More selective removal of myeloperoxidase-anti-neutrophil cytoplasmic antibody from the circulation of patients with vasculitides using a novel double-filtration plasmapheresis therapy.

Our aim was to investigate the removal of myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA) from the circulation of patients with vasculitides by double-filtration plasmapheresis (DFPP) using various primary separator and secondary separator combinations. Nineteen patients diagnosed with vasculitides positive for serum MPO-ANCA were enrolled and received 56 sessions of DFPP. One patient received three sessions of DFPP using MPS07 (the primary filter)/EC50W (the secondary filter), nine patients received 27 sessions of DFPP using MPS07/EC20W, and the other nine patients received 26 sessions of DFPP using EC50W/EC20W. The sieving coefficients (SC) of albumin, immunoglobulin (Ig)A, IgG and IgM were measured, as well as the reduction ratio in plasma protein concentrations and MPO-ANCA titer after a single session of DFPP. The MPS07 filter was well permeable for all the above-mentioned plasma proteins; the EC50W and EC20W filters were permeable for albumin and IgG, less for IgA and IgM. During DFPP using MPS07/EC50W, the reduction ratio of IgG was much lower than IgM and IgA (30.5 ± 9.0% vs. 89.7 ± 5.4% and 61.7 ± 14.8%). During DFPP using MPS07/EC20W, the decline in IgM, IgA, and IgG was 94.2 ± 3.1%, 96.2 ± 2.3%, and 64.7 ± 21.0%, respectively. During DFPP using EC50W/EC20W, the decline in IgM, IgA, and IgG was 2.8 ± 12.9%, 90.9 ± 4.4%, and 43.5 ± 13.8%, respectively. The percentage reduction in MPO-ANCA titer after a single session of DFPP using EC50W/EC20W was 34.6 ± 14.3%. DFPP using EC50W/EC20W filters may be more selective for the removal of pathogens such as IgG, with subsequently effective reduction of serum ANCA titer.