PB2107 UPREGULATION OF PD‐1 CHECKPOINT RECEPTOR MOLECULE ON BONE MARROW T‐CELLS FROM PATIENTS WITH MULTIPLE MYELOMA, AND ITS POTENTIAL IMPACT ON CLINICAL OUTCOME

• Published in: HemaSphere Vol. 3; no. S1; pp. 949 - n/a
• Main Authors: Perez‐Montero, P., Paniagua, A., Prieto, M., Llorente, L., Serrano, A., Bengochea, M., Mendez, G., Jimenez, P. Marí, Varea, S., Rodrigo, E., Rios, F. Lopez, De Oteyza, J. Perez
• Format: Journal Article
• Language: English
• Published: 01-06-2019
• ISSN: 2572-9241; 2572-9241
• DOI: 10.1097/01.HS9.0000566912.48165.f4

Background:
Multiple myeloma (MM) is associated with complex immune deregulation that includes loss of myeloma‐reactive effector T‐cell populations. PD‐1 cell surface expression is a characteristic marker of T cell exhaustion. Therefore, the role of the PD‐1/PD‐L1 pathway in mediating immune escape in MM could have an influence in response to therapy. Although some investigators have analyzed the presence of PD1 in cell suspension samples from myeloma patients, little is known about their potential impact on clinical outcome.
Aims:
In the present study, we hypothesized that the presence of PD1+ T‐cells in the bone marrow from patients with MM, could be related to the pattern of marrow infiltration and might have an impact on survival.
Methods
Bone marrow tissue samples from MM patients were obtained at initial diagnosis. Both PD1 expression on T cells, and CD138+ plasma cells were measured by immunohystochemical methods. Plasma cell infiltration pattern was considered diffuse when the percentage of CD138 + cells exceeded 40%. Correlation between number of PD1+ cells, and pattern of infiltration, or the presence of ostheolytic lesions, was evaluated by logistic regression. Kaplan‐Meier estimates and Cox regression were used to analyze the impact of PD1 expression on, either progression free survival (PFS), or overall survival (OS).
Results:
Thirty‐one MM patients, diagnosed and treated at a single institution, were included. Median age at diagnosis was 66y (38‐89). 59.4% of the patients were on ISS‐R clinical stage 2. Poor risk cytogenetic abnormalities were present in 14.3% of the cases. Median percentage of CD138+ plasma cells in the bone marrow was 45% (range 8‐100), showing a diffuse pattern in 58.6% of the cases. Maximum PD‐1+ T‐cell count was highly variable, ranging from 0 to 42 cells per field, with a median of 8 c/f. PD‐1+ cells were distributed heterogeneously, either in focal aggregates,or in a widespread fashion. There was no correlation between a diffuse CD138+ plasma cell infiltration pattern, and the number of PD‐1+ cells (p = 0.216) There was also no correlation between PD1+ count and the presence of ostheolytic lesions. Kaplan‐Meier estimates showed median PFS and OS of 42 and 90 months, respectively. The presence of a high PD1+ cell count (>10/field) showed no impact on PFS (Log‐rank p = 0.75) or OS (log‐rank p = 0.95)
Summary/Conclusion:
Taken together, our results showed upregulation of PD1 in bone marrow T‐cells from MM patients. Nevertheless this finding had no apparent impact on clinical outcome, in terms of PFS or OS. Larger studies are needed.