen used in the present study significantly minimized proteinuria, stabilized renal function and alleviated histological lesions in patients with IgAN without causing overt adverse effects during the short-term follow-up. In addition to proteinuria, renal pathological changes should be appraised when considering the withdrawal of immunosuppressants from IgAN treatment.

Glomerular mannose-binding lectin deposition is a useful prognostic predictor in immunoglobulin A nephropathy

There is accumulating evidence to support a hypothesis of the activation of the lectin complement pathway in immunoglobulin A nephropathy (IgAN). The glomerular deposition of mannose-binding lectin (MBL), an initiator of the lectin pathway, has been identified, but its clinical significance has not been defined consistently. The aim of the present study was to investigate the value of glomerular MBL deposition as a useful histological biomarker in evaluating the severity and predicting the prognosis of IgAN. We included all consecutive patients with biopsy-proven primary IgAN from December 2008 to July 2010. Renal deposition of MBL was detected by immunofluorescence. The biopsy material from 131 patients (72 men) was thus used for MBL staining. The deposition of MBL was observed in a predominantly mesangial pattern in 45 patients (34·35%), which presented as global or segmental deposition. Compared with the patients without glomerular MBL deposition, those with glomerular MBL deposition had more severe proteinuria, decreased renal function, lower levels of serum albumin and a greater possibility of hypertension at the time of renal biopsy; they had more severe histological changes according to the Oxford classification (i.e. mesangial hypercellularity, segmental glomerulosclerosis, endocapillary hypercellularity and tubular atrophy/interstitial fibrosis), and their ratio presented an increase as the histopathological phenotypes segregated according to Lee's classification; furthermore, the follow-up data demonstrated that they had a lower renal remission rate. In conclusion, glomerular MBL deposition may predict a poor prognosis, and thus can be a new prognostic factor in IgA nephropathy.

A case of arteriovenous fistula after renal biopsy in an IgA nephropathy patient with macroscopic hematuria

Macroscopic hematuria is a common symptom in IgA nephropathy and is also one of the most frequent complications after a percutaneous renal biopsy. Here, we describe a patient with IgA nephropathy and recurrent macroscopic hematuria who developed an arteriovenous fistula after renal biopsy.

Clinical implication of crescentic lesions in immunoglobulin A nephropathy

BACKGROUND

To date, there has been much controversy about the role of crescentic lesion as a significant prognostic factor in immunoglobulin A nephropathy (IgAN). This study evaluated whether crescentic lesions predict adverse renal outcomes in IgAN patients.

METHODS

A total of 430 patients with biopsy-proven IgAN between January 2000 and December 2009 were included. Histological variables of the Oxford classification (Oxford-MEST) and the presence of crescents were assessed. The primary endpoint was a 50% decline in estimated glomerular filtration rate.

RESULTS

Of the 430 patients, 81 (18.8%) had a crescentic lesion. During a mean follow-up of 61 months, the primary outcome occurred in 19 (23.5%) patients with crescents compared with 40 (11.5%) patients without crescents (P=0.01). A Kaplan-Meier plot showed that the 10-year renal survival rate was significantly lower in patients with crescents than patients without crescents (P=0.01). However, in a multivariable Cox analysis which included clinical factors and the Oxford-MEST, crescents were not significantly associated with an increased risk of developing the primary outcome [hazard ratio: 0.71, 95% confidence interval (CI) 0.36-1.41, P=0.33]. Furthermore, adding crescents to the Oxford-MEST did not improve the discriminative ability for the prediction of renal outcomes [c-statistic: 0.86 (0.81-0.91) vs. 0.86 (0.80-0.91), P=0.21].

CONCLUSION

Crescentic lesion was not an independent prognostic factor, suggesting that crescents have limited value in predicting renal outcomes of IgAN.

