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Medline ® Abstract for Reference 33

of 'Autoimmune lymphoproliferative syndrome (ALPS): Clinical features and diagnosis'

Elevated vitamin B₁₂levels in autoimmune lymphoproliferative syndrome attributable to elevated haptocorrin in lymphocytes.
Bowen RA, Dowdell KC, Dale JK, Drake SK, Fleisher TA, Hortin GL, Remaley AT, Nexo E, Rao VK
Clin Biochem. 2012 Apr;45(6):490-2. Epub 2012 Jan 28.
OBJECTIVE: Identify the etiology of elevated B(12) in autoimmune lymphoproliferative syndrome (ALPS).
DESIGN: Peripheral blood of ALPS patients with elevated B(12) and controls were evaluated.
RESULTS: Total and holo-haptocorrin (HC) levels were 26- and 23-fold higher in ALPS patients, respectively. No abnormal B(12)-binding proteins were found. Western blot revealed HC in lymphocyte lysates only from ALPS patients.
CONCLUSION: Elevated concentrations of B(12) found in ALPS patients were due to increased lymphocyte expression of HC.
Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA. rbowen@stanfordmed.org