ABERRANT CONTROL OF GALACTOSYLTRANSFERASE IN PERIPHERAL B-LYMPHOCYTESAND EPSTEIN-BARR-VIRUS TRANSFORMED B-LYMPHOBLASTS FROM PATIENTS WITH RHEUMATOID-ARTHRITIS

It is now well established that hypogalactosylation of IgG is a molecu lar marker for rheumatoid arthritis (RA). However. the mechanism for t he alteration of the galactosylation status has not been resolved. We compared the galactosyltransferase activities of anti-CD 19 selected p eripheral B lymphocytes of healthy subjects and patients with RA using ovalbumin as the acceptor substrate. In addition, certain samples of lymphocytes were assayed after Epstein-Barr virus (EBV) transformation and. also, the ability of bovine milk galactosyltransferase to galact osylate IgG in vitro was examined. Our results indicate that there is a significant difference between the galactosyltransferase activities of rheumatoid and control peripheral B lymphocytes and that EBV transf ormation causes a variable increase (15-1225 %) in galactosyltransfera se activity, over that present in the peripheral B lymphocytes from wh ich the transformed cells were derived. Also the ubiqitous ''lactose s ynthetase'' type galactosyltransferase (EC 2.4.1.38) will galactosylat e normal native IgG at concentrations of 500 mU/ml in vitro. We conclu de that there is no evidence from our study for an IgG specific galact osyltransferase and that galactosyltransferase is an enzyme that is ab errantly modulated in peripheral B lymphocytes and EBV transformed B l ymphoblasts derived from patients with RA.