ABSTRACT
This chapter explores the in vitro system to study the mechanisms controlling the glycosylation changes of acute-phase proteins (APP). It demonstrates that glycosylation alterations of APP observed in serum result from changes occurring within hepatocytes, are mediated by cytokines, and are regulated by mechanisms independent of that regulating gene expression of APP. There are major findings of the studies of mechanisms regulating glycosylation: Peripheral Blood Monocytes isolated from active systemic lupus erythematosus (SLE) and active Rheumatoid Arthritis (RA) patients have different capabilities to induce alterations of APP in vitro. Glycosylation alterations of APP in serum are not found in active SLE, while, when SLE patients have intercurrent infections, a significant increase of a number of APP may be observed. The results obtained indicate that differences in the pattern of APP glycosylation observed in active SLE and active RA may be associated with the different secretion of cytokines involved in these processes.
