Plebani A

Intravenous gammaglobulin therapy for prophylaxis of infection in high-risk neonates

The safety and effectiveness of intravenously administered gammaglobulin therapy for prophylaxis of infection was evaluated in 133 high-risk neonates. The infants were stratified into two groups: infants with birth weight less than or equal to 1500 g and gestational age less than or equal to 34 weeks, and infants with birth weight greater than 1500 g and receiving intensive care and assisted ventilation. Forty-three infants in group 1 and 25 in group 2 were given gammaglobulin at a dose of 0.5 g/kg/wk, for 1 month in group 1 and during intensive care in group 2. Forty infants in group 1 and 25 in group 2 served as controls. Serum total IgG and group B streptococcus-, Escherichia coli-, and CMV-specific IgG levels similar to those in adult controls were observed in the treated infants 2 hours after gammaglobulin administration. In the treated infants in group 1, the incidence of infection was 51%, and of septicemia 5%; in the controls the incidence of infection was 77% (P less than 0.02), and of septicemia 20% (P less than 0.05). Infection was the main cause of death in one treated and six control infants in group 1 (P less than 0.04). In the infants with birth weight greater than 1500 g receiving intensive care and assisted ventilation, no significant differences were observed in the incidence of infection or septicemia in treated and control infants. No side effects were observed after intravenous gammaglobulin administration. These data show that intravenously administered gammaglobulin is both safe and effective for prophylaxis of infection in preterm very low birth weight infants.

Serum IgG subclass concentrations in healthy subjects at different age: Age normal percentile charts

IgG subclass levels were determined in 448 normal children from 6 months to 18 years of age and in 141 healthy adults by radial immunodiffusion using monoclonal antibodies. Age-normal percentile values were calculated for each year of age up to 18 years for IgG1, IgG2, IgG3 and in adults for all four subclasses. The broad spread of IgG4 values in children did not permit calculation of reference values.

An avidin-biotin ELISA for the measurement of serum and secretory IgD

This paper describes an improved microtiter solid-phase enzyme immunoassay for the determination of serum and secretory IgD. Use of the interaction between biotinylated anti-human IgD and horseradish peroxidase(HRP)-avidin conjugate permits quantitation of human IgD in the range of 1-64 ng/ml. IgD was detected in all samples of serum, saliva and nasal secretions of 28 normal adults. In only one subject both serum and secretory IgD were undetectable. The mean concentration of serum IgD determined by this assay is similar to that reported by other authors using radioimmunoassay. The assay described is not only rapid and inexpensive but at least as sensitive as the radioimmunoassays usually employed for quantitation of IgD.

An enzyme-linked immunosorbent assay for cow's milk protein-specific IgE using biotinylated antigen. Avoidance of interference by specific IgG

Detection of specific IgE by the radioallergosorbent test (RAST) which uses labelled antibody can be hampered by the presence of antibodies other than IgE but with the same specificity and may limit usefulness of the RAST for diagnosis of IgE-mediated milk allergy in infancy when high titres of cows milk protein-specific IgG antibodies are known to be present. This can be avoided by using a system employing labelled antigen, such as the enzyme-linked immunosorbent assay (ELISA) described here, where IgE in the test serum is immunoadsorbed to anti-human IgE coated to microtitre plates. Biotinylated antigen, in this case cows milk proteins, binds to specific IgE and the reaction is revealed colorimetrically by adding horseradish peroxidase (HRP)-avidin conjugate.

IgG subclass serum levels in juvenile chronic arthritis.

