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

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

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.

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%.

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.