The proteasome to immunoproteasome (iPS) switch consists of β1, β2 and β5 subunit replacement by low molecular weight protein 2 (LMP2), LMP7 and multicatalytic endopeptidase-like complex-1 (MECL1) subunits, resulting in a more efficient peptide preparation for major histocompatibility complex 1 (MHC-I) presentation. It is activated by toll-like receptor (TLR) agonists and interferons and may also be influenced by genetic variation. In a previous study we found an iPS upregulation in peripheral cells of patients with immunoglobulin A nephropathy (IgAN). We aimed to investigate in 157 IgAN patients enrolled through the multinational Validation Study of the Oxford Classification of IgAN (VALIGA) study the relationships between iPS switch and estimated glomerular filtration rate (eGFR) modifications from renal biopsy to sampling. Patients had a previous long follow-up (6.4 years in median) that allowed an accurate calculation of their slope of renal function decline. We also evaluated the effects of the PSMB8/PSMB9 locus (rs9357155) associated with IgAN in genome-wide association studies and the expression of messenger RNAs (mRNAs) encoding for TLRs and CD46, a C3 convertase inhibitor, acting also on T-regulatory cell promotion, found to have reduced expression in progressive IgAN. We detected an upregulation of LMP7/β5 and LMP2/β1 switches. We observed no genetic effect of rs9357155. TLR4 and TLR2 mRNAs were found to be significantly associated with iPS switches, particularly TLR4 and LMP7/β5 (P < 0.0001). The LMP7/β5 switch was significantly associated with the rate of eGFR loss (P = 0.026), but not with eGFR at biopsy. Fast progressors (defined as the loss of eGFR >75th centile, i.e. -1.91 mL/min/1.73 m2/year) were characterized by significantly elevated LMP7/β5 mRNA (P = 0.04) and low CD46 mRNA expression (P < 0.01). A multivariate logistic regression model, categorizing patients by different levels of kidney disease progression, showed a high prediction value for the combination of high LMP7/β5 and low CD46 expression.
BACKGROUND: It is unknown whether renal pathology lesions in immunoglobulin A nephropathy (IgAN) correlate with renal outcomes over decades of follow-up. METHODS: In 1130 patients of the original Validation Study of the Oxford Classification for IgA Nephropathy (VALIGA) cohort, we studied the relationship between the MEST score (mesangial hypercellularity, M; endocapillary hypercellularity, E; segmental glomerulosclerosis, S; tubular atrophy/interstitial fibrosis, T), crescents (C) and other histological lesions with both a combined renal endpoint [50% estimated glomerular filtration rate (eGFR) loss or kidney failure] and the rate of eGFR decline over a follow-up period extending to 35 years [median 7 years (interquartile range 4.1-10.8)]. RESULTS: In this extended analysis, M1, S1 and T1-T2 lesions as well as the whole MEST score were independently related with the combined endpoint (P < 0.01), and there was no effect modification by age for these associations, suggesting that they may be valid in children and in adults as well. Only T lesions were associated with the rate of eGFR loss in the whole cohort, whereas C showed this association only in patients not treated with immunosuppression. In separate prognostic analyses, the whole set of pathology lesions provided a gain in discrimination power over the clinical variables alone, which was similar at 5 years (+2.0%) and for the whole follow-up (+1.8%). A similar benefit was observed for risk reclassification analyses (+2.7% and +2.4%). CONCLUSION: Long-term follow-up analyses of the VALIGA cohort showed that the independent relationship between kidney biopsy findings and the risk of progression towards kidney failure in IgAN remains unchanged across all age groups and decades after the renal biopsy.
