PT  - JOURNAL ARTICLE
AU  - Gergely Toldi
AU  - Patrizia Batel
AU  - Sándor Baráth
AU  - Péter Szerémy
AU  - András Apjok
AU  - Kata Filkor
AU  - Sándor Szántó
AU  - Gabriella Szűcs
AU  - Szilvia Szamosi
AU  - Thomas Häupl
AU  - Andreas Grützkau
AU  - Zoltán Szekanecz
TI  - Peripheral Lymphocyte Multidrug Resistance Activity as a Predictive Tool of Biological Therapeutic Response in Rheumatoid Arthritis
AID  - 10.3899/jrheum.180793
DP  - 2019 Feb 01
TA  - The Journal of Rheumatology
PG  - jrheum.180793
4099  - http://www.jrheum.org/content/early/2019/02/25/jrheum.180793.short
4100  - http://www.jrheum.org/content/early/2019/02/25/jrheum.180793.full
AB  - Objective Multidrug resistance (MDR) transporters may be used as biomarkers to monitor disease progression in RA and as a predictive tool to establish responsiveness to biological therapy. In this multicenter clinical trial, we aimed to assess the predictive value of activity measurement of transporters MDR1, MD resistance protein (MRP)1, and breast cancer resistance protein (BCRP) for biological therapeutic response in RA before the initiation of biological therapy as well as 4 to 6 and 12 weeks after. Methods Peripheral blood samples were collected from 27 responders and 12 nonresponders to biological disease-modifying antirheumatic drugs (bDMARD) at the indicated timepoints as well as from 35 healthy controls. MDR activity factor (MAF) of MDR1, MRP1, and BCRP was measured in CD3+ and CD19+ cells using the Solvo MDQ Kit and cell surface staining by flow cytometry following peripheral blood mononuclear cells isolation. Results At the start of therapy, MAFC (composite MAF of MRP1 and MDR1) and MAFMDR values, and at 4 to 6 weeks of treatment, MAFC, MAFMRP, and MAFMDR values of CD3 cells were higher in nonresponders compared to responders. Receiver-operation characteristic curve analysis revealed that RA patients with MAFC values above 21.3 in CD3 cells at the start of bDMARD therapy are likely to be nonresponders. At 4 to 6 weeks of treatment, these also predict unfavorable response: MAFC values above 20.3, MAFMRP values above 6.0, and MAFMDR values above 13.9 in CD3 cells. Conclusion Our results indicate that the determination of MAFC values in CD3 cells of patients with RA may be of predictive value prior to the initiation of biological therapy, to establish whether the patient will demonstrate sufficient therapeutic response.