Glomerular diseases: emerging tests and therapies for IgA nephropathy

The last decade has seen major progress in understanding the pathogenesis as well as the prognosis and treatment of patients with IgA nephropathy (IgAN). Although the diagnostic criterion of a kidney biopsy demonstrating dominant or codominant IgA deposition remains unchanged, much more is known about the genetic and environmental factors predisposing to disease development and progression. These advances have led to the identification of novel diagnostic and prognostic markers. Among the most promising clinically are genetic profiling, quantification of galactose-deficient IgA1 levels, and measurement of anti-IgA1 immunoglobulins. While targeted treatment for IgAN remains elusive, there is mounting evidence for therapeutic interventions that alter the disease course. The appropriate validation and integration of these discoveries into clinical care represent a major challenge, but one that holds tremendous promise for refining prognostication, guiding therapy, and improving the lives of patients with IgAN.

Increased risk of IgA nephropathy among individuals with celiac disease

GOAL

To determine the risk of future biopsy-verified IgA nephropathy (IgAN) among individuals with biopsy-verified celiac disease (CD).

BACKGROUND

Individuals with CD suffer increased risk of end-stage renal disease. An association between CD and IgAN has been suggested; however, results have been inconclusive and no previous study has considered the risk of IgAN in biopsy-verified CD.

STUDY

We performed a population-based prospective cohort study. We identified 27,160 individuals with CD (Marsh stage III) and no previous renal disease through small-intestinal biopsy reports obtained between July 1969 and February 2008 in all (n=28) Swedish pathology departments. Individuals with IgAN were identified by biopsy reports acquired at the 4 Swedish pathology departments specialized in renal pathology. Cox regression analysis was used to determine the risk of future IgAN among individuals with CD compared with 133,949 age-matched and sex-matched reference individuals.

RESULTS

Seven (0.026%) individuals with CD and 11 (0.008%) reference individuals developed IgAN. We found an increased risk of biopsy-verified IgAN among individuals with CD [hazard ratio, 3.03; 95% confidence interval, 1.22-7.56]. The risk increase remained statistically significant after adjustment for prior liver disease and country of birth.

CONCLUSIONS

Individuals with CD suffer a 3-fold increased risk of future IgAN. Our findings warrant awareness of renal function in individuals with CD.

Synergistic effect of mesangial cell-induced CXCL1 and TGF-β1 in promoting podocyte loss in IgA nephropathy

Podocyte loss has been reported to relate to disease severity and progression in IgA nephropathy (IgAN). However, the underlying mechanism for its role in IgAN remain unclear. Recent evidence has shown that IgA1 complexes from patients with IgAN could activate mesangial cells to induce soluble mediator excretion, and further injure podocytes through mesangial-podocytic cross-talk. In the present study, we explored the underlying mechanism of mesangial cell-induced podocyte loss in IgAN. We found that IgA1 complexes from IgAN patients significantly up-regulated the expression of CXCL1 and TGF-β1 in mesangial cells compared with healthy controls. Significantly higher urinary levels of CXCL1 and TGF-β1 were also observed in patients with IgAN compared to healthy controls. Moreover, IgAN patients with higher urinary CXCL1 and TGF-β1 presented with severe clinical and pathological manifestations, including higher 24-hour urine protein excretion, lower eGFR and higher cresentic glomeruli proportion. Further in vitro experiments showed that increased podocyte death and reduced podocyte adhesion were induced by mesangial cell conditional medium from IgAN (IgAN-HMCM), as well as rhCXCL1 together with rhTGF-β1. In addition, the over-expression of CXCR2, the receptor for CXCL1, by podocytes was induced by IgAN-HMCM and rhTGF-β1, but not by rhCXCL1. Furthermore, the effect of increased podocyte death and reduced podocyte adhesion induced by IgAN-HMCM and rhCXCL1 and rhTGF-β1 was rescued partially by a blocking antibody against CXCR2. Moreover, we observed the expression of CXCR2 in urine exfoliated podocytes in IgAN patients. Our present study implied that IgA1 complexes from IgAN patients could up-regulate the secretion of CXCL1 and TGF-β1 in mesangial cells. Additionally, the synergistic effect of CXCL1 and TGF-β1 further induced podocyte death and adhesion dysfunction in podocytes via CXCR2. This might be a potential mechanism for podocyte loss observed in IgAN.

