Plasma markers for diagnosis and progression of IgA nephritis and recurrence in kidney transplantation

RESUMEN La nefritis por IgA (NIgA) es la glomerulonefritis más frecuente, y produce insuficiencia renal crónica hasta en el 40% de pacientes. Su gravedad es muy variable y puede recidivar en el trasplante. Se desconocen los mecanismos implicados en la patogénesis y variabilidad clínica. Nuevas herramientas y marcadores serológicos podrían permitir identificar los pacientes de mayor riesgo de forma no invasiva, desconociéndose exactamente la utilidad de dichos marcadores en el seguimiento de la NIgA y en la recurrencia. En esta tesis se aplicó la calculadora de progresión IgANPC por primera vez a una población europea, confirmando utilidad independiente del MEST-C. También observamos que valores de APRIL elevados en sangre postrasplante se asociaron con la reaparición de la NIgA en el injerto. Por último, valores más elevados de IgA1-Gd en el momento de la biopsia de riñones nativos se relacionaron con una peor evolución de la enfermedad en estos pacientes.SUMMARY IgA nephropathy (IgAN) is the most common glomerulonephritis, causing chronic kidney disease in up to 40% of patients. Its severity is highly variable and can recur in transplantation. The mechanisms involved in the pathogenesis and clinical variability are unknown. New tools and serological markers could make it possible to identify patients at higher risk in a non-invasive way, the usefulness of these markers in the follow-up of IgAN and in recurrence being exactly unknown. In this thesis, the IgANPC progression calculator was applied for the first time to a european population, confirming its utility independently of MEST-C. We also observed that elevated APRIL serum levels in post-transplant patients were associated with the recurrence of IgAN in the graft. Lastly, higher IgA1-Gd values at the time of the native kidney biopsy were related to a worse outcome of these patients

Measurement of galactosyl-deficient IgA1 by the monoclonal antibody KM55 contributes to predicting patients with IgA nephropathy with high risk of long-term progression

Backgroundandobjective:About25%ofpatientswithIgAnephropathy(IgAN)progresstostage5chronickidneydisease(CKD)afteryearsofevolution.Varioustoolshavebeendevelopedinrecentyearsdesignedtopredictwhichofthepatientswillhadpooreroutcomes.Thevalueofcirculatinggalactosyl-deficientIgA1(Gd-IgA1)hasbeenrelatedtoaworseevolutionofIgANinseveralstudies.TherearealsosomepublicationsthatrelatehigherAPRILvalueswithaworseevolution.Recently,anewmethodhasbeendevelopedthatallowsmeasuringthevalueofcirculatingGd-IgA1inasimplerwaythanthosepreviouslyavailable.TheobjectiveofthisstudyistoanalyzetheinfluenceofcirculatingGd-IgA1,measuredbythismethod,ontheprogressionofIgAN.Materialsandmethods:Forty-ninepatientswithadiagnosisofIgANdemonstratedbyrenalbiopsywereselectedinourcenter,withouthavingreceivedpriorimmunosuppressivetreat-ment,forwhomfrozenserumwasavailable.Themedianfollow-upwas4years.Gd-IgA1wasmeasuredbylectin-independentELISAwiththemonoclonalantibodyKM55(IgA1kitCat.No.30111694.IBLInt.,Hamburg,Germany).Likewise,APRILlevelswerealsomeasuredinthesepatients.Results:19(38.8%)patientsreachedstage5CKD.ThefourthquartileofcirculatingGd-IgA1wasrelatedtoahighercumulativeriskofreachingstage5CKDintheKaplan?Meieranalysis(riskatthe5thyear39.4%vs.24.3%,logrankp=0.019).TheGd-IgA1valuewasrelatedto anincreasedriskofCKDstage5(HR1.147,95%CI1.035?1.270,p=0.009),regardlessofglomerularfiltrationrate,proteinuria,thepercentageofsclerosedglomeruliandthevalueofsegmentalsclerosis.WedidnotfindsignificantdifferencesintheAPRILvalues.Conclusions:ThevalueofcirculatingGd-IgA1measuredbythemonoclonalantibodyKM55isrelatedtoaworseevolutionofpatientswithIgANindependentlyofothervariables,soitcouldbeincludedinthestudyofpatientstoimprovethepredictionoftheriskofdiseaseprogression

