319 - T-cell Receptor Excision Circles and Postnatal Cytomegalovirus Infection in Very Low Birth Weight Infants

Poster Number: 319
Publication Number: 319.124

Alexandra H. Towne, Emory University School of Medicine, Atlanta, GA, United States; Ravi M. Patel, Emory University and Children's Healthcare of Atlanta, Atlanta, GA, United States; Neeta Shenvi, Emory University, atlanat, GA, United States; Kirk A. Easley, Emory University, Atlanta, GA, United States; Cassandra Josephson, Emory University School of Medicine, Atlanta, GA, United States; Lisa Kobrynski, Emory University School of Medicine, Atlanta, GA, United States

Background: Postnatal Cytomegalovirus (p-CMV) infection can cause morbidity in very low birth weight (VLBW) infants, with CMV infected maternal breastmilk being the primary source of infection. Despite the high prevalence of CMV in breast milk of women with past CMV infection, transmission rates of CMV from a mother to VLBW infant during the initial birth hospitalization are low ( < 20%) and risk factors for infant susceptibility to infection are not well understood.

Objective: We investigated cellular immunity using T-cell receptor excision circles (TRECs) as a potential host risk factor for p-CMV infection and hypothesized that significantly decreased levels of TRECs may indicate impairment of cellular immunity, increasing the risk for p-CMV infection in VLBW infants.

Design/Methods: We performed a retrospective secondary analysis of a prospective birth cohort study at 3 hospitals in Atlanta, Georgia. We included VLBW infants receiving CMV-PCR positive maternal breast milk. TREC levels were obtained from routine newborn screen samples and compared by gestational age, infant white blood cell (WBC) count at birth, and development of p-CMV infection based on PCR testing of infant blood or urine after 2 weeks of age with a negative initial test within 5 days of age (to exclude congenital infection). T-tests and linear regression were used for TREC analyses.

Results: Of the 112 infants with CMV positive MBM exposure, 16% developed p-CMV infection (n=18). There was no statistically significant difference in TREC levels among infants with and without p-CMV infection (P=0.17) (Figure 1). There was a linear association between increasing gestational age and increasing TREC levels (P=0.006) (Figure 2). There was no significant relationship between WBC count at birth and p-CMV infection (P=0.31), although WBC count at birth was associated with the TREC level at the time of newborn screening (P=0.002).Conclusion(s): Although limited by sample size, these results do not support any causal relationship between variable T-cell development, as measured by TRECs, and the development of p-CMV infection following exposure to CMV positive maternal breast milk. Notably, TREC levels do not provide information on T-cell function, which may contribute to an infant’s risk of p-CMV infection. Further research is needed to elucidate host and exposure factors responsible for the observed, variable pattern of postnatal CMV transmission from mother-to-infant during the initial birth hospitalization in VLBW infants.
Table 1Descriptive Statistics by Infant CMV Status
Figure 1TREC Levels Among Infants With and Without Postnatal CMV Infection