Validation of the absolute renal risk of dialysis/death in adults with IgA nephropathy secondary to Henoch-Schönlein purpura: a monocentric cohort study

Background

We established earlier the absolute renal risk (ARR) of dialysis/death (D/D) in primary IgA nephropathy (IgAN) which permitted accurate prospective prediction of final prognosis. This ARR was based on the potential presence at initial diagnosis of three major, independent, and equipotent risk factors such as hypertension, quantitative proteinuria ≥ 1 g per day, and severe pathological lesions appreciated by our local classification scoring ≥ 8 (range 0–20). We studied the validity of this ARR concept in secondary IgAN to predict future outcome and focused on Henoch-Schönlein purpura (HSP) nephritis.

Methods

Our cohort of adults IgAN concerned 1064 patients with 101 secondary IgAN and was focused on 74 HSP (59 men) with a mean age of 38.6 at initial diagnosis and a mean follow-up of 11.8 years. Three major risk factors: hypertension, proteinuria ≥1 g/d, and severe pathological lesions appreciated by our global optical score ≥8 (GOS integrated all elementary histological lesions), were studied at biopsy-proven diagnosis and their presence defined the ARR scoring: 0 for none present, 3 for all present, 1 or 2 for the presence of any 1 or 2 risk factors. The primary end-point was composite with occurrence of dialysis or death before (D/D). We used classical statistics and both time-dependent Cox regression and Kaplan-Meier survival curve methods.

Results

The cumulative rate of D/D at 10 and 20 years post-onset was respectively 0 and 14% for ARR = 0 (23 patients); 10 and 23% for ARR = 1 (N = 19); 27 and 33% for ARR = 2 (N = 24); and 81 and 100% (before 20 y) in the 8 patients with ARR = 3 (P = 0.0007). Prediction at time of diagnosis (time zero) of 10y cumulative rate of D/D event was 0% for ARR = 0, 10% for ARR = 1, 33% for ARR = 2, and 100% by 8.5y for ARR = 3 (P = 0.0003) in this adequately treated cohort.

Conclusion

This study clearly validates the Absolute Renal Risk of Dialysis/Death concept in a new cohort of HSP-IgAN with utility to individual management and in future clinical trials.

Effect of treatment on urinary kidney injury molecule-1 in IgA nephropathy

Background

Kidney injury molecule-1 (KIM-1) is a biomarker useful for detecting early tubular damage and has been recently reported as a useful marker for evaluating kidney injury in IgA nephropathy (IgAN). We therefore investigated whether treatment decreases urinary KIM-1 excretion in IgAN.

Methods

We prospectively enrolled 37 patients with biopsy-proven IgAN. Urinary KIM-1 was assessed before and after treatment, which included low salt diet, blood pressure control, pharmacotherapy with angiotensin receptor blockers and/or angiotensin converting enzyme inhibitors, and immunosuppressive agents as necessary. The median treatment duration was 24 months.

Results

Urinary KIM-1/creatinine (Cr) was significantly decreased in patients with IgAN after treatment compared to baseline (P < 0.0001, 1.16 [0.51-1.83] vs 0.26 [0.12-0.65] ng/mg). There was a decrease in the amount of proteinuria after treatment, but it was not statistically significant (P = 0.052, 748.1 [405-1569.7] vs 569.2 [252.2-1114] g/d). Estimated glomerular filtration rate (eGFR) did not change with treatment (P = 0.599, 79.28 ± 30.56 vs 80.98 ± 32.37 ml/min/1.73 m²). Urinary KIM-1 was not correlated with proteinuria baseline or follow up (pre-: R = - 0.100, P = 0.577, post-: R = 0.001, P = 0.993). In patients with higher baseline urinary KIM-1, both urinary KIM-1 level and proteinuria were significantly decreased following treatment.

Conclusions

Treatment decreases urinary KIM-1/Cr in patients with IgAN. It also reduces proteinuria in patients with higher baseline urinary KIM-1. These results suggest a potential role for urinary KIM-1 as a biomarker for predicting treatment response in IgAN, however, further study is needed to verify this.

