P1344: METHODOLOGY OF AN INTERNATIONAL MULTI-CENTER RETROSPECTIVE REVIEW OF TRANSPLANT-ASSOCIATED THROMBOTIC MICROANGIOPATHY (TA-TMA) BY THE TA-TMA WORKING GROUP. (23rd June 2022) - Ho, V.; Duarte, R. F.; Boelens, J.-J.; Cairo, M. S.; Champlin, R. E.; Giralt, S.; Hamadani, M.; Higham, C. S.; Jerkins, J. H.; Laurence, J.; Mayer, S.; Nakamura, R.; et al.