Presented at the Neonatal Society 2003 Summer Meeting.
Chuang S-L, Hayes P, Ogundipe E, MacDonald TT, Fell JM (introduced by N Modi)
Departments of Neonatal Medicine, Paediatric Gastroenterology, Chelsea and Westminster Hospital, 369 Fulham Road, Imperial College, London, UK
Introduction: There are several putative mechanisms by which intestinal luminal contents may be implicated in the pathogenesis of necrotising enterocolitis (NEC). The potential role of dietary antigens has yet to be fully explored.
Aim: To characterise, in vitro, the mucosal and systemic cytokine response to stimulation with milk antigens in infants with NEC.
Subjects and Samples: Nine infants with NEC stage 2/3 (modified Bell’s staging) and 19 neonatal controls without intestinal inflammation were studied. Median post-conceptual age of NEC subjects was 32 weeks (range 27-37) and of controls was 38 (29-42) weeks. Blood samples were collected from all subjects. Mucosal specimens were obtained from surgical resection margins in 8 of the NEC patients. Control mucosal specimens (n=11) were non-inflamed surgical resections or biopsies.
Methods: Cytokine secretion, interferon-γ (IFN-γ) and interleukin-4 (IL-4), was quantified at a single cell level using the enzyme linked immunospot technique (ELISPOT). Freshly isolated peripheral blood and mucosal mononuclear cells were incubated in the presence or the absence of phytohaemagglutinin (PHA), β-lactoglobulin (BLG) and α-casein for 20-24h.
Statistical analysis: Case and control groups were compared using Mann-Whitney test.
Results:
Peripheral Blood IFN-γ secreting cells per 100 000 cells:
Peripheral Blood IL-4 secreting cells per 100 000 cells:
* p<0.05; ** p<0.01; *** p< 0.001
Mucosal Cytokines: In control mucosal specimens, virtually no IFN-γ and IL-4 secreting cells were identified before or after stimulation. In NEC specimens, there was a small but significant increase in IFN-γ positive cells following stimulation with PHA (p< 0.001) and IL-4 positive cells following stimulation with PHA (p< 0.001) and BLG (p<0.01).
Conclusions: These data demonstrate sensitization to dietary antigens in the systemic and the mucosal compartments in infants with NEC. The cytokine profile is of both Th1 and Th2 type. These results may have potential implications both for understanding the pathogenesis of NEC and for developing management strategies for infants recovering from NEC.