A nylon ball solid-phase radioimmunoassay for specific antibodies in human sera. Application to measurement of IgG antibodies to pollen allergens.

The principle of the radioallergosorbent test (RAST) has been used to measure IgG antibodies to timothy grass pollen allergens in sera from desensitized allergic subjects. 125I-labeled goat anti-human IgG was used as detector protein. Non-specific binding was eliminated by use of a non-porous nylon ball an antigen carrier and by use of a special buffer with high ionic strength and pH, containing 1% bovine gamma globulin and 5% normal rabbit serum as 'balance proteins'. At dilution 1:80 non-specific binding was only 0.28% and the binding ratio for a high-liter serum was about 10. By inhibition experiments the assay was demonstrated to be specific for IgG antibodies to timothy grass pollen. The results obtained with this assay correlated statistically significantly with those found th a double -antibody method (rs equal 0.68, n equal 20, t equal 3.93, P less than 0.001). Serum dilution curves were parallel, indicating that the assay is in allergen excess. The within-assay coefficient of variation ranged from 3.9 to 7.6%; the between-assay coefficient of variation from 8.4 to 19.5%. The assay is very simple to perform, requiring no centrifugation. The allergen-coated balls are stable for at least 3 months. The assay should be applicable to measurement of IgG antibodies and IgG subclass antibodies to any protein antigen of interest.

A triple antibody assay for the quantitation of plasma IgG subclass antibodies to acetylcholine receptors in patients with myasthenia gravis.

Monoclonal anti-human IgG subclass antibodies have been used in an immunoprecipitation assay for the determination of anti-acetylcholine receptor IgG subclasses in plasma from patients with myasthenia gravis. Solubilized acetylcholine receptors labelled with 125I-alpha-bungarotoxin were incubated with patient plasma. Monoclonal mouse antibodies to human IgG subclasses 1-4 were added to the incubation and finally precipitated with anti-mouse IgG antibody. A maximal IgG subclass precipitation of 62-76% was determined with 125I-labelled myeloma IgG subclasses 1-4 added to normal human plasma. The anti-IgG subclass antibodies were added in excess which ensured that the precipitation of IgG2, IgG3 or IgG4 were unchanged, and that of IgG1 was only reduced by 17%, when the plasma IgG concentration was increased by a factor of two. The anti-IgG subclass antibodies were highly specific for their complementary subclasses. Determination of the IgG subclass of the anti-acetylcholine receptor antibodies from 8 patients with myasthenia gravis showed that IgG1 and IgG3 antibodies are predominant. This may support the hypothesis that complement mediated lysis of the neuromuscular end-plate plays a pathogenetic role in myasthenia gravis.

[Clinical consequences of intranasal insulin therapy in insulin-dependent diabetes mellitus]. / Kliniske konsekvenser af intranasal insulinbehandling ved insulinkraevende diabetes mellitus.

Metabolic control, hypoglycaemia frequency and nasal mucosal physiology were evaluated in 31 insulin-dependent diabetics treated with intranasal insulin at mealtimes for one month and with subcutaneous fast-acting insulin for another month in a randomized crossover trial. During both periods the patients were treated with intermediate-acting insulin at bedtime. Six of the patients were withdrawn from the study during intranasal insulin therapy due to metabolic dysregulation. Insulin concentrations increased more rapidly and decreased more quickly during intranasal as compared with subcutaneous insulin administration. Metabolic control, assessed by haemoglobin A1c concentrations, deteriorated after intranasal as compared with subcutaneous insulin therapy. The bioavailability of intranasally applied insulin was low, since intranasal insulin doses were approximately 20 times higher than subcutaneous doses. The frequency of hypoglycemia was similar during intranasal and subcutaneous insulin therapy, and nasal mucosal physiology was unaffected after intranasal insulin. We conclude that due to low bioavailability and to a high rate of therapeutic failure, intranasal insulin treatment is not a realistic alternative to subcutaneous insulin injections at the present time.

