Placental mast cell heterogeneity in pregnancy complicated by diabetes class C

In humans, a strict classification into mucosal and connective tissue-type mast cells (MC) is not possible. On the basis of neutral protease composition, human MC have been classified into two phenotypes. One phenotype, which is designated MC sub(T) (tryptase-positive, chymase-negative mast cells), contains tryptase but not chymase, while another phenotype, designated MC sub(TC) (tryptase-positive, chymase-positive mast cells), expresses both tryptase and chymase. No tryptase-negative subpopulations of mast cells in humans have been found, although the MC type in human placenta is still unknown. Some investigators have studied correlations between placental MC number and placental pathology during the course of pregnancy and labour. Class C diabetes in pregnancy (after White) is the last stage without recognized vascular changes. The results of our recent studies showed, that in diabetes class C an increased density of the villous network of vessels correlates with higher histamine concentrations and increased MC number. Here we examined numbers and distribution of MC sub(T) and MC sub(TC) in White class C diabetes.