Characteristics of Cord Blood Immunologic Parameters of Infants <32 Weeks Gestation

Characteristics of Cord Blood Immunologic Parameters of Infants < 32 Weeks Gestation

Infants in the NICU are at high risk for morbidity and mortality from infections of any onset. Diagnosis of these infections is imperfect at best. Patterns of inflammatory and regulatory proteins (cytokines & chemokines, in addition to antigen detection on antibody secreting cells (ASC's)may provide a more accurate and rapid approach to diagnosis of infections in these high-risk patients.

Sampling methods/Data collection

Samples: Serum (1-2ml) from enrolled infants will be collected from cord blood (T0). Serial samples (0.5-1ml) will be collected at 3 other times: T1= 4-7 days, T2=10-14 days, T3= 20-30 days. These can be drawn at initiation of any sepsis work-up, or prior to any transfusion of PRBC's or when any blood ≥0.5ml will be wasted. These collections are intended to analyze the immunologic milieu in infants at various stages of natal and post-natal immune adaptation:

1. baseline levels from a relatively privileged environment (cord blood T0)
2. peak of immunogenic response after prenatal exposure (T1)
3. plateau of immunogenic response after perinatal exposure (T2)
4. relative state of equilibrium with surrounding flora (T3)

Data collection:

Baseline statistics at enrollment: Birth weight, obstetrical assessment of gestational age, mode of delivery, presence of labor, presence of IAI, ROM, intrapartum antibiotics type and length, With each sampling, data will be gathered via chart review on each infant. We will also gather data at 60 DOL, discharge, or death on any infant enrolled.

Measurements:

Experimental laboratory:

Cytokines- Each sample will have plasma analyzed by Luminex (Biorad) to determine profiles of cytokines: IL-2, IL-6, IL-8, IL-13, MIP1b, MCP1, IL-1b, IL-4, IL-5, IL-7, IL-10, IL-12p70, IL-17, GMCSF, IFN-gamma, and TNF-alpha. Standard curves for each cytokine measurement were run to determine upper and lower limits of detection.

ASC- will be quantified by enzyme-linked immunospot assay (ELISPOT) for specific isotypes IgA, IgM, and IgG. They will also be linked to 3 particular immunogenic agents: GBS, Candida, and CoNS.

Clinical laboratory:

Total WBC and band ratio will be run in the routine course of care for these infants. This is not an additional sample.

serious bacterial infections other than sepsis (meningitis, UTI)

• Course of Study- 0-30 days of life for sampling. 0-60 days of life for data collection.
• Enrollment- consecutive admissions of NICU under the following criteria

Inclusion:

Admitted to NICU at MHCH

• 1500gm or ≤ 32 wk GA Birth to <31 days of life at time of enrollment

Exclusion:

Known or suspected immunodeficiency (including maternal HIV or other known congenital infection) Known major congenital anomaly

• Recruitment Will include each eligible infant by the primary investigator or co-investigators. Assuming an incidence of LOS of ~25% and EOS of ~1-3%, a power of 80%, we should enroll 50 infants. This coincides with prior studies evaluating ASC's response in neonates, and those evaluating cytokines in cord blood and post-natally.
• Known Risks There will be no additional blood draws. There will be collection of a greater volume of blood (additional 0.5ml-1.0ml depending on size of infant) during clinical indications for blood draws. No clinical decisions will be made based on the data obtained.

Inclusion Criteria:

• Infants born at Children's Memorial Hermann Hospital with cord blood available < 1500gm or < 32 weeks gestation by OB estimate

Exclusion Criteria:

• Outborn infants transferred to CMHH without cord blood available
• Parents to not consent
• > 1500gm or > 32 weeks gestation by OB estimate