The subclass nature and clinical significance of the IgG antibody response in patients undergoing allergen-specific immunotherapy.

The purpose of this paper is to discuss the methodological difficulties in quantitation of human IgG subclass antibodies to allergens, to describe the subclass nature of the IgG antibody response in patients undergoing allergen-specific immunotherapy, and to discuss the possible immunological functions and clinical significance of allergen-specific IgG antibodies of different subclasses. Based on results obtained by use of assays with documented specificity it is concluded that the IgG antibody response during allergen-specific immunotherapy is IgG1 and IgG4 restricted, although low levels of IgG2 and IgG3 antibodies to some allergens may occur. In most patients the early IgG antibody response is IgG1 dominated and the late IgG4 dominated. A too early or too pronounced IgG4 dominated antibody response seems to indicate a poor clinical outcome of immunotherapy with inhalant allergens, whereas a pronounced early IgG1 antibody production has been found to be associated with a decrease in synthesis of IgE antibodies to an insect venom. It is therefore proposed that an early IgG1 dominated response is necessary to induce suppression of the ongoing IgE antibody production, which in its turn may be a prerequisite for long-lasting clinical effect. The possibility of induction of an early IgG1 dominated response in every patient by use of alternative immunotherapy procedures is discussed.

Adrenoceptors: molecular nature and role in atopic diseases.

Since Szentivanyi proposed the idea that asthma and other atopic diseases are due to a beta adrenergic defect there has been much interest in the role of the adrenergic receptors in allergy. The radioactive ligand binding techniques developed within the last few years have greatly increased our knowledge concerning the molecular nature of the adrenoceptors and the events following receptor stimulation. The adrenoceptors have shown to be very dynamic structures. Their number and affinity may be altered due to various physiological and pharmacological stimuli. Their role in the pathogenesis of atopic diseases has not been definitely settled, but there seem to be a true beta adrenergic hyporesponsiveness and alpha hyperresponsiveness in asthma. This article briefly describes the radioligand binding technique and summarizes our present knowledge of the nature of the alpha and beta adrenoceptors and their possible role in atopic diseases.

IgG subclass antibody response in grass pollen-allergic patients undergoing specific immunotherapy. Prognostic value of serum IgG subclass antibody levels early in immunotherapy.

All four subclasses of IgG antibodies to timothy grass pollen extract were measured by a three-layer immunoradiometric assay in sera from 20 grass pollen-allergic patients who underwent specific immunotherapy in a 3-year prospective study. Both IgG1 and IgG4 antibody levels rose significantly during the first 8 weeks of immunotherapy. IgG1 antibody level passed its peak (median 5.4 U/ml) after 12 weeks. At this time, the ratio between the medians of IgG1 and IgG4 antibodies was 2.25. IgG4 antibody level reached its peak (median 11.6 U/ml) just before termination of immunotherapy. At this time IgG1/IgG4 ratio was 0.43. Two years after the end of immunotherapy, IgG1 and IgG4 antibody levels were 0.0 and 1.8 U/ml in median, respectively. The amounts of IgG2 and IgG3 antibodies detected in the sera were less than 1.6 U/ml and were considered insignificant. Preseasonal serum IgG1 and IgG4 antibody levels did not correlate significantly with symptom scores in the subsequent season. Serum IgG4 level obtained after 12 weeks of immunotherapy was significantly correlated to symptom score in the third season, i.e. the season just after termination of therapy (rs = 0.529, t = 2.567, P = 0.02). In this work, a serum IgG4 antibody level higher than 8.0 U/ml after 12 weeks of therapy predicted poor clinical result at the end of immunotherapy with 100% sensitivity and 87% specificity. An IgG4/IgG1 ratio greater than 1.0 after 12 weeks' therapy had the same predictive value.

Diagnosis and immunotherapy of mould allergy. VII. IgG subclass response and relation to the clinical efficacy of immunotherapy with Cladosporium.

