Chitotriosidase activity in colostrum from African and Caucasian women

Chitotriosidase (ChT), a protein produced by activated macrophages, belongs to the chitinases, a group of enzymes able to hydrolyze chitin, a structural component of fungi and nematodes. A codominant inherited deficiency in ChT activity is frequently reported in plasma of Caucasian subjects, whereas in the African population this deficiency is rare. This study compares ChT activity in colostrum of 53 African women and 50 Caucasian women. Samples were collected at 24-48 and 72 h after delivery. We found elevated ChT in colostrum of African women on the first day after delivery (1230+/-662 nmol/mL/h) which decreased to 275+/-235 nmol/mL/h on the third day. The ChT activity on the first day after delivery in the colostrum of Caucasian women, however, was significantly lower (293+/-74 nmol/mL/h) and decreased to 25+/-20 and 22+/-19 nmol/mL/h on the 2nd and 3rd day, respectively. The ChT activity in plasma of African women was also higher (101+/-80 nmol/mL/h) than that of Caucasian women (46+/-16 nmol/mL/h), but no correlation was found between plasma and colostrum ChT activity. The elevated ChT activity in colostrum of African women suggests the presence of activated macrophages in human milk, consistent with the genetic characteristics of the African population.