Herein, we report, by lymph node flow cytometry, that we promptly recognised and successfully treated an ultra early onset of PTLD after an HLA-matched sibling allo-HSCT (10/10) followed by a successful treatment with anti-CD20 antibody (rituximab) in a patient in progress disease for angioimmunoblastic T-cell Lymphoma (AITL). Here, MS4A1 is linked to angioimmunoblastic T-cell lymphoma.