Development and validation of a nomogram to predict kidney survival at baseline in patients with C3 glomerulopathy

Background C3 glomerulopathy is a rare and heterogeneous complement-driven disease. It is often challenging to accurately predict in clinical practice the individual kidney prognosis at baseline. We herein sought to develop and validate a prognostic nomogram to predict long-term kidney survival. Methods We conducted a retrospective, multicenter observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. The dataset was randomly divided into a training group (n = 87) and a validation group (n = 28). The least absolute shrinkage and selection operator (LASSO) regression was used to screen the main predictors of kidney outcome and to build the nomogram. The accuracy of the nomogram was assessed by discrimination and risk calibration in the training and validation sets. Results The study group comprised 115 patients, of whom 46 (40%) reached kidney failure in a median follow-up of 49 months (range 24?112). No significant differences were observed in baseline estimated glomerular filtration rate (eGFR), proteinuria or total chronicity score of kidney biopsies, between patients in the training versus those in the validation set. The selected variables by LASSO were eGFR, proteinuria and total chronicity score. Based on a Cox model, a nomogram was developed for the prediction of kidney survival at 1, 2, 5 and 10 years from diagnosis. The C-index of the nomogram was 0.860 (95% confidence interval 0.834?0.887) and calibration plots showed optimal agreement between predicted and observed outcomes. Conclusions We constructed and validated a practical nomogram with good discrimination and calibration to predict the risk of kidney failure in C3 glomerulopathy patients at 1, 2, 5 and 10 years.ACKNOWLEDGEMENTS: Work on this study was supported by the Instituto de Salud Carlos III / Fondo Europeo de Desarrollo Regional (ISCIII/FEDER; grants PI16/01685 and PI19/1624) and Red de Investigación Renal (RD12/0021/0029; to M.P.) and the Autonomous Region of Madrid (S2017/BMD-3673; to M.P.). S.R.d.C. is supported by the Ministerio de Economia y Competitividad (grant PID2019-104912RB-I00) and the Autonomous Region of Madrid (grant S2017/BMD-3673). None of the funders had any role in the study design, data collection, analyses, reporting or decision to submit for publication

Mucosal Immune Defence Gene Polymorphisms as Relevant Players in the Pathogenesis of IgA Vasculitis?

ITGAM–ITGAX (rs11150612, rs11574637), VAV3 rs17019602, CARD9 rs4077515, DEFA (rs2738048, rs10086568), and HORMAD2 rs2412971 are mucosal immune defence polymorphisms, that have an impact on IgA production, described as risk loci for IgA nephropathy (IgAN). Since IgAN and Immunoglobulin-A vasculitis (IgAV) share molecular mechanisms, with the aberrant deposit of IgA1 being the main pathophysiologic feature of both entities, we assessed the potential influence of the seven abovementioned polymorphisms on IgAV pathogenesis. These seven variants were genotyped in 381 Caucasian IgAV patients and 997 matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of these seven polymorphisms when the whole cohort of IgAV patients and those with nephritis were compared to controls. Similar genotype and allele frequencies of all polymorphisms were disclosed when IgAV patients were stratified according to the age at disease onset or the presence/absence of gastrointestinal or renal manifestations. Likewise, no ITGAM–ITGAX and DEFA haplotype differences were observed when the whole cohort of IgAV patients, along with those with nephritis and controls, as well as IgAV patients, stratified according to the abovementioned clinical characteristics, were compared. Our results suggest that mucosal immune defence polymorphisms do not represent novel genetic risk factors for IgAV pathogenesis

