In order to investigate the role of type 1 and type 2 cytokines in the remi
ssion of Graves' disease (GD) during pregnancy, spontaneous and mitogen-sti
mulated production of interleukin (IL)-4, IL-6, IL-10, IL-12, interferon-ga
mma (IFN-gamma), and tumour necrosis factor-alpha, (TNF-alpha) were measure
d by enzyme-linked immunospot assay of peripheral blood mononuclear cells f
rom 10 pregnant women with GD, 8 healthy pregnant women, and 10 healthy non
pregnant women. Tests were performed in the first, second, and third trimes
ters of pregnancy and 10-17 weeks after delivery. IL-4 production was not a
ffected greatly by normal or GD pregnancy, whereas IFN-gamma production was
suppressed throughout pregnancy but returned to normal levels after delive
ry in both controls and patients. IL-6 and TNF-alpha tended to be higher in
GD pregnancy than normal pregnancy, especially in the second and third tri
mesters. Controls had raised IL-10 in the first trimester with a return to
normal levels by the third trimester, whereas patients had raised levels th
roughout pregnancy. IL-12 levels were suppressed to a greater extent in con
trol than Graves' pregnancy, especially during the second and third trimest
ers. Ratios of IL10:IL12 in phytohemaglutinin (PHA)-stimulated cultures wer
e much lower in GD than normal pregnancy and cross-regulation of IL-10 and
IL-12 may be deficient in GD.