Removal of albumin and immunoglobulins from canine cerebrospinal fluid using depletion kits: a feasibility study

BACKGROUND: Highly abundant proteins in biological fluids such as serum or cerebrospinal fluid (CSF) can hinder the detection of proteins in lower abundance, e.g., potential biomarkers. Commercial products are available for the depletion of albumin and immunoglobulins (Igs), although most of these kits have not been validated for dog samples. The present study therefore examines the use of different types of depletion kits for dog CSF. FINDINGS: Three kits, with different mechanisms for the depletion of albumin and Igs, were tested with dog CSF specimens. One product significantly decreased the amount of albumin; with all kits, IgG was less efficiently removed than albumin. Mass spectrometry of the fractions eluted from the depletion columns revealed considerable co-depletion of other CSF proteins. CONCLUSIONS: A commercially available depletion kit was identified which depletes albumin and (to a lower extent) immunoglobulins from dog CSF. However, the limited efficacy and the concomitant loss of other proteins from the sample should be taken into account when using this product.