Clonally expanded T lymphocytes have T effector memory and T effector memory RA phenotype. (A) Immunophenotyping analysis of the patient’s PB lymphocytes on day +354 posttransplant revealed an expansion of the TCRBV19⁺ T-cell population with the CD27⁻ T effector memory phenotype (CD3⁺ CD8⁺ CD45RA⁻ CD27⁻ CCR7⁻ CD95⁺) and the T effector memory RA phenotype (CD3⁺ CD8⁺ CD45RA⁺ CD27⁻ CCR7⁻ CD95⁺). The 2 T-cell clones of interest accounted for 92.5% of all TCRBV19⁺ PB CD8 lymphocytes, as determined by bulk TCR Vβ sequencing. (B) Immunophenotyping of PB lymphocytes from a healthy donor. (C) A systematic review of published cases of AA onset or relapse temporally related to vaccinations.