Association of lymphopenia and eosinophilia with dimethylfumarate treatment efficacy and tolerability in psoriasis: a retrospective study.

Background: Dimethylfumarate (DMF) is an effective treatment for psoriasis, which may cause side effects in a considerable group of patients. Alterations in white blood cell (WBC) counts may predict treatment success and the occurrence of side effects.
Objectives: To analyze WBC counts with respect to efficacy and the prevalence of side effects during DMF therapy for psoriasis.Methods and materials: Psoriasis patients were treated with DMF. Retrospective data (WBC counts, treatment results, and side effects) were analyzed to assess correlations with respect to efficacy, tolerability, and leukocyte subsets.
Results: Of 95 patients treated with DMF, 60 patients (63.2%) had treatment success at week 16 and 77 patients (81.1%) experienced side effects. Absolute lymphocyte counts were more decreased in the treatment success group versus the treatment failure group: 1.1 (±0.7 SD) versus 0.6 (±0.6 SD); p<.05. Eosinophil counts were more increased in the group with side effects versus the group without side effects: 3.8 (±5.5 SD) versus 1.2 (±2.5 SD); p<.05. However, direct correlation studies showed no statistically significant correlations.Conclusions: Lymphopenia is associated with better clinical results of DMF treatment for psoriasis, whereas eosinophilia is associated with the occurrence of side effects.