Abstract

Cord blood can be used as an alternative source for bone marrow transplantation and its use is developing into a new field of treatment for patients presenting with haematological disorders, immunological defects and specific genetic diseases; including haemoglobinopathies. The aim was to assess the viability of frozen cord blood as a source of HSC which may be suitable for transplantation. Blood specimens were obtained from umbilical cords of 30 consenting mothers and dispensed into 5 cryovials with glycerine for freezing at -20°C; while quantitative assay was carried out on a fresh citrated sample by immunophenotyping using CD34 as marker of HSC. Partec Cyflow cube 6 was used to measure viable cells after labelling the cells with specific fluorochrome/antibody obtained from Sysmex Partec. A repeat quantification was carried out at one month interval for 5 consecutive months and results generated were analysed using T- independent test. The mean ± standard error of mean (SEM) for the 6 consecutive counts were 20,798±2750, 19849±2691, 19223±2637, 18363±2582, 17052±2583 and 16184±2423. The p values obtained when the cryoprotected samples were compared to the baseline were 0.806, 0.681, 0.521, 0.325 and 0.213; reflecting that subsequent counts were insignificantly different from the baseline count. Thus, it is a safe alternative in resource-poor setting to store stem cells in a cryoprotective agent and freeze at -20°C for up to 6 months, without significant depreciation in viability. This alternative should be explored and further researches should be conducted with possibility of extending the number of months.

Key words: CD34+ cells, immunophenotyping, stem cells, cryopreservation.