Pregnancy-associated alpha-2-glycoprotein in recurrent oral ulceration and Behçet's syndrome.

Estimation of the serum concentration of pregnancy-associated alpha 2-glycoprotein (alpha 2-PAG) in male patients with recurrent oral ulcers (ROU) and Behçet's syndrome (BS) revealed significant increases in both groups of patients. The concentrations of alpha 2-PAG in 24 control subjects were less than 10 micrograms/ml, whereas 11/26 (42%; p less than 0.001) of patients with ROU and 20/33 (61%; p less than 0.0005) with BS had concentrations greater than 10 micrograms/ml. Indirect immunofluorescence staining for alpha 2-PAG on the surface membrane of blood mononuclear cells suggests that there is an increase in the number of alpha 2-PAG-positive cells in BS. It is not clear at present whether the increased concentrations of alpha 2-PAG might exert an inhibitory effect on the immune response. No correlation was observed between the levels of alpha 2-PAG in ROU and BS and concentrations of alpha 1-acid glycoprotein, C9, factor B or lysozyme. It is therefore unlikely that the increase in alpha 2-PAG is a manifestation of an increase in acute phase protein.