Case Report: TCD8 Proliferation Secondary To CMV In A Post Transplant Patient.

CD4+ and CD8+ lymphocytes regenerate within the first year after Bone Marrow Transplant (BMT). The survival and peripheral expansion of donor memory T-cells transfused with the graft is the dominant mechanism in the first year after the BMT, with the predominant expansion of TCD8+ cells. This explains the inverted CD4/CD8 ratio detected in post-BMT patients. That is the reason why it is not a surprise to find elevated TCD8 cells in an immune profile of a patient submitted to bone marrow transplant. However, post-transplant patients are prone to viral infections, and CD8 T cells display unique profiles depending on their viral specificity: Cells are predominantly CCR7+ CD27+ CD28+ during latent infection with HCV, CCR7(-) CD27+ CD28+ in EBV, CCR7(-) CD27+ CD28(-) in HIV, and CCR7(-) CD27(-) CD28(-) in CMV. Female patient, 25 years old, Previous diagnosis of B-Acute Lymphoid leukemia, D+180 after bone marrow transplantation, post-stem cell transplant immune profile, with progressive lymphocytosis, Peripheral blood sample with white blood count 6,900 cells. 58% T Cells (4/8 = 0.2): *46.2% TCD8+ TCRCBeta1+36% (polyclonal) 21.75% TD phenotype with increased absolute levels (1501 cells/μL - normal age range 1-384) CD45RA+ CD27(-), 21.45% EM phenotype with increased absolute levels (1480 cells/μL - normal age range 5-69) CD45RA(-) CD27(-), 0.2% Naive CD45RA+ CD27+, 2.8% CM/TM CD45RA(-) CD27+; *9.8% TCD4+ TCRCBeta1+36,5% (polyclonal) 0.6% Naive CD45RA+ CD27+, 2.5% CM/TM CD45RA(-) CD27+, 0.1% TD CD45RA+ CD27(-, 6.6% EM CD45RA(-) CD27+ (Fig. 1). peripheral blood sample showing a relative (58%) and absolute (4,005/mm 3 ) increase in mature (CD3+) T lymphoid cells (CD45++), with a predominant phenotype (42%) of polyclonal effector (terminally differentiated) CD8+ T cells / memory effector cells (CD27(-) CD28(-) CCR7(-) CD45RA+/- CD45RO-/+), with negative CCR7/CD27/CD28 expression, a phenotype suggestive of viral infection, most likely CMV, later confirmed with serologic tests.