Temperature dependent protein removal by large pore membrane filtration

Area of Science:

• Biomedical Engineering
• Nephrology
• Immunology

Background:

• Plasma exchange (PLEX) is costly and has side effects, necessitating alternative treatments.
• Cryoglobulinemia involves cryoprecipitable proteins (CPP) and immune complexes (IC) that can be targeted.
• On-line plasma fractionation offers a potential alternative to traditional PLEX.

Purpose of the Study:

• To investigate the efficacy of cold membrane filtration (cryofiltration) for removing cryoglobulins.
• To evaluate the temperature-dependent effects on cryoglobulin removal using a specific membrane filter.
• To assess the potential of cryofiltration as a cost-effective and safer alternative to PLEX.

Main Methods:

• In vitro study using a large pore (3 microns) membrane filter with a low surface area (0.14 m2).
• Filtration experiments were conducted at different temperatures (4°C and 23°C).
• Plasma from cryoglobulinemic patients with high concentrations of CPP and IC was used.

Main Results:

• Cryoglobulin removal was highly temperature-dependent, with significantly higher removal rates at 4°C.
• High removal ratios for IC and CPP were achieved, with sieving coefficients (SC) of 0.05 for CPP at 4°C.
• Albumin removal remained high across temperatures (SC = 0.94 at 4°C, 0.95 at 23°C), indicating selectivity.

Conclusions:

• Cryofiltration is a selective and effective method for removing cryoglobulins from plasma.
• The technique is capable of processing clinically relevant volumes of plasma ( > 2L).
• This high-performance cryofiltration may significantly reduce the clinical reliance on plasma replacement products.