INCREASED GD(3) GANGLIOSIDE IN PLASMA OF CHILDREN WITH T-CELL ACUTE LYMPHOBLASTIC-LEUKEMIA

The presence of tumor-associated GD(3) in the plasma of 12 patients wi th T-cell acute lymphoblastic leukemia (T-ALL) was determined utilizin g microscale ganglioside isolation and thin layer chromatography (TLC) immunodetection with an anti-GD(3) monoclonal antibody, R24. Immunost aining of control plasma gangliosides revealed two nearly equal subspe cies groups of GD(3), GD(3U) and GD(3L). Plasma from those T-ALL patie nts with a high R24-positive lymphoblast count (>60 000/mm(3)) had a s ignificant increase in total GD(3) and each of the GD(3) subspecies gr oups, and a disproportionate increase in GD(3L) resulted in an increas ed ratio GD(3L)/GD(3U) in these samples. In contrast, total GD(3), GD( 3) subspecies, and GD(3L)/GD(3U) was not increased in plasma from thos e cases with low R24-positive blast count (<20 000/mm(3)) or in pre-B ALL plasma. The altered GD(3) content in R24-positive T-ALL plasma was reversible, since total GD(3) and GD(3L)/GD(3U) in plasma from a pati ent in remission from R24-positive T-ALL was near that of controls. Re sorcinol staining of TLC-separated gangliosides confirmed the results observed with R24 detection methods. The results strongly suggest that GD(3) is shed in vivo from T-ALL blasts in patients with R24-positive T-ALL, resulting in both qualitative and quantitative changes in circ ulating GD(3) in these