Figure 4.

Flow cytometry Vbeta analysis results and TCRB CDR3 repertoire landscape of two T-LGL leukemia patients. STAT3 mutation VAF are shown in the titles of the analyzed fractions. (A) Patient 8 had one major Vb3⁺ expansion (93%) in Vbeta analysis, corresponding to the major TCRB rearrangement in the sorted Vb3⁺ fraction. Vb3^neg fraction appeared polyclonal in the Vbeta analysis, but TCRB sequencing revealed a single major TCRB clone. The TCRB rearrangement observed in the Vb3^neg fraction was also present in the sorted Vb3⁺ sample, due to impurity of the sorting (86% of sorted cells were Vb3⁺). (B) Patient 48 presented with a monoclonal pattern in Vbeta analysis, but TCRB analysis of flow cytometry-sorted Vb21⁺ cells revealed two TCRB rearrangements with different amino acid sequences, recognized by the same monoclonal antibody, whereas the Vb21^neg fraction of the same patient showed only minor TCRB rearrangements. CDR3: complementarity determining region 3; TCRB: T-cell receptor beta chain; VAF: variant allele frequency.