CAR T-cell detection. CAR T-cell detection in peripheral blood by PCR (VCN per milliliter) including the HD-Cy cohort (solid line; 14/17 patients detected for at least 1 time point measured) and LD-Cy (dotted line, 4 of 8 patients detected for at least 1 time point measured). Detection of CAR T cells following allo-HSCT was not standardized. However, 14 patients had samples taken after allo-HSCT with 4 patients demonstrating 1 positive sample each (median, 121 days after allo-HSCT; range, 44-195 days) without subsequent positive test.