CD8A and rheumatoid arthritis: However, recent studies demonstrated no significant difference in the peripheral blood expression of BTLA in CD4+ and CD8+T-cells in CHB patients and healthy individuals, (64, 65) and the expression levels were similar in the 4 subtypes of CD4+T and CD8+T cells (TEM-RA, Tnaïve, Tcm, and Tem) (64).