Rapid Detection of Neonatal Immune System Activation
Methods: Prospective observational unmasked study. Blood and clinical data were collected serially at and after presentation from infants diagnosed with NEC, SIP and matched controls admitted to NICU of Women and Infants Hospital. Infants with NEC were diagnosed by Bell's staging criteria (≥ stage 2 or 3). Infants with SIP were diagnosed by clinical and radiological findings. Controls were matched for gestational age, gender and weight. IAIP levels were measured via a competitive enzyme-linked immunosorbent assay which has a sensitivity of 50 mcg/ml, intra-assay variability (coefficient of variation, CV) of <3% and inter-assay CV of <7%. Mean biomarker levels were subjected to ANOVA and Student Newman Keuls analysis.
Results: There were 28 infants studied in three groups.
|NEC (n=5)||SIP (n=6)||Controls (n=17)||P Value|
|Gestational age, weeks*||275±34||264±15||275±26||0.64|
|Age at presentation, days*||12.2±11.5||8.1±4.8||10.2±7.1||0.11|
|Birth weight, grams*||1025±705||825±243||1067±570||0.69|
|Gender, male %||20%||66%||35%||0.25|
|IAIP at presentation, mcg/ml*||139 ± 21||319 ± 72||276 ± 110||0.01|
Mean±SD IAIP levels measured serially on days 1, 3 and 5 after initial presentation in infants with NEC (170±40, 201±19 and 239±24 mcg/ml) were significantly lower than those with SIP (269±64, 377±84 and 326±47 mcg/ml respectively) (p<0.05).
Conclusion: IAIP levels are decreased in states of immune system activation. As a biomarker, IAIP may assist in early detection of NEC and distinguish NEC from SIP. This distinction at presentation may lead to earlier effective treatments and improved outcomes including long term neurodevelopmental sequelae. Since IAIP correlates with disease progression, it may serve as a surrogate to monitor response to therapy in NEC.
J. Padbury, None