Asthma in childhood

The -159 C-->T polymorphism of CD14 is associated with nonatopic asthma and food allergy

BACKGROUND

CD14, the receptor for LPS, plays an important role in innate immunity. A polymorphism in the promotor for CD14, -159 C-->T, has been implicated in atopy.

OBJECTIVE

We explored the relationship of this polymorphism with both atopic and nonatopic asthma, as well as with food allergy.

METHODS

Patients with asthma and food allergy were recruited along with nonatopic, nonasthmatic control subjects. The -159 C-->T polymorphism was genotyped by using the PCR-based RFLP assay.

RESULTS

The -159 T allele was more common among patients with nonatopic asthma and food allergy than among control subjects (chi(2) = 6.03, P =.01 and chi(2) = 4.94; P =.03, respectively). Patients with food allergy had a 4-fold increased odds of having the TT genotype versus carriers of the C allele compared with control subjects (odds ratio [OR] = 3.9, 95% CI = 1.5-10.3), whereas patients with nonatopic asthma had a 3-fold increased odds of having the TT genotype (OR = 3.1 [95% CI = 1.1-9.1]). Controlling for sex differences between groups did not alter this relationship, which remained significant for patients with food allergy (OR = 3.7 [95% CI = 1.4-10.1]) or nonatopic asthma (OR = 2.7 [95% CI = 0.9-8.0]). We performed a stratified analysis, limited to white patients, to reduce population stratification. The relationship with the TT genotype was stronger in white patients with nonatopic asthma (OR = 4.4 [95% CI = 1.3-14.8]) and patients with food allergy (OR = 5.1 [95% CI = 1.6-16.2]), even adjusting for sex differences (OR = 3.9 [95% CI = 1.1-13.5] and OR = 4.6 [95% CI = 1.4-14.8], respectively).

CONCLUSIONS

The TT genotype of -159 C-->T CD14 is associated with nonatopic asthma and food allergy, particularly in white subjects. Thus CD14 is a candidate gene specifically for nonatopic asthma and not for asthma in general. This indicates that atopic and nonatopic asthma might be distinct conditions in their genetic predisposition, despite the fact that they are very similar once they have been established.

Five-year follow-up of high-risk infants with family history of allergy who were exclusively breast-fed or fed partial whey hydrolysate, soy, and conventional cow's milk formulas

BACKGROUND

Allergy is a common cause of illness. The effect of feeding different infant formulas on the incidence of atopic disease and food allergy was assessed in a prospective randomized double-blind study of high-risk infants with a family history of atopy.

METHODS

216 high-risk infants whose mothers had elected not to breast-feed were randomized to receive exclusively a partial whey hydrolysate formula or a conventional cow's milk formula or a soy formula until 6 months of age. Seventy-two high risk infants breast-fed for > or = 4 months were also studied.

RESULTS

Follow-up until 5 years of age showed a significant lowering in the cumulative incidence of atopic disease in the breast-fed (odds ratio 0.422 [0.200-0.891]) and the whey hydrolysate (odds ratio 0.322 [0.159-0.653) groups, compared with the conventional cow's milk group. Soy formula was not effective (odds ratio 0.759 [0.384-1.501]). The occurrence of both eczema and asthma was lowest in the breast-fed and whey hydrolysate groups and was comparable in the cow's milk and soy groups. Similar significant differences were noted in the 18-60 month period prevalence of eczema and asthma. Eczema was less severe in the whey hydrolysate group compared with the other groups. Double-blind placebo-controlled food challenges showed a lower prevalence of food allergy in the whey hydrolysate group compared with the other formula groups.

CONCLUSIONS

Exclusive breast-feeding or feeding with a partial whey hydrolysate formula is associated with lower incidence of atopic disease and food allergy. This is a cost-effective approach to the prevention of allergic disease in children.

Factors associated with asthma in school children

To investigate the factors associated with asthma in school children, a case-control study of 203 asthmatic and 203 non-asthmatic children (103 males and 100 females in each group) aged 6 to 18 years, was organized during the period September 1992 to May 1993 in Al Ain city, United Arab Emirates. Cases comprised known asthmatic children who were regularly receiving medication for asthma and were confirmed as asthmatics by a physician. Cases and controls were matched by age and sex. A questionnaire was used to obtain information about respiratory illnesses (pneumonia, bronchitis, bronchiolitis, sinusitis and croup); atopy (allergic rhinitis and atopic dermatitis) and familial allergic diseases (parental asthma and atopy). Information about socioeconomic status and limitations to children as a result of asthma were also obtained. Logistic regression analysis showed that bronchitis, atopy (allergic rhinitis and atopic dermatitis), croup, parental asthma and parental atopic dermatitis were significant risk factors for childhood asthma after adjusting for other confounding covariates. The model also showed that parental asthma (p < 0.0001) is much more influential than parental atopic dermatitis (p = 0.01) as a risk factor for asthma. Although pneumonia and sinusitis were significant risk factors when analyzed univariately, they were not significant after adjusting for other covariates. Bronchiolitis, smoking and socioeconomic status were beyond the reach of statistical significance as risk factors to asthma in our sample.

Childhood asthma: diagnosis and treatment

This discussion of asthma management should be regarded as providing guidelines, not dogma. The underlying principles of asthma management include recognition of the variability of the disease and the importance of the underlying inflammatory condition. Clinical assessment is not enough and objective monitoring with PEFR or spirometry provides important data. The treatment protocols require individualization. It is important that the patient and family are team members working together with the medical staff toward a goal of good asthma management. In the discussion of the management of asthma, much emphasis was placed on spirometry and home measurement of PEFR. Office use of spirometry is now the norm for asthma management. Providing asthmatic patients with peak flow meters and instructions in their use is part of the routine care of asthma. Instruction of the patient and family in the proper use of medications is paramount. The MDI devices need to be prescribed with careful instructions regarding their use. When the patient comes in for follow-up, part of the examination should include the patient's demonstration of how he uses this device. Discussion of the proper and safe use of bronchodilators is important. Overuse of inhaled bronchodilators may be a reflection of increasing asthma or, at the very least, evidence that the patient does not understand appropriate treatment of asthma. If a patient is dependent on regular use of an inhaled beta agent, it is likely that he would benefit from therapy directed at the underlying inflammation of asthma. The patient and the family should understand the purpose of each medication, the side effects, and the risks and benefits of their use. In particular, if steroid medications are necessary, the reasons for their use should be explained. Carefully matching the severity of the asthma with the therapeutic protocols provides an organized approach to asthma treatment. Avoiding triggers of asthma and controlling the environmental exposure to potential triggers leads to lower medication requirements and less lability. Offering the family written instructions to cope with changes in the child's condition, based on assessment of clinical and PEFR observations, allows them more autonomy and comfort in the day-to-day care of the asthmatic child.