Figure 2.

Flow cytometry data of 5 selected samples, indicating particles exceeding a side scattering cross-section of 6 nm². In panels A and B, data were fitted on the first 3 data points that exceed a count rate of 1.5 × 10² events·s⁻¹. Open symbols resemble data points that deviate >20% from the fit lines. (A) Count rate (events·s⁻¹) plotted vs the dilution factor, fitted with a linear function (lines; slope, −1; R², 0.94, 0.94, 0.99, 0.99, and 0.97 for donors 1 to 5, respectively). Open data points on the left are affected by swarm detection, while those on the right are attributed to background counts. Purple dashed lines visualize a count rate of 3.0 ×·10³ events·s⁻¹ (horizontal) and a dilution of 1.1 × 10³-fold (vertical). Measurements exceeding a dilution of 1.1 × 10²-fold and below a count rate of 1.1 × 10⁴ events·s⁻¹ are unaffected by swarm detection (black dotted line). (B) Total particle concentration plotted vs the count rate (events·s⁻¹), fitted with a horizontal line. Open symbols on the left are attributed to background events (<1.5 × 10² events·s⁻¹), while open data points on the right area are affected by swarm detection. The black dotted line represents a 1.1 × 10²-fold dilution and a count rate of 1.1 × 10⁴ events·s⁻¹ and distinguishes eligible measurements from those affected by swarm detection. (C) Median side scattering cross-section (nm²) plotted vs the dilution factor, fitted with a reciprocal function (+ offset) on data points <2 × 10⁴-fold diluted. Open symbols do not fulfill the defined criteria represented by the black lines in panels A and B. Measurements of donor 1 were performed in another time frame than the measurements of donors 2 to 5, thereby affecting the median side scattering cross-section. (D) Median fluorescence on the APC detector plotted vs the dilution factor. APC, allophycocyanin; MESF, molecules of equivalent soluble fluorophore.