Evaluation of a daily dose of 25 micrograms vitamin K1 to prevent vitamin K deficiency in breast-fed infants.

Vitamin K prophylaxis is recommended to prevent the hazard of hemorrhage caused by vitamin K deficiency in young infants. A single administration after birth seems inadequate to completely prevent late haemorrhagic disease in breast-fed infants. The preventive effect of a daily oral dose of 25 micrograms vitamin K1, which is comparable to about half the dose ingested by formula-fed infants, was evaluated in 58 breast-fed infants. No clinical or biochemical signs of vitamin K deficiency occurred; PIVKA-II was not detectable, and vitamin K1 concentrations were moderately elevated. Vitamin K1 levels were negatively correlated with the number of hours elapsed since the most recent gift. Twenty to 28 h after the administration, median (P10-P90) levels were 1,262 (267-4,328), 1,072 (293-3,427), and 882 (329-2,070) pg/ml at 4, 8, and 12 weeks of age, respectively. Vitamin K1 levels in formula-fed infants (n = 10) were around 7,000 pg/ml. In conclusion, daily supplementation of 25 micrograms vitamin K1 can be recommended for breast-fed infants to prevent vitamin K deficiency beyond the neonatal period.

Familial selective IgA deficiency with circulating anti-IgA antibodies: a distinct group of patients?

Two families were investigated in which the mothers had selective IgA deficiency and circulating class-specific anti-IgA antibodies. Both gave birth to two children who were found to be IgA deficient. Three of these children developed anti-IgA antibodies before puberty. In vitro immunoglobulin production studies performed in the children of both families revealed an IgA B cell defect combined with IgA-specific excessive T suppressor function in all four. The mechanisms by which transplacental passage of maternal anti-IgA antibodies could have interfered with the developing IgA system in the offspring are discussed.