Good syndrome presenting with CD8⁺ T-Cell large granular lymphocyte leukemia

Good Syndrome is an adult-onset combined immunodeficiency defined by hypogammaglobulinemia, low or absent number of B cells, T cell deficiency and thymic tumor. We have characterized CD8+ T cells from a patient with Good syndrome that presented with CD8+T-cell large granular lymphocytic leukemia (LGL). Characterization of peripheral blood CD8+ T cells revealed that majority of CD8+ T cells were terminally differentiated effector memory phenotype (TEMRA; CD8+CCR7-CD45RA+), and were PD-1high (CD279), ICOSlow (CD278), and granzymehigh. Almost all CD8+ T cells were IFN-γ+. CD8 Treg (CD8+CD183+CCR7+CD45RA-) were decreased. TEMRA phenotype along with CD279high, demonstrates that these are exhausted CD8+ T cells. This phenotype along with CD278low may also explain severe T cell functional deficiency in our patient. In the present patient, T-LGL appears to be a clonal expansion of CD279+granzyme+IFN-γ+CD8+TEMRA cells. To best of our knowledge this is the first case of CD8+T-cell LGL leukemia associated with Good syndrome.