Evolution of serum C3, IgG, IgA and IgM levels of healthy mothers and their mature newborns during the early neonatal period

Susceptibility to infections is most pronounced during the perinatal period. The main characteristic feature of the clinical course is a proneness to generalisation; this can be attributed to immaturity of the immune system. In addition to a series of laboratory parameters, quick and exact determinations of immunoglobulins and complement fractions repeatedly performed within a short time may be useful in confirming a suspected infection and in following the course of the disease. In order to establish the normal basal levels and the dynamics of changes 30 mothers, all healthy, having no abnormality during pregnancy or shortly after delivery, and their healthy mature neonates were examined for IgG, IgA, IgM and C3 serum levels. These basal values are useful in judging the parameters under pathological conditions.     

Serum anti-streptococcal IgA,IgG and IgM antibodies in IgA-associated diseases

Serum anti-streptolysin-O antibody (ASO) and anti-streptococcal polysaccharide antibody (ASP) of IgA, IgG and IgM classes were measured using an enzyme-linked immunosorbent assay in 41 children with IgA nephropathy (Group A), 15 children with uncomplicated anaphylactoid purpura (Group B) and 13 children with purpura nephritis (Group C). The serum concentrations of the IgA, IgG and IgM classes were measured by single radial immunodiffusion. When compared with sex- and age-matched controls, the concentrations of serum IgA (but not of IgG or IgM) were significantly increased in the three groups studied. The titers of ASO of the IgA and IgM classes, and those of ASP of the IgA and IgG classes, were significantly increased in Group A. In Group B, only the ASP titers of the IgA class were significantly increased. No significant difference was noted in the titers of either ASO or ASP of any class in Group C. Thus, increased antibody response in IgA nephropathy is not restricted to IgA. Anaphylactoid purpura with or without renal disease appears to be different in its humoral anti-streptococcal response from IgA nephropathy.     

Serum immunoglobulin (IgG, IgM, IgA) and IgG subclass concentrations in healthy children: a study using nephelometric technique

Immunoglobulin (Ig) G, IgM, IgA and IgG subclass (IgG1, IgG2, IgG3, IgG4) concentrations were determined in more than 500 healthy Turkish children using nephelometric technique. These parameters were thought to be highly varied for different ethnic groups because of environmental and genetic factors. Methodology used in previous studies has been reported to affect age-related normal values. Serum IgG, IgM, IgA and IgG1, IgG2, IgG3, IgG4 levels were measured in 510, 491, 486, 542, 511, 515, and 545 healthy children, respectively. According to their age, the patients were divided into 14 groups. In contrast to most of the previous studies, age-related normal values for IgG4 levels were also obtained. In conclusion, it has been suggested that our study as an example for Caucasians using nephelometric technique will supply useful information about age-related normal serum immunoglobulin and IgG subclass concentrations.     

IgG1, IgG2 and IgM responses to two Haemophilus influenzae type b conjugate vaccines in young infants.

PRP-meningococcal outer membrane protein complex (PRP-OMPC) and oligosaccharide linked to variant diphtheria toxin (HbOC) Haemophilus influenzae type b (HIB) conjugate vaccines have both been licensed for United States infants at 2 months of age. Differences in serologic responses for these vaccines have been noted with PRP-OMPC producing an early response at 2 months of age and HbOC producing a higher response after a third dose at 6 months of age. To further characterize the nature of these distinct responses, we measured the IgG1, IgG2 and IgM anti-HIB concentrations by enzyme-linked immunosorbent assay after administration of both vaccines. PRP-OMPC produced an IgM and IgG1 anti-HIB response following the initial dose at 2 months of age. After two doses of HbOC an increase in IgG1 and IgM were noted and after a third dose at 6 months of age an IgG2 anti-HIB response occurred. In addition 33 study subjects were boosted with PRP-OMPC at age 18 months and compared with 34 subjects who received only a primary dose. The anti-HIB IgG1 and IgG2 concentrations following the booster dose were both significantly higher for the primed group (P = 0.0001 and P = 0.001, respectively). Both HIB conjugate vaccines produce predominantly IgG1 anti-HIB antibody responses. The early response to PRP-OMPC vaccine at 2 months of age may result from adjuvant characteristics of the OMPC.     

