Validation using additional patient samples and a second array platform. CD4⁺ T cells were isolated from lymph nodes of 5 patients with HL, 4 patients with RLN, and 6 patients with FL. Three samples with aberrant diagnosis are labeled as follows: T-cell–rich B-cell lymphoma (B-NHL); lymphocyte-predominant Hodgkin lymphoma (LPHL); and Hodgkin lymphoma with premedical history of follicular lymphoma (HL/FL). cRNA was hybridized to Illumina Sentrix BeadChip Version 2. The RNA fingerprints of (A) TGFβ and (B) PD-1 were used to differentiate HL and RLN samples using hierarchic clustering. Hierarchic cluster analysis of FL and RLN samples based on the (C) TGFβ fingerprints and (D) PD-1 fingerprints.