IgA vasculitis: influence of CD40, BLK and BANK1 gene polymorphisms

CD40, BLK and BANK1 genes involved in the development and signaling of B-cells are identified as susceptibility loci for numerous inflammatory diseases. Accordingly, we assessed the potential influence of CD40, BLK and BANK1 on the pathogenesis of immunoglobulin-A vasculitis (IgAV), predominantly a B-lymphocyte inflammatory condition. Three genetic variants within CD40 (rs1883832, rs1535045, rs4813003) and BLK (rs2254546, rs2736340, rs2618476) as well as two BANK1 polymorphisms (rs10516487, rs3733197), previously associated with inflammatory diseases, were genotyped in 382 Caucasian patients with IgAV and 955 sex- and ethnically matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of CD40, BLK and BANK1 when IgAV patients and healthy controls were compared. Similar results were found when CD40, BLK and BANK1 genotypes or alleles frequencies were compared between patients with IgAV stratified according to the age at disease onset or to the presence/absence of gastrointestinal or renal manifestations. Moreover, no CD40, BLK and BANK1 haplotype differences were disclosed between patients with IgAV and healthy controls and between patients with IgAV stratified according to the clinical characteristics mentioned above. Our findings indicate that CD40, BLK and BANK1 do not contribute to the genetic background of IgAV.Funding: This study was supported by European Union FEDER funds and “Fondo de Investigaciones Sanitarias” (grants PI18/00042 and PI21/00042) from “Instituto de Salud Carlos III” (ISCIII, Health Ministry, Spain). D.P.-P. is a recipient of a Río Hortega program fellowship from the ISCIII, co-funded by the European Social Fund (ESF, “Investing in your future”) (grant number CM20/00006). F.G. is supported by funds of the RICORS Program from ISCIII, co-funded by the European Union (grant number RD21/0002/0025). V.P.-C. is supported by funds of PI18/00042. S.R.-M. is supported by funds of the RETICS Program (RD16/0012/0009) (ISCIII, co-funded by the European Regional Development Fund (ERDF)). O.G. is a staff member of Xunta de Galicia (Servizo Galego de Saude (SERGAS)) through a research-staff stabilization contract (ISCIII/SERGAS) and his work is funded by ISCIII and the European Union FEDER fund (grant numbers RD16/0012/0014 (RIER) and PI17/00409). He is a beneficiary of project funds from the Research Executive Agency (REA) of the European Union in the framework of MSCA-RISE Action of the H2020 Program, project 734899—Olive-Net. R.L.-M. is a recipient of a Miguel Servet type II program fellowship from the ISCIII, co-funded by ESF (“Investing in your future”) (grant number CPII21/00004). Acknowledgments: We are indebted to the patients and healthy controls for their essential collaboration on this study. We also thank the National DNA Bank Repository (Salamanca) for supplying part of the control samples

Role of the IL33 and IL1RL1 pathway in the pathogenesis of Immunoglobulin A vasculitis

Cytokines signalling pathway genes are crucial factors of the genetic network underlying the pathogenesis of Immunoglobulin-A vasculitis (IgAV), an inflammatory vascular condition. An influence of the interleukin (IL)33- IL1 receptor like (IL1RL)1 signalling pathway on the increased risk of several immune-mediated diseases has been described. Accordingly, we assessed whether the IL33-IL1RL1 pathway represents a novel genetic risk factor for IgAV. Three tag polymorphisms within IL33 (rs3939286, rs7025417 and rs7044343) and three within IL1RL1 (rs2310173, rs13015714 and rs2058660), that also were previously associated with several inflammatory diseases, were genotyped in 380 Caucasian IgAV patients and 845 matched healthy controls. No genotypes or alleles differences were observed between IgAV patients and controls when IL33 and IL1RL1 variants were analysed independently. Likewise, no statistically significant differences were found in IL33 or IL1RL1 genotype and allele frequencies when IgAV patients were stratified according to the age at disease onset or to the presence/absence of gastrointestinal (GI) or renal manifestations. Similar results were disclosed when IL33 and IL1RL1 haplotypes were compared between IgAV patients and controls and between IgAV patients stratified according to the clinical characteristics mentioned above. Our results suggest that the IL33-IL1RL1 signalling pathway does not contribute to the genetic network underlying IgAV.Acknowledgements: We are indebted to the patients and healthy controls for their essential collaboration to this study. We also thank the National DNA Bank Repository (Salamanca) for supplying part of the control samples. This study was supported by European Union FEDER funds and `Fondo de Investigaciones Sanitarias´ (Grant PI18/00042) from ‘Instituto de Salud Carlos III’ (ISCIII, Health Ministry, Spain). DP-P is a recipient of a Río Hortega programme fellowship from the ISCIII, co-funded by the European Social Fund (ESF, `Investing in your future´) (Grant Number CM20/00006). SR-M is supported by funds of the RETICS Program (RD16/0012/0009) (ISCIII, cofunded by the European Regional Development Fund (ERDF)). VP-C is supported by a pre-doctoral grant from IDIVAL (PREVAL 18/01). BA-M is a recipient of a `López Albo´ Post-Residency Programme funded by Servicio Cántabro de Salud. LL-G is supported by funds from IDIVAL (INNVAL20/06). OG is staff personnel of Xunta de Galicia (Servizo Galego de Saude (SERGAS)) through a research-staff stabilization contract (ISCIII/SERGAS) and his work is funded by ISCIII and the European Union FEDER fund (Grant Numbers RD16/0012/0014 (RIER) and PI17/00409). He is beneficiary of project funds from the Research Executive Agency (REA) of the European Union in the framework of MSCA-RISE Action of the H2020 Programme, project 734899—Olive-Net. RL-M is a recipient of a Miguel Servet type I programme fellowship from the ISCIII, co-funded by ESF (`Investing in your future´) (Grant Number CP16/00033)

