Thymosin alpha 1 in milk specimens from Guatemalan women

Thymosin alpha 1 was determined in milk samples obtained from 67 Guatemalan women 5 days, and 1-3 and 6-18 months postpartum. All the specimens collected 5 days after delivery contained measurable levels (583 +/- 304 pg/ml) of thymosin alpha 1 but only 33% of those obtained 1-3 months postpartum and none collected thereafter did. Since thymosin alpha 1 has been shown to increase T-cell mediated immunity, and to enhance host resistance to infection, it may play an important role in the maturation of mucosal immunity and host resistance in general in the neonate. This study is the first to document the presence of a thymic hormone in early postpartum milk.