Elevated IgA antiphospholipid antibodies in healthy pregnant women in Sudan but not Sweden, without corresponding increase in IgA anti-β glycoprotein I domain 1 antibodies.

OBJECTIVE

The role of antiphospholipid antibodies (aPL) during apparently normal pregnancy is still unclear. IgA aPL are prevalent in populations of African origin. Our aim was to measure all isotypes of anticardiolipin (anti-CL) and anti-β glycoprotein I (anti-βGPI) in healthy pregnant and non-pregnant women of different ethnicities.

METHODS

Healthy Sudanese pregnant women ( = 165; 53 sampled shortly after delivery), 96 age-matched Sudanese female controls and 42 healthy pregnant and 249 non-pregnant Swedish women were included. IgA/G/M anti-CL and anti-βGPI were tested at one time point only with two independent assays in Sudanese and serially in pregnant Swedes. IgA anti-βGPI domain 1 and as controls IgA/G/M rheumatoid factor (RF), IgG anti-cyclic citrullinated peptide 2 (anti-CCP2) and anti-thyroid peroxidase (anti-TPO) were investigated in Sudanese females.

RESULTS

Pregnant Sudanese women had significantly higher median levels of IgA anti-CL, IgA anti-βGPI ( < 0.0001 for both antibodies using two assays) and IgM anti-βGPI (both assays;  < 0.0001 and 0.008) compared with non-pregnant Sudanese. IgA anti-CL and anti-βGPI occurrence was increased among Sudanese pregnant women compared with national controls. No corresponding increase during pregnancy was found for IgA anti-βGPI domain 1 antibodies. Both IgG anti-CL and IgG control autoantibodies decreased during and directly after pregnancy among Sudanese. Serially followed Swedish women showed no changes in IgA aPL, whereas IgG/M anti-CL decreased.

CONCLUSIONS

IgA aPL are increased in Sudanese but not in Swedish women, without corresponding increase in IgA domain 1. Whether due to ethnicity and/or environmental influences the occurrence of IgA aPL during Sudanese pregnancies, and its clinical significance, is yet to be determined.