In this issue

One of the major justifications for having a separate and independent Journal of Pediatric Allergy & Immunology has been to highlight the importance of early life events in the generation of allergic diseases. It is very timely that a large group of pediatric allergists gathered to review the evidence base of observational and intervention studies in dietary prevention, at a specially constituted Section of Pediatrics meeting within the European Academy of Allergology and Clinical Immunology. Antonella Muraro has done a magnificent job in pulling together all the information which will be published in three parts over the next three issues of the Journal. The first section reviews fetal and early life immune ontogeny in relation to the development of allergic disease as it has been highlighted from many observational studies. The second section of the review discusses the definition of hypoallergenicity as it might be employed in preventive studies. Watch this space for the second two components of this report! While the current state of the art in relation to dietary prevention of allergic disease has focused on exposure to allergenic foods, it is clear that nutritional status has a far more important generic effect on immune responsiveness. This is highlighted in a murine study from Goteborg in Sweden, investigating the influence of dietary essential fatty acid (EFA) intake on the induction of oral tolerance to a food allergen, ovalbumin. Interestingly, pregnant rats fed an EFA supplemented diet had offspring that, when subsequently exposed to ovalbumin in the neonatal period, did not develop transforming growth factor beta induced oral tolerance. Thus, subtle variations in EFA intake during pregnancy may have significant influences on allergic outcomes and this needs to be investigated in more detail in humans. One assumes that alterations to cell membrane lipids are having an effect on regulatory T cell responses. An intriguing paper from Linkoping in Sweden investigates the hypothesis that epithelial leakiness in the mammary gland might lead to increased allergen in breast milk and thereby an increased risk of sensitisation in the breast-fed children. This was investigated by looking at sodium potassium ratios in breast milk. While there was no difference in the ratios between atopic and non-atopic women, there was a trend to a difference in allergic outcomes amongst the infants after 18 months with higher skin prick test positivity and atopic symptoms in those fed with breast milk containing higher sodium potassium levels. There are, of course, numerous other potential factors which may be associated with this observation other than an increased allergen load. This could represent significant differences in cellular function and thereby production of a host of proor anti-inflammatory mediators. A group from Copenhagen has previously shown that the thymus of breast fed infants at 8 months of age is larger than that of their formula fed peers. This phenomenon is further investigated by studying T lymphocyte subsets in long term breast fed vs. variably fed infants. They found a correlation between the CD8+ cells and thymic size. Furthermore, duration of breast feeding had an impact on the absolute numbers of both CD4+ and CD8+ cells. This highlights yet again the very important immune modulatory influence of human breast milk which, of course, is a major focus in relation to dietary interventions. The key issue to address in the future is whether these modulatory influences are affected by maternal health, atopic status, diet, environment and genotype. There has been a recent renewed interest in the inverse relationship between parasitic infestation and allergy. We publish two papers on this topic. The first from Togo in Africa concentrates on falciparum malaria and amoebiasis in pregnant women in relation to cord blood mononuclear cell cytokine responses to parasite specific stimulation. Newborns of infected mothers generated a mixed range of Th-1 and Th-2 cytokines which, in turn, one could hypothesise would modify the potential for subsequent allergic sensitisation. The second from Brazil shows an inverse relationship between house dust mite skin test positivity and exposure to schistosoma mansoni despite equivalent exposures to the mite allergens themselves. Is there any chance that we will be Pediatr Allergy Immunol 2004: 15: 101–102