IFNG and pertussis: We and others have previously reported a strong production of IFN-γ in response to in vitro stimulation with B. pertussis antigens, such as filamentous hemagglutinin (FHA) of PBMC from children presenting with whooping cough [9, 14–16] or vaccinated with pertussis vaccines [17–20], including preterm infants with very low gestational age [21].