[Rinshō ketsueki] The Japanese journal of clinical hematology
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The mechanism of the cause of hyperleukocytosis induced by differntiation induction therapy of acute promyelocytic leukemia (APL) by all-trans retinoic acid (ATRA) was studies. Of 11 patients treated by ATRA in our hospital, 3 developed hyperleukocytosis. Moreover, 2 out of 4 patients with retinoic acid syndrome (ATRA syndrome) had hyperleukocytosis. ⋯ Moreover, APL cells that differentiated into monocytoid cells possessed the capability of producing endogenous cytokines such as TNF alpha, which might be involved in the development of ATRA syndrome. Compared to cells from patients without hyperleukocytosis they had a stronger TNF alpha producing capability and lower sensitivity to TGF beta, showing hyperdifferentiation in response to ATRA. Depending on the case, those with the same sensitivity to ATRA might show different sensitivities to cytokines.