Thymic output changes in children with clinical findings signaling a probable primary immunodeficiency

Özet

Thymic maturation evaluation is inevitable for patients with clinicaland laboratory findings for a primary immunodeficiency, as the T cellimmunodeficiencies are the most severe type. In this study, we aimed to showthe usage of T cell surface molecule “CD31” for the evaluation of thymicoutput in patients (n: 66) with a large spectrum of findings signing a probableprimary immunodeficiency. Besides the classical clinical and laboratoryapproach for these patients, T cell subpopulations as naive, memory, recentthymic emigrant cells were also investigated. The humoral immunodeficiency(34.8%), combined immunodeficiency (34.8%) and cardiopathy (7.6%) werethe most frequent diagnosis groups. CD4+CD45RA+ naive T-cells percentages(p: 0.011) and absolute counts (p: 0.004) and absolute CD4+CD45RA+CD31+RTE (recent thymic emigrant) cell counts (p: 0.007) were significantly lowerin combined immunodeficiency group. Naive T-cells (p: 0.037) and RTE cells(p: 0.032) were also lower in patients who had cardiac surgery in the past.In conclusion, flow cytometric CD31+thymic naive RTE cell evaluation mayprovide rapid clinical information especially on T-cell immune dysfunctionand CD4+CD45RA+CD31+ RTE cells may be used as an alternative to TRECsin the diagnosis of combined immunodeficiencies.