O-acetyl sialic acid binding lectin as a probe for detection of subtle change on cell surface induced during acute lymphoblastic leukemia (ALL) and its clinical application

A novel probe, a 9-O-acetylated sialic acid binding lectin, namely achatininH (ATNH) has been used for the detection of changes on the cell surface during acute lymphoblastic leukemia (ALL). ATNH does not agglutinate normal human erythrocytes, however it is capable of agglutinating erythrocytes and peripheral blood mononuclear cells (PBMC) of patients suffering from ALL. The differential expression of a key receptor, 9-O-acetylated sialo glyco conjugate (9-O-AcSG), on PBMC was observed using a simple lymphoproliferative assay (LA). The extent of expression of 9-O-AcSG was used as an index to distinguish ALL patients of different clinical stages and assess the probability of relapse. The amount of ATNH needed for maximum stimulation served as a tool to indirectly measure the extent of expression of 9-O-AcSG on PBMC surface. The acetylated sialo glycoconjugate was expressed at a very high concentration during acute phase of the disease. Subsequently it decreased during treatment persisted during maintenance therapy and reappeared with relapse. PBMC of normal human donors required 80 times more ATNH in comparison to the untreated acute phase ALL patients. No cross reactivity was found in non Hodgkin's lymphoma, chronic myelogenous leukemia and thalassaemia patients.