- MeSH
- dítě MeSH
- dospělí MeSH
- hodnoty glomerulární filtrace MeSH
- IgA nefropatie klasifikace patologie MeSH
- kohortové studie MeSH
- ledviny patofyziologie MeSH
- lidé MeSH
- mladiství MeSH
- následné studie MeSH
- prognóza MeSH
- progrese nemoci MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- validační studie MeSH
BACKGROUND: Complement is thought to play a role in immunoglobulin A nephropathy (IgAN), though the activating mechanisms are unknown. This study focused on the gene expression of CD46 and CD55, two key molecules for regulating C3 convertase activity of lectin and alternative complement pathways at a cellular level. METHODS: The transcriptional expression in peripheral white blood cells (WBCs) of CD46 and CD55 was investigated in 157 patients enrolled by the Validation of the Oxford Classification of IgAN group, looking for correlations with clinical and pathology features and estimated glomerular filtration rate (eGFR) modifications from renal biopsy to sampling. Patients had a previous median follow-up of 6.4 (interquartile range 2.8-10.7) years and were divided into progressors and non-progressors according to the median value of their velocity of loss of renal function per year (-0.41 mL/min/1.73 m2/year). RESULTS: CD46 and CD55 messenger RNA (mRNA) expression in WBCs was not correlated with eGFR values or proteinuria at sampling. CD46 mRNA was significantly correlated with eGFR decline rate as a continuous outcome variable (P = 0.014). A significant difference was found in CD46 gene expression between progressors and non-progressors (P = 0.013). CD46 and CD55 mRNA levels were significantly correlated (P < 0.01), although no difference between progressors and non-progressors was found for CD55 mRNA values. The prediction of progression was increased when CD46 and CD55 mRNA expressions were added to clinical data at renal biopsy (eGFR, proteinuria and mean arterial blood pressure) and Oxford MEST-C (mesangial hypercellularity, endocapillary hypercellularity, segmental glomerulosclerosis, tubular atrophy/interstitial fibrosis, presence of any crescents) score. CONCLUSIONS: Patients with progressive IgAN showed lower expression of mRNA encoding for the complement inhibitory protein CD46, which may implicate a defective regulation of C3 convertase with uncontrolled complement activation.
- MeSH
- antigeny CD46 krev genetika MeSH
- biologické markery krev MeSH
- dospělí MeSH
- IgA nefropatie krev diagnóza genetika MeSH
- inhibitory komplementu krev MeSH
- lidé středního věku MeSH
- lidé MeSH
- messenger RNA krev genetika MeSH
- prognóza MeSH
- progrese nemoci MeSH
- regulace genové exprese MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: There is a need for early identification of children with immunoglobulin A nephropathy (IgAN) at risk of progression of kidney disease. METHODS: Data on 261 young patients [age <23 years; mean follow-up of 4.9 (range 2.5-8.1) years] enrolled in VALIGA, a study designed to validate the Oxford Classification of IgAN, were assessed. Renal biopsies were scored for the presence of mesangial hypercellularity (M1), endocapillary hypercellularity (E1), segmental glomerulosclerosis (S1), tubular atrophy/interstitial fibrosis (T1-2) (MEST score) and crescents (C1). Progression was assessed as end stage renal disease and/or a 50 % loss of estimated glomerular filtration rate (eGFR) (combined endpoint) as well as the rate of renal function decline (slope of eGFR). Cox regression and tree classification binary models were used and compared. RESULTS: In this cohort of 261 subjects aged <23 years, Cox analysis validated the MEST M, S and T scores for predicting survival to the combined endpoint but failed to prove that these scores had predictive value in the sub-group of 174 children aged <18 years. The regression tree classification indicated that patients with M1 were at risk of developing higher time-averaged proteinuria (p < 0.0001) and the combined endpoint (p < 0.001). An initial proteinuria of ≥0.4 g/day/1.73 m2and an eGFR of <90 ml/min/1.73 m2were determined to be risk factors in subjects with M0. Children aged <16 years with M0 and well-preserved eGFR (>90 ml/min/1.73 m2) at presentation had a significantly high probability of proteinuria remission during follow-up and a higher remission rate following treatment with corticosteroid and/or immunosuppressive therapy. CONCLUSION: This new statistical approach has identified clinical and histological risk factors associated with outcome in children and young adults with IgAN.
- MeSH
- analýza přežití MeSH
- biopsie MeSH
- chronické selhání ledvin epidemiologie patologie MeSH
- dítě MeSH
- hodnoty glomerulární filtrace MeSH
- hormony kůry nadledvin terapeutické užití MeSH
- IgA nefropatie farmakoterapie epidemiologie patologie MeSH
- imunosupresiva MeSH
- kohortové studie MeSH
- kojenec MeSH
- ledviny patologie MeSH
- lidé MeSH
- předškolní dítě MeSH
- progrese nemoci MeSH
- proteinurie epidemiologie patologie MeSH
- retrospektivní studie MeSH
- rizikové faktory MeSH
- sexuální faktory MeSH
- stanovení cílového parametru MeSH
- věkové faktory MeSH
- Check Tag
- dítě MeSH
- kojenec MeSH
- lidé MeSH
- mužské pohlaví MeSH
- předškolní dítě MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Evropa epidemiologie MeSH