IgA Vasculitis: Influence of CD40, BLK and BANK1 Gene Polymorphisms

CD40, BLK and BANK1 genes involved in the development and signaling of B-cells are identified as susceptibility loci for numerous inflammatory diseases. Accordingly, we assessed the potential influence of CD40, BLK and BANK1 on the pathogenesis of immunoglobulin-A vasculitis (IgAV), predominantly a B-lymphocyte inflammatory condition. Three genetic variants within CD40 (rs1883832, rs1535045, rs4813003) and BLK (rs2254546, rs2736340, rs2618476) as well as two BANK1 polymorphisms (rs10516487, rs3733197), previously associated with inflammatory diseases, were genotyped in 382 Caucasian patients with IgAV and 955 sex- and ethnically matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of CD40, BLK and BANK1 when IgAV patients and healthy controls were compared. Similar results were found when CD40, BLK and BANK1 genotypes or alleles frequencies were compared between patients with IgAV stratified according to the age at disease onset or to the presence/absence of gastrointestinal or renal manifestations. Moreover, no CD40, BLK and BANK1 haplotype differences were disclosed between patients with IgAV and healthy controls and between patients with IgAV stratified according to the clinical characteristics mentioned above. Our findings indicate that CD40, BLK and BANK1 do not contribute to the genetic background of IgAV

Henoch-Schönlein purpura in northern Spain: clinical spectrum of the disease in 417 patients from a single center

The severity of clinical features and the outcomes in previous series of patients reported with Henoch-Schönlein purpura (HSP) vary greatly, probably due to selection bias. To establish the actual clinical spectrum of HSP in all age groups using an unselected and wide series of patients diagnosed at a single center, we performed a retrospective review of 417 patients classified as having HSP according to the criteria proposed by Michel et al. Of 417 patients, 240 were male and 177 female, with a median age at the time of disease diagnosis of 7.5 years (interquartile range [IQR], 5.3-20.1 yr). Three-quarters of the patients were children or young people aged 20 years or younger (n = 315), and one-quarter were adults (n = 102). The most frequent precipitating events were a previous infection (38%), usually an upper respiratory tract infection, and/or drug intake (18.5%) shortly before the onset of the vasculitis. At disease onset the most common manifestations were skin lesions (55.9%), nephropathy (24%), gastrointestinal involvement (13.7%), joint symptoms (9.1%), and fever (6.2%). Cutaneous involvement occurring in all patients, mainly purpuric skin lesion, was the most common manifestation when the vasculitis was fully established, followed by gastrointestinal (64.5%), joint (63.1%), and renal involvement (41.2%). The main laboratory findings were leukocytosis (36.7%), anemia (8.9%), and increased serum IgA levels (31.7%). The most frequent therapies used were corticosteroids (35%), nonsteroidal antiinflammatory drugs (14%), and cytotoxic agents (5%). After a median follow-up of 12 months (IQR, 2-38 mo), complete recovery was observed in most cases (n = 346; 83.2%), while persistent, usually mild, nephropathy was observed in only 32 (7.7%) cases. Relapses were observed in almost a third of patients (n = 133; 31.9%).In conclusion, although HSP is a typical vasculitis affecting children and young people, it is not uncommon in adults. The prognosis is favorable in most cases, depending largely on renal involvement

Development and validation of a nomogram to predict kidney survival at baseline in patients with C3 glomerulopathy

