RESUMO
BACKGROUND: The clinical and immunologic features of CD27 deficiency remain obscure because only a few patients have been identified to date. OBJECTIVE: We sought to identify novel mutations in TNFRSF7/CD27 and to provide an overview of clinical, immunologic, and laboratory phenotypes in patients with CD27 deficiency. METHODS: Review of the medical records and molecular, genetic, and flow cytometric analyses of the patients and family members were performed. Treatment outcomes of previously described patients were followed up. RESULTS: In addition to the previously reported homozygous mutations c.G24A/p.W8X (n = 2) and c.G158A/p.C53Y (n = 8), 4 novel mutations were identified: homozygous missense c.G287A/p.C96Y (n = 4), homozygous missense c.C232T/p.R78W (n = 1), heterozygous nonsense c.C30A/p.C10X (n = 1), and compound heterozygous c.C319T/p.R107C-c.G24A/p.W8X (n = 1). EBV-associated lymphoproliferative disease/hemophagocytic lymphohistiocytosis, Hodgkin lymphoma, uveitis, and recurrent infections were the predominant clinical features. Expression of cell-surface and soluble CD27 was significantly reduced in patients and heterozygous family members. Immunoglobulin substitution therapy was administered in 5 of the newly diagnosed cases. CONCLUSION: CD27 deficiency is potentially fatal and should be excluded in all cases of severe EBV infections to minimize diagnostic delay. Flow cytometric immunophenotyping offers a reliable initial test for CD27 deficiency. Determining the precise role of CD27 in immunity against EBV might provide a framework for new therapeutic concepts.