D1.457 - Clinical and immune profile of newborns born to mothers with inflammatory diseases exposed to biological drugs during pregnancy

The management of immune-mediated diseases (IMIDs) during pregnancy is a challenge, as uncontrolled inflammatory activity has adverse consequences for both the mother and fetus. The use of biologic drugs (mainly mAbs) allows good control of IMID activity, but their use during pregnancy can lead to impaired immune function in newborns due to the transplacental passage of mAbs.

OBJECTIVE: To describe the basic clinical and immunological profile (immunoglobulins, vaccine response, TBNK profile, and neutrophils) of children of mothers with IMID who receive mAb during pregnancy and to analyze whether there is a correlation between drug exposure and clinical and immunological variables collected during the first year of life.

Methods Descriptive, prospective study conducted in two reference centers between 2014 and 2024. A review of medical records was performed after the signing of the informed consent form approved by the Ethics Committee, following up on newborns at 3, 6, and 12 months of age.

Fifty-one patients were recruited. The IMIDs were inflammatory bowel disease (Crohn's disease and ulcerative colitis) and rheumatological diseases (rheumatoid arthritis, juvenile idiopathic arthritis, SAPHO, and spondyloarthritis). Prenatal exposure to mAb was not associated with malformations, perinatal complications, or significant infections during the first year of life. Patients exposed to tumor necrosis factor inhibitors (TNFi) had atopic dermatitis (AD) at a similar rate to that of the general pediatric population; only 1 patient exposed to vedolizumab (VDZ) had mild AD. Three cases of food allergy were reported, none with autoimmune diseases at the time of study closure. In our cohort, 9/51 patients received the rotavirus vaccine in the first 2-4 months, with no adverse reactions. The TBNK lymphocyte and humoral profile remained within the normal range during the 12-month follow-up period for both TNFi and VDZ and natalizumab (NTZ). In 12/36 infants treated with TNFi, we observed transient mild-to-moderate neutropenia, but not in the children of untreated mothers.

The use of TNFi, VDZ, and NTZ drugs during pregnancy, including the third trimester, in our cohort has been shown to be safe. However, studies with a larger number of patients and an adequate control group are needed to confirm these results.