Distinctive CD8+ T cell and MHC class I signatures in polycythemia vera patients

• DOI: 10.1007/s00277-018-3332-7
• Publication Date: 2018-05-22T04:50:27Z
• Authors: Elsa M. Cardoso; André J. Esgalhado; Luís Patrão; Mónica Santos; Vasco Pinto Neves; Jorge Martinez; Maria Assunção Va...; Helena Silva; Fernando A. Arosa
• Keywords: Adult; Aged, 80 and over; Male; 0301 basic medicine; CD8-Positive T-Lymphocytes; Middle Aged; 3. Good health; 03 medical and health sciences; HLA Antigens; T-Lymphocyte Subsets; Case-Control Studies; Humans; Female; Polycythemia Vera; Aged

Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by overproduction of red blood cells. We have performed a comprehensive characterization of blood immune cells for expression of naïve and memory receptors as well as β2m-associated and β2m-free MHC class I heavy chains, also known as closed and open conformers, respectively, in PV patients and age-matched controls (CTR). We show that the peripheral CD3+CD8+ T cell pool in PV patients is clearly divided into two discrete populations, a more granular CD3+CD8high T cell population enriched in effector-memory CD45RA+ T cells (CD8+ TEMRA) when compared to CTR (P < 0.001), and a less granular CD3+CD8int T cell population that is completely absent in the CTR group (78 vs. 0%, P < 0.001) and is a mixture of naïve (CD8+ TN) and CD8+ TEMRA cells expressing intermediate levels of CD28, i.e., CD3+CD8intCD28int. While the percentage of CD3+CD8int TN cells correlated positively with the number of erythrocytes, the percentage of CD3+CD8int TEMRA correlated negatively with the number of platelets. Finally, we report that PV patients' lymphocytes and monocytes display lower levels of closed (W6/32+) MHC-I conformers at the cell surface while exhibiting increased amounts of open (HC-10+) MHC-I conformers. The implications of this distinctive immune signature are discussed.