Dynamics of the NK-cell subset redistribution induced by cytomegalovirus infection in preterm infants

Human cytomegalovirus (HCMV) infection promotes an expansion of NK-cells expressing the CD94/NKG2C receptor. We prospectively monitored the effects of HCMV on the NK-cell receptor (NKG2C, NKG2A, KIR, LILRB1) distribution in preterm infants. As compared to non-infected moderately preterm newborns (. n=. 19, gestational age: 32-37. weeks), very preterm infants (. n=. 5, gestational age: <32. weeks) suffering symptomatic postnatal HCMV infection displayed increased numbers of NKG2C%2b, KIR%2b NK-cells, encompassed by a reduction of NKG2A%2b NK-cells. A similar profile was observed in HCMV-negative newborns (. n=. 4) with asymptomatic infection, during follow-up at ~4 and 10. months of age. Of note, viremia remained detectable in three symptomatic cases at ~10. months despite the persistent expansion of NKG2C%2b NK-cells. Our study provides original insights on the dynamics of the imprint exerted by primary HCMV infection on the NK-cell compartment, revealing that the expansion of NKG2C%2b NK-cells may be insufficient to control viral replication in very preterm infants. © 2015 American Society for Histocompatibility and Immunogenetics.

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