Analysis of Protein Removal Properties During Cryofiltration Apheresis Using the Evaflux‐5A Plasma Fractionator in a Patient With Hepatitis C Virus‐Associated Cryoglobulinemic Glomerulonephritis

Cryofiltration (CF) is a technique in which separated plasma is chilled before being subjected to a plasma fractionator (PF), leading to cryoglobulin precipitation or cryogel formation. In CF using the Evaflux-5A as the PF, there is no consensus on the necessity of albumin supplementation, and when or how often the PF column should be washed. We analyzed the sieving effects of various solutes (albumin, IgG, IgM, LDL, HCV-RNA, and cryoglobulin) depending on transmembrane pressure (TMPPF) during CF using the Evaflux-5A in a patient with hepatitis C virus-associated cryoglobulinemic glomerulonephritis. Five CF treatments were initially performed and a sixth one later, at disease recurrence. Quantitative detection of cryoglobulin and a marked rise in TMPPF to 400 mm Hg were observed only at the first and sixth treatment, and albumin losses during these treatments were very high, at 16.8 g, and 14.6 g, respectively, while those of others (from the second to fifth) were 6.7 g, 6.4 g, 5.9 g, and 7.0 g, respectively. The sieving coefficients (SCs) of both albumin and IgG were stable (0.8–1.0) at TMPPF < 200 mm Hg, but significantly decreased at TMPPF ≥ 200 mm Hg (P < 0.01). The SC of IgM tended to decrease at TMPPF ≥ 200 mm Hg, but not significantly, while that of LDL was zero regardless of the TMPPF. Albumin loss per treatment likely depends on degree of TMPPF rise, which is mainly affected by the patient's cryoglobulinemic status. In CF using Evaflux-5A, washing the PF column to keep TMPPF < 200 mm Hg during treatment may be a recommended for selective removal and albumin salvage.