Therapeutic depletion of myeloid lineage leukocytes in patients with generalized pustular psoriasis indicates a major role for neutrophils in the immunopathogenesis of psoriasis

Background Generalized pustular psoriasis (GPP) is a chronic autoimmune disease characterized by fever, erythema, and neutrophilic pustules over large areas of the skin. GPP does not respond well to pharmacologic intervention. Objective We sought to assess efficacy of selectively depleting the myeloid lineage leukocytes in patients with GPP. Methods Fifteen patients with persistent moderate to severe GPP despite conventional therapy were included. Eligible patients had more than 10% of their skin area covered by pustules. Treatment with oral etretinate, cyclosporine, methotrexate, prednisolone, and topical prednisolone/vitamin D3 was continued if had been initiated well in advance of study entry. Five sessions of adsorptive granulocyte and monocyte apheresis (GMA) with the Adacolumn (JIMRO Co Ltd, Takasaki, Japan) were administered (1 session/wk over 5 weeks) to selectively deplete Fcγ receptor and complement receptor bearing leukocytes. Efficacy was assessed by measuring the skin areas covered by pustules at baseline and 2 weeks after the last GMA session. Results One patient did not complete the first GMA session. Based on the GPP severity scores relative to entry, the overall scores improved (n = 14, P = .0027), and the area of erythroderma ( P = .0042), pustules ( P = .0031), and edema ( P = .0014) decreased. Likewise, Dermatology Life Quality Index improved ( P = .0016), reflecting better daily function and quality of life. Twelve patients were judged as responders (85.7%), and 10 patients maintained the clinical response for 10 weeks after the last GMA session without any change in medication. Limitations This study was unblinded and without a placebo arm. Conclusion GMA in this clinical setting was safe and effective, suggested a major role for granulocytes/monocytes in the immunopathogenesis of GPP.