Detection of infliximab in breast milk of nursing mothers with inflammatory bowel disease.

INTRODUCTION: Limited data suggest the absence of infliximab in breast milk, thereby implying the safety of this drug during breast-feeding. We aimed to re-evaluate the presence of infliximab in breast milk of nursing IBD patients.
METHODS: Serum and breast milk were obtained post-partum from 3 breast-feeding patients with Crohn's disease before and after re-initiation of infliximab. ELISA assay was employed to measure infliximab level in maternal serum and in breast milk. The level of infliximab was also measured in breast milk of a control group of 8 nursing healthy mothers.
RESULTS: Infliximab was undetectable in breast milk prior to the first infusion and was also not measurable in 8 lactating women not exposed to infliximab. Infliximab levels in breast milk rose up to 101ng/ml within 2-3days of the infusion. These levels of infliximab in breast milk were roughly 1/200th of the level in blood.
CONCLUSIONS: In contrast with prior reports, infliximab can be detected in the breast milk of nursing mothers. The miniscule amounts of infliximab transferred in breast milk are unlikely to result in systemic immune-suppression of the infant. Nonetheless, local effects of this exposure on the neonates' intestine and potential immune sensitization or tolerization towards the drug can not be excluded and merit further investigations.