Malaria parasitaemia and immunoglobulin levels in paired maternal-cord sera from south western Nigeria.

Blood samples were collected from one hundred and sixteen parturient women and one hundred and seventeen umbilical cords at delivery for the detection of malaria parasitaemia and determination of total serum immunoglobulins (IgG, IgM and IgA). Immunoglobulin levels were measured by the single radial immunodiffusion method and the enzyme-linked immunosorbent assay for cord blood IgM. Malaria parasites were found in 2.6% (3/117) of cord blood and 22.4% (26/116) of maternal samples. Primiparae had the highest incidence and density of parasites compared with multiparae. A negative correlation was obtained between parasite density and parity of the parturient women (r = -0.54, P < 0.005). Mean cord blood IgG (P < 0.001) and IgM (P < 0.0001) were significantly lower than the mean maternal IgG and IgM. Maternal IgG (r = 0.65, P < 0.001) but not IgM (r = 0.09, P < 0.50) correlated with those of cord blood. Mean IgM (P < 0.001) but not IgG (P > 0.50) and IgA (P < 0.40) was significantly higher in malaria positive parturient women compared with malaria negative women. These data confirms the transplacental transfer of IgG across the placenta and the higher incidence of malaria parasitaemia in primiparae. The presence of IgM in cord blood samples suggest intrauterine sensitization of the foetus to common infections.