Impact of Extracorporeal Photopheresis on Blood Parameters of Atopic Dermatitis Patients

Background: Extracorporeal photopheresis (ECP) is a safe treatment modality with immunomodulatory effects. The latter may also explain efficacy of ECP in patients with atopic dermatitis (AD). Objective: We aimed to assess various blood parameters of AD patients who underwent ECP over a maximum 1-year treatment period. Methods: We performed a retrospective single-center chart review (clinical data, laboratory data) of adult patients with AD who had received for at least 3 ECP cycles, in part combined with other treatment modalities. Results: We studied 60 patients with AD (85% extrinsic type, 15% intrinsic type) who had median number of 14 (4-23) ECP cycles within a maximum 1-year treatment. When compared with baseline, leukocytes and lymphocytes remained significantly decreased after 3-, 6-, 9-, and 12-month ECP (P = 0.014 and P = 0.0012, respectively). A significant decline of eosinophils, as well as eosinophilic cationic protein levels, was observed after 3-, 6-, 9-, and 12-month ECPs (P = 0.011 and P = 0.0017, respectively). Total serum immunoglobulin E (IgE), as well as lactate dehydrogenase, were significantly decreased at 3-, 6-, 9-, and 12-month evaluation compared with baseline (P < 0.00001 and P = 0.00007, respectively). Patients with slight or marked improvement of AD after their ECP treatment period had significantly higher median baseline serum IgE levels than patients who did not respond to ECP (P = 0.0023). Conclusions: Several laboratory parameters, including eosinophils, eosinophilic cationic protein, total serum IgE, and lactate dehydrogenase, which declined under ECP, are well-known disease biomarkers for AD patients. With normalization of the abovementioned laboratory parameters, a clinical response to ECP treatment was observed in almost two thirds of patients, confirming that ECP may be an effective combination treatment modality for AD.