Unveiling the hidden syndrome: The enigma of anti-transcobalamin receptor autoantibodies.

The transcobalamin receptor (CD320) functions as a critical mediator for vitamin B12 uptake in cells, with emerging evidence linking autoantibodies against CD320 to various autoimmune conditions. Pluvinage et al.'s recent study identified anti-CD320 autoantibodies as a cause of autoimmune vitamin B12 central deficiency, specifically affecting the central nervous system while sparing peripheral nerves. Their findings align with our previous work showing anti-CD320's role in cutaneous arteritis. Both studies identified overlapping CD320 epitopes targeted by autoantibodies and demonstrated the therapeutic efficacy of high-dose vitamin B12 supplementation in mitigating symptoms. Expanding on these findings, we observed anti-CD320 autoantibodies in other inflammatory disorders such as systemic sclerosis, suggesting a broader clinical relevance. The work by Pluvinage et al. and our group supports the concept of an "anti-CD320-associated syndrome," with high-dose B12 supplementation as a promising treatment strategy. Further research is needed to fully elucidate the tissue-specific mechanisms and pathophysiology underlying these autoimmune conditions.