An immunoassay for histamine based on monoclonal antibodies

Development of ELISA and chemiluminescence enzyme immunoassay for quantification of histamine in drug products and food samples

Histamine (HA) is a biogenic amine associated with allergies and food poisoning. It is an important indicator of food freshness and quality. In recent years, a series of medical negligence cases have been reported to be related to the intravenous injection of antibiotics produced via fermentation with fish peptone due to HA contamination. To detect HA efficiently, mouse monoclonal antibody was developed. An enzyme-linked immunosorbent assay (ELISA) and a chemiluminescence enzyme immunoassay (CLEIA) were developed and compared with conventional HPLC analysis. Both immunoassays showed low cross-reactivity, low 50% inhibitive concentration (IC₅₀; 1.2 μg/mL and 1.1 μg/mL), low limits of detection (LODs, IC₁₀; 89.0 ng/mL and 73.4 ng/mL), and appreciable recoveries in spiked foods and drugs (from 73.4 to 131.0% and from 77.0 to 119.0%, espectively), demonstrating that the developed methods are sensitive, specific, fast, and reliable for HA detection in complicated real samples. Graphical abstract.

Modulating Linker Composition of Haptens Resulted in Improved Immunoassay for Histamine

Histamine (HA) is an important food contaminant generated during food fermentation or spoilage. However, an immunoassay for direct (derivatization free) determination of HA has rarely been reported due to its small size to induce the desired antibodies by its current hapten-protein conjugates. In this work, despite violating the classical hapten design criteria which recommend introducing a linear aliphatic (phenyl free) linker into the immunizing hapten, a novel haptens, HA-245 designed and synthesized with a phenyl-contained linker, exhibited significantly enhanced immunological properties. Thus, a quality-improved monoclonal antibody (Mab) against HA was elicited by its hapten-carrier conjugates. Then, as the linear aliphatic linker contained haptens, Hapten B was used as linker-heterologous coating haptens to eliminate the recognition of linker antibodies. Indirect competitive ELISA (ic-ELISA) was developed with a 50% inhibition concentration (IC₅₀) of 0.21 mg/L and a limit of detection (LOD) of 0.06 mg/L in buffer solution. The average recoveries of HA from spiked food samples for this ic-ELISA ranged from 84.1% and 108.5%, and the analysis results agreed well with those of referenced LC-MS/MS. This investigation not only realized derivatization-free immunoassay for HA, but also provided a valuable guidance for hapten design and development of immunoassay for small molecules.

Biomimetic magnetic sensor for electrochemical determination of scombrotoxin in fish

This work addresses a novel, rapid and cost-effective approach for the electrochemical sensing of scombrotoxin (histamine) in fish based on magnetic molecularly imprinted polymer (magnetic-MIP). The histamine magnetic-MIP was synthesized by the core-shell method using histamine as a template, and 2-vinyl pyridine as functional monomer. The magnetic-MIP was characterized by TEM, SEM, and confocal microscopy. Additionally, the binding capacity of magnetic-MIP towards histamine was investigated and compared with magnetic non-molecularly imprinted polymer (magnetic-NIP). This biomimetic material merged the advantages of MIPs and magnetic particles (MPs), including low cost of production, stability, high binding capacity and can be easily separated by the aid of a permanent magnet. The magnetic-MIP was integrated into magneto-actuated electrodes for the direct electrochemical detection of histamine preconcentrated from fish samples. The results revealed that this approach succeeded in the preconcentration and determination of histamine with a LOD as low as 1.6 × 10^-6 mg L^-1, much lower than the index for fish spoilage (50 mg kg^-1) accordingly to the legislation. Furthermore, the analytical performance was validated for the determination of histamine in scombroid fish samples with recovery values ranging from 96.8 to 102.0 %, confirm so it can be applied easily for routine food examination.

