A preliminary study on SLAMF6 expression in patients with severe aplastic anemia / 中华血液学杂志

Objective: To explore the expression of SLAMF6 on CD8(+) T cells in patients with severe aplastic anemia (SAA) and its correlation with disease immune status. Methods: By flow cytometry (FCM), SLAMF6 expression level in peripheral blood CD8(+) T cells was detected in 21 patients with SAA and 15 normal controls respectively from February 2017 to April 2018. The correlation between SLAMF6 expression level and hematopoietic functions, including HGB, PLT, the neutrophil granulocyte and reticulocyte absolute value in peripheral blood, hyperplasia degree (percentage of granulocytes, erythrocytes, lymphocytes and megakaryocytes in bone marrow) and perforin, granzyme B, IFN-γ expression level in CD8(+) T cells were evaluated. To further confirm the effect of SLAMF6 on CD8(+) T cells, anti-SLAMF6 Ab was used to block SLAMF6 pathway (IgG as control), and FCM was used to detect the perforin, granzyme B, and IFN-γ production of CD8(+) T cells. Results: The expression of SLAMF6 on CD8(+) T cells in untreated SAA patients[(56.29±12.97)%]was significantly lower than that of normal controls[(80.96±7.36)%](t=-7.672, P<0.001). The expression of SLAMF6 on CD8(+) T cells in SAA patients were positively correlated with the HGB, PLT, the neutrophil granulocyte and reticulocyte absolute value in peripheral blood, percentage of granulocytes, erythrocytes in bone marrow (all P<0.05), but they were negatively correlated with the percentage of lymphocytes in bone marrow, and the expression of perforin, granzyme B, and IFN-γ of CD8(+) T cells (all P<0.05). After blocking SLAMF6 pathway by anti-SLAMF6 Ab, the expression levels of perforin, granzyme B and IFN-γ in SAA patients were significantly higher than those in the untreated group, and the differences were statistically significant (all P<0.05). Conclusions: SLAMF6 is significantly down-regulated on CD8(+) T cells in SAA patients, which may act as a negative immunoregulatory molecule participating in the mechanism of SAA by affecting the functional molecules secretion on CD8(+) T cells.

Influence of Costimulatory Signaling Molecules on Immun Functons of B Lymphocytes in Patients with Immune Thrombocytopenia / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the effect of costimulatory signaling molecules (CD80, CD86) expression on the quantity and function of B lymphocytes in peripheral blood (PB) of the patients with immune thrombocytopenia (ITP).</p><p><b>METHODS</b>A total of 55 ITP patients (30 cases were newly diagnosed and 25 cases were in remission), 25 healthy volunteers as controls were enrolled in this study. The levels of CD19(+)CD5(+), CD19(+)CD80(+), CD19(+)CD86(+), CD41a(+)IgG, CD41a(+)IgM and IgG, IgM in CD19(+)B cells were measured by flow cytometry (FCM). The correlation of CD19(+)B cells with clinical parameters of ITP patients was analyzed.</p><p><b>RESULTS</b>The level of B1 (CD19(+)CD5(+)) of newly diagnosed ITP patients was significantly higher than that of remitted ITP patients and controls (P<0.05). The level of CD19(+)CD80(+) of newly diagnosed ITP patients was significantly higher than that of remitted ITP patients and controls (P<0.05). And the expression of IgG and IgM in CD19(+)B cells of newly diagnosed ITP patients was significantly higher than that of remitted ITP patients and controls (P<0.05). The levels of IgG and IgM in remitted ITP patients after treatment were significantly lower than that before treatment (P<0.05). The level differences of IgG and IgM before and after treatment in refractory ITP patients were not statistically significant (P>0.05). The expression of CD19(+)CD80(+) in newly diagnosed ITP patients positively correlated with the level of Th1 and Th1/Th2 (r=0.502, r=0.471, P<0.05). The expression of CD19(+)CD80(+) of newly diagnosed ITP patients positively correlated with the level of IgG and IgM in CD19(+)B cells (r=0.552, r=0.467, P<0.05), and negatively correlated with PB platelet count (r= -0.424, P<0.05). The levels of IgG and IgM in CD19(+)B cells of newly diagnosed ITP patients negati- vely correlated with PB platelet count (r=-0.658, r=-0.526, P<0.05).</p><p><b>CONCLUSION</b>The enhacement of costimulatory signaling pathway of CD19(+)B cells in ITP patients results in the abnormal activation of B lymphocytes, thereby mediates the dysfunction of immune system and involves in the pathogenesis of ITP.</p>

The mechanisms underlying bone marrow damage by iron overload in pancytopenic patients with positive BMMNC-Coombs test / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the mechanisms underlying bone marrow damage by iron overload in pancytopenic patients with positive BMMNC-Coombs test (IRP).</p><p><b>METHODS</b>Twenty-one iron overloading, 26 non-iron overloading IRP patients and 10 normal controls were enrolled in this study. The expressions of ROS, Bcl-2, Caspase-3 and apoptosis of BMMNC were analyzed by flow cytometry (FCM). Antioxidants were added to iron overloading IRP BMMNC, and then the changes of indices above were detected by FCM. The number and apoptosis of T lymphocytes of IRP patients were also detected.</p><p><b>RESULTS</b>ROS and apoptosis of BMMNC, myelocytes, erythrocytes and stem cells of iron overloading IRP patients were significantly higher than that of non-iron overloading IRP ones and normal controls (P < 0.05). The expressions of Bcl-2 on BMMNC, erythrocytes and stem cells of iron overloading IRP patients were significantly lower than those of non-iron overloading IRP ones (P < 0.05). The levels of Caspase-3 on myelocytes, erythrocytes and stem cells of iron overloading IRP patients were significantly higher than those of non-iron overloading IRP ones and normal controls (P < 0.05). After treatment with antioxidants, the expressions of ROS, Caspase-3 and apoptosis of iron overloading IRP BMMNC significantly decreased, but opposite for Bcl-2. The percentages of CD4(+) lymphocytes [ ( 40.86 ± 8.74）%] and CD4(+)/CD8(+) (1.44 ± 0.36) in PB of iron overloading IRP patients were significantly higher than that of non-iron overloading IRP ones [(35.96 ± 7.03)% and 1.14 ± 0.37] and normal controls [(28.00 ± 6.73)% and 0.79 ± 0.21], respectively (P < 0.05), as opposite for CD8(+) lymphocytes (P < 0.05). The apoptosis of CD8(+) lymphocytes [(27.35 ± 10.76)%] and the ratio of CD8(+) apoptosis/CD4(+) apoptosis (2.51 ± 0.81) in BM of iron overloading IRP patients were significantly higher than those of non-iron overloading IRP ones [(15.47 ± 8.99)%] and normal controls (1.39 ± 0.47), respectively (P < 0.05). The apoptosis of erythrocytes and stem cells coated with auto-antibodies in BM of iron overloading IRP patients were significantly higher than those of non-iron overloading IRP and normal controls.</p><p><b>CONCLUSION</b>Mechanisms underlying bone marrow damage by iron overload might be through the follows: ①The increased ROS induced by excessive iron deposition affected the expressions of Caspase-3 and Bcl-2, which caused more BMMNC apoptosis; ②The abnormal number and ratio of T lymphocytes caused by iron overload aggravated the abnormality of immunity of IRP; ③Iron overload may increase the damage to erythrocytes and stem cells coated with auto-antibodies.</p>