title: The induction of apoptosis by methotrexate in activated lymphocytes as indicated by fluorescence hyperpolarization: a possible model for predicting methotrexate therapy for rheumatoid arthritis patients.
abstract: The objectives of this study were to test the in vitro response of healthy non-activated, activated, and rheumatoid arthritis (RA) lymphocytes to methotrexate (MTX), and design an in vitro model for predicting the efficiency of MTX treatment for RA patients. Considering the RA profile of clonal-expanded CD4(+) T cells, phytohemagglutinin-activated mononuclear cells taken from healthy donors were incubated with different concentrations of MTX. The MTX-immunosuppressive effect was tested by fluorescence intensity measurements, including PI assay and annexin V assay. For simple detection, we used the Individual Cell Scanner (IC-S), which enables the measurement of early events in individual cells. Healthy mononuclear cells (MNC), and MNC derived from RA patients, were tested by the IC-S while utilizing fluorescence polarization (FP) measurements of fluorescein diacetate (FDA) as an established marker of activation or suppression. In healthy activated MNC, we found that MTX, through its early incubation period, interferes with the activation signal obtained by PHA and exerts an apoptotic signal, which is noted by increases in the FP. Comparing our model to six long-standing RA patients and five newly-diagnosed patients revealed significant differences in the FP measurements, including fluorescence depolarization as an early established measurement of lymphocyte activation, and hyperpolarization as a measurement of an early immunosuppressive effect. We conclude that MTX, an effective therapy for RA patients, could easily be tested by fluorescence polarization measurements of FDA before (or during) clinical use in order to predict its efficiency on a specific RA patient. Moreover, the FP measurements can be used for the diagnosis, and making timing and dosage decisions.
authors.affiliation: The Biophysical Interdisciplinary Schottenstein Center for the Research and the Technology of the Cellome, Physics Department, Bar-Ilan University, Ramat-Gan 52900, Israel.
authors.forename: Shoshy
authors.initials: S
authors.lastname: Herman
authors.forename: Naomi
authors.initials: N
authors.lastname: Zurgil
authors.forename: Pnina
authors.initials: P
authors.lastname: Langevitz
authors.forename: Michael
authors.initials: M
authors.lastname: Ehrenfeld
authors.forename: Mordechai
authors.initials: M
authors.lastname: Deutsch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018501:Antirheumatic Agents / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects* / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000276:immunology / Q000503:physiopathology / Q000628:therapy*; D002478:Cells, Cultured; D004351:Drug Resistance / Q000502:physiology*; D005260:Female; D005452:Fluoresceins; D005454:Fluorescence Polarization; D016231:Fluorescence Polarization Immunoassay; D005470:Fluorometry / Q000379:methods; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects* / Q000276:immunology; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D008297:Male; D008727:Methotrexate / Q000494:pharmacology* / Q000627:therapeutic use; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D015203:Reproducibility of Results
chemical_list: D018501:Antirheumatic Agents; D005452:Fluoresceins; C018506:diacetylfluorescein; D008727:Methotrexate