Implicit Flow Cytometric Diagnosis of Classic Hodgkin Lymphoma Using CD3+CD4+CD26- T-Cells.

Background: Flow cytometry is not routinely performed in clinical laboratories for the diagnosis of classic Hodgkin lymphoma (CHL).

Methods: Fourteen cases of CHL and 132 cases of the control group were studied by 10-color flow cytometry, with markers including CD3, CD4, CD7, CD8, and CD26, as well as calculated parameters such as the CD4:CD8 ratio, percent CD3⁺CD4⁺CD26^- T-cells of CD3⁺CD4⁺ T-cells, percent CD3⁺CD4⁺CD26^- T-cells of total events, CD7 coefficient of variation among CD3⁺CD4⁺CD26^- T-cells, and CD7 median fluorescence intensity of CD3⁺CD4⁺CD26^- T-cells relative to CD3⁺CD8⁺ T-cells.

Results: CHL cases showed a median percent CD3⁺CD4⁺CD26^- of CD3⁺CD4⁺ T-cells of 72.3% with range from 41.1% to 94.4%, median percent CD3⁺CD4⁺CD26^- T-cells of total events of 17.4% with range from 4.6% to 52.5%, CD7 coefficient of variation among CD3⁺CD4⁺CD26^- T-cells less than 100%, and CD7 median fluorescence intensity of CD3⁺CD4⁺CD26^- T-cells relative to CD3⁺CD8⁺ T-cells of 1.7 with range from 0.4 to 3.5. In the control group, every entity showed some degree of overlap with CHL in terms of these parameters. A "Hodgkin score" was thus constructed to enhance separation of CHL from other entities. A threshold Hodgkin score of 15.35 achieved a sensitivity of 78.6% and specificity of 96.2% in the diagnosis of CHL. Incorporating the Hodgkin score into a simple algorithm raises the specificity to 100%.

Conclusion: In this study, we used flow cytometry to demonstrate increased CD3⁺CD4⁺CD26^- T-cells in CHL, and derived a Hodgkin score for the diagnosis of CHL.