Form of B12 Deficiency Affecting the Central Nervous System May Be New Autoimmune Disease

Alternative Pathways

Lastly, Dr. Pluvinage and colleagues set out to explain why patients with anti-CD320 in their blood did not show any signs of B12 deficiency. They hypothesized that another receptor may be compensating and still allowing blood cells to take up B12. Using CRISPR screening, the team identified the low-density lipoprotein receptor as an alternative pathway to B12 uptake.

“These findings suggest a model in which anti-CD320 impairs transport of B12 across the BBB, leading to autoimmune B12 central deficiency (ABCD) with varied neurologic manifestations but sparing peripheral manifestations of B12 deficiency,” the authors wrote.

The work was supported by the National Institute of Mental Health, National Center for Chronic Disease Prevention and Health Promotion, Department of Defense, UCSF Helen Diller Family Comprehensive Cancer Center Laboratory for Cell Analysis Shared Resource Facility, National Multiple Sclerosis Society, Valhalla Foundation, and the Westridge Foundation. Dr. Pluvinage is a co-inventor on a patent application related to this work. Dr. Diamond had no relevant disclosures.

A version of this article first appeared on Medscape.com.