_:vb50945774 . _:vb50945774 . _:vb50945774 "A severe combined immunodeficiency characterized by severe combined immunodeficiency, selective CD4 lymphopenia, and lack of CD28 expression on CD8+ T cells that has_material_basis_in homozygous or compound heterozygous mutation in LCK on chromosome 1p35.2."^^ . _:vb50945774 . _:vb50945774 "url:https://pubmed.ncbi.nlm.nih.gov/9664084/"^^ . _:vb50945774 . _:vb50945774 .