The IgG subclass response was evaluated by a sensitive allergen- and subclass-specific solid phase immunoradiometric assay during a 1-year placebo-controlled, double-blind study of immunotherapy with Cladosporium herbarum in 22 adult asthmatics. The IgG response was mainly restricted to subclasses 1 and 4 but a few patients were IgG2 and IgG3 responders. An intense and early IgG1 response was observed during the first clusters of injection followed by a levelling down of the titer. The IgG4 response had a later onset and showed slowly increasing levels during the 12 months of immunotherapy. The graded clinical efficacy estimated by symptom-medication score was significantly correlated to the preseasonal IgG1 value, with high values indicating a deleterious response of immunotherapy (deterioration of disease activity). Likewise, the fold increase of IgG1 and IgG4 after two clusters of immunotherapy (i.e. after 4 weeks) was significantly related to the clinical outcome. Little or no increase of IgG1 and IgG4 was associated with improvement, i.e. decrease in symptom-medication score. The magnitude of the IgG1 response during the dose-increase phase was directly correlated to the number of systemic side effects. No relation of IgG1, IgG4 or IgG4/IgG1 ratio to changes in the IgE-mediated parameters (skin prick test, bronchial challenge and circulating specific IgE) was observed. Our data, which are based on few patients and only one allergen system, do not support the hypothesis of IgG acting as blocking antibody being the immunologic mechanism of immunotherapy. The association between high IgG4 values and a deleterious efficacy of immunotherapy might be caused by IgG4 acting as sensitizing antibodies. This explanation, however, is opposed by the lack of relation to systemic side effects.

Glucose recovery after intranasal glucagon during hypoglycaemia in man.

We compared the hyperglycaemic effect of intranasal and intramuscular (i.m.) administration of glucagon after insulin-induced hypoglycaemia. Twelve healthy subjects were examined twice, receiving on both occasions an intravenous insulin bolus. Somatostatin and propranolol were administered to block endogenous glucose counterregulation, and glucose turnover was estimated by a 3-[3H]-glucose infusion. When hypoglycaemia was reached, the subjects received either i.m. glucagon of pancreatic extraction (1 mg) or intranasal genetically engineered glucagon (2 mg). The incremental values for plasma glucose concentrations 15 min after intranasal and i.m. administration of glucagon differed marginally. However, after 5 min the glucose appearance rate, as well as the incremental values for plasma glucose, were significantly higher for the i.m. glucagon treatment. The mean time taken for incremental plasma glucose to exceed 3 mmol.l-1 was significantly shorter for i.m. glucagon. The mean plasma glucagon level increased faster after i.m. glucagon than after intranasal glucagon, and the levels remained higher throughout the study period. We conclude that glucose recovery was significantly better after i.m. administration of glucagon than after intranasal administration. However, the differences between the incremental plasma glucose and the time for incremental plasma glucose to exceed 3 mmol.l-1 were not considered of major clinical importance.

High IgG4 antibody level is associated with failure of immunotherapy with inhalant allergens.

We have analysed all available data on the relationship between IgG4 Ab level and clinical effect of immunotherapy (IT) with inhalant allergens. The data from three of the seven independent studies could, without reservations, be analysed by a joint statistical analysis. We found that late high IgG4 Ab level, measured at the end of IT, was strongly associated with treatment failure (P = 6.54 x 10(5); n = 67). The ratio of risks for treatment success in the group with late low IgG4 Ab level was 1.82, whereas the ratio of risks for treatment failure in the group with late high IgG4 Ab level was 11.4. The data from a fourth, presumably comparable, study further supported the existence of an association between high IgG4 Ab level and treatment failure. In contrast, two other studies found that high mean IgG4 Ab level was associated with good clinical response. Possible reasons for this apparent discrepancy are discussed. We also found that early high IgG4 Ab level, measured within 3 months after initiation of IT, was strongly associated with treatment failure after 1-2 years of IT (P = 1.05 x 10(-4); n = 30). The sensitivity and specificity of early high IgG4 Ab level as indicator for treatment failure was 100% and 83%, respectively. At the prevalences found in the present study, the predictive value of early high IgG4 Ab level for treatment failure was 0.6, whereas the predictive value of early low IgG4 Ab level for treatment success was 1.00.

