SYK and Immunodeficiency: The GPVI-spleen tyrosine kinase (SYK) signalling cascade has been shown recently to be downregulated in critically ill adult patients with sepsis, hinting towards a key role in sepsis pathophysiology.64 Given the known hyporesponsiveness of TLR 4 in monocytes from this age group, and the fact that SYK is involved in both pathways, it is tempting to hypothesise that this represents a key intracellular step in the relative immunodeficiency in neonates.65