[Expression and Significance of PD-1, PD-L1 and CTLA-4 in the Bone Marrow of Patients with Multiple Myeloma].

Objective: To study the expression and significance of PD-1, PD-L1 and CTLA-4 tumor-associated antigens in multiple myeloma.

Methods: Bone marrow specimens from 122 patients with multiple myeloma were collected and divided into new-onset group (NDMM), complete remission group (CRMM) and relapsed and refractory group (RRMM) according to the disease progression stage. The proportion of CD4 T lymphocytes, CD8 T lymphocytes, Treg cells and plasma cells in the specimens and the expressions of PD-1, PD-L1 and CTLA-4 were detected by multi-parameter flow cytometry.

Results: There was no significant difference in the proportion of CD8T and Treg cells among the three groups (>0.05), while the proportions of CD4T cells and PC in NDMM group were significantly higher than those in the CRMM group (<0.05), the ratios of CD4 to CD8T in the NDMM and RRMM groups were significantly higher than those in the CRMM group (<0.05). The expressions of PD-1, PD-L1 and CTLA-4 in CD8 T cells was no significant difference among NDMM, CRMM and RRMM groups (>0.05). While the expressions of PD-1, PD-L1 and CTLA-4 in CD4 T cells and PC in the NDMM group were significantly lower than that in the CRMM group (<0.05). There was significantly difference among the three groups in the expression of PD-1 in Treg cells, of which the NDMM group was significantly lower than that of the CRMM group (all <0.05). The expressions of PD-1 and CTLA-4 in PC were significantly higher than those in CD8 T, CD4 T and Treg cells (<0.05), the expression of PD-L1 in CD8 T cells was significantly higher than that in CD4 T and Treg cells (<0.05).

Conclusion: There is a correlation between the immune status of multiple myeloma and the expressions of PD-1, PD-L1 and CTLA-4 in plasma cells and lymphocyte subsets .