| Objective: To study the level of plasma SDF-1 and the expression of CXCR4 in childhood acute leukemia and discover their clinical implications. SDF-1 and CXCR4 were measured by enzyme-linked immunoabsorbent assay (ELISA) and flow cytometry respectively.Methods:1 Patients and groups: 43 children who were newly diagnosed with acute leukemia were collected in our hospital from May, 2006 to October, 2007. There were 29 patients with acute lymphoblastic leukemia (ALL) who were 5 cases of L1 and 24 cases of L2. 2 cases of T-ALL and 27 cases of B-ALL were confirmed by flow cytometry. There were 14 patients with acute myeloid leukemia (AML) who were 3 cases of M2, 6 cases of M3, 3 cases of M4 and 2 cases of M5.After chemical therapy and followed up for six months from first remission, 41 cases were complete remission and considered as remission groups except for 2 cases without follow-up. Continuing clinical observation for two months, 38 patients were defined as continuous complete remission and 3 cases were in poor prognosis. By the extramedullary infiltration symdrom, experimental group was devided into extramedullary infiltration group (37 cases) and non-extramedullary infiltration group (6 cases). Control group included 10 children of non-malignant hematological disease and 20 healthy children.2 Samples collection and operating sequence: peripheral blood and bone marrow were collected from all the 43 patients with acute leukemia, 10 cases of non-malignant hematological disease and 20 healthy children. SDF-1 and CXCR4 were measured by ELISA and flow cytometry respectively.3 Statistic analysis: SPSS 13.0 was used, and the data was described as mean±SD. Analysis methods include t-test, t′-test ,analysis of variance (ANOVA), Kruskal-Wallis H test and correlation analysis. A P value of less than 0.05 was considered as significant.Results:1 The level of plasma SDF-11.1 The level of SDF-1 in 43 acute leukemia patients (802.94±244.00pg/ml) was significantly higher than in 30 control cases (391.83±119.77pg/ml) (P<0.05).1.2 The level of SDF-1 in ALL group (871.64±240.87pg/ml) was significantly higher than in AML group (660.64±187.20pg/ml) (P<0.05).The levels in the subtypes of ALL (L1 and L2, T-ALL and B-ALL) and AML (M2, M3, M4 and M5) were no significant difference (P>0.05).1.3 The level of SDF-1 in 41 complete remission patients at diagnosis was higher than that at remission. There was significant difference between them (P<0.05).And the level of SDF-1 at remission was significantly higher than in 30 control cases (P<0.05).1.4 3 patients relapsed after remission. The levels of SDF-1 in 3 cases were 791.59±254.56,699.03±238.97,926.60±138.29 (pg/ml),at diagnosis, remission and relapse respectively. The level at diagnosis was significantly higher than that at remission (P<0.05). When patients relapsed, the level increased notablely. There was significant difference between remission and relapse cases (P<0.05). But the level between diagnosis and relapse cases was not significant different (P>0.05).1.5 The levels of SDF-1 in 37 patients with extramedullary infiltration and 6 patients without extramedullary infiltration at the diagnosis time were 815.91±248.95 (pg/ml), 722.93±211.97 (pg/ml) respectively. There was no significant difference between them (P>0.05).1.6 The level of plasma SDF-1 was positively correlated with the peripheral blood WBC counts at the diagnosis time (rSDF-1:WBC=0.57,P<0.05). There was no relationship between the level of SDF-1 and peripheral blood PLT counts and HGB content (P>0.05).2 The expression of CXCR42.1 The relative fluorescence intensity of CXCR4 in experimental group (69.14±37.13) was significantly higher than in control group (4.78±1.62) (P<0.05).2.2 The relative fluorescence intensity of CXCR4 in ALL group (89.42±26.33) was significantly higher than in AML group (27.16±12.02) (P<0.05).2.3 The difference of the relative fluorescence intensity of CXCR4 between L1 group and L2 group was not obvious (P>0.05).But the expression in T-ALL group was significantly higher than in B-ALL group (P<0.05).In the subtypes of AML (M2, M3, M4 and M5), only the differences between M2 group and M3 group, M3 group and M4 group were obvious (P<0.05).While the expression level of CXCR4 in M4+M5 group was higher than in M2 group and M3 group. The differences were significant (P<0.05).2.4 At the diagnosis time, the relative fluorescence intensity of CXCR4 in patients with extramedullary infiltration was higher than that in patients without extramedullary infiltration. There was significant difference between them (P<0.05).2.5 The relative fluorescence intensity of CXCR4 was positive correlated with the peripheral blood WBC counts at the diagnosis time (r=0.58,P<0.05). There was no relationship between the expression of CXCR4 and peripheral blood PLT counts and HGB content (P>0.05).3 In 43 patients with acute leukemia, the relative fluorescence intensity of CXCR4 was positive correlated with the level of plasma SDF-1 (r=0.70,P<0.05).Conclusions:1 High expression level of SDF-1 and CXCR4 in childhood acute leukemia at diagnosis could be considered as a detective index.2 SDF-1 and CXCR4 in ALL were higher than in AML, which indicated that SDF-1 and CXCR4 were correlated with the classification of acute leukemia.3 High level of SDF-1 was detected from the patients with acute leukemia at diagnosis time, decreased at remission, and increased again when relapsed. So monitoring the level of SDF-1 was helpful to judge the developing trends of acute leukemia and estimate the prognosis.4 High expression of CXCR4 in childhood acute leukemia was closely associated with extramedullary infiltration and peripheral blood WBC count at diagnosis time. |
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