PB2067 PROGNOSTIC ROLE OF ACTIVE AND LATENT TRANSFORMING GROWTH FACTOR β1 LEVELS IN BLOOD OF PATIENTS WITH NON‐HODGKINS LYMPHOMA AND CHRONIC LYMPHOCYTIC LEUKEMIA
Authors: V. Barilka, V. Matlan, O. Shalay, S. Prymak, V. Loginsky
Journal: HemaSphere (2019)

Background: Transforming growth factor β1 (TGFβ1), member of TGFβ‐ superfamily, is a potent inhibitor of hematopoietic cells proliferation which is synthesized as an inactive protein, latent TGFβ1. Active form of TGFβ1 appears in microenvironment under the influence of various physiological activators such as thrombospondin‐1, plasminogen and released via proteolytic cleavage. In vitro an active form owns growth‐inhibitory activity in relation to leukemia cells. However, in vivo TGFβ1 is often involvement in the pathological conditions and his behavior sometimes is complex and paradoxical. Dysregulation of the TGFβ1 pathway has been implicated in course of lymphoid malignancies. According to published data TGFβ1 concentration in blood usually is determined by the immunological method (ELISA) which detects total cytokine level including inactive epitopes of TGFβ1 molecules and its inability to measure biologically active TGFβ1. Aims: The aim of this study was to determine the prognostic role of active and latent TGFβ1 levels in blood of patients with non‐Hodgkins lymphoma (NHL) and chronic lymphocytic leukemia (CLL). Methods The TGFβ1 concentration was determined by bioassay using cells line CCL64, mink lung epithelial cells. The measure both of active and latent TGFβ1 levels has been applied in plasma and supernatants (SP) of mononuclear cells from peripheral blood (MCPB) of 43 untreated of non‐Hodgkins (NHL) patients (pts) and 63 pts with chronic lymphocytic leukemia (CLL). The results were compared with respective indexes in 15 healthy donors. For active TGFβ1 assay CCL64 cells were incubated with native plasma or with SP of MCPB. For total, latent TGFβ1 assay respective samples had been initially treated by 1 N HCl‐acid and than 1 N NaOH. Whereafter 3 H‐methylthymidine was added to CCL64 cells after 24 h incubation with samples. The concentration of TGFβ1 was determined using a calibration curve based on the results of rhTGFβ1 influence in various doses on CLL64 cells. Results: It was discovered that latent concentration of TGFβ1 in plasma both of NHL (4,918 ± 1,240 ng/ml) and CLL pts (3,53 ± 0,40 ng/ml) was significantly higher in comparison with donors (2,11 ± 0,38 ng/ml; p &lt; 0,001 and p &lt; 0,05, respectively). Especially high level of latent TGFβ1 was detected in plasma of pts with aggressive NHL (4,60 ± 0,18 ng/ml) comparing with indolent NHL (2,91 ± 0,58 ng/ml; p &lt; 0,001). Latent TGFβ1 levels in SP MCPB of NHL (7,06 ± 1,23 ng/ml) and CLL pts (2,78 ± 0,78 ng/ml ) significantly exceeded (p &lt; 0,001 in both cases) respective contents of TGFβ1 active form. Concentration of an active form of TGFβ1 in SP MCPB of CLL pts was significantly higher (1,32 ± 0,38 ng/ml) than in NHL pts (0,42 ± 0,28 ng/ml; p &lt; 0,001), which may some relation to the indolent course of CLL. In the group of NHL pts with complete remission latent level of TGFβ1 in plasma (1,72 ± 0,83 ng/ml) was significantly lower than in pts with partial remission (3,283 ± 0,570 ng/ml) or without remission (4,66 ± 1,25 ng/ml). Summary/Conclusion: An increase concentration of TGFβ1 in blood of pts with NHL or CLL can arise up through making of latent form by leukemia cells and to influence on the course of these neoplasms. Simultaneous measurement of both active and latent TGFβ1 levels would help us understand the mechanism of progressive lymphoid malignancies. Obtained results may allow to recommend determination both of active and latent TGFβ1 levels in plasma and in SP MCPB in order to predict the course of NHL and CLL.