Phenotype properties and status of corticosteroid resistance among patients with uncontrolled asthma

Control cannot be achieved in some asthmatics although optimal monitoring and treatment is administered. Glucocorticoid (GC) resistance is one of the reasons of poor asthma control. We aimed to investigate GC resistance by lymphocyte proliferation suppression test (LPST) in uncontrolled asthmatics.

After assessing asthma control level of 77 asthmatics their treatment was adjusted upon GINA guidelines. They were followed-up for three to six months and the patients who remained uncontrolled were accepted as uncontrolled patients. Steroid resistance test (SRT) was applied to them (7-14 days oral prednisolone) and the patients who were still uncontrolled and/or had a FEV1 increase <15% after SRT were assessed as the "case group" while the remaining composed the "control group". Optimal treatment was adjusted and at the end of a follow-up period LPST was performed to both groups.

Fourteen of the case (n=22) and four (n=8) of the control groups could be evaluated by LPST. Proliferated lymphocytes were observed to be significantly suppressed in all dexamethasone concentrations in the control group (p=0.001). However, in the case group LPST was positive only at 10(-6) and 10(-4) concentrations although statistically not significant (p=0.147). There was no significant relationship between clinically GC resistance and LPST positivity (p=0.405).

We determined that in vitro responses to the GCs were significantly declined in the uncontrolled asthma cases. An SRT alone does not seem to be very sensitive for evaluating GC sensitivity, LPST may be performed for demonstrating GC responsiveness in asthmatic patients in addition to SRT.