CD34+ hematopoietic stem cells were among the cell types with the highest levels of amphiregulin expression.47 In adults, circulating CD34+ cell levels have also been shown to increase during the first week following sepsis.48 Collectively, these findings, along with our results, suggest that CD34+ cell counts may fluctuate in response to bacterial infections in preterm infants. The gene discussed is AREG; the disease is bacterial infectious disease.