LACTATE-DEHYDROGENASE ISOENZYME PATTERNS IN BLOOD-CELLS FROM HISTIOCYTOSIS X CHILDREN

To find a clinical assay for histiocytosis X (HX) diagnosis, measureme nts were made of both activity and isoenzyme distribution of lactate d ehydrogenase (LDH; EC 1.1.1.27) from the blood cells of 6 acute phase and 9 remission patients. A significant increase in the LDH activity m easured in the monocytes and lymphocytes isolated from the blood of th e acute phase patients was found. The increased activity was due to an enhancement of the normal pattern of LDH isoenzymes in these cells an d not to a change in isoenzyme distribution. No increase was found in monocyte LDH isoenzymes from the patients in remission.