H. P. Van Bever

Does the use of antibiotics in early childhood increase the risk of asthma and allergic disease

One of the mechanisms evoked to explain the increasing prevalences of asthma and allergy, in particular among children, is the ‘Western lifestyle’ or ‘hygiene’ hypothesis. As early childhood infections are assumed to hold a protective effect on the development of asthma and allergies, the use of antibiotics at that sensitive age may lead to an increased risk of asthma and allergy.

Differences in circulating dendritic cell subtypes in cord blood and peripheral blood of healthy and allergic children

Background Different types of circulating dendritic cells have been described. Dendritic cells influence differentiation of naive T lymphocytes into T helper type 1 (Th1) and Th2 effector cells.

Long-term effects of specific immunotherapy, administered during childhood, in asthmatic patients allergic to either house-dust mite or to both house-dust mite and grass pollen.

In a retrospective study, asthmatic patients allergic to either house‐dust mite (HDM) (Dermatophagoides pteronyssinus) (n=34) or to both HDM and grass pollen (GP) (n=14), and who were treated with specific immunotherapy (SIT) during childhood (mean duration of SIT: 61±9.70 months), were re‐evaluated in early adulthood after mean cessation of SIT for 9.3±2.76 years. The results were compared to those of a control group of asthmatic patients (n=42) with comparable asthma features, who were treated with appropriate antiasthmatic drugs during childhood, but who never received SIT. Re‐evaluation was carried out with a standardized questionnaire, skin prick tests (SPT), and lung‐function assessments. At the time of re‐evaluation, the mean age in the SIT‐treated group was 23.1±3.50 years; in the control group, it was 22.7±3.40 years. At re‐evaluation, the risk of frequent asthmatic symptoms was three times higher in the control group than in the SIT‐treated group (prevalence ratio: 3.43; P=0.0006). The frequent use of antiasthmatic medication was also more pronounced in the control group, although the difference was not statistically significant (P=0.38). Lung‐function parameters and results of SPT with HDM were comparable in both groups. It is concluded that SIT has long‐term effects on asthmatic symptoms in young adults.

Perinatal risk factors for sensitization, atopic dermatitis and wheezing during the first year of life (PIPO study)

Objective To evaluate the influence of perinatal environmental factors on early sensitization, atopic dermatitis and wheezing during the first year.

Modification of the late asthmatic reaction by hyposensitization in asthmatic children allergic to house dust mite (Dermatophagoides pteronyssinus) or grass pollen

The frequency and severity of the late asthmatic reaction (LAR) was studied in asthmatic children allergic to house dust mite (HDM) or grass pollen (GP) with and without hyposensitization (HS). The four groups were comparable according to their severity of asthma. AU children were allergic to HDM (Dermatophagoides pteronyssinus) or GP according to history, skin testing and specific IgE determination via the RAST. The LAR occurred less frequently (29% versus 73%) (P < 0.001) and was less severe in children receiving HS. The difference was significant between the children allergic to HDM as well as between children allergic to GP. The immediate asthmatic reaction (IAR) was also less severe in children allergic to HDM who received HS, compared to those who never received HS, (P=0.033) although the PD20 of the HDM challenge (PD20HDM) was not different between the two groups. In children allergic to GP, there was no difference in PD20 of the GP challenge (PD20GP) or in severity of the IAR, whether the children received HS or not. There was no difference between the PD20HDM in patients who developed a LAR and in patients who did not. There was no relation between the type of asthmatic reaction following the allergen provocation test and the level of circulating immune complexes (CIC) and the level of house dust mite‐specific IgG (IgGHDM) or grass pollen‐specific IgE (IgGGP) in the different groups, determined before the challenge. There was a decrease in the level of IgG containing GIG (IgGCIC) during the LAR. It is concluded that the LAR occurs less frequently and is less severe in asthmatic children who receive HS.

Critical evaluation of prognostic factors in childhood asthma

Current knowledge of the natural history of asthma is improving through the establishment of a more precise definition of asthma linked with information from a number of large‐scale longitudinal studies. Risk factors for the development of childhood asthma are now more clearly understood. They include gender, atopic status, genetic and familial factors, respiratory infections, and outdoor and indoor pollution ( 1 ). In the present review two types of asthma and their prognosis will be discussed:

Immune complexes and Pseudomonas aeruginosa antibodies in cystic fibrosis.

