Fig. 2.

Total levels of IgG1 and IgA1 in individual patients.A, for three patients (P18, P51, and P52) levels of IgA1 (left) and IgG1 (right) are depicted as determined by direct Fab profiling LC-MS (FP-MS), illustrating high variability. In gray, the average concentration of all donors is plotted. B, comparison of total levels of IgG1 and IgA1 as measured by FP-MS and by shot-gun data-independent acquisition (DIA-) MS. For quantification by FP-MS, the sum of all unique Fab concentrations was taken. For shot-gun proteomics, quantification was based on unique peptides of the constant regions of either IgG1 or IgA1. Although the data for the FP-MS approach are limited to a subcohort of the data gathered for the DIA-NN approach, the results are very much in agreement with each other, indicating that IgA1 levels in nonsurvivors are on average relatively higher than in survivors, especially at the earliest timepoints. Diamonds outside the box and whiskers indicate outlier values.