TP53BP1 and in situ carcinoma: To further scrutinize the possible association of lymphocytic DNA double-strand break markers and MS, we herein analyzed nuclear γ-H2AX and 53BP1 foci in freshly isolated PBMCs from 25 patients with clinically isolated syndrome (CIS) or early RRMS and 27 healthy controls as well as in previously frozen PBMCs from 20 Patients with CIS or early RRMS and 10 healthy controls using fully automated immunofluorescence microscopy [14,15].