Investigating Cell Surface Markers on Normal Hematopoietic Stem Cells in Three Different Niche Conditions

Hematopoietic stem cells are of therapeutic interest to the clinicians and researchers due to their promising assistance in management of malignant and inherited hematological conditions. Evaluation of cell surface markers using multiparametric flow cytometry is a well adapted qualitative measure of cells in question for many years. An artillery of these markers has been studied in hematological malignancies and related disorders. However, their role and differential expression on normal hematopoietic stem cells from clinically available sources is not always described carefully. In the present study, we attempted to evaluate expression of CD44, CD90, CD96 and CD123 in three clinically available sources of normal HSCs (Hematopoietic stem cells). Sources of HSCs in the present study involved umbilical cord blood (UCB), normal bone marrow (NBM) and bone marrow from idiopathic thrombocytopenic purpura (ITP) patients (IBM). CD44 is an important homing receptor while CD90 is involved in maintaining stem cell quiescent. CD96 is known to be leukemia specific marker and CD123 is involved in stem cell differentiation and survival. We observed a significant difference in expression CD44, CD90 and CD123 on normal HSCs derived from umbilical cord and ITP marrow. CD96 was highly expressed on HSCs obtained from ITP marrow. Investigating expression of these markers on normal HSCs in different niches will be helpful in correlating their function with niche condition and delineating their 'abnormal' expression from the normal.

Delayed response to donor lymphocyte infusion [DLI] in a relapsed chronic myeloid leukaemia post allogenic bone marrow transplantation

Donor lymphocyte infusion [DLI] is nowadays routinely used for inducing remission in patients who relapse into chronic myeloid leukaemia [CML] after allogeneic bone marrow transplantation. In the present case, it took more than 10 months and several DLI along with alpha interferon injection for development of post DLI acute GVHD and remission of the disease. One of the surprising findings was development of accelerated phase like symptoms and blood picture with rising white cell counts, rising basophils, eosinophils and circulating blast cells when the patient developed acute GVHD. Clinically the patient also developed 8 cms enlarged tender splenomegaly at the same time. After a short period of acute GVHD and accelerated phase like blood picture, he entered into clinical and haematological remission with mild persistent chronic GVHD in the skin and mouth. The present case showed that DLI may need to be repeated several times and persistence may often be rewarded