Stimulation of beta 2-microglobulin synthesis in lymphocytes after exposure to Cuprophan dialyzer membranes

We tested beta 2-microglobulin (beta 2m) synthesis by peripheral blood lymphocytes of non-uremic donors after contact with dialyzer membranes. Under serum-free conditions, lymphocytes were incubated with different dialyzer membranes for four hours. After subsequent culture in the absence of membranes to yield an overall culture time of 24 hours, RNA was extracted. Messenger RNA for beta 2m was quantitated by Northern blotting with specific probes. Increased beta 2m mRNA was seen after a minimum of one hour contact time with Cuprophan both in the presence and absence of cycloheximide. While no consistent stimulation was seen with polyacrylonitrile or polycarbonate-polyether membranes, respectively, the stimulation of beta 2m mRNA with Cuprophan was of the same order of magnitude as that obtained with interferon gamma. Stimulation of beta 2m mRNA by Cuprophan was stereospecifically diminished by 5 mM L-fucose. Apart from stimulated transcription of beta 2m we could also show increased surface expression of MHC class I molecules, using FACS technique. The results further prove complement-independent blood cell activation by Cuprophan membranes. It is uncertain whether the results are relevant for beta 2m amyloidosis.