The effect of methylprednisolone on proliferation of PBMCs obtained from steroid-sensitive and steroid-resistant rheumatoid arthritis patients

Objective: Glucocorticoids (GCs) are among the most frequently used drugs for the treatment of rheumatoid arthritis (RA). Unfortunately, up to 30% of patients with RA fail to respond to the treatment. We investigated the hypothesis that patients with RA who did not respond to GC treatment have steroid-resistant peripheral blood mononuclear cells (PBMCs). Methods: Forty-four patients with RA were enrolled in the study. PBMCs were isolated from blood samples. The effect of methylprednisolone (MP) on the proliferation of stimulated cells was measured. After taking the blood samples, 10 days of MP therapy (20 mg i.v.) was started, in order to classify the patients into either a GC-sensitive (RA/GCS) or a GC-resistant (RA/GCR) group. Results: A quarter of our patients did not show any improvement after short-term GC therapy and were assigned to the RA/GCR group. The inhibition of PBMC proliferation after NIP treatment was significantly lower in the RA/GCR as compared to the RA/GCS group. Conclusion: Based on the close relationship between clinically observed GC resistance and a diminished response of PBMCs to NIP treatment, we conclude that measurement of the steroid sensitivity of PBMCs may be a useful too] in predicting the therapeutic effect of GC in patients with RA.