G-banding analysis, fluorescence in situ hybridization (FISH) with the IGH (Cgamma and VH) and oncogene (c-MYC, BCL1, BCL2, and BCL6) probes, and long-distance polymerase chain reaction (LD-PCR) were performed on 6 patients with B-cell lymphoma, one with angioimmunoblastic T-cell lymphoma, and one with acute lymphoblastic leukemia (ALL) with B-cell phenotype.
Our study assesses the utility of an immunohistochemical panel of 5 TFH markers (CD10, BCL6, PD-1, CXCL13, and ICOS) for identification of TFH phenotype in angioimmunoblastic T-cell lymphoma (AITL) and PTCL not otherwise specified (NOS).
We measured the percentage positivity of the T<sub>FH</sub> markers, BCL6 and PD1, in AITL CD4-positive cells to be approximately 26% and 45%, with 12% coexpressing both markers.