Sorted By Test Name - Mayo Medical Laboratories

MBL
81051
1 0.35-0.69 Equivocal
2 0.70-3.49 Positive
3 3.50-17.4 Positive
4 17.5-49.9 Strongly positive
5 50.0-99.9 Strongly positive
6 > or =100 Strongly positive Reference values
apply to all ages.
Clinical References: Homburger HA: Allergic diseases. In Clinical Diagnosis and Management by
Laboratory Methods. 21st edition. Edited by McPherson RA, Pincus MR. WB Saunders, Publ, New York,
Chapter 53, Part VI, pp. 961-971, 2007
Mannose-Binding Lectin, Serum
Clinical Information: Mannose-binding lectin (MBL) is a member of the collectin family of proteins
that are characterized structurally by the presence of collagenous regions and lectin domains in the same
subunit. The subunit structure of MBL is comprised of three 32kDa peptide chains organized in a triple
helix with 3 C-terminal lectin domains. Circulating (functional) MBL is comprised of oligomers of
subunits (dimers through tetramers account for approximately 75% of circulating MBL) that are
associated with an MBL-associated serine protease (MASP). There is a single MBL gene (4 exons) on
chromosome 10 with 4 known allelic variants: wild type MBL (A), and 3 mutant forms B, C, and D
caused by point mutations in 3 different codons. The mutant forms of MBL form oligomers poorly, and
have diminished complement activating activity (see below). Multimeric MBL binds to many different
oligosaccharide moieties, including those in the cell walls of many different bacteria, yeasts, and some
viruses, including HIV 1, HIV 2, and influenza A. Binding of MBL results in complement activation by
the classical pathway through activation of complement 4 (C4) by MASP, and surface bound MBL
enhances phagocytosis by interacting with collectin receptors on phagocytic cells. Mutations of MBL
codons (homozygous or heterozygous haplotypes) are associated with diminished opsonophagocytic
activity and diminished serum levels of MBL measured immunochemically (MBL deficiency).
MBL-deficient individuals have increased susceptibility to infection particularly if MBL deficiency
occurs concomittantly with another heritable immune system abnormality, eg, C4 null alleles or
immunoglobulin class or subclass deficiencies.
Useful For: Evaluation of children and adults with a clinical history of recurrent infections Results
may be useful for genetic counseling and support aggressive management of recurrent infections in
patients with reduced levels of mannose-binding lectin
Interpretation: Diminished levels of serum mannose-binding lectin (MBL) are consistent with the
diagnosis of MBL deficiency. Levels or =7.8 ng/mL
This reference range applies only to adults.
See Cautions for further information regarding the reference range and clinical interpretation.
Clinical References: 1. Pettigrew HD, Teuber SS, Gershwin ME: Clinical significance of
complement deficiencies. Ann NY Acad Sci 2009;1173:108-123 2. Botto M, Kirschfind M, Maco P, et al:
Complement in human diseases: lessons from complement deficiencies. Mol Immunol
2009;48:2774-2783 3. Thiel S, Frederiksen PD, Jensenius JC: Clinical manifestations of mannan-binding
lectin deficiency. Mol Immunol 2006;43:86-96
FMPLE
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