 Clonal T-cell receptor gene rearrangements are detected in 75% of cases, and immunoglobin gene rearrangements are seen in 10% of cases, and these cases are believed to be due to expanded EBV-driven B-cell populations.Similarly, EBV-related sequences can be detected in most cases, usually in B-cells but occasionally in T-cells.Trisomy 3, trisomy 5, and +X are the most frequent chromosomal abnormalities found in AITL cases.