Download Alterations in circulating NK cells in MS patients during and after

Alterations in circulating NK cells in MS patients during and after pregnancy
Maija Saraste
Background: Multiple sclerosis (MS) is the most common disabling neurological disease affecting young
adults including women of childbearing years. MS typically ameliorates during pregnancy, but the relapse
rate often increases after delivery, because of reasons not yet completely understood.
Objective: To study immunologic mechanisms involved in the changing disease activity of MS during and
after pregnancy.
Methods: 42 MS patients were followed-up prospectively during pregnancy and six months postpartum.
Groups of pregnant and non-pregnant healthy women and non-pregnant MS patients served as controls.
The proportions of circulating T, B and natural killer cells (NK) and their subtypes were measured from
blood samples taken during and after pregnancy by immunofluorescence staining and flow cytometry. In
addition, pregnant MS patients were also followed-up clinically.
Results: The proportion of peripheral blood NK cells decreased significantly during the last trimester of
pregnancy and increased after delivery. Simultaneously, the annualized relapse rate was also first
decreased and then increased. The subtype analysis of NK cells showed that the proportion of CD56bright NK
cells was increased during the last trimester of pregnancy, whereas there was a decrease in the proportion
of CD56dim NK cells. The proportions of T and B cells remained unchanged during the follow-up.
Conclusions: This study suggests that CD56bright regulatory NK cells might have a role in controlling the
autoimmune inflammation during pregnancy in MS.