Natalizumab treatment during pregnancy - effects on the neonatal immune system

Abstract

Background: Pregnancies in women with severe relapsing-remitting multiple sclerosis treated with natalizumab constitute a major challenge, because withdrawal of the drug may cause relapses but continuation might have unknown effects on the infantile immune system.

Aims of the study: To identify the impact of maternal natalizumab treatment during pregnancy on basic immune functions of the newborn.

Methods: Basic immunological testing and assessment of the chemotaxis rate of freshly isolated T lymphocytes in the presence and absence of CXCL12 was performed in two neonates, whose mothers were treated with natalizumab until the 34th week of pregnancy (pw).

Results: Both children had an uneventful birth. However, a reduction in the CXCL12-induced T-cell chemotaxis was found in both children. In contrast, the chemotaxis rate of unstimulated T lymphocytes was not altered. The distribution of the lymphocyte subpopulations was investigated only in case 1 and was normal.

Conclusions: Here, we present to our knowledge the first assessment of T lymphocytes chemotaxis rate in two natalizumab-exposed newborns. A significant reduction in the CXCL12-induced chemotaxis rate of T lymphocytes has been observed and may compromise host defence function in early life. More clinical and immunological data on natalizumab-exposed neonates are warranted.