title: Highlighting the problematic reliance on CD18 for diagnosing leukocyte adhesion deficiency type 1.
abstract: Leukocyte adhesion deficiency type 1 (LAD-1) is an autosomal recessive primary immunodeficiency, hallmarked by defective polymorphonuclear transmigration. It is caused by mutations in the gene encoding CD18, which interfere with the CD18/CD11 heterodimerization and expression on leukocyte cell surface. LAD-1 diagnosis rests primarily on the measurement of CD18 expression. However, CD18 measurement entails its pitfalls. Here we present a cohort of ten LAD patients and a review of the relevant literature illustrating the difficulties in sole reliance on CD18 measurement for initial diagnosis. These include normal range expression in some mutations, great variability between patients with the same mutation and subjective interpretation of results. We think there is a need for additional markers as part of the initial LAD diagnostic algorithm. We suggest CD11a expression, which was near absent in all patients in our cohort. The dual use of CD18 and CD11a can increase testing sensitivity and prevent delayed diagnosis of LAD-1.
authors.affiliation: Pediatric Department and the Immunology Service, "Edmond and Lily Safra" Children's Hospital, Chaim Sheba Medical Center, 52621, Tel Hashomer, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.|Jeffrey Modell Foundation Center, Tel Aviv, Israel.
authors.forename: Sarina
authors.initials: S
authors.lastname: Levy-Mendelovich
authors.affiliation: Pediatric Department and the Immunology Service, "Edmond and Lily Safra" Children's Hospital, Chaim Sheba Medical Center, 52621, Tel Hashomer, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.|Jeffrey Modell Foundation Center, Tel Aviv, Israel.
authors.forename: Erez
authors.initials: E
authors.lastname: Rechavi
authors.affiliation: Nablus Speciality Hospital, Palestinian Authority, Nablus, Palestine.
authors.forename: Omar
authors.initials: O
authors.lastname: Abuzaitoun
authors.affiliation: Hematology Laboratories, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Helly
authors.initials: H
authors.lastname: Vernitsky
authors.affiliation: Pediatric Department and the Immunology Service, "Edmond and Lily Safra" Children's Hospital, Chaim Sheba Medical Center, 52621, Tel Hashomer, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.|Jeffrey Modell Foundation Center, Tel Aviv, Israel.|Hematology Laboratories, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Amos J
authors.initials: AJ
authors.lastname: Simon
authors.affiliation: Pediatric Department and the Immunology Service, "Edmond and Lily Safra" Children's Hospital, Chaim Sheba Medical Center, 52621, Tel Hashomer, Israel.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.|Jeffrey Modell Foundation Center, Tel Aviv, Israel.
authors.forename: Atar
authors.initials: A
authors.lastname: Lev
authors.affiliation: Pediatric Department and the Immunology Service, "Edmond and Lily Safra" Children's Hospital, Chaim Sheba Medical Center, 52621, Tel Hashomer, Israel. raz.somech@sheba.health.gov.il.|Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. raz.somech@sheba.health.gov.il.|Jeffrey Modell Foundation Center, Tel Aviv, Israel. raz.somech@sheba.health.gov.il.
authors.forename: Raz
authors.initials: R
authors.lastname: Somech
mesh_terms: D015415:Biomarkers; D018821:CD18 Antigens / Q000235:genetics / Q000378:metabolism*; D016022:Case-Control Studies; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D016130:Immunophenotyping; D007223:Infant; D007231:Infant, Newborn; D007958:Leukocyte Count; D018370:Leukocyte-Adhesion Deficiency Syndrome / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism* / Q000628:therapy; D007962:Leukocytes / Q000276:immunology / Q000378:metabolism; D008297:Male; D009154:Mutation; D010641:Phenotype; D015203:Reproducibility of Results; D014184:Transplantation, Homologous
chemical_list: D015415:Biomarkers; D018821:CD18 Antigens
keywords: CD11a; CD18; FACS; Leukocyte adhesion deficiency