IgG subclass levels of sera from 26 patients with juvenile chronic arthritis (JCA) were determined by means of mouse monoclonal antibodies. Patients were divided into three groups according to clinical activity of the disease: active disease, partial remission, and remission. One hundred and sixty four age matched, healthy children served as controls. IgG subclass concentrations were log transformed, and a robust regression method was applied to obtain expected values for the different ages. We found a significant increase of IgG3 (p less than 0.0001), IgG1 (p less than 0.002), and IgG2 (p less than 0.035) in JCA sera, while IgG4 values did not differ significantly from those of controls. When patients were divided according to clinical activity significant increases of IgG2 and IgG4 were observed in the patients in partial remission. Our data suggest that differential increase of IgG subclasses during the courses of JCA may be of relevance to the pathogenesis of the disease.

A new immunoperoxidase assay for Lolium perenne-specific IgE in serum based on the biotin/avidin system (BAS).

A new solid‐phase immunoassay based on the biotin/avidin system (BAS) for measuring scrum Lolium perenne (LP)‐specific IgE antibody is described. LP‐specific IgE was assayed by the BAS assay and RAST for comparison in the sera of thirty‐two normal asymptomatic subjects R AST‐negative for LP and of twenty‐six subjects with hay fever and R AST‐positive for LP. The specificity of the BAS assay for LP‐specific IgE was demonstrated by absorption experiments. An overall agreement of 91% (53/58) was observed between the BAS and RAST and a high correlation (r= 0.87. P < 0.001) was found between the LP‐specific IgE determined by the two methods. The advantages of ihe BAS assay as compared to both the RAST and classical ELISA arc discussed.

Different role of secretory IgA in the pathogenesis of RAST-positive and RAST-negative atopic dermatitis

Secretory‐IgA (SIgA) concentrations were determined in whole saliva, unstimulated or stimulated by lemon juice, of thirty‐eight children with atopic dermatitis, which comprised three adolescents, sixteen with IgE detected by RAST to one or more common allergen and twenty‐two without specific IgE by RAST. There were thirty healthy controls matched for age and sex.

Variation of serum IgG subclass concentrations with disease activity in juvenile chronic arthritis.

Nineteen patients with juvenile chronic arthritis were followed up and serum IgG subclass concentrations measured at different stages of disease activity. Patients were divided into three groups according to clinical activity of the disease: active disease, partial remission, and remission. The results were compared with normal values obtained in 448 healthy children aged 6 months to 18 years with a homogeneous distribution for each year of age. Serum IgG subclass concentrations of each child were first log transformed and then age corrected, taking the deviation of the log transformed value from that expected for a child of the same age. It was found that patients with partial remission had increased concentrations of IgG2 and decreased concentrations of IgG1 compared with patients with active disease. This suggests that the remission inducing process, at least in juvenile chronic arthritis, is accompanied by a switch of IgG subclass production.

Intravenous Gammaglobulin Replacement for Prophylaxis of Infection in Preterm Neonates

Despite the improvements made in medical care in recent years, infection remains a major problem in newborn infants, because rapid diagnosis is difficult and therapy is not always effective (Eisenfeld et al. 1983). Preterm infants with gestational age ≤ 34 weeks and birth weight ≤ 1500 g are particularly at risk: the incidence of systemic infection in these infants, in fact, is about 32%, with a mortality rate of 11% (Usher 1981). The high susceptibility to infections is mainly due to the neonatal impairment of host defenses; both the aspecific and antigen-specific components of the immune system are deficient in the preterm neonate. The antibody deficiency is one of the most important contributory factors in the neonate’s high susceptibility to infections: levels of IgG, all acquired via transplacental passage from the mother, are, in fact, definitely low and often similar to those found in patients with congenital agammaglobulinemia. This is because the transplacental passage occurs almost exclusively during the last 6 weeks of gestation (Hobbs and Yeung 1968; Pilgrim et al. 1975).

A simple hemolytic micromethod for the quantitative and kinetic evaluation of the alternative activating pathway of complement

SummaryA simple, rapid and sensitive hemolytic micromethod for quantitative and kinetic assessment of the alternative pathway of complement activity is described. The test was performed in microtitre plates using a multiscan photometer for ELISA and permits the simultaneous evaluation of as many as 20 different serum samples.