Lymphoproliferative Syndrome 2 (LPFS2)

Lymphoproliferative syndrome 2 (LPFS2), also known as CD27 deficiency, is a primary immunodeficiency disease (PID) with autosomal recessive trait. A 21-year-old Moroccan, born of consanguineous parents, with combined immunodeficiency and persistent symptomatic Epstein-Barr virus (EBV) viremia since early childhood was identified to have a defect of CD27 in 2012 (van Montfrans et al. 2012). Total of 17 patients from 9 families with LPFS2 have been reported to date (van Montfrans et al. 2012; Alkhairy et al. 2015; Salzer et al. 2013; Seidel 2012). LPFS2 is associated with persistent symptomatic EBV viremia, hypogammaglobulinemia, and impairment in specific antibody function resulting from impaired T cell-dependent B cell responses and T cell dysfunction, and it can mimic the clinical phenotype of X-linked lymphoproliferative syndrome (XLP) as well as LPFS1 (ITK deficiency). The median age of onset was reported to be 6 years (1–22 years).