A novel bioassay to predict the clinical response to cryofiltration treatment. A preliminary report

Phagocytosis by normal human mononuclear monocytes grown in vitro was examined after incubation with known concentrations of aggregated human gamma-globulin (AHG) and in plasma obtained from patients suffering from immunologic diseases. When the phagocytes were pretreated with AHG, an inverse relationship between amounts of AHG and phagocytosis of radiolabeled Candida albicans was found. Inhibition of phagocytosis by patient plasma was independent of other laboratory determinations including antinuclear antibody, C3, C4, CH50, DNA-binding and circulating immune complexes. Plasma from 5 patients subjected to cryofiltration treatment (CFT) demonstrated less inhibition after than before CFT. This lessened inhibition of phagocytosis in vitro correlated with the clinical response due to CFT. The response to CFT could not be predicted by the conventional laboratory parameters investigated. Improvement between pre- and post-CFT plasma estimated by using the present bioassay may provide a quantitative description of which patient may benefit from plasmapheresis treatment procedures.