In vitro tests for drug hypersensitivity reactions: an ENDA/EAACI Drug Allergy Interest Group position paper

Drug hypersensitivity reactions (DHRs) are a matter of great concern, both for outpatient and in hospital care. The evaluation of these patients is complex, because in vivo tests have a suboptimal sensitivity and can be time-consuming, expensive and potentially risky, especially drug provocation tests. There are several currently available in vitro methods that can be classified into two main groups: those that help to characterize the active phase of the reaction and those that help to identify the culprit drug. The utility of these in vitro methods depends on the mechanisms involved, meaning that they cannot be used for the evaluation of all types of DHRs. Moreover, their effectiveness has not been defined by a consensus agreement between experts in the field. Thus, the European Network on Drug Allergy and Drug Allergy Interest Group of the European Academy of Allergy and Clinical Immunology has organized a task force to provide data and recommendations regarding the available in vitro methods for DHR diagnosis. We have found that although there are many in vitro tests, few of them can be given a recommendation of grade B or above mainly because there is a lack of well-controlled studies, most information comes from small studies with few subjects and results are not always confirmed in later studies. Therefore, it is necessary to validate the currently available in vitro tests in a large series of well-characterized patients with DHR and to develop new tests for diagnosis.

Systematic analysis of histamine and N-methylhistamine concentrations in organs from two common laboratory mouse strains: C57Bl/6 and Balb/c

OBJECTIVE

Histamine plays a role in several (patho) physiological processes that are commonly studied in mouse models. However, a systematic quantification of histamine and its metabolite N-methylhistamine in mouse organs has not been reported so far.

METHODS

Balb/c and C57Bl/6 mice were grouped according to their sex and age. Brains, hearts, lungs, livers, kidneys, stomachs, intestines, thymi, spleens, and lymph nodes were excised, weighed, and homogenized. Histamine and N-methylhistamine were quantified simultaneously by a HPLC-mass spectrometry method.

RESULTS

In all organs analyzed, histamine and N-methylhistamine were detected; however, with quantitative differences. Histamine was present most abundantly in the stomach, lymph nodes, and thymus. The lowest histamine concentrations were detected in brain, liver, lung, and intestine. In most organs, the histamine concentrations increased age-dependently. Substantial concentrations of N-methylhistamine were detected only in lung, intestine and kidney, while in all other organs it was present only in minor quantities.

CONCLUSION

HPLC-mass spectrometry is a useful method for the highly sensitive and simultaneous detection of histamine and N-methylhistamine. Histamine is present in virtually all organs, not only in those traditionally associated with histamine-mediated disease. Highest concentrations are found in stomach, lymph node, and thymus; medium concentrations in heart, spleen, and kidney; and lowest concentrations detected in intestine, brain, liver, and lung.

Early detection of allergic diseases in otorhinolaryngology

Asthmatic diseases have been reported since the ancient world. Hay fever for instance, was described for the first time in the late 18(th) century, and the term "allergy" was introduced about 100 years ago. Today the incidence of allergies is rising; almost one third of the Western population suffers from its side effects. Allergies are some of the most chronic medical complaints, which results in high health expenditures. Therefore, they have a large health and political relevance.Caused by genetic and environmental factors, the group of IgE mediated allergies is large. It consists of e.g. atopic dermatitis, allergic asthma or allergic rhinitis. This paper aims to emphasize the ways of early diagnosis of allergic rhinitis (AR) as AR represents the most important representative of allergic diseases in ENT.

Comparison of serum tryptase and urine N-methylhistamine in patients with suspected mastocytosis

BACKGROUND

The disease extent of mastocytosis can be assessed by measurement of mediators or their metabolites, secreted from mast cells. In the present study, we compared results of urinary N-methylhistamine measurements with analysis of total tryptase in serum from patients with suspected mastocytosis.

METHODS

Tryptase in serum was determined with the UniCAP tryptase fluor-enzyme-immunoassay, according to the manufacturers' instructions (Pharmacia, Woerden, Netherlands). N-methylhistamine in urine was determined by competitive radioimmunoassay, according to the manufacturers' instructions (Pharmacia).

RESULTS

A significant correlation between serum tryptase and urine N-methylhistamine was found both for 138 patients aged 14 or older (Spearman Rank r(s)=0.43, p<0.0001) and for 23 younger patients (Spearman Rank r(s)=0.46, p=0.0267). The between-run coefficient of variation of the tryptase assay was half (6.7%) of the one (13%) found with the urinary N-methylhistamine assay. Both for urine N-methylhistamine and serum tryptase, a significant difference was found between corresponding biopsies with an increased number of mast cell aggregates and biopsies without such an increase. The difference between tryptase levels however was stronger (Mann-Whitney: p=0.0012) than the difference between N-methylhistamine levels (Mann-Whitney: p=0.0140).

