In instances of lung inflammation such as in mouse models of influenza and nematode infection, TSG-6, the secreted product of TNF-stimulated gene-6 protein [25] catalyzes the covalent transfer of the heavy chains (HC) belonging to the inter-α-inhibitor (IαI) family of proteoglycans onto HA, to form ‘HC•HA’ complexes [15,16,26]. The gene discussed is TNFAIP6; the disease is influenza.