[The immunological effect of anti-leukemic tumor induced by eosinophilic granulocyte].

Objective: To investigate the biological effect of anti-leukemic cells induced by eosinophilic granulocyte (EOS) in bone marrow of patients with chronic myelogenous leukemia (CML).

Methods: The BCR-ABL fusion gene as well as the expression of IL-12 and IL-17 mRNA were performed by RT-PCR. The serum concentrations of cytokine IL-12 and IL-17 were determined by enzyme-linked immuno sorbent assay (ELISA). Immunochemistry staining and cytochemistry staining were used to observe the peroxidase (POX) and human leukocyte antigen (HLA)-DR expression of EOS in bone marrow. Immunofluorescence staining was used to observe mannose receptor (MR), IL-12, IL-17A and IL-17 receptor A (IL-17RA) expression of EOS. The results between the CML patients and the healthy controls were compared.

Result: Serum levels of IL-12 and IL-17 were higher in the 60 CML patients [(196.33 ± 21.79) ng/L and (36.55 ± 3.01) ng/L] than those in the controls [(96.60 ± 4.92) ng/L and (23.74 ± 1.36) ng/L]. In the 32 patients with activated EOS, the levels of IL-12 and IL-17 were (273.12 ± 17.16) ng/L and (40.11 ± 6.13) ng/L, which were significantly higher than those in the non-activated EOS [(126.16 ± 14.27) ng/L and (28.14 ± 5.29) ng/L] (P values < 0.01). IL-12 and IL-17 mRNA were expressed in activated EOS, while BCR-ABL fusion gene was not found. The amounts of EOS were increased abnormally in the bone marrow and peripheral blood of the CML patients with POX positive staining in the cytoplasm and weakly positive HLA-DR staining. It was observed easily by a microscope that EOS could attack leukemic cells in bone marrow through adhesion, capture and phagocytosis. Activated EOS could express IL-12, IL-17A and MR, which was related with the serum levels of these cytokines.

Conclusions: Activated EOS in bone marrow of CML patients could express IL-12 and IL-17. Activated EOS could induce coup injury to leukemic cell by releasing POX and expressing IL-12 and IL-17. It can also capture or swallow target cells via the expression of MR on the membrane. EOS may play an important role in the anti-tumor immunologic function in bone marrow of CML patients.