Phagocytosis by normal polymorphonuclear leukocytes of immune complexes from serum of patients with Felty's syndrome and rheumatoid arthritis with special reference to IgE immune complexes.

Sera from patients with Felty's syndrome, rheumatoid arthritis (RA) and controls were investigated for the presence of immune complexes (IC) using phagocytosis by normal polymorphonuclear leukocytes and direct immunofluorescence technique. IC visible as large cytoplasmic inclusions were seen in 19 of 24 cases of Felty's syndrome, 3 of 16 cases of RA, and all 3 patients with extraarticular manifestations, and none of 21 control sera. IC containing IgG, IgA and complement C3 were found in nearly all positive cases. IgM IC were found in only 8 of the Felty's syndrome cases, IgE in 5 and beta-2-microglobulin in one case, respectively. A tendency to increasing number of large inclusion positive cells in vitro was found inversely correlated to the number of circulating leukocytes in the Felty patients at the time of serum sampling. In contrast, small cytoplasmic inclusions were found both in Felty's syndrome and RA patients and in some of the controls, and IgG and C3 were the most frequent constituents in these cases. As these inclusions were found in all groups it may have little significance. IgE IC as determined by a PEG precipitation technique were positive in the same 5 cases of Felty's syndrome with IgE containing inclusions, and in one case of RA with extraarticular manifestations. The complexed IgE amounted to about 3% of the total serum concentration of IgE. Phagocytosed IC may be involved in the pathogenesis of neutropenia and contribute to the inflammatory processes in Felty's syndrome.

A modified crossed radioimmunoelectrophoretic method for determination of allergen-specific IgG antibodies. Elimination of non-specific binding by use of F(ab')2-fragments of rabbit antibodies and 125I-labelled protein A.

A crossed radioimmunoelectrophoretic (CRIE) method for detection of specific IgG antibodies in patients' sera against horse hair and dander was developed. The unacceptably high non-specific binding encountered when substituting 125I-labelled antihuman IgG for 125I-labelled antihuman IgE in an ordinary CRIE was eliminated by the combined use of 125I-labelled Protein A as detector, and F(ab')2-fragments of the allergen-specific rabbit antibodies. The low background binding thus obtained makes the method useful for detection of specific IgG in sera where the ratio between specific and non-specific IgG is low. Therefore the method should also be applicable to other antigen/allergen systems.

Characterization of IgG-subclass antibodies to individual allergens by crossed radioimmunoelectrophoresis.

A crossed radioimmunoelectrophoretic (CRIE) method for detection of human IgG subclass specificities against individual antigens is described. After crossed immunoelectrophoresis (CIE) of the antigens the immunoplates are incubated with serum, washed and incubated with mouse monoclonal anti-human IgG-subclass antibodies. After washing, the plates are finally incubated with the 125I-labelled detector protein, rabbit anti-mouse IgG, and washed. The plates are then placed on an X-ray film for autoradiography. The specificity of the method was tested by inhibition with antigens in the first layer and by inhibition with myeloma sera containing only one IgG subclass protein in the second layer. The specificity of the third layer was assured by affinity purification of the rabbit anti-mouse IgG antibodies. The method was shown to be sensitive and specific. The test systems were timothy (Phleum pratense) pollen antigens and house dust mite (Dermatophagoides pteronyssinus) antigens.

Glomerular size and charge selectivity in insulin-dependent diabetes mellitus.