Mortality in patients with IgA nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is the most common glomerulonephritis globally. Few studies have investigated mortality in patients with IgAN compared with the age- and sex-adjusted general population.

STUDY DESIGN

Cohort study with record linkage between the Norwegian Kidney Biopsy Registry, Norwegian Cause of Death Registry, and Norwegian Renal Registry.

SETTING & PARTICIPANTS

633 patients diagnosed with IgAN in 1988-2004.

PREDICTOR

Estimated glomerular filtration rate (eGFR), age, and sex.

OUTCOMES

Deaths and causes of death before and after the onset of end-stage renal disease through 2008.

RESULTS

Mean follow-up was 11.8 (range, 0-20.8) years. During the observation period, the observed number of deaths was 80 and the expected number was 42.1, resulting in a standardized mortality ratio (SMR) of 1.9 (95% CI, 1.5-2.4). Risk stratification based on initial eGFR showed that SMR was 1.0 (95% CI, 0.6-1.6) if eGFR was ≥60 mL/min/1.73 m(2), 1.9 (95% CI, 1.3-2.8) if eGFR was 30-60 mL/min/1.73 m(2), and 3.6 (95% CI, 2.6-5.0) in patients with eGFR <30 mL/min/1.73 m(2). Renal replacement therapy (RRT) was initiated in 146 patients and 35 of the 80 deaths occurred after the start of RRT. The age- and sex-adjusted SMR was not increased significantly in the pre-RRT period (1.3; 95% CI, 1.0-1.7), but was increased after initiation of RRT (4.9; 95% CI, 3.5-7.0). The most common cause of death was cardiovascular disease, accounting for 45% of all deaths.

LIMITATIONS

Treatment during follow-up is not known.

CONCLUSIONS

Mortality in patients with IgAN was twice the expected rate, but not significantly increased before RRT. The risk of end-stage renal disease was substantially higher than risk of death.

Comparison of prednisolone and lamivudine combined therapy with prednisolone monotherapy on carriers of hepatitis B virus with IgA nephropathy: a prospective cohort study

OBJECTIVE

Chronic hepatitis B virus (HBV) carrier status has a critical impact on clinical management of patients with IgA nephropathy (IgAN) who are treated with corticosteroids, because corticosteroids may enhance HBV replication. This study compared corticosteroids and antivirals combined therapy with corticosteroids monotherapy on patients of IgAN who were also HBV carriers.

METHODS

This was a prospective, open-label cohort study on Chinese adults of HBV inactive carriers with concurrent IgAN (proteinuria ≥ 3.5 g/day). The patients were self-assigned to combined therapy group (prednisolone + lamivudine) or monotherapy group (prednisolone). Prednisolone 1 mg/kg/day for 2 months, tapered gradually, duration 12 months. Lamivudine (100 mg/day) was administrated 2 weeks before starting prednisolone and maintained 6 months after prednisolone withdrawal. All patients were followed up for 18 months. Outcome measures were rates of complete remission of proteinuria (<0.5 g/day), persistent massive proteinuria (≥ 3.5 g/day), HBV reactivation (detectable serum HBV-DNA or HBeAg), and significant alanine aminotransferase (ALT) elevation (>120 μ/L).

RESULTS

Except 3 patients were lost to follow-up, 46 patients (29 of combined therapy group, 17 of monotherapy group) were included in the analysis. There were no differences in baseline characteristics of clinical and histopathological features between two groups (p > 0.05). At the end of follow-up, 19/29 (65.52 %) in combined therapy group and 9/17 (52.94 %) in monotherapy group achieved complete remission of proteinuria (p = 0.399), while 0/29 (0 %) and 2/17 (11.76 %) remained persistent massive proteinuria (p = 0.059). HBV reactivation and significant ALT elevation was 3/17 (17.65 %) of patients in monotherapy group, more than 0/29 (0 %) of combined therapy group (p = 0.019). Three HBV recurrent patients using prednisolone monotherapy were all male and young, with relatively short term of HBV infection history, HBV reactivation and severe liver impairment developed after 3 months of corticosteroids treatment, and daily proteinuria increased remarkably after prednisolone withdrawal.

