High anti-IgE levels at birth are associated with a reduced allergy prevalence in infants at risk: a prospective study.

Development of atopic disease was prospectively studied in 148 children from birth to the age of 18 months and related to serum levels of IgG anti-IgE antibody. Children with a dual heredity of allergy, but remaining healthy, had significantly higher IgG anti-IgE levels at birth than children with a similar predisposition to allergy, who became allergic. Children with increased allergy risk, defined by elevated IgE levels at birth (> = 0.53 kU/l) and with probable allergy symptoms had also significantly higher IgG anti-IgE levels at birth than children of the same risk group, developing definite allergy. Independent of allergy risk, there was a significantly lower prevalence of atopic disease in children with cord serum levels of IgG anti-IgE above 350 AU/l than in children with lower levels. Additionally, we showed that the allergy predictive capacity of IgE levels in cord serum was slightly improved in specificity, sensitivity and efficiency by including not only the family history of allergy, but also cord serum levels of IgG anti-IgE. Our results thus raise the possibility that high levels of IgG anti-IgE protect children of increased allergy risk from early development of atopic disease and reduce the severity of symptoms.

Slight steroid-sparing effect of intravenous immunoglobulin in children and adolescents with moderately severe bronchial asthma.

Twenty subjects (aged 6-20 years) with moderately severe bronchial asthma participated in an open controlled trial with intravenous immunoglobulin (IVIG) given as five monthly infusions with a mean dose of 0.8 g/kg body weight. A follow-up was performed 4 and 14 months after the treatment period. Nine of 14 children in the treatment group completed the trial. Two children experienced severe headache after the first infusion, another two patients were taken off the study for reasons unrelated to the IVIG therapy, and one patient dropped out from lack of motivation. In six of the IVIG-treated children, there was a reduction in the daily intake of inhaled steroids at an unchanged or reduced histamine reactivity. Of the remaining three children, two showed a reduction in bronchial hyperreactivity, but their steroid dose was not reduced. Six patients participated in a reference group to determine seasonal variations of symptoms. One of them improved during the study period, and the condition of the other five deteriorated, as indicated by increased medication without reduced histamine reactivity. After 14 months, there were no significant differences in clinical symptoms, nor in sensitivity to histamine between the treated patients and the controls, as the condition had improved also in the latter. We have thus been able to confirm, in a group larger than those in previously published reports, some clinical improvement of asthma by IVIG therapy at a lower dose than previously used and in children with only moderately severe disease. The effect was still present 4 months after the termination of IVIG therapy but not after 14 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Natural anti-IgE auto-antibodies interfere with diagnostic IgE determination.

A simple method is described which enables measurement of anti-IgE antibodies in free form as well as in immune complexes of IgE and anti-IgE. Anti-IgE antibodies were purified from serum of one selected blood donor with highly elevated levels of such autoantibodies. These purified anti-IgE auto-antibodies inhibited the measurement of myeloma IgE. Purification also revealed that 98% of the subject's serum IgE was masked by anti-IgE auto-antibodies. Our data suggest that IgE determinations in sera containing anti-IgE antibodies might be underestimated.

[The clinical significance of anti-IgE antibodies in the treatment of allergic rhinopathy]. / Die klinische Bedeutung von Anti-IgE-Antikörpern für die Behandlung der allergischen Rhinopathie.

A simple assay, based on monoclonal antibodies, was used to measure "free" anti-IgE antibodies or anti-IgE antibodies in immune complexes of IgE and anti-IgE. No significant correlation was found between serum IgE levels and the concentration of anti-IgE antibodies. Furthermore, patients who were successfully treated by hyposensitization therapy showed only unmeasurable or extremely low anti-IgE antibody levels in their serum. However, patients who were unsuccessfully treated by hyposensitization had elevated anti-IgE serum titers. Thus, determination of anti-IgE antibodies might become a tool for predicting the success of hyposensitization therapy.

Influence of IgE fragments on IgE determination.

IgE fragments were detected by polyclonal and monoclonal anti-IgE antibodies using Western blot techniques and immunoassays. Other antibodies detected only intact IgE molecules. In the presence of IgE fragments, higher IgE levels were estimated, depending on the epitope specificity of the antibodies used in the IgE determination assays. IgE fragments have been found together with intact IgE in isolated material from different human sera and also from culture supernatant of an IgE-producing cell line. Our data demonstrate that IgE fragments may be assessed and represent a potential pitfall in diagnostic IgE determinations.