The pathogenesis of clinical nephropathy in Type 1 (insulin-dependent) diabetes was investigated by measuring renal fractional clearances of albumin, total IgG, IgG4 and beta 2-microglobulin, four plasma proteins which differ in size and charge. Seventy patients and eleven control subjects were studied. In diabetic patients with normal urinary albumin excretion (less than 30 mg/24 hr), fractional IgG clearance was two to three times higher than in control subjects, whereas fractional clearance of the anionic plasma proteins IgG4 and albumin was similar to that of control subjects. These alterations indicate an increase in anionic pore charge within the glomerular basement membrane concomitant with an increase in either pore size or impairment of tubular reabsorption. Diabetic patients, whose urinary albumin excretion has started to rise (30 to 100 mg/24 hr), had unchanged fractional IgG compared to patients with normal albumin excretion, while fractional IgG4 and albumin clearances were increased three- to fourfold; indicating unchanged glomerular pore size, but a decrease in anionic pore charge. In patients demonstrating urinary albumin excretion of greater than 100 mg/24 hr fractional IgG clearance increased to the same extent as fractional albumin clearance, indicating an increase in large pore area. Fractional beta 2-microglobulin clearances were similar to that of control subjects in the different patient groups indicating unchanged tubular reabsorption of proteins. Thus, the increase in large pore area seen in patients with clinical nephropathy is preceded by loss of anionic charge in the glomerular basement membrane. It is likely that this loss of anionic charge is due to loss of heparan sulphate-proteoglycan.

IgG subclass concentrations in sera from 200 normal adults and IgG subclass determination of 106 myeloma proteins: an interlaboratory study.

The IgG subclass protein concentrations in sera from 200 normal subjects were determined independently in two laboratories, using the same technique (radial immunodiffusion), the same subclass-specific antibodies and the same calibrator. The coefficients of correlation (rs) between IgG subclass concentrations determined in the two laboratories were 0.487, 0.883, 0.928 and 0.926 for IgG1, IgG2, IgG3 and IgG4, respectively (p less than 0.0005 in all four cases). By the chi-square test for goodness of fit, the frequency distributions observed in the two laboratories were found to differ significantly for all four subclasses (p less than 0.01). In one laboratory, the distributions of IgG1 and IgG2 were not significantly different from normal distributions, whereas the distributions of IgG3 and IgG4 deviated significantly. In the other laboratory, all four subclass distributions were significantly different from normal distributions. In the first laboratory, the IgG2 concentrations were log-normal distributed, whereas in the second, IgG1, IgG2 and IgG4 concentrations were log-normal distributed. We conclude that use of identical reagents does not ensure identical frequency distributions. This finding emphasizes the need for standardization of the measurement technique too. Furthermore, we argue that at present, intralaboratory reference intervals for IgG subclass protein concentrations are necessary. The reference intervals should be based on non-parametric statistics. The subclass of 106 monoclonal IgG proteins, which were demonstrated by agarose gel electrophoresis, was identified by RID for 89 samples. The subclass of the remaining 16 M-components was readily determined by qualitative immunoelectrophoretic analysis using the same subclass-specific antibodies.

Clustered immunotherapy with Yellow Jacket venom. Evaluation of the influence of time interval on in vivo and in vitro parameters.

To evaluate difference in clinical efficacy, side effects, in vivo and in vitro parameters, 25 patients allergic to Yellow Jacket were treated with clustered immunotherapy using either 7 or 14 days interval between clusters. Twenty-one patients completed the 6 months' treatment period and four were withdrawn due to adverse reactions (2 cases of anaphylactic shock). Sixteen patients were challenged by in-hospital sting and the clinical efficacy was complete. Local side effects were observed in the majority of patients, but only rarely limited the course of immunotherapy. Skin sensitivity estimated as the venom concentration eliciting a wheal equal to histamine HCl 0.1 mg/ml using intradermal test was significantly reduced after 6 months of treatment. Specific IgE showed an initial increase, thereafter declining to pretreatment levels. IgG subclasses were determined by a triple antibody assay. Only subclasses 1 and 4 showed response. Subclass 4 showed a steady increase contrary to subclass 1 which decreased after reaching maintenance dose. No unambiguous relation between either the absolute value or the change of IgG1 and IgG4 at the time of challenge was observed in the patients who tolerated a sting. Furthermore, the IgG response was not correlated to the cumulative dose of venom administered. No simple regulatory function of IgG subclasses in the skin and IgE response was found, and the occurrence of local side effects did not seem to be determined by IgG antibodies. We conclude that clustered immunotherapy with Yellow Jacket venom is highly effective and that the frequency of side effects is acceptable.(ABSTRACT TRUNCATED AT 250 WORDS)

The IgE and IgG subclass antibody response in patients allergic to yellow jacket venom undergoing different regimens of venom immunotherapy.