Serum samples from 57 patients with cystic fibrosis were tested for the presence of IgG, IgA, IgM, IgE, and circulating immune complexes containing IgG, IgA, and IgM. Titres of class specific antibodies to Pseudomonas aeruginosa, and class specific antibodies to Ps aeruginosa in circulating immune complexes, were also measured. According to the Shwachman score the patients were divided into three clinical groups: group 1-moderate and severe disease, group 2-mild disease, and group 3-well. The results of the immunological investigations were correlated with the clinical state of the patients as assessed by the Shwachman score. Serum concentrations of IgG, IgA, and IgM were inversely correlated with the Shwachman score, but the differences between the groups were only significant for IgG and IgA. The same correlations were found for circulating immune complexes containing IgG and IgA. Antibodies to Ps aeruginosa could be detected in most of the patients serum samples. IgA antibody specific to Ps aeruginosa was the most often raised, even in patients in group 3. It is therefore suggested that IgA antibody specific to Ps aeruginosa could be an early marker of colonisation by Ps aeruginosa and a sensitive measurement of infection with Ps aeruginosa in young children with cystic fibrosis. Moreover, in the circulating immune complexes, class specific antibodies to Ps aeruginosa were found in nearly half the patients. The highest titres of IgG and IgA antibodies specific to Ps aeruginosa in the circulating immune complexes were detected in the patients with the worst clinical state (group 1).

Nebulization treatment with saline compared to bromhexine in treating chronic sinusitis in asthmatic children

Twenty children aged 3 to 14 years with a history of bronchial asthma complicated by chronic sinusitis were studied in a double‐blind study. Patients received, at random, over a period of 2 weeks, either 2 ml saline or 2 ml bromhexine (2 mg/ml) t.i.d. by means of a home nebulizer. A significant decline of clinical symptoms during both nebulization treatments as compared to the pretreatment symptom score was observed (mean score of 1.5 ± 0.7 and 0.5 ± 0.8, respectively, (P 0.01). Both types of nebulization were equally efficient in reducing the symptom score. Radiological abnormalities were significantly more reversed after saline nebulization as compared with bromhexine (P< 0.05), although both treatments showed radiological improvement (P< 0.01). The present study indicates that nebulization with saline may have some beneficial effect on chronic sinusitis in asthmatic children. Bromhexine was not superior to saline for this purpose.

Detection of hypodense eosinophils by Percoll multilayer density gradient centrifugation in subjects with normal or slightly elevated eosinophilia. Poor reproducibility and eosinophils of density < 1.077 g/ml.

In patients with marked hypereosinophilia hypodense and normodense eosinophils have been found after density gradient centrifugation. Subsequently this terminology has also been used in studies of patients with milder eosinophilia. However, in these cases the differentiation between normo- and hypodense eosinophils was less clear. This might be due to the high imprecision of the test of density gradient centrifugation, as demonstrated in the first part of this study: the mean within-assay variance of the number of eosinophils in the different density layers was 35%. It was calculated that the test must be performed eight times to obtain an estimate of the true mean for the individual patient. In the second part of the study, the absolute number of hypodense eosinophils in groups of patients with asthma (adults and children) and rheumatoid arthritis (adults) were compared to normal controls. Although a difference in the absolute number of hypodense eosinophils between groups of patients and controls could be demonstrated, the high imprecision of the test of density gradient centrifugation suggested that the technique used was not useful in an individual with normal or slightly elevated eosinophils in the peripheral blood.

Influence of hyposensitization on soluble interleukin-2 receptor, eosinophil cationic protein, in vitro lymphocyte proliferation, in vitro lymphocyte adhesion, and lymphocyte membrane markers in childhood asthma

Soluble interleukin‐2 receptor (sIL‐2R), eosinophil cationic protein (ECP), the lymphoproliferative response to house‐dust mite (HDM), adhesion to human umbilical vein endothelial cells (HUVEC), and lymphocyte membrane markers were studied in three groups of children: healthy children, asthmatic children without hyposensitization (HS), and asthmatic children with HS. HS was associated with significantly lower numbers of peripheral blood eosinophils (PBE) and lower sIL‐2R serum levels and with a tendency to lower ECP serum levels and lymphoproliferative response to HDM. There were no changes in the T‐lymphocyte phenotypic markers CD4 and CDS among the three groups. The interleukin‐2 receptor (IL‐2R, CD25) on HDM‐stimulated T lymphocytes increased over unstimulated T lymphocytes in the three groups. The CD25 expression was higher on HDM‐stimulated lymphocytes in both asthmatic groups than in healthy children. Adhesion of lymphocytes on HUVEC increased significantly after HDM stimulation in asthmatic children without HS, whereas no change was observed in the two other groups. However, there was no change in the expression of adhesion molecules CD29 and CD1 la on lymphocytes in either of the groups. This study provides further evidence that HS can modify lymphocyte and eosinophil functions.