CONCLUSIONS

This study successfully treated with combined lamivudine and prednisolone in inactive HBV carriers with IgAN. We believe the combination of prednisolone and lamivudine was more efficacious than prednisolone alone in providing long-term viral suppression and liver enzyme normalization in inactive HBV carrier with IgAN.

Review of cases of IgA nephropathy

OBJECTIVES

A review of 26 years of British military renal pathology showed the commonest diagnosis to be immunoglobulin A (IgA) nephropathy affecting 115/346 (33%) of cases. It was possible to follow-up 50/115 military patients with this condition with the primary objective to determine whether initial observations enabled a confident prediction of prognosis. Additionally, unpublished observations have shown that the incidence of glomerulonephritis in an Indo-Asian British military racial group was fourfold that in the majority Caucasians although the nature of pathology (IgA vs non-IgA nephropathy) was not statistically significantly different. The present study secondarily sought to determine if prognosis of IgA nephropathy was different in this Indo-Asian military group. Finally, some conclusions concerning the traditionally restrictive policy towards applicants for military service with evidence of active nephritis were attempted.

METHODS

An archive of military renal patients covering 1985-2011 was reviewed and clinical details of cases of IgA nephropathy were extracted and analysed.

RESULTS

95 cases (80 Caucasian, 15 Indo-Asian) were reviewed. There was no racial difference (p=0.2) in initial median estimated glomerular filtration rate (eGFR, 86 vs 83 ml/min/1.73 m(2)). Altogether, initial median of mean arterial pressure (MAP) was 96 mm Hg (IQR=87-103) and median proteinuria was 485 mg/24 h (IQR=195-925). There was an inverse correlation between initial eGFR and both MAP (p=0.0008) and proteinuria (p=0.0006). In the 50 patients who were followed up, the change in eGFR with time (ΔeGFR) was calculated. 10 of the 44 Caucasians and 3/6 Indo-Asians showed significant changes in eGFR but population proportions were not significantly different (p=0.2). Altogether, 11/50 (22%) showed deteriorating eGFR despite therapeutic interventions, compared with those without deterioration; this was not due to different duration of observation (p=0.08), initial MAP (p=0.23) or initial proteinuria (p=0.07). There was no statistically significant correlation between ΔeGFR and initial MAP (p=0.6) or proteinuria (p=0.7).

CONCLUSIONS

The proportion of military cases of IgA nephropathy with deteriorating renal function (22%) was not different from that described in civilians, suggesting that military medical management (including operational restriction where necessary) was appropriate. Initial clinical observations, including racial group, did not permit confident prediction of prognosis thus mandating follow-up for all military cases. Relaxing current enlistment policy would be inadvisable given the inability to confidently predict prognosis in individual cases.

Correlation of serum levels of complement C4a desArg with pathologically estimated severity of glomerular lesions and mesangial hypercellularity scores in patients with IgA nephropathy

The aim of the present study was to explore serum biomarkers for the pathology of IgA nephropathy using serum proteomics. The subjects were 57 patients with IgA nephropathy who were divided into two groups (group 1, n=25; group 2, n=32) and 14 healthy controls. Serum protein profiles were analyzed using the ProteinChip surface-enhanced laser desorption ionization (SELDI) system. Associations between signal intensities of proteins and histological findings in patients with IgA nephropathy were studied in group 1. Serum levels of a candidate biomarker protein (complement component C4a desArg) for IgA nephropathy were determined by enzyme linked-immunosorbent assay (ELISA) in group 2 and the relationships of these levels with histological findings were evaluated. There were significant differences in 93 protein signals between patients in group 1 and controls. Among these signals, 3 proteins at 8592, 8757 and 8806 m/z were significantly correlated with the severity of glomerular lesions. The protein at 8592 m/z was identified as C4a desArg and the signal intensity of 8592 m/z was strongly correlated with serum C4a levels, including C4a desArg, determined by ELISA. In addition, the serum levels of C4a (mainly C4a desArg) were significantly higher in patients in group 2 compared to controls and were correlated with the severity of glomerular lesions and with mesangial hypercellularity scores. In conclusion, the serum levels of complement C4a desArg are significantly higher in patients with IgA nephropathy compared to healthy controls and are significantly correlated with the severity of glomerular lesions and mesangial hypercellularity scores. Thus, serum C4a desArg is a potential biomarker for the severity of histological findings in patients with IgA nephropathy.

