Methods: A clinical study was conducted at KK Women’s and Children’s Hospital, where 55 cord blood samples from Caesarean section-delivered infants were collected to evaluate the response to allergens in the cord blood cells. Freshly isolated cord-blood mononuclear cells (CBMCs) were cultured in a 96-well plate at 100,000 cells per well (in triplicate per condition) and stimulated with the extracts from either one of major house dust mite species: Blomia tropicalis (BloT) and Dermatophagoides pteronyssinus (DerP). Phytohemagglutinin (PHA) and Lipopolysaccharide (LPS) were used as positive controls. The supernatants of these cutures were harvested after 5-day stimulation and were analyzed using the Bio-Plex ProTM Human Cytokine assay. The production of IL-5, IL-13, IFN-gamma and TNF-alpha by the allergen-stimulated CBMCs were analyzed.
Results: DerP stimulation induced a higher response as compared to BloT stimulation. Following DerP stimulation, the median value of IL-5 was 2.5 pg/mL (0-172 pg/mL), IL-13 – 9.1 pg/mL (0-158 pg/mL), IFN-gamma - 321 pg/mL (69-1978 pg/mL) and TNF-alpha - 1393 pg/mL (74-5658 pg/mL). Among the 55 analysed subjects, while 3 subjects (5%) showed higher expression of IFN-gamma (above 1000 pg/mL) and lower expressions of IL-5 and IL-13 (both below 20 pg/mL), 6 subjects (11%) displayed higher expressions of IL-5 and IL-13 (both above 20 pg/mL). TNF-alpha levels were detected high in most subjects. Of note, no correlation between strong production of TH2-like cytokines (IL-5 and IL-13) and parental allergy history was observed.
Conclusion: We observed a strong production of TH2-like cytokines in 11% of C-section-delivered infants upon DerP stimulation. Interestingly, these infants did not have any history of parental allergy. This finding might indicate in utero sensitization of these infants. The TH2-like cytokine profile in cord blood might be useful as an early sign of atopic manifestations in future. We plan to follow-up these subjects in order to monitor the development of allergic response later in life.