We developed a three-layer immunoradiometric assay for quantitation of IgG antibodies of all four subclasses to YJV. We studied the IgE and IgG subclass antibody response to YJV in 31 patients allergic to YJV who were undergoing three different kinds of venom immunotherapy. Group A received weekly single injections with alum-adsorbed venom, group B received weekly clustered injections with aqueous venom, and group C received fortnightly clustered injections with aqueous venom during the increasing dose phase of our study. All patients received alum-adsorbed venom during maintenance therapy. Results from the first 6 months of observation are reported. After 6 months of therapy the IgE antibody level rose significantly in group A, was unchanged in group B, and tended to fall in group C. The fall in IgE antibody level in group C correlated significantly to the pretreatment IgE antibody level. The IgG subclass antibody assays measured IgG antibodies of different subclasses in comparable units. No IgG2 or IgG3 antibodies to YJV were found. Before the start of immunotherapy, 23 patients had significant concentrations of IgG1 antibodies to YJV, and 14 had significant concentrations of IgG4 antibodies. In group A the IgG1 antibody level rose significantly after 6 months, and the IgG4 antibody level rose significantly after 3 months. In group B the IgG1 antibody level rose after 2 weeks and the IgG4 antibody level rose after 3 weeks. In group C the IgG1 antibody level rose after 2 weeks and the IgG4 antibody concentration rose after 8 weeks. When the maintenance dose was reached, the IgG1 antibody level in group C was significantly higher than that in group A. The possibility that IgG1 antibodies formed during venom immunotherapy take part in a feedback inhibition of the IgE antibody production is discussed.

A three-layer immunoradiometric assay for determination of IgG subclass antibodies in human sera ("IgG subclass RAST"). Validation of the subclass specificity, and establishment of equipotency.

We report the development of a three-layer immunoradiometric assay (TIRA) for measurement of IgG antibodies of all four subclasses in human sera. The first layer consists of diluted human serum, the second layer is monoclonal mouse antibodies to human IgG subclasses, and the third layer is 125I-labelled rabbit anti-mouse IgG. Monoclonal anti-IgG1, anti-IgG3 and anti-IgG4 reacted only with their complementary IgG subclass, whereas the anti-IgG2 showed slight cross-reactivity to immunoglobins of other subclasses and classes and to light chain proteins. The observed cross-reactivity was found to be without importance, when the TIRA was applied to measurement of IgG subclass antibodies. Equipotency was established by use of appropriate dilutions of the monoclonal antibodies, and the assay was calibrated by use of human reference serum. The TIRA therefore permits reliable inter-individual and intra-individual comparisons of the IgG antibody response in all four subclasses. Non-specific binding obtained with pooled normal human serum was below 0.33%. Inter-assay coefficient of variation was between 18 and 27%. The TIRA was applied to measurement of IgG subclass antibodies to timothy grass pollen in sera from grass pollen allergics undergoing immunotherapy.

Urinary excretion and origin of 11-dehydro-2,3-dinor-thromboxane B2 in man.

