Monoclonal immunoglobulins in congenital toxoplasmosis.

Monoclonal immunoglobulins in serum and cerebrospinal fluid (CSF) were found in newborns with congenital toxoplasmosis. The M-components were of IgG-class and of both κ and λ type. The monoclonal proteins were found in the serum of newborns but not in the serum of their mothers. The monoclonal immunoglobulins were therefore selectively transferred or synthesized by the newborn. There was a local production or selective local accumulation of immunoglobulins in the cerebrospinal fluid. The M-components disappeared and the IgM level in serum and cerebrospinal fluid decreased after therapy. IgA was found to be elevated between 2–4 months of age. CRP was elevated in the first weeks after birth but afterwards returned to normal. The Dye test localized antibody activity to the site of the M-components in the electrophoresis of both serum and cerebrospinal fluid. The Dye test antibodies of mothers' sera also showed restricted heterogeneity with about the same electrophoretic localization as in the children's sera. Rheumatoid factors were found in serum and CSF of newborns with congenital toxoplasmosis, but not in serum of their mothers.