Correlation between Expression of CD200 and Regulatory T Cells in Multiple Myeloma and Its Significance in Prognostic Stratification

Abstract

To study the correlation between expression of CD200 and regulatory T cells (Tregs) in multiple myeloma(MM) patients and to explore its significance in prognostic stratification. CD200 and other immunophenotypes, including CD38, CD138, CD56, CD19, CD20, CD117, cytoplasm light chain Kappa and Lambda in bone marrow samples, and Tregs in peripheral blood were detected by flow cytometry from 78 newly diagnosed MM patients. Serum concentrations of hemoglobin(Hb), β2 microglobulin (β2-MG) and lactate dehydrogenase (LDH) were detected, respectively. The new risk stratification of patients was carried out according to international stage system (ISS) and cytogenetic characteristics. The correlation between expression of CD200 and Tregs in MM patients was analyzed and their differences in prognosis were compared. The positive rate of CD200 expression was 71.79% in 78 patients (56/78). The expression of CD200 in sex and age of patients was no significant different. The expression of CD117 in CD200+ group was significantly higher than that of in CD200- group (P=0.032). There was no significant difference in the expression of CD20, CD56 and CD19 between 2 groups. The level of Hb in CD200+ group was significantly lower than that in CD200- group (P=0.035). The level of β2-MG in CD200+ group was significantly higher than that in CD200- group (P=0.013). There was no significant difference in the level of LDH between 2 groups. In CD200+ group, 17 patients were in stageⅠ, accounting for 58.62% (17/29), 30 patients were in stageⅡ, accounting for 75% (30/40), 9 patients were in stage Ⅲ, accounting for 100% (9/9). With the increase of CD200 expression intensity, the risk of prognostic stratification went up (P=0). The brighter CD200 expressed, the worse the prognosis was. The percentage of Trges in CD200+ group was significantly higher than that of in CD200- group (P=0.043). The content of Tregs was positively correlated with the expression of CD200 (r=0.743, P=0.044). Overall survival in CD200- group was significantly higher than that in CD200+ group (P=0.036). Progression-free survival in CD200- group was a bit higher than that of in CD200+ group, but it wasn't statistically significant. The expression of CD200 positively correlates with the percentage of Tregs in MM patients. It is an important factor of poor prognosis and a reliable indicator for the evaluation by clinical efficacy in MM patients.