Studies on humoral immunity in pregnancy: immunoglobulins, alloantibodies and autoantibodies in healthy pregnant women and in pregnant women with rheumatoid disease.

Levels of immunoglobulins, alloantibodies and the presence of autoantibodies were prospectively studied during and after pregnancy in healthy women and in women suffering from rheumatoid arthritis (RA) and ankylosing spondylitis (AS). A decrease of IgG and IgA during pregnancy was found in all women while levels of IgM and alloantibodies remained stable. Multiparous women had higher levels of IgG during pregnancy when compared to primigravidae. No difference in the frequency of rheumatoid factor (RF) or antinuclear antibodies (ANA) was found when healthy pregnant women were compared to healthy non pregnant controls. None of the RF negative patients conversed to seropositivity during or after pregnancy. Decrease of ANA was correlated to remission of disease activity in the patients with RA.