Editor’s summary: “Vitamin B12 deficiency can lead to neurological deficits, sometimes in the absence of anemia, and mice and patients with mutations in the transcobalamin receptor CD320 do not develop anemia, suggesting that the mechanisms governing B12 uptake in different tissues are not fully understood. Here, Pluvinage and colleagues identified an autoantibody against CD320 in a patient with progressive neurological symptoms that blocked B12 uptake in endothelial cells and was associated with central but not peripheral vitamin B12 deficiency. The authors identified additional individuals with anti-CD320 autoantibodies and also found an association with neuropsychiatric systemic lupus erythematosus. The low-density lipoprotein receptor was identified as a noncanonical transcobalamin receptor in the periphery only, potentially explaining why anti-CD320 autoantibodies lead to central but not peripheral vitamin B12 deficiency. ”

Pluvinage JV et al. : Transcobalamin receptor antibodies in autoimmune vitamin B12 central deficiency. Science  Translational Medicine 16. (753): DOI: 10.1126/scitranslmed.adl3758 , June 26, 2024.

https://www.science.org/doi/10.1126/scitranslmed.adl3758