Background: It has been hypothesised that inflammatory reactions could play an important role in the pathway(s) leading to sudden and unexpected death in infancy. On a molecular level, these reactions are regulated by various cytokines.
Methods: To characterise the role of IL-1ß, IL-6 and TNFα more precisely, the concentrations of these cytokines were determined quantitatively using specific ELISA techniques in serum and cerebrospinal fluid (CSF) in 119 cases of sudden infant death. The infants were grouped into four categories (SIDS, SIDS with infection, natural death due to infection and unnatural death).
Results: A good correlation was found between CSF and serum for IL-6 (Spearman correlation coefficients (SCC), 0.73) and also for TNFα (SCC, 0.57), although the CSF concentrations were lower than that from the serum. There were no significant differences between the categories of death for any of the serum or CSF cytokines. Compared with normal values, increased serum concentrations of IL-1ß, IL-6 and TNFα were found in 70%, 69% and 38% of the cases respectively, indicating possible agonal or post-mortem changes of cytokine concentrations. In three cases very high cytokine concentrations were found (mainly for IL-6). This may have contributed to the mechanism of death (cytokine storm) in two of the cases.
Conclusions: In a small group of patients, very high cytokine concentrations are a possible explanation for the cause of death ("cytokine storm").