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

Abstract

To study the expression and significance of PD-1, PD-L1 and CTLA-4 tumor-associated antigens in multiple myeloma. 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. There was no significant difference in the proportion of CD8+T and Treg cells among the three groups (P>0.05), while the proportions of CD4+T cells and PC in NDMM group were significantly higher than those in the CRMM group (P<0.05), the ratios of CD4+ to CD8+T in the NDMM and RRMM groups were significantly higher than those in the CRMM group (P<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 (P>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 (P<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 P<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 (P<0.05), the expression of PD-L1 in CD8+ T cells was significantly higher than that in CD4+ T and Treg cells (P<0.05). 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 in vivo.