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.
Study Type
OBSERVATIONAL
Enrollment
52
Mass spectrometry (LC/MS) of purified immunoglobulins
CHRU de Montpellier
Montpellier, France
CHU de Nimes
Nîmes, France
Glycopeptide signature of serum from children with Rheumatoid Purpura
Mass spectrometry to identify the glycopeptides present and their level
Time frame: Day 0
Repeatability of mass spectrometry in measuring glycopeptide signature
Mass spectrometry to identify the glycopeptides present and their level
Time frame: Day 0
Reproducibility of mass spectrometry in measuring glycopeptide signature
Mass spectrometry to identify the glycopeptides present and their level
Time frame: Day 0
Control of conservation of samples for measuring glycopeptide signature
Mass spectrometry to identify the glycopeptides present and their level
Time frame: Day 0
Glycopeptide signature of serum from all patients of the cohort
Mass spectrometry to identify the glycopeptides present and their level
Time frame: Day 0
Difference between a normally glycosylated IgA and an IgA with GalNac polymer in Rheumatoid Purpura patients with / without renal impairment versus controls
Mass spectrometry to identify the glycopeptides present and their level
Time frame: Day 0
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
Mass spectrometry of IgA
Time frame: Day 0
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
Mass spectrometry of IgA
Time frame: Day 0
Number of subjects with IgA glycosylation abnormalities in each group
Mass spectrometry of IgA
Time frame: Day 0
Percentage of subjects with IgA glycosylation abnormalities in each group
Mass spectrometry of IgA
Time frame: Day 0
Serum immunoglobulin levels in patients with acute Rheumatoid Purpura and in remission
Mass spectrometry of immunoglobulins IgA, IgM and IgG (g/L)
Time frame: Day 0
Quantification of blood cell lines in patients with acute Rheumatoid Purpura and in remission.
Blood cell lines, particularly Treg and Breg (number/mm3)
Time frame: Day 0
Serum cytokine levels in patients with acute Rheumatoid Purpura and in remission
pg/ml of TGF-β, IL-1, IL-6, TNF-α, IL-8, IL-10 and IL-17
Time frame: Day 0
Bacterial Translocation in patients with Rheumatoid Purpura
Plasma levels of 16S rDNA (copies/µl)
Time frame: Day 0
Plasma levels of LBP in patients with Rheumatoid Purpura
µg/ml
Time frame: Day 0
Plasma levels of CD14s in patients with Rheumatoid Purpura
µg/ml
Time frame: Day 0
Bacterial diversity in the gut microbiota in patients with Rheumatoid Purpura
Diversity Index
Time frame: Day 0
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