In this issue

While there has been an excellent recent state of the art supplement of the Journal of Allergy and Clinical Immunology on hereditary angioedema (1), it is entirely appropriate that we should publish a report from the immunology department in the Royal Children’s Hospital, Melbourne Australia on management in children. Mimi Tang and her colleagues provide some excellent and very easy to follow procedural guidelines. I strongly recommend them to you all. While it is now clear that gut associated lymphoid tissue develops relatively early in the second trimester of pregnancy, very little information is available on bronchus associated lymphoid tissue. It is, therefore, with great pleasure that we publish a paper on this topic from Hanover in Germany. It is remarkable that, under normal circumstances, airway lymphoid tissue is relatively underdeveloped by comparison with that in the gut (2). It is only in situations where there is significant choreo-amniitis that it becomes apparent antenatally. The key issue to address is why there is this big difference in tissues of the same embryological origin. The foetal gut is bathed in a range of immunoregulatory factors originating from decidual tissues and present in amniotic fluid. However, while the foetus makes respiratory movements, there is a net egress of lung fluid rather than ingress of amniotic fluid to the airways. We publish a remarkable paper from Groningen studying diurnal variations in peripheral blood mononuclear cell generation of TH-1 and TH-2 cytokines and the effect of an overnight hydrocortisone infusion in a double-blind crossover study. While the hydrocortisone abrogated the nocturnal dip in lung function, it had no effects on the levels of cytokine production from stimulated mononuclear cells. The authors hypothesize that the effect of the hydrocortisone was on local lung tissue inflammation rather than circulating cells. This seems rather surprising given that the steroid was administered systemically rather than to the airway. It is perhaps more likely that the steroid had an impact on cell traffic into the airway. Non-steroidal anti-inflammatory drugs employed in asthma have been relatively disappointing as therapeutic agents, with perhaps the exception of montelukast which has now achieved a place in the therapeutic algorithm. In a study from Taiwan, ketotifen was shown to have a significant effect on some immune mediators of inflammation despite the fact that as a therapeutic intervention its effect is remarkably small. Montelukast on the other hand did not modify the same parameters but had a greater effect in improving exhaled nitric oxide, lung function and asthma symptoms. Thus, extrapolating from in-vitro to in-vivo effects can lead to inappropriate conclusions. Recently, a great deal of attention has focused on the regulatory cytokine transforming growth factor b (TGFb) which also has a significant impact in influencing fibroblast activity. Inevitably, therefore, several studies have attempted to identify polymorphisms of the TGFb gene as a risk factor for asthma. A study from Germany has failed to show any associations between asthma in a Caucasian population and TGFb1 gene polymorphisms. While there is some limited evidence that the allergy epidemic is perhaps subsiding in developed countries (3), the same does not appear to be true of developing countries that have more recently adopted a western lifestyle; this is highlighted again in a study from Estonia, particularly in relation to seasonal allergic rhinitis. This study also showed that the effects of adopting a westernised lifestyle is not restricted to infants but has an effect throughout the childhood age range. We highlighted this issue in two other recent publications (4, 5). The journal has published many of the outputs from large birth cohort studies investigating risk factors for the development of allergic disease. Many now also include interventions particularly to reduce exposure to house dust-mite. The Dutch researchers are pre-eminent in this field and there is now a new study in progress known as PREVASC. It will be very interesting to compare the results of this study with that of PIAMA, which also originates from the Netherlands (6), and SPACE, a pan-European mite avoidance study (7). In this issue the design of the study is Pediatr Allergy Immunol 2005: 16: 286–287 Copyright 2005 Blackwell Munksgaard