We found that LPS co-administration significantly boosted the production of anti-GPIbα and anti-β3 antibodies, and miscarriage occurred in most of these co-stimulated GPIbα−/− and β3−/− mice, while miscarriage infrequently occurred in the dams immunized with low-dose WT platelets alone. This evidence concerns the gene IGKV4-1 and Miscarriage.