Clinical features associated with a rapid decline in renal function among Japanese patients with type 2 diabetes mellitus: microscopic hematuria coexisting with diabetic retinopathy

Four patients who exhibited the greatest decline in the estimated glomerular filtration rate [12.3-23.5 ml/min/1.73 m(2)/year] among 320 patients with type 2 diabetes and were followed for a median of 6.8 years had several clinical features in common, including marked albuminuria, microhematuria, retinopathy and poor medication adherence.

Genetic evidence for involvement of adaptive immunity in the development of IgA nephropathy: MHC class II alleles are protective in a Caucasian population

There is evidence suggesting that IgA nephropathy (IgAN) is an immunological disease. The role of HLA class II DR beta 1 (DRB1) has previously not been well studied. The aim of our study was to investigate the association of HLA-DRB1 variants with IgAN in a Swedish Caucasian cohort. Our study consisted of 213 patients with biopsy proven IgAN, all of self-reported Caucasian ancestry. As a control cohort, 1569 healthy subjects from the same population in Sweden were included. HLA-DRB1 low-resolution genotyping was performed and odds ratios were calculated to assess the risk. In an allelic model the HLA-DRB1(*)03 and (*)10, demonstrated association for IgAN after correction for multiple comparison, with subsequent OR=0.54 (95% CI 0.37-0.78) and 3.44 (95% CI 1.67-7.07). When the influence of risk allelic groups was adjusted for protective allelic groups and vice versa, only a protective effect of HLA-DRB1(*)03 remained significant. In conclusion, the variants of HLA-DRB1 were associated with IgAN of which the HLA-DRB1(*)03 revealed a strong protective effect for IgAN. Our data replicates finding from other Caucasian populations and suggest that involvement of adaptive immunity may be of importance in the development of the disease.

Military nephrology: a review of cases 1985-2011

OBJECTIVE

Evidence of the prevalence of renal pathology in military populations is rare, probably as a result of a traditionally cautious military medical attitude that limits applicants with evidence of renal disease joining the Armed Forces and the continued service of military personnel who develop this later. The aim of this paper is to provide the first comprehensive review of renal diseases in a British military population.

METHODS

An archive of out-patient consultations, discharge summaries and renal biopsies between 1985 and 2011 was reviewed. Cases were classified according to diagnosis providing a frequency distribution over this 26-year period. Serum creatinine concentration and demographic data permitted retrospective calculation of estimated glomerular filtration rate (eGFR) at presentation and follow-up. Calculation of an annualised rate of deterioration of eGFR (ml/min/1.73 m2/y) was undertaken when there were at least four follow-up values. In those cases where there was a statistically significant negative correlation with time, the probability of deterioration of renal function according to diagnosis was calculated. Where numbers of patients with a given diagnosis were sufficient for statistical purposes, correlations were also attempted between initial eGFR and both initial mean arterial pressure (MAP) and initial proteinuria.

RESULTS

The most frequent condition was IgA nephropathy, present in 115/346 (33%) of cases. Follow-up data permitted analysis of change in eGFR in 50 of these and 11 (22%) deteriorated. In this condition, there were statistically significant negative correlations between initial eGFR and MAP (r = -0.35, p = 0.0008) and proteinuria (r = -0.4, p = 0.0006). Other conditions showing deterioration despite therapeutic interventions included adult polycystic kidney disease (15/2 2 = 68%) and membranous nephropathy (4/ 7 = 57%). Altogether, 8/13 (61%) conditions included cases where eGFR deteriorated and this was present in 40/161 (25%) individual cases.

CONCLUSIONS

Cases of renal disease are discovered de novo in serving military personnel and, despite interventions to maintain renal function, a significant proportion deteriorate supporting the traditionally restrictive policy concerning applicants with evidence of renal disease.