Correlation between SLAMF6 expression and perforin and granzyme B on circulating CD8 +T cells and the clinical significance in patients with severe aplastic anemia / 中华检验医学杂志

ABSTRACT

Objective:To explore the correlation between the expression of signaling lymphocyte activation molecule family 6 (SLAMF6) on peripheral blood CD8 +T cells and perforin and granzyme B and the clinical significance in patients with newly diagnosed severe aplastic anemia(SAA). Methods:The indicators of blood routine and bone marrow and peripheral blood samples of 32 newly diagnosed SAA patients admitted to Henan Provincial People′s Hospital from January 2016 to June 2019 were collected for retrospective analysis. Flow cytometry was used to detect the expression of SLAMF6, perforin and granzyme B on samples CD8 +T cell before therapy and 6 months after therapy (11 cases received transplantation, 21 cases received immunosuppressive therapy [IST]). Spearman correlation analysis was performed to determine the association between clinical indicators and laboratory test results. The expression of SLAMF6, perforin and granzyme B was also detected in 10 healthy people (normal group) and 13 myelodysplastic syndromes/paroxysmal nocturnal hemoglobinuria (MDS/PNH) patients (MDS/PNH group). Results:(1) At diagnosis the expression of SLAMF6 was significantly lower in the SAA group than that in the normal group and the MDS/PNH group ([56.40±6.37]% vs [84.34±5.81]% and [82.24±4.98]% (both P<0.001]). The expression of perforin was significantly higher in the SAA group (32.73±8.46) than that in the normal control group (23.75%±5.10%), and the MDS/PNH group (26.12%±5.53%) (both P<0.05). The expression of granzyme B was also significantly higher in the SAA group (36.23%±7.94%) than that in the normal control group (21.67%±5.05%) and the MDS/PNH group (21.79%±5.10%) (both P<0.001). The expression of SLAMF6 was positively correlated with the hemoglobin ( r=0.804), and reticulocyte absolute values ( r=0.656) in peripheral blood, percentage of granulocytes ( r=0.643) and erythrocytes ( r=0.622) in bone marrow of SAA patients (all P<0.05). Expression of SLAMF6 was negatively correlated with perforin ( r=-0.792) and granzyme B ( r=-0.908) on CD8 +T cells in patients with SAA (both P<0.001). (2) After treatment the expression of SLAMF6 in peripheral blood CD8 +T cells of 30 surviving patients was higher than pre-treatment ([79.19±12.69]% vs [56.40±6.37]%, P<0.001). The expressions of perforin and granzyme B were lower than pre-treatment level (both P<0.05). The expression of SLAMF6 on CD8 +T cells in 11 transplanted patients was higher than before transplantation ([86.54±3.75]% vs [56.40±7.35]%, P<0.001). The expressions of perforin and granzyme B were lower than before transplantation (both P<0.05). The expression of SLAMF6 on CD8 +T cells in 12 IST-respond patients was higher than that before treatment, while the perforin and granzyme B levels were lower than pre-treatment (all P<0.05). The post-treatment expressions of SLAMF6, perforin and granzyme B were similar as before treatment levels in 7 IST-unrespond patients (all P>0.05). Conclusion:SLAMF6 is significantly down-regulated on CD8 +T cells in newly diagnosed SAA, negatively correlated with the effective factors of CD8 +T cells, which might participate in the immune regulatory of CD8 +T cells as a negative regulatory factor in patients with SAA. The SLAMF6 is significantly up-regulated after hematopoietic recovery, while there is no significant change in treatment-unrespond patients, which could thus serve as an useful diagnostic and therapeutic index of patients with SAA.