[Expression and Significance of IL-9 and IL-6 in Patients with BCR-ABL- MPN]

To investigate the expression of IL-9 and IL-6 in patients with BCR-ABL- bone marrow proli- ferative tumor (MPN), and to explore its role in the occurrence and development of MPN.

A total of 71 newly diagnosis MPN patients treated in Tianjin Medical University General Hospital from 2018 to 2019 were selected, including 32 patients with polycythemia vera (PV) and 22 patients with primary thrombocytosis (ET), and 17 patients with primary myelofibrosis (PMF). Then 58 patients who retestine after treatment were selected as therapy group，and 20 healthy volunteers were recruited as control group. ELISA was used to detect the expression level of IL-6 and IL-9 in bone marrow supernatant, and the relative expression level of IL-6 and IL-9 mRNA in BMMNC was detected by real-time PCR. The proportion of Th9 cells in peripheral blood were detected by flow cytometry (FCM). The expression level of IL-6 mRNA and IL-9 mRNA of BMMNC and clinical indicators were analyzed, and the correlation between JAK2 gene mutation load and IL-9 level was further analyzed.

The level of IL-6 in bone marrow supernatant and the expression of IL-6 mRNA in BMMNC were higher in the newly diagnosed group as compared with those in the treated group and the control group (P<0.001). The expression level of IL-9 in bone marrow supernatant and the expression of IL-9 mRNA in BMMNC were lower in the newly diagnosed group as compared with those in the treated group and the control group (P<0.05). The proportion of Th9 cells in peripheral blood was lower in the newly diagnosed group as compared with that in the treated group and the control group (P<0.001). The level of IL-6 in bone marrow supernatant and the expression of IL-6 mRNA in BMMNC in JAK2⁺ group were higher than those in JAK2^- group (P<0.05). The expression level of IL-9 in bone marrow supernatant and the expression of IL-9 mRNA in BMMNC were lower in JAK2⁺ group as compared with those in JAK2^- group (P<0.05). The expression of IL-6 and IL-9 in the patient group showed correlation with the number of lymphocytes (IL-6: r=-0.49, P<0.01; IL-9: r=0.53, P<0.001), and also related with Hb in PV patients (IL-6: r= 0.87, P<0.001; IL-9: r=-0.54, P<0.01), and platelets in ET patients (IL-6: r=0.64, P<0.05; IL-9: r=-0.46, P<0.05).

The increased expression of IL-6 in MPN and hyperfunction may promote the progression of BCR-ABL- MPN disease. The expression of IL-9 in MPN decreases, and it negatively correlates with the mutation load of JAK2 gene, which may be related with the decrease of tumor environmental antitumor immune effect.