TNF and rheumatoid arthritis: In addition, to understand which cell subset was more susceptible to the anti-inflammatory PE-EVOO effect, cytofluorimetric analyses were performed on RA patients and HSs to evaluate the effect of PE-EVOO treatment on TNF-α production from T helper cells and monocytes, characterized by different cell surface markers (CD3+/CD4+ for T helper subset and CD3−/CD14+ for monocytes).