Clinical trial NCT04655378: Validation of the IgA1 Detection Method With Gradient Glycosylation by Mass Spectrometry as a Potential Marker of Renal Involvement in Pediatric Rheumatoid Purpura
Official title: Recherche d'un Marqueur Pronostique de l'Atteinte rénale du Purpura Rhumatoïde de l'Enfant. Validation de la méthode de détection Des IgA1 Avec Gradient de la Glycosylation Par spectrométrie de Masse
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Rheumatoid Purpura
Pediatric ALL
Lead sponsor: Centre Hospitalier Universitaire de Nīmes
Sponsor class: OTHER
First posted: 2020-12-07
Enrollment: 52
Sex: ALL
Minimum age (years): 3
Maximum age (years): 16
Standard ages: CHILD
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: This is an ancillary study on the patient biobank of the FoxTreg study (NCT02317133). All these patients had given their consent for blood sampling and the conservation of biological samples within the Biological Resources Center (CRB) of Nîmes. A total of 97 patients were recruited, forming three groups:

* Group A (n = 30): patients with active Rheumatoid Purpura according to the criteria of EULAR / PRES / PRINTO 2010 \[Ozen et al. 2010\].
* Group B (n = 30): patients in remission of Rheumatoid Purpura according to the criteria of EULAR / PRES / PRINTO 2010 \[Ozen et al. 2010\].
* Group C (n = 37): age-matched control subjects free of infectious / inflammatory / autoimmune pathology.

For this "FoxIgA-2020" study, only sera collected from these patients not analyzed in the "FoxIgA" study will be used.

Thus 52 samples will be analyzed for the FoxIgA-2020 study:

* 10 sera from group A
* 14 sera from group B
* 28 sera of group C

Brief summary: In this ancillary study on the FoxTreg cohort, the study investigators will select variables to input and thus develop two models (Linear Discriminant Analysis and Decision Tree). The aim of this study is to validate the method in terms of repeatability, reproducibility, control of pre-analytical conditions and sample conservation, to complete the screening of IgA glycosylation in individuals of the FoxTreg cohort and to refine the glycopeptide signature to predict renal involvement.


Eligibility criteria: Inclusion Criteria:

Patient sera from biobank of the FoxTreg study (NCT02317133)

Primary outcomes:
measure: Glycopeptide signature of serum from children with Rheumatoid Purpura
timeFrame: Day 0
Secondary outcomes:
measure: Repeatability of mass spectrometry in measuring glycopeptide signature
timeFrame: Day 0
measure: Reproducibility of mass spectrometry in measuring glycopeptide signature
timeFrame: Day 0
measure: Control of conservation of samples for measuring glycopeptide signature
timeFrame: Day 0
measure: Glycopeptide signature of serum from all patients of the cohort
timeFrame: Day 0
measure: Difference between a normally glycosylated IgA and an IgA with GalNac polymer in Rheumatoid Purpura patients with / without renal impairment versus controls
timeFrame: Day 0
measure: Number of subjects with IgA glycosylation abnormalities in Rheumatoid Purpura patient population with renal impairment polymer in Rheumatoid Purpura patients with / without renal impairment versus controls
timeFrame: Day 0
measure: Percentage of subjects with IgA glycosylation abnormalities in Rheumatoid Purpura patient population with renal impairment polymer in Rheumatoid Purpura patients with / without renal impairment versus controls
timeFrame: Day 0
measure: Number of subjects with IgA glycosylation abnormalities in each group
timeFrame: Day 0
measure: Percentage of subjects with IgA glycosylation abnormalities in each group
timeFrame: Day 0
measure: Serum immunoglobulin levels in patients with acute Rheumatoid Purpura and in remission
timeFrame: Day 0
measure: Quantification of blood cell lines in patients with acute Rheumatoid Purpura and in remission.
timeFrame: Day 0
measure: Serum cytokine levels in patients with acute Rheumatoid Purpura and in remission
timeFrame: Day 0
measure: Bacterial Translocation in patients with Rheumatoid Purpura
timeFrame: Day 0
measure: Plasma levels of LBP in patients with Rheumatoid Purpura
timeFrame: Day 0
measure: Plasma levels of CD14s in patients with Rheumatoid Purpura
timeFrame: Day 0
measure: Bacterial diversity in the gut microbiota in patients with Rheumatoid Purpura
timeFrame: Day 0
Other outcomes:
Locations:
city: Montpellier
country: France
facility: CHRU de Montpellier
city: Nîmes
country: France
facility: CHU de Nimes
Study officials:
affiliation: CHU de Nimes
name: Tu Anh TRAN
role: PRINCIPAL_INVESTIGATOR
References:
citation: Ozen S, Pistorio A, Iusan SM, Bakkaloglu A, Herlin T, Brik R, Buoncompagni A, Lazar C, Bilge I, Uziel Y, Rigante D, Cantarini L, Hilario MO, Silva CA, Alegria M, Norambuena X, Belot A, Berkun Y, Estrella AI, Olivieri AN, Alpigiani MG, Rumba I, Sztajnbok F, Tambic-Bukovac L, Breda L, Al-Mayouf S, Mihaylova D, Chasnyk V, Sengler C, Klein-Gitelman M, Djeddi D, Nuno L, Pruunsild C, Brunner J, Kondi A, Pagava K, Pederzoli S, Martini A, Ruperto N; Paediatric Rheumatology International Trials Organisation (PRINTO). EULAR/PRINTO/PRES criteria for Henoch-Schonlein purpura, childhood polyarteritis nodosa, childhood Wegener granulomatosis and childhood Takayasu arteritis: Ankara 2008. Part II: Final classification criteria. Ann Rheum Dis. 2010 May;69(5):798-806. doi: 10.1136/ard.2009.116657.