P1256: A NOVEL DROP-OFF DIGITAL PCR ASSAY FOR CXCR4 MUTATION SCREENING IN IGM GAMMOPATHIES: FIRST DATA FROM THE FONDAZIONE ITALIANA LINFOMI BIO-WM STUDY. (23rd June 2022) - Drandi, D.; Ferrante, M.; Zibellini, S.; Marcheselli, L.; Cappello, E.; Borriero, M.; Ragaini, S.; Dogliotti, I.; Varraso, C.; Cavallo, F.; Ferrari, A.; Merli, M.; et al.