Humoral response to John Cunningham virus during pregnancy in multiple sclerosis

Pregnancy induces an immunosuppressive state in the mother to ensure immunological acceptance of the foetus. Impairment of cell-mediated immune responses may render the mother susceptible to intracellular pathogens. It is not presently known whether pregnancy alters the immunosurveillance for John Cunningham virus (JCV), an opportunistic pathogen associated with natalizumab treatment for multiple sclerosis (MS).

To evaluate whether the humoral immune response to JCV is altered during pregnancy among MS patients and healthy controls to get insight to potential pregnancy-induced alterations related to immune response to JCV during pregnancy.

Serum anti-JCV-antibody-indices (JCV-Ab-index) were determined by a two-step second-generation enzyme-linked immunosorbent assay in 49 MS patients during and after pregnancy and in 49 healthy controls during pregnancy. For comparison, total IgG levels and antibodies against Epstein-Barr, cytomegalo and measles viruses were similarly measured.

The JCV-Ab-indices of MS patients were not altered during the pregnancy (1st vs. 3rd trimester, 0.62 vs. 0.77, p = 0.99). Contrary to this, in the healthy controls JCV-Ab-indices (p = 0.005), antibody levels to the other viruses, and total IgG levels (p < 0.0001) decreased significantly during pregnancy.

JCV-Ab levels remain unaltered during MS pregnancy, while the total IgG concentration is reduced/diluted due to increasing plasma volumes during the course of pregnancy. This may imply a biologically significant alteration in the immune response to JCV during MS pregnancy.