IgG subclasses in chronic brucellosis patients

: The data on the levels of immunoglobulins belonging to the main classes (IgA, IgM, IgG) and IgG subclasses (IgG1, IgG2, IgG3, IgG4) in the sera of 52 patients with chronic brucellosis lasting 1-10 years are presented; in 10 of these patients immunoglobulin levels before and after vaccinal therapy are given. The blood sera of chronic brucellosis patients were found to contain IgG of 4 subclasses, the concentration of IgG1, IgG2 and IgG4 being, on the average, normal and the concentration of IgG3, elevated. A certain correlation between the increase of the IgG level and the presence of 2-mercaptoethanol-resistant specific antibodies was observed. After brucellosis patients received the injections of therapeutic vaccine, their levels of IgG and IgG1 increased, while the concentration of IgG3 decreased and that of IgG2 and IgG4 remained unchanged.