Abstract
During the course of studies on the complement content of human blood, we noted that the cord blood of the newborn infants consistently was of a lower titer than that of adults. We, therefore, determined simultaneously the complement titer of a series of newborn (cord) bloods and of the mother's blood taken at the time of delivery.
The titration was made according to the method outlined by Ecker, et al. 1 The serum was diluted 1 to 15 and a series of tubes set up starting with 0.01 cc of the diluted serum and increasing by 0.01 cc to reach 0.15 cc. The volume in all tubes was adjusted to 0.15 cc with saline and 1 cc of cells sensitized with 5 units of hemolysin was added. The tubes were incubated at 37°C for 30 minutes, centrifuged and examined for the point of first hemolysis which was taken as the end point. The volume of the undiluted serum necessary for this first hemolysis was considered as the indes of the complement titer.
The comparative titers of the 48 samples are illustrated in Fig. 1 The cord blood titer varies considerably, ranging from 0.0023 to 0.0080, with a mean of 0.0046. The maternal bloods, which had in each case been drawn immediately after delivery, presented titers ranging froni 0.0016 to 0.004 ivith but one exception which fell to 0.0063. The mean for the niaternal blood was 0.0030.
Statistical analysis of the data reveals that a “reliability of difference” of 7 exists between the coniplement titer of maternal and newborn (cord) blood. This tlefiiiitely indicates that a distinctly smaller amount of coniplenieiit is present in the newborn than in the adult.
Of perhaps greater significaiicc than the means is the fact that a comparison of the cord and maternal bloods of individual instances almost invariably reveals a higher complement titer in the maternal blood.
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