[OA-17] The expression of CD15 in placental vessels belonging haemoglobin Bart's hydrops foetalis

Nawaluk Atiroj and Mana Taweevisit

Department of Pathology, Facolty of Medicine, Cholalongkorn University, Bangkok, Thailand

Haemoglobin Bart can lead to hydrops foetalis (HF). Its placental findings include abnormally increased intermediate villi with immature endothelium. CD15 assists in diagnosis of delayed villous maturation by identification of foetoplacental endothelial immaturity. Thus, investigation of CD15 expression has benefit for understand pathophysiology of Hb Bart's HF. This study aimed to evaluate CD15 immunoreactivity in placental endothelium of Hb Bart's HF in comparison to that in other causes of HF. CD15 was performed in 14 cases of Hb Bart and 9 cases of HF by other causes (4 cases from anaemia of non-Hb Bart and 5 cases from causes other than anaemia). Twenty-seven cases of control group being gestational age-matched were compared. CD15 was measured by counting stained placental vessels per 100 proximal and distal vessels. The immunoreactivity was recorded as positive, and graded as continuous or discontinuous intense expression. Compared to the control, mean number of distal vascolature that expresses CD15 in continuous pattern was significantly higher in Hb Bart, anaemic HF other than Hb Bart and non-anaemic HF. In conclusion, the significant CD15 expression in distal vascolature proves that Hb Bart's disease is caused by delayed villous maturation, leading to ineffective oxygen transport with later HF.

Keywords: CD15; endothelium; haemoglobin Bart; placenta