Engraftment-associated hypophosphatemia - the role of cytokine release andsteep leukocyte rise post stem cell transplantation

Hypophosphatemia associated with bone marrow transplantation has been infre quently reported. The suggested mechanism is phosphate uptake by the replic ating cells. Various cytokines are associated with the development of hypop hosphatemia. The present study evaluated the interrelationship between cyto kine release, the rise in WBC and the development of hypophosphatemia durin g the engraftment period. Blood samples were obtained from 60 patients unde rgoing peripheral blood stem cell transplant, on the day of admission and t hen daily from the day of transplant until discharge. Hypophosphatemia deve loped in 62% of the patients, The median day of minimal phosphorus level wa s +8 and it antedated engraftment by 2 days. There was a significant correl ation between the day of minimal phosphorus level and the day of maximal WB C and a significant correlation between the fall in phosphorus level and WB C rise. IL-6 and IL-8 showed similar kinetics. Higher IL-6 and IL-8 levels were directly associated with lower phosphorus levels, In conclusion, hypop hosphatemia commonly occurs in the post-transplant period, We assume that b oth a direct effect of cytokine release and an increased consumption by the dividing WBCs contribute to its appearance, As its occurrence usually ante dates engraftment it can be used as a forerunner for WBC recovery.