Attenuation of monocyte proinflammatory cytokine responses to Neisseria meningitidis in children by erythropoietin

Meningococcal disease is a leading infectious cause of death in children in industrialized countries. The induction of high levels of proinflammatory cytokines has been implicated in the pathogenesis of Neisseria meningitidis-related multi-organ failure. Here, we demonstrate that N. meningitidis serotypes A and B induce significantly higher levels of tumour necrosis factor (TNF)-α positive cells in vitro in infants and young children compared with adults (serotype A/B; infants: 64.9%/63.9%; children: 77.8%/64.3% versus adults: 27.7%/32%; P < 0.005). Serotype A induces also higher levels of interleukin (IL)-6 positive cells in neonates and infants compared with adults (serotype A; newborn 55.4%; infants 58.8% versus adults 49%; P < 0.05). Treatment with human recombinant erythropoietin in vitro resulted in significant attenuation of the N. meningitidis-induced proinflammatory response in all age groups (reduction rate of erythropoietin for IL-6 after stimulation with serotype B: newborn 28%, infants 15%, children 23% and adults 28% and for TNF-α after stimulation with serotype B: newborn 27%, infants 22%, children 20% and adults 28%; P < 0.05). We conclude that (i) Neisseria meningitidis induces a higher TNF-α response in infants and children compared with adults and (ii) erythropoietin was able to attenuate IL-6 and TNF-α production in all investigated age groups. These data may explain the high incidence of meningococcal infection in infants and makes erythropoietin a potentially attractive candidate for interventional strategies in an otherwise devastating course of the disease.