Proteomic profile of retained proteins from hfr cartridge

Hemodiafiltration with on-line endogenous reinfusion (HFR) is a dialytic method, which combines the processes of diffusion, convection and adsorption. The performance of this system is linked to the optimal combination of the membrane permeability and cartridge resin bed. Lupus nephritis (LN) remains one of the most severe manifestations of systemic lupus erythematous (LES), associated with considerable morbidity and mortality. In this preliminary study, ESI-QTOF Mass Spectrometer was used for identification of protein ultrafiltrate (UF) and for the protein captured by resin bed, obtained from one dialysed patient with LN. Methods: Plasma and UF (pre and post cartdrige) samples of one patient with LN treated with HFR, were collected at 15 min and at 235 min of the dialytic session. The cartridge utilized during treatment, containing styrenic resin, was then opened and the proteins kept by the resin were eluted by incubation O/N with 60% ACN and 1%TFA. Samples were desalted and separated by SDS-page, interesting bands were picked and “in-gel” tryptic digested before ESI-QTOF mass spectrometer analysis. Results: ESI-QTOF results of the retained proteins allowed to identifies several biomarker of kidney injury in LN, such as Retinol binding protein 4, Neutrophil gelatinase-associated lipocain, and Cystatin-C (and also TRFE, A1AG1, PTGDS, TTHY). Moreover we identify several fragments of Immunoglobulin, which are implicated in the etiopathogenesis of LES. Conclusion: The results of this preliminary study demonstrate that styrenic resin retain several proteins implicated in the LN pathogenesis, in fact the corresponding bands in the UF precartdrige at 240 min disappear confirming the removal of this proteins from the cartridge.