CD300LB (CD300 molecule like family member b) is an activating immune receptor that functions through dual signaling mechanisms. It acts as an activating immune receptor through interaction with ITAM-bearing adapter TYROBP and independently through recruitment of GRB2 [UniProt]. The protein is expressed on various immune cell populations and plays important roles in immune regulation and inflammatory responses. CD300LB has been identified as a hub gene in diabetic peripheral neuropathy, showing differential expression in both mouse models and human patients, with confirmed upregulation in high-glucose treated neuronal cells 1. In heart failure patients with DNMT3A mutations, CD300LB is upregulated in classical monocytes alongside other immunoglobulin superfamily members involved in T-cell stimulation, suggesting a role in monocyte-T-cell interactions and inflammatory activation 2. The gene shows altered DNA methylation patterns in systemic lupus erythematosus patients, with methylation changes correlating with specific clinical phenotypes including skin lesions and renal pathology 3. CD300LB expression has also been associated with diabetic retinopathy through immune-related gene signatures and is involved in T cell activation and immune response regulation pathways 4. These findings indicate CD300LB's significance in immune dysfunction across multiple diabetic complications and autoimmune diseases.