10 p.-4 fig.-2 tab. 1 graph. abst.Background: C3 glomerulopathy is a rare and heterogeneous complement-driven disease. It is often challenging to accurately predict in clinical practice the individual kidney prognosis at baseline. We herein sought to develop and validate a prognostic nomogram to predict long-term kidney survival.Methods: We conducted a retrospective, multicenter observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. The dataset was randomly divided into a training group (n = 87) and a validation group (n = 28). The least absolute shrinkage and selection operator (LASSO) regression was used to screen the main predictors of kidney outcome and to build the nomogram. The accuracy of the nomogram was assessed by discrimination and risk calibration in the training and validation sets.Results: The study group comprised 115 patients, of whom 46 (40%) reached kidney failure in a median follow-up of 49 months (range 24–112). No significant differences were observed in baseline estimated glomerular filtration rate (eGFR), proteinuria or total chronicity score of kidney biopsies, between patients in the training versus those in the validation set. The selected variables by LASSO were eGFR, proteinuria and total chronicity score. Based on a Cox model, a nomogram was developed for the prediction of kidney survival at 1, 2, 5 and 10 years from diagnosis. The C-index of the nomogram was 0.860 (95% confidence interval 0.834–0.887) and calibration plots showed optimal agreement between predicted and observed outcomes.Conclusions: We constructed and validated a practical nomogram with good discrimination and calibration to predict the risk of kidney failure in C3 glomerulopathy patients at 1, 2, 5 and 10 years.Work on this study was supported by the Instituto de Salud Carlos III / Fondo Europeo de Desarrollo Regional (ISCIII/FEDER; grants PI16/01685 and PI19/1624) and Red de Investigación Renal (RD12/0021/0029; to M.P.) and the Autonomous Region of Madrid (S2017/BMD-3673; to M.P.). S.R.d.C. is supported by the Ministerio de Economia y Competitividad (grant PID2019-104912RB-I00) and the Autonomous Region of Madrid (grant S2017/BMD-3673).Peer reviewe

Longitudinal change in proteinuria and kidney outcomes in C3 glomerulopathy

11 p.-4 fig.-4 tab.Introduction: The association between a change in proteinuria over time and its impact in kidney prognosis has not been analyzed in C3 glomerulopathy. This study aims to investigate the association between the longitudinal change in proteinuria and the risk of kidney failure.Methods: Retrospective, multicenter observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases (GLOSEN). Patients diagnosed with C3 glomerulopathy between 1995 and 2020 were enrolled. A joint modeling of linear mixed-effects models was applied to assess the underlying trajectory of a repeatedly measured proteinuria, and a Cox model to evaluate the association of this trajectory with the risk of kidney failure.Results: The study group consisted of 85 patients, 70 C3 glomerulonephritis and 15 dense deposit disease, with a median age of 26 years (range 13-41). During a median follow-up of 42 months, 25 patients reached kidney failure. The longitudinal change in proteinuria showed a strong association with the risk of this outcome, with a doubling of proteinuria levels resulting in a 2.5-fold increase of the risk. A second model showed that a ≥ 50% proteinuria reduction over time was significantly associated with a lower risk of kidney failure (HR: 0.79; 95% CI : 0.56-0.97; p < 0.001). This association was also found when the ≥50% proteinuria reduction was observed within the first 6 and 12 months of follow-up.Conclusion: The longitudinal change in proteinuria is strongly associated with the risk of kidney failure. The change in proteinuria over time can provide clinicians a dynamic prediction of kidney outcomes.This study was supported by the Instituto de Salud Carlos III/Fondo Europeo de Desarrollo Regional (ISCIII/FEDER) grant PI16/01685 and PI19/1624, and Red de Investigación Renal (RedInRen) (RD12/0021/0029) (to M.P.), the Autonomous Region of Madrid (S2017/BMD-3673) (to M.P.); E.G.d.J. was supported by the Spanish ‘Ministerio de Ciencia, Innovación y Universidades’ (RYC-2013-13395 and RTI2018-095955-B-100); S.R.d.C. was supported by Ministerio de Economía y Competitividad/FEDER grant SAF2015-66287R and Autonomous Region of Madrid grant S2017/BMD3673.Peer reviewe