Fig 1.
Analysis of total Gd-IgA1, Gd-IgA1-specific IgG, and Gd-IgA1-specific IgA in serum samples from patients with IgAN (IgAN), chronic-kidney disease controls (CKD), and healthy controls (HC).
Box and Whisker plots of 10-90th percentiles with additional points shown as circles (IgAN), squares (CKD), and triangles (HC). Group statistics, including the mean and standard deviation (SD) as well as the result of the D’Agostino & Pearson normality tests, are shown in the tables. Log transformation of each measurement is plotted in the corresponding units, as outlined in Methods.
Fig 2.
Serum levels of Gd-IgA1-specific IgG autoantibodies correlate with serum levels of Gd-IgA1 only in patients with IgAN.
Plots of Gd-IgA1 versus Gd-IgA1-specific IgG (A-D) or Gd-IgA1-specific IgA (E-H) in serum samples of patients with IgAN (blue circles; A, E, D, H), CKD controls (red squares; B, F, D, H), or healthy controls (purple triangles; C, G, D, H). Overlays of A-C and E-G are presented in D and H, respectively. Correlation is observed only for Gd-IgA1-specific IgG in IgAN patients (blue circles, r = 0.491) which is depicted by the blue line in panels A and D. No such correlation was observed in either CKD (red) or healthy controls (purple). No correlation was observed for Gd-IgA1-specific IgA autoantibodies. Pearson correlation (r) values and significance (P) are shown for panels A-C and E-G.
Fig 3.
IgAN patients predominantly display increased Gd-IgA1-specific IgG.
Plot of the Gd-IgA1-specific IgG versus IgA autoantibodies for the healthy controls (red, H) and IgAN patients (blue, I). Cutoffs were set at 2-standard deviations from the mean values for the healthy controls (1.536 and 0.763 units for IgG and IgA, respectively). Percent occupancy in each quadrant is depicted where occupancy was observed.