Affiliations: Department of Allergy, Asthma and Immunology, Immanuel
St. Joseph's Specialty Clinic, Mayo Clinic Health System, Mankato, MN,
USA | Department of Allergy and Immunology, Springfield
Clinic, Lincoln, IL, USA | Department of Pediatrics, University of Illinois
College of Medicine at Peoria, Peoria, IL, USA | Department of Laboratory Medicine, Division of
Clinical Biochemistry and Immunology, and Pathology, Mayo Clinic, MN, USA
Note: [] Correspondence: Dr. Roshini Sarah Abraham, Department of
Laboratory Medicine, Division of Clinical Biochemistry, Hilton 210e, Mayo
Clinic, 200 1st St SW, Rochester, MN 55905, USA. Tel.: +1 507 266 9292; Fax: +1
507 266 4088; E-mail: abraham.roshini@mayo.edu
Abstract: In this case report, we describe for the first time the
identification of a compound heterozygote mutation in the β2 integrin gene (ITGB2), which is associated with
Leukocyte Adhesion Deficiency type 1 (LAD-1). The patient was a 6-year-old male
referred for evaluation of multiple recurrent infections. Laboratory evaluation
revealed persistent leukocytosis with normal immunoglobulins, complement,
mannose-binding lectin, and vaccine antibodies. There was also a complete
absence of the integrins – CD18 and CD11a on monocytes, granulocytes and
lymphocytes, and CD11b on monocytes and lymphocytes with normal expression on
granulocytes. Gene sequencing showed two heterozygous mutations, one being a
missense mutation, G284S in exon 7 (c.850G>A), and the
second, a single base-pair deletion resulting in a premature stop codon
(c.2070delT). Based on the clinical and laboratory findings, a diagnosis of
LAD-1 was reached, but it was delayed by an apparent lack of early recognition
of the clinical features. LAD-1 should be considered as a potential diagnosis
and aggressively pursued in any patient who presents with leukocytosis, delayed
umbilical cord separation and non-purulent recurrent infections. Key diagnostic
work-up includes flow cytometry for CD18, CD11a and CD11b on white blood cells
followed by appropriate confirmatory gene sequencing analysis.
