CD14 -550 C/T, which is related to the serum level of sCD14, is associated with the development of RSV bronchiolitis in the Japanese population. This study's results indicate that, in different ethnic groups, different genetic factors contribute to the development of RSV bronchiolitis.

SUMMARYThe immunological mechanisms by which respiratory syncytial virus (RSV) contributes to the development of asthma are poorly understood. gd T cells are important in mucosal defence, and may contribute to the establishment of primary immune responses by producing cytokines early during respiratory infections. Thus, we used flow cytometry and intracellular cytokine staining to investigate the expression of interferon (IFN)-g and interleukin (IL)-4 by mitogen-stimulated gd T cells from the peripheral blood of 15 hospitalized infants with RSV bronchiolitis, seven rotavirus-infected infants and eight normal controls. gd T cells from RSV-infected infants had a lower proportion of IFN-g -producing cells (median, 4.00%; range, 0.58-6.60%) and a slightly but significantly higher proportion of IL-4-producing cells (median, 0.40%; range, 0.13-2.76%) than rotavirus-infected infants (median, 32.10%; range, 14.43-61.21%; P < 0·01, median, 0.00%; range, 0.00-0.00%; P < 0·05) in the acute phase. By contrast, differences in cytokine production by total CD3 + T cells did not differ significantly between patient groups. Thus, reduced IFN-g -production by gd T cells in the peripheral blood of RSV-infected infants is accompanied by increased Th2 cytokine production during the acute phase of disease. At follow-up, eight children had recurrent episodes of wheezing. The frequencies of IFN-g -producing gd T cells were significantly lower in patients who developed recurrent wheezing (median, 0.65%; range, 0.02-1.75%) than in patients without recurrent wheezing (median, 6.90%; range, 5.25-10.98%; P < 0·005). Cytokine production by gd T cells may therefore be important in the pathogenesis of acute RSV disease, and play a part in the development of recurrent childhood wheezing after bronchilolitis.

Background: In allergic rhinitis, the major symptoms of runny nose, sneezing, and stuffy nose tend to become worse upon waking up in the morning, and yet the mechanisms underlying this phenomenon are poorly understood. We investigated whether the worsening of allergic rhinitis in the morning is associated with changes in the activity of inflammatory cells. Methods: Nasal reactivity to methacholine was assessed twice in 8 children with allergic rhinitis and 8 healthy control subjects at 6.00 a.m. and 3.00 p.m. The amounts of eosinophil cationic protein (ECP), histamine and tryptase in induced nasal secretions and peripheral blood were also measured. Results: Nasal reactivity to methacholine was higher at 6.00 a.m. not only in patients but also in healthy controls. Serum ECP and plasma histamine levels showed no circadian patterns. On the other hand, significantly higher levels of inflammatory activation products were found in nasal secretions at 6.00 a.m., thus showing a direct association with nasal reactivity. Conclusion: These results suggest that the circadian variation in nasal reactivity is associated with changes in the activity of eosinophils and basophilic cells in the nasal mucosa.

The CD14-159 and -550 polymorphisms might not play a major role in the pathogenesis of food allergy in Japanese children.

SummaryLower numbers of Vc9Vd2 T cells in cord blood (CB) than in adult peripheral blood (PB), as well as their impaired ability to produce interferon-c (IFN-c) in response to stimulation, are associated with functional deficiency in the immune system in newborns. In this study, we stimulated CB Vc9 T cells with their T-cell receptor-specific ligand, isopentenyl pyrophosphate (IPP), plus exogenous costimulatory cytokines such as interleukin-2 (IL-2), IL-12 and tumour necrosis factor-a (TNF-a), which are known to play important roles in the activation of PB cd T cells. Our data show that CB Vc9 T cells are able to produce IFN-c at levels comparable to PB Vc9 T cells by the addition of TNF-a in the presence of IPP and IL-2; however, under the same culture conditions, IL-12 does not efficiently activate CB Vc9 T cells to produce IFN-c. The frequency of TNF-a receptor II-positive Vc9T cells and the expression levels of TNF-a receptor II are similar in CB and PB; in contrast, the frequency of IL-12 receptor bI (IL-12RbI) -positive Vc9T cells and expression levels of IL-12RbI are significantly lower in CB than PB. TNF-a but not IL-12 increases the expression of IL-2Rb on CB Vc9 T cells. These results provide new insights into the role of TNF-a in the activation of CB Vc9 T cells.