The in vivo biosynthesis of thromboxane B2 (TXB2) in man is currently evaluated by measuring urinary excretion of its major urinary metabolites, 11-dehydro-TXB2 and 2,3-dinor-TXB2. 11-Dehydro-2,3-dinor-TXB2, another prominent metabolite of exogenous TXB2 in man, has never been measured in human urine. We measured urinary 11-dehydro-2,3-dinor-TXB2 in parallel with 11-dehydro-TXB2 and 2,3-dinor-TXB2 by immunoaffinity extraction/gas chromatography-mass spectrometry in healthy non-smokers (n = 12) and age-matched smokers (n = 11). In non-smokers, urinary excretion of 11-dehydro-2,3-dinor-TXB2, 11-dehydro-TXB2 and 2,3-dinor-TXB2 was 29.7 +/- 11.1, 53.6 +/- 15.0 and 13.5 +/- 2.8 ng/h (mean +/- SD), respectively. In smokers, only urinary excretion of 2,3-dinor-TXB2 was significantly different (19.7 +/- 6.7 ng/h, p < 0.01). Selective inhibition of platelet thromboxane biosynthesis by chronic low-dose aspirin (30 mg/day for 8 days, 4 subjects) comparably reduced platelet-derived metabolites and 11-dehydro-2,3-dinor-TXB2, suggesting that the latter also derives from platelets in healthy subjects.

Acetylcholine receptor antibody in myasthenia gravis: predominance of IgG subclasses 1 and 3.

The concentrations of IgG subclass antibodies (Ab) to acetylcholine receptor (AchR) were quantified in 36 patients with myasthenia gravis (MG) treated with pyridostigmine only, and in eight patients who underwent thymectomy, using an IgG subclass-specific immunoprecipitation assay. IgG1, IgG2, IgG3, and IgG4 subclass Ab to AchR were present in 100%, 33%, 64% and 39% of the pyridostigmine-treated patients, respectively. The concentration of IgG1 Ab increased significantly with disease severity as graded by the Osserman-Genkins classification (rs = 0.37, P less than 0.05). IgG1 and IgG3 subclass protein concentrations were significantly higher (P less than 0.0003) in the 36 pyridostigmine-treated MG patients than in 44 age- and sex-matched healthy subjects. Thymectomy induced an appreciable reduction in anti-AchR IgG1 concentration in two patients, whereas six patients showed no changes in Ab to AchR. The results support the hypothesis that binding of anti-AchR IgG1 and IgG3 on AchR in the neuromuscular junction followed by complement-mediated cell lysis or phagocytosis, may play a role in the pathogenesis of MG.

Raised serum IgG4 levels in patients with atopy and filariasis: application of an automated particle-counting immunoassay using monoclonal antibody.

We show here an automated (50 samples/h) assay for serum IgG4 having a throughput time of 40 min per sample and a sensitivity of 10 micrograms/ml. The assay procedure is based on the inhibition by sample of the agglutination reaction between monoclonal anti-IgG4 antibodies and latex particles to which IgG4 myeloma protein has been coupled. Assay reliability was ascertained by testing for linearity, analytical recovery (96.4%), interassay precision (less than or equal to 8%), specificity and correlation between the results obtained with monoclonal and polyclonal anti-IgG4 antibodies (n = 84; rs = 0.97). Application of the assay to sera from various groups of patients indicated significantly (p less than 0.00005) higher geometrical means (Gx) in patients suffering from atopy (n = 87; Gx = 617 micrograms/ml), atopic dermatitis (n = 28; Gx = 1,043 micrograms/ml), filariasis with Onchocerca volvulus (n = 48; Gx = 1,681 micrograms/ml) and Brugia malayi (n = 20; Gx = 1,078 micrograms/ml) as compared to nonatopic subjects (n = 103; Gx = 302 micrograms/ml) and randomized paired maternal/cord sera (n = 41; Gx = 276 and 296 micrograms/ml, respectively). IgG4 in the paired maternal/cord sera correlated (r = 0.98; p less than 0.00005). There was no significant influence of age or sex on the IgG4 levels either among the nonatopics or the atopics even though low IgG4 (less than or equal to 30 micrograms/ml) was more common among women. The results suggest that IgG4 and IgE responses are somehow closely related in atopic and parasite-infested patients at the physiological, pathogenic or genetic level.