Identification and Characterisation of IgA With Nephritogenic Potential in IgA Deposition Nephropathies (Rep-IgAN) (Rep-IgAN)

Identification and Characterisation of IgA With Nephritogenic Potential in IgA Deposition Nephropathies

IgA nephropathy (IgA Nephropathy), or Berger's disease, is the most common form of primary glomerulonephritis. It is a major cause of end-stage renal failure, often leading to dialysis or kidney transplantation. Recurrence is common after transplantation, compromising graft survival. Rheumatoid purpura (or IgA vasculitis) shares a common pathophysiology with IgA N, characterised by mesangial deposits containing IgA-rich immune complexes, but differs in its systemic involvement (skin, joints and digestive system).

In terms of pathophysiology, the histological signature of these conditions is based on the accumulation of abnormal IgA within the glomerulus. The mechanisms responsible for the nephrotoxicity of these IgA remain partially unclear. In patients with NIgA, several qualitative abnormalities of IgA have been well described, including a glycosylation defect that promotes IgA polymerisation and the emergence of anti-IgA autoantibodies. These immune complexes, found in glomerular deposits, induce a local inflammatory reaction. Experimental work conducted on mouse models developed at the CRIBL laboratory has shown that these abnormalities may be linked to a dysregulation of the immune response, leading to the production of IgA with physicochemical properties that promote their deposition in the kidney.

However, the location of nephritogenic IgA-secreting B cells remains poorly understood. Recent data suggest that this production could occur directly within the renal parenchyma, where activated B lymphocytes would locally produce pathogenic IgA. Following on from these observations, our study aims to characterise the immunoglobulin (Ig) repertoires in patients with IgA nephropathy, particularly those from renal lymphoid infiltrates, and to compare them with the repertoires of circulating B cells.

We hypothesise that certain sequence motifs within the variable domains of IgA, particularly the CDR3 regions, could constitute specific biomarkers of NIgA. Their detection in peripheral blood could enable non-invasive or predictive diagnosis, complementing the renal biopsy that is currently essential.

Study Overview

• Status: Recruiting
• Conditions: Kidney Disease
• Intervention / Treatment: Diagnostic test: Blood sample

• Study Type: Interventional
• Enrollment (Estimated): 150
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Virginie PASCAL, Physician; Phone Number: 05 55 08 71 11; Email: virginie.pascal@chu-limoges.fr

Study Locations

• France
  • Limoges, France, 87042
    • Recruiting
    • CHU Limoges
    • Contact: MOCAER; Phone Number: 0555058630; Email: cheikhououmar.seck@chu-limoges.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients of interest: all patients with IgA nephropathy or rheumatoid purpura aged 18 years or older whose treatment requires a renal biopsy
• Control patients: all patients with a renal disease other than IgA nephropathy or rheumatoid purpura whose treatment requires a renal biopsy

Exclusion Criteria:

• Patient opposition
• Persons under legal guardianship
• Persons whose psychological health prevents the collection of non-opposition

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Blood sample taken in a Tempus tube during a blood test performed at the same time as the kidney bio; Blood sample taken in a Tempus tube during a blood test performed at the same time as the kidney biopsy.	Diagnostic test: Blood sample; Blood sample taken in a Tempus tube during a blood test performed at the same time as the kidney biopsy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Variable domains of IgA	Describe the repertoire of variable domains of IgA with nephritogenic potential in patients with IgA nephropathies	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Direct in situ lymphoid infiltrate mapping within the kidney	Search circulating repertoires, based on a blood sample taken at the time of diagnosis and at the same time as the renal biopsy, for the presence of nephritogenic IgA previously identified using the renal Ig repertoire.	6 months

Collaborators and Investigators

• Sponsor: University Hospital, Limoges

Study record dates

Study Major Dates

• Study Start (Actual): June 25, 2025
• Primary Completion (Estimated): June 25, 2029
• Study Completion (Estimated): July 25, 2029

Study Registration Dates

• First Submitted: December 8, 2025
• First Submitted That Met QC Criteria: December 8, 2025
• First Posted (Actual): December 22, 2025

Study Record Updates

• Last Update Posted (Actual): December 22, 2025
• Last Update Submitted That Met QC Criteria: December 8, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Kidney disease; Immunoglobulin A; Berger's disease
• Additional Relevant MeSH Terms: Urogenital Diseases; Male Urogenital Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Autoimmune Diseases; Immune System Diseases; Glomerulonephritis; Nephritis; Kidney Diseases; Glomerulonephritis, IGA; Investigative Techniques; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative; Blood Specimen Collection
• Other Study ID Numbers: 87RI24_0003 - Rep-IgAN

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No