Examples of γ-H2AX and 53BP1 foci in PBMCs.

<p>(A) Multiple nuclear γ-H2AX foci (green) are clearly discernible in a lymphocyte of a healthy control. (B) Single 53BP1 focus (red) in a lymphocyte nucleus of a patient with RRMS. (C) Colocalization of nuclear γ-H2AX and 53BP1 foci in a lymphocyte of a healthy control. In the automated focus detection, the blue circle represents the DAPI stained nucleus. Small green and red circles highlight γ-H2AX and 53BP1 foci as automatically detected by the AKLIDES^® reading system. The system assigns distinct image (I) and object (O) numbers and indicates the number of foci detected in each fluorescence channel (FITC or APC). Note the difference in highlighted (n = 7) and counted (n = 6) γ-H2AX foci in (A), which is explained by a weaker focus fluorescence intensity not meeting the preset definitions for scoring of γ-H2AX foci.