Consecutive appearance of coagulation factor XIII subunit A in macrophages,
megakaryocytes, and liver cells during early human development
J Kappelmayer, G Bacsko, L Birinyi, R Zakany, E Kelemen and R Adany
Department of Clinical Chemistry, University School of Medicine, Debrecen,
Hungary.
Thirty embryonic and fetal samples were investigated to study the
appearance and characteristics of factor XIII subunit A (FXIIIA)-
containing cells in the course of human development. Samples were either
vacuum-embedded in paraffin for staining FXIIIA by a sensitive
biotin-streptavidin system or snap-frozen for double-labeling studies to
characterize FXIIIA-containing cells. FXIIIA appeared as early as the fifth
gestational week in yolk sac samples in stellate-shaped cells.
Nonparenchymal cells in liver samples showed intense labeling for FXIIIA
from the sixth week of gestation. The relative amount of FXIIIA-containing
cells rapidly diminished up to the 13th gestational week. When
characterized, the majority of these cells proved to be KiM7- positive
macrophages, while GPIb (CD42b)-labeled cells accounted for less than 10%
of FXIIIA-positive cells. Liver cells did not show any staining for FXIIIA
in first trimester samples. The earliest liver specimen showing FXIIIA was
at the 20th week, when FXIIIA appeared in some liver cells, particularly in
those surrounding the central veins. In bone marrow smears, FXIIIA-positive
cells started to appear at week 10 in the clavicles and increased in number
in subsequent stages of development. Intracellular FXIIIA was distributed
between GPIb-, RFD7-, and KiM7-positive cells. The results indicate that,
apart from liver cells, at least three different cell populations (KiM7+
RFD7+ GPIb-, KiM7- RFD7- GPIb-, and KiM7- RFD7- GPIb+) contain FXIIIA in
the early phase of human development. We conclude that FXIIIA appears very
early during human development and is detectable in both extra- and
intraembryonic hematopoietic organs. Intracellular FXIIIA in early human
development is distributed between different macrophages and
megakaryocytes, and by week 20, it appears in liver cells as well.
Volume 86,
Issue 6,
pp. 2191-2197,
09/15/1995
Copyright © 1995 by The American Society of Hematology
