Figure 1.

Peripheral blood B cell subset composition assessed with multicolor flow cytometry. Five erythema migrans patients (black circles, average age of group: 57, 60% female), and 9 controls (healthy: empty circles; tick bite: gray filled rhombi, average age of group: 60, 22% female) are shown. Two-tailed unpaired t-test showed no difference in age between both groups. Doublenegative B cell (A), memory B cell (B), naive B cell (C), non-switched memory B cell (D), plasmablast (E), IgG+ memory B cell (F), IgM+ memory B cell (G), activated naive B cell (H) and autoreactive B cell (I) subpopulations were gated as described in Supplementary Figure 1. For color compensation, cells from one healthy donor (“Comp ctrl”) were combined with color compensation beads, stained and measured individually with each antibody. This donor sample was also analyzed with the antibody cocktail (multicolour control sample represented in this figure). “Comp ctrl”: Healthy donor sample used for compensation control and to assess reproducibility between the three experiments (each dot represents one experiment). “Healthy”: healthy individuals sampled at a single timepoint. “Tick bite” and “Acute”: Individuals with a recent tick bite or acute Borreliosis respectively sampled 3 times (T0: ~diagnosis, T1: 1 week after T0, T2: 4 weeks after T0) over 1 month. An unpaired two tailed t- test with 95% CI was used to compare single timepoints of the two groups: T0 for the acute patients (= closest to diagnosis and beginning of treatment); T2 for tick bite donors (= closest to healthy status quo ante and farthest away from the tick bite). For this analysis “Comp Ctrl,” “Healthy,” and “Tick bite” donors were grouped into a single “Control” group (for more information please consult Supplementary Figure 2).