Exploration of Immunology

Table 2. Effects of vitamin B12 deficiency on innate immune components and cytokines [2, 13, 14].

Immune cell	Vitamin B12 optimal status	Vitamin B12 deficiency	Consequences	Mechanisms	References
Macrophages	Phagocytosis, ROS, NO production	Impaired function	Reduced bacterial killing (experimental models)	Reduced mitochondrial energy; decreased adenosylcobalamin-dependent TCA cycle flux	[2, 13, 14]
Neutrophils	Chemotaxis, ROS generation	Impaired migration	Reduced pathogen clearance	Impaired energy metabolism; altered NADPH production via HMP shunt	[2, 14]
NK cells	Cytotoxicity, proliferation	Decreased activity	Reduced anti-viral/tumor responses	Altered signaling; impaired proliferation and function	[2, 13, 14]
Cytokines	IL-6, TNF-α, IL-10 regulation	Dysregulated	Pro-inflammatory shift	NF-κB modulation; redox-sensitive pathways	[13, 14]

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HMP: hexose monophosphate; NADPH: nicotinamide adenine dinucleotide phosphate; NF-κB: nuclear factor kappa-light-chain-enhancer of activated B cells; NK: natural killer; NO: nitric oxide; ROS: reactive oxygen species; TCA: tricarboxylic acid; TNF-α: tumor necrosis factor alpha.

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Acknowledgments

AI-Assisted Work Statement: During the preparation of this work, author(s) used ChatGPT for assistance in generating Figure 1. After using the tool, author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the publication.

The authors wish to sincerely thank the patients and clinicians of the Strasbourg B12 research group (CARE B12) at the Hôpitaux Universitaires de Strasbourg (HUS, France) for their invaluable contributions to this study.

Author contributions

EA: Conceptualization, Investigation, Writing—original draft, Writing—review & editing. NLV: Conceptualization, Investigation, Writing—original draft, Writing—review & editing. TL: Validation, Writing—review & editing, Supervision. All authors read and approved the submitted version.

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The authors declare no conflict of interest.

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