IgG rheumatoid factors behaviour in young normal subjects following vaccination

In order to contribute to explain the finding of Rheumatoid Factors of the IgG class in all normal subjects, even at low levels, a study on their behaviour in a group of young subjects serving in the army, at the time of anti-typhoid and antitetanic vaccination, and in the following two months, was conducted. Parallely some aspecific serological parameters of autoimmunity were determined. The results demonstrate, first of all, a good antibody response to the vaccine in all subjects observed. Immunoglobulins of the IgG, IgA, and IgM class were normal in all samples. Complement factors C3 and C4 were slightly decreased after the second dose of vaccine, suggesting a modest consumption probably due to immune complexes formation. Factor C3A showed a slight increase, may be to be considered as its property of an acute phase reactant. Autoantibodies determined by immunofluorescence were constantly negative. IgM rheumatoid factors became transitory positive in a significant proportion. IgG rheumatoid factors demonstrated a two-phase increase, more evident after the second dose of vaccine. We can conclude, mainly for the latest parameter, that these results reveal an autoimmune serological response, even quantitatively modest, concomitant to the specific sensitization resulting from vaccination.