Immunoglobulins IgG, IgM and IgA levels in preterm and small for date newborns.

Forty preterm [14 small for gestational age (SGA), 26 average for gestational age (AGA)] and 40 term (10 SGA and 30 AGA) babies were tested for immunoglobulins (Ig), G, M and A levels. IgG levels increased with gestational age from 922.00 +/- 14.00 mg/dl at 34 weeks to 1827.33 +/- 184.09 mg/dl at 40 weeks. Mean immunoglobulins were lower in SGA babies. IgG was 1029.59 +/- 122.80 mg/dl in SGA preterm babies and increased to 1262.00 +/- 200.0 mg/dl in 2 kg babies. IgM and IgA although increased with higher birth weight but rise was not statistically significant. More care to avoid infections in preterm and SGA babies, with lower immunoglobulin levels and less resistance, is recommended.     

Antibiotic choices by paediatric residents and recently graduated paediatricians for typical infectious disease problems in children

OBJECTIVE

To evaluate antibiotic choices and recommendations for duration of therapy made by paediatric residents (PRs) and recently graduated paediatricians (RGPs) in several typical infectious disease conditions.

METHODS

In autumn 2002, a two-page questionnaire was sent to 276 core PRs in Canadian residency programs and to a random selection of 276 RGPs from across Canada. The questionnaire described 10 scenarios: otitis media, pharyngitis, sinusitis, bronchopneumonia, lobar pneumonia, meningitis, pyelonephritis, osteomyelitis, cellulitis, and fever and neutropenia. The participants were asked primarily about initial antibiotic selection and duration of treatment for each scenario.

RESULTS

There were 251 participants (overall response rate of 45%). The two most common antibiotic recommendations constituted 85% or more of the total for all scenarios except acute otitis media, sinusitis, cellulitis, and fever and neutropenia. There was a twofold or more difference in the range of recommended duration of treatment for all scenarios and a threefold or more difference for sinusitis, meningitis and osteomyelitis. PRs were more likely than RGPs to use broader spectrum cephalosporins for pneumococcal pneumonia (33% versus 15%, respectively; P=0.001) and to treat sinusitis for just five to 10 days (39% versus 22%, respectively; P=0.01). Also, 33% of all participants recommended amoxicillin/clavulanate or a cephalosporin rather than amoxicillin for sinusitis.

CONCLUSION

PRs and RGPs made similar and reasonable recommendations, largely in line with published guidelines, for most of the infectious disease scenarios presented. For some conditions, a significant minority of respondents unnecessarily recommended broad-spectrum antibiotics. The most variable responses were for duration of treatment, reflecting the lack of certainty in the published evidence base for many conditions.     

Diagnosis of autoimmune neutropenia by neutrophil-bound IgG and IgM antibodies

Autoimmune neutropenia (AIN) in infancy is caused by antineutrophil (granulocyte-specific) autoantibodies. These antibodies are rarely found in circulation because their serum levels are extremely low. We hypothesized that a direct granulocyte immunofluorescence test (D-GIFT) that enables us to detect neutrophil-bound autoantibodies consisting of both immunoglobulin (Ig) G and IgM has better diagnostic value than the detection of circulating autoantibodies. Whole blood (100 μL) was obtained from 50 infants with AIN, 12 infants with transient neutropenia, and 37 control infants. D-GIFT was performed using both fluorescein isothiocyanate-conjugated antihuman IgG Fc portion monoclonal antibodies and fluorescein isothiocyanate antihuman IgM monoclonal antibodies. Results were assessed as relative fluorescence intensity (RFI). The RFIs of antineutrophil IgG-bound and antineutrophil IgM-bound cells in patients with AIN were significantly higher than those in patients with transient neutropenia and in controls. Positive results, as assessed by RFI scores of more than 1.81 in either antineutrophil IgG-bound or antineutrophil IgM-bound cells, showed the sensitivity and specificity of D-GIFT, and the areas under the receiver operating characteristic curve (0.98, 0.98, and 0.997, respectively) in the diagnosis of AIN. D-GIFT detecting both neutrophil-bound IgG autoantibodies and IgM autoantibodies has discriminatory power for identifying patients with AIN and, therefore, can be a useful diagnostic test.