Further Exploration of the Influence of Immune Proteins in Sudden Infant Death Syndrome (SIDS).

Aim: This study aimed to further explore immune protein patterns in cases of sudden infant death syndrome (SIDS) by describing additional findings from an initial proteomic study to investigate whether an unbalanced immune response may contribute to the occurrence of SIDS in certain cases.

Method: The subjects included 46 SIDS cases and 39 controls autopsied at the Department of Forensic Sciences, Oslo, Norway. The causes of death in the controls were accidents/trauma. The normalised protein expression of 92 proteins were analysed in samples of cerebrospinal fluid (CSF) by Proximity Extension Assay (PEA).

Results: For the purpose of this report, 17 of the immune system-related proteins in the assay were chosen for a more in-depth analysis. The major finding was a downregulation in the proteins Retinoic Acid-Inducible Gene I (DDX58/RIG-I), Phosphoinositide-3-Kinase Adaptor Protein 1(PIK3AP1), Interferon Regulatory Factor 9 (IRF9), Tripartite Motif Containing 5 (TRIM5), TRAF Family Member-Associated Nuclear factor kappa B (NF-Κb) Activator (TANK) and TNF Receptor Associated Factor 2 (TRAF2), and upregulation of CXADR Ig-like cell adhesion molecule (CXADR).

Conclusions: The results are in keeping with the findings of earlier studies, supporting the role of immune system dysregulation as a potential predisposing factor for SIDS.