[Serum and secretory immunoglobulins in immature infants]

The authors determined the serum and salivary concentration of albumin and immunoglobulins G, A and M in 16 dysmature and 16 healthy infants, born at term, mean age 4.8 +/- 1.8 and 4.7 +/- 1.4 respectively. The ratio of the amounts of salivary immunoglobulins transmitted from the blood to those secreted locally, applying the formula of Deuschl and Johansson, completed by the authors. The mean albumin, IgA and IgG levels were lower in the dysmature infants probably due to immaturity of the elements that synthesize these proteins, i.e. accelerate protein metabolism. Marked differences were observed in serum IgM between the two lots. In the saliva of immature infants albumin concentrations were very high probably due to the permeability of the physiologic barriers higher in these children due to insufficient biological maturity of the tissues. IgG concentration in the saliva showed no marked differences between the two groups, but the fraction filtered from the blood was greater in the immature infants, likewise attributed to massive transudation. More than 99% of immunoglobulin A in the saliva is of local origin and shows no considerable difference between the two groups.