Suppression of beta 2-microglobulin release from lymphocytes by dialysis membranes

As lymphocytes are one of the main sources of circulating beta 2-microglobulin (beta 2M), the direct effect of different dialysis membranes on beta 2M release from those cells was studied in vitro. Lymphocytes were isolated from 11 long-term haemodialysis patients and nine healthy controls. Cells were cultured on flat sheet membranes made from either Cuprophan, Hemophan, or polyacrylonitrile. Polystyrole petri dishes were used as controls. Beta 2M concentrations in the supernatant were measured after 3 and 7 days of culture by ELISA techniques. Beta 2M release from lymphocytes obtained from uraemic patients was almost identical to the release from healthy subjects. In the presence of all three membranes the release of beta 2M was less than that produced on polystyrole. This held true for lymphocytes isolated from both healthy and uraemic subjects. As for the three membranes the release of beta 2M into the supernatants was statistically the same when the adsorptive capacity of polyacrylonitrile was taken into account. However, there was a tendency for Cuprophan to exert the strongest inhibition, while Hemophan and polyacrylonitrile reduced beta 2M release to a lesser degree. Based on these data it seems that prolonged interaction between dialysis membranes and lymphocytes does lead to a reduction in beta 2M release.