Evaluation of arsenic species in leukocytes and granulocytes of acute promyelocytic leukemia patients treated with arsenic trioxide

• A HPLC-ICP-MS method was developed for intracellular arsenic speciation. • Arsenic species in leukocyte and granulocyte were analyzed for the first time. • Distribution trend of arsenic species in leukocytes and granulocytes was clarified. Concentrations of arsenic metabolites were important to clarify the sensitivity and resistance of APL (acute promyelocytic leukemia) patients to arsenic trioxide (As 2 O 3 ). Our purpose was to evaluate levels and distributions of arsenic species in leukocytes and granulocytes of APL patients. Inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were measured by high performance liquid chromatography coupled inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Leukocytes were collected from 21 patients treated with As 2 O 3 during induction, consolidation, and drug-withdrawal period. The upregulation of granulocytes in induction period was closely related to the differentiation of promyelocytes. Therefore, granulocytes were collected during induction period from 4 APL patients and purified by flow cytometry sorting using a panel of monoclonal antibodies specific for CD45, CD3, CD14, and CD19. The developed HPLC-ICP-MS method was precise and accurate with the limit of quantification of 0.5 ng/mL. During induction, consolidation, and drug-withdrawal period, the general trend of arsenic species was iAs > MMA > DMA ( P < 0.05) in leukocytes. iAs was predominant arsenic species with median concentration of 10.84 (6.03–14.62) ng/mL. MMA was major methylated metabolite with median concentration of 0.94 (0.60–2.50) ng/mL. Moreover, arsenicals were detected in leukocytes during drug-withdrawal. In granulocytes, iAs was found during induction period with median concentration of 1.08 ng/mL, while MMA and DMA were not detected. These results showed that iAs was the primary arsenic species in leukocytes and granulocytes from APL patients treated with As 2 O 3 . This study suggested that iAs might play a dominant therapeutic role during the whole treatment process of APL.