NEONATAL SOCIETY ABSTRACTS
Cord blood lymphocyte count as a potential screening tool for severe combined immunodeficiency (SCID)
Presented at the Neonatal Society 2018 Summer Meeting (programme).
Timon J1, Wrafter A2, Gilmore R2, Moylett E1
1 Academic Department of Paediatrics, NUI Galway
2 Department of Haematology, UHG
Background: SCID is a rare inherited disease of the immune system commonly characterised by lymphopenia at birth. The condition is typically fatal unless corrected. The aim of our study was to investigate a useful cut-off absolute lymphocyte value (cord blood sample) as a potential screening tool for SCID; a secondary aim was to evaluate the feasibility of cord sampling as a screening method for SCID.
Methods: All healthy term infants delivered during an 8-week study period were viable for inclusion. Consent was obtained as an ‘opt-out’ during antenatal visits or at onset of labour. A full blood count was performed on each cord blood sample focusing on a lower absolute lymphocyte limit of 2 x 10^9 as a predictor for possible SCID. The study was approved by the Clinical Research Ethics Committee.
Results: Over the 8-week period, there were approximately 360 births in UCHG with 324 of these fitting our inclusion criteria, despite this cord samples were obtained from only 133 healthy term newborns. 26 of these samples were clotted; therefore 107 samples were fully analysed. We report a mean lymphocyte value at birth of 5.51 x10^9L (SD, 1.787; range, 0.9-11.7), neutrophils a mean of 6.98x10^9L (SD, 2.67; range, 2.9-14.4) and platelets a mean of 276.36x10^9L (SD, 65.2; range, 39-430). One newborn had a lymphocyte count below our cut off point (0.9 x10^9), this child was followed up and values normalized within the first few weeks of life.
Conclusion: Cord samples are easy to obtain however many missed opportunities would negate this approach for a national screening approach. Normative data for full blood count values were generated. A lower white cell count of 1.5 would be acceptable for SCID screening purposes.
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