Comparative analysis of the patterns of reactivity of IgM of patients and healthy blood donors with self-antigens.

IgM in the plasma of patients with WAIHA and healthy blood donors was interacted at 20 μg/mL with self-antigens, as described in Materials and Methods. For each individual, the densitometric profile of reactivity with a given tissue extract was divided into sections corresponding to peaks of reactivity. Respective peak areas were calculated in the case of each tissue extract. The data were subjected to PCA within a 40- to 56-dimension vector space, depending on the tissue extract, and fitted within a 2-dimensional linear subspace (factor 1/factor 2). PCA discriminated between repertoires of patients and controls in the case of all tissue extracts tested (.0001 < P < .001, depending on the tissue extract, by the Mann-Whitney U test). The figure shows the results of the comparative analyses in the case of kidney antigens (A) and RBC extracts (B). Percentages of variance accounted for by factor 1 and factor 2 are indicated on the abscissa and ordinate, respectively. Each symbol represents the reactivity of IgM of a single individual for the group of patients with WAIHA (●) and healthy blood donors (□).