Early treatment with IVIG prevents FNAIT caused by maternal anti-CD36 antibodies. (A) Naive and immunized Cd36^−/− female mice were bred with WT mice. During pregnancy, naive (cohort #4; n = 3) or immunized Cd36^−/− mothers were treated with IVIG (1 g/kg) on days 10, 15, and 20 (cohort #5a; n = 7), or on days 7, 12, and 17 (cohort #5b; n = 9). High mortality of pups was observed in immunized mothers (cohort #5a) receiving IVIG on days 10, 15, and 20 compared with naive mothers (cohort #4) (P < .001). The number of dead pups was significantly decreased in immunized Cd36^−/− mothers treated with IVIG 3 days earlier (cohort #5b), on days 7, 12, and 17 (P < .01). Significance was analyzed by using the χ² test (**P < .01; ***P < .001). (B) Anti-CD36 antibodies in Cd36^−/− immunized (cohort #5b; n = 9) were measured before (on day 7) and after (on days 12, 17, and 22) IVIG administrations by flow cytometry and are represented as median fluorescence intensity (MFI). Sera from naive mothers (Ctrl) were run as controls (n = 10). Data are expressed as mean ± standard deviation. Significance (*P < .05) was analyzed by using a two-tailed unpaired Student t test. n.s, not significant.