[IgG subclass antibodies in children of Vallidolid. Low materno-fetal protection].

The anti-tetanus serology was studied in Valladolid during 1988. IgG-antibodies and every one of four IgG-subclasses were determined by ELISA in 144 sera. In this study were included 31 parturient women, 20 newborn, 68 children 1.5-14 years old and 25 younger than 18 months. A 0.01 UI/ml sensibiling and a 8.5% interassay variability coefficient were achieved. The highest mean antibodies level (70.9-39.6 Ua/ml) was presented by children 1.5-3 years old and the lowest (31.1 +/- 15.9 Ua/ml) by 3-5 years old; nevertheless in mothers it was only 1.0 +/- 1.6 Ua/ml. Among children 1.5-14 years old we found only 5/63 (7.9%) cases with non-protective antibodies level. On the contrary, in mothers it increased until 23/31 (74%) and until 16/20 (80%) in cord blood. Antibodies of four IgG subclasses has each other a good correlation, especially IgG1/G2/G4 (p less than 0.001). The IgG2 and IgG3 subclasses were the antibodies which lesser decreased after vaccination. We emphasize the poor anti-tetanus protection of mothers and newborns, lower than levels reported in other countries.