In vitro glucocorticoid sensitivity is associated with clinical glucocorticoid therapy outcome in rheumatoid arthritis
1 Department of Internal Medicine, Erasmus MC, University Medical Center, 's-Gravendijkwal 230, Rotterdam, 3015 CE, The Netherlands
2 Department of Rheumatology, Erasmus MC, University Medical Center, 's-Gravendijkwal 230, Rotterdam, 3015 CE, The Netherlands
3 Department of Rheumatology, Maasstad Hospital, Maasstadweg 21, Rotterdam, 3079DZ, The Netherlands
4 Department of Rheumatology, Sint Franciscus Gasthuis, Kleiweg 500, Rotterdam, 3045PM, The Netherlands
Arthritis Research & Therapy 2012, 14:R195 doi:10.1186/ar4029Published: 24 August 2012
Genetic and disease-related factors give rise to a wide spectrum of glucocorticoid (GC) sensitivity in rheumatoid arthritis (RA). In clinical practice, GC treatment is not adapted to these differences in GC sensitivity. In vitro assessment of GC sensitivity before the start of therapy could allow more individualized GC therapy. The aim of the study was to investigate the association between in vitro and in vivo GC sensitivity in RA.
Thirty-eight early and 37 established RA patients were prospectively studied. In vitro GC sensitivity was assessed with dexamethasone-induced effects on interleukin-2 (IL-2) and glucocorticoid-induced leucine zipper (GILZ) messenger RNA expression in peripheral blood mononuclear cells (PBMCs). A whole-cell dexamethasone-binding assay was used to measure number and affinity (1/KD) of glucocorticoid receptors (GRs).
In vivo GC sensitivity was determined by measuring the disease activity score (DAS) and health assessment questionnaire disability index (HAQ-DI) score before and after 2 weeks of standardized GC treatment.
GR number was positively correlated with improvement in DAS. IL-2-EC50 and GILZ-EC50 values both had weak near-significant correlations with clinical improvement in DAS in intramuscularly treated patients only. HAQ responders had lower GILZ-EC50 values and higher GR number and KD.
Baseline cellular in vitro glucocorticoid sensitivity is modestly associated with in vivo improvement in DAS and HAQ-DI score after GC bridging therapy in RA. Further studies are needed to evaluate whether in vitro GC sensitivity may support the development of tailor-made GC therapy in RA.