CONCLUSION

Serum tryptase discriminates better than urinary N-methylhistamine between patients with an increased number of mast cell aggregates and persons without such an increase.

Comparison of ELISA and HPLC for the determination of histamine in cheese

A competitive direct enzyme-linked immunosorbent assay (CD-ELISA) for histamine in cheese was compared with a reversed-phase liquid chromatography (RP-HPLC) method. Cheese was homogenized with phosphate-buffered saline (PBS), centrifuged, and filtered, and the supernatant was diluted with PBS for CD-ELISA. For RP-HPLC, biogenic amines (histamine, tyramine, putrescine, and cadaverine) were derivatized with 9-fluorenylmethylchloroformate, followed by reversed-phase chromatography and fluorescence detection. Detection limits and mean recoveries (10-1000 mg/kg) were 2 mg/kg and 93% for CD-ELISA and 1 mg/kg and 99% for RP-HPLC, respectively. Analysis of 50 commercial cheeses according to both methods showed good agreement for histamine (r = 0.979; concentration range = 2-1800 mg/kg). At a threshold level of 10 mg/kg, the ELISA gave no false-negative and three false-positive results. The results show that the ELISA is suitable for the determination of histamine in cheese.

Dust from carpeted and smooth floors. V. Cat (Fel d I) and mite (Der p I and Der f I) allergen levels in school dust. Demonstration of the basophil histamine release induced by dust from classrooms

Sixty dust samples from schools in Norway were analysed for major allergens from cat and mite after sampling with the regularly used vacuum cleaners for 5 days and with a new model vacuum cleaner for 10 days, respectively. The major feline allergen Felis domesticus allergen I (Fel d I) was detected in all the classrooms, with ranges from 12 to 16,840 ng/m2 floor area. The mean Fel d I concentration was about 11 times higher per unit area carpeted floors as compared with smooth floors after the 10 days sampling period. Mite allergens Dermatophagoides pteronyssinus allergen I (Der p I) and Dermatophagoides farinae allergen I (Der f I) were detected in very low concentrations, with ranges from < 1 ng to 104 ng/m2 floor area. These findings suggest that the school is a protective environment against mite infestation, while the prevalence of cat allergens in classrooms seems higher than previously assumed. Basophil histamine release was measured after provocation with 20 dust extracts from 10 different schools. In nine of the 10 schools examined, the basophil histamine release caused by challenge with carpet dust was higher than the corresponding release with smooth floor dust. The calculated floor areas in each school in which dust led to 15% histamine release were from 2 to 55 times larger for smooth floors compared with carpeted floors. These results emphasize previous findings regarding higher allergen concentrations in classrooms with carpeted floors.

Diurnal variation of urinary histamine and 1-methylhistamine excretion in healthy children

In order to establish a noninvasive method of monitoring immediate hypersensitivity reactions in children, we studied the diurnal variation of urinary histamine and 1-methylhistamine excretion and the influence of food intake in a group of 14 healthy nonatopic children (aged 2-16 years). Histamine and 1-methylhistamine in spontaneous urine samples were determined by radioimmunoassay. Mean variation of 2-h intervals was much higher for urinary histamine than for 1-methylhistamine (45% of base-line level versus 24%). There was no circadian rhythm or influence of food intake. The short half-life of histamine released into blood circulation may be the main reason for the higher variation of histamine excretion. In children, urinary 1-methylhistamine is less influenced by diurnal variation and is therefore more suited to monitor immediate hypersensitivity reactions than urinary histamine itself.

[Early biological markers of anaphylactoid reactions occurring during anesthesia]

Three markers of in vivo histamine release, i.e. plasma histamine and tryptase, and urinary methylhistamine, were assessed using sensitive radioimmunoassays in 18 patients who had experienced an adverse reaction to an anaesthetic agent. Controls were obtained from 35 patients following a general anaesthetic, which included a muscle relaxant, and who remained free from any adverse reaction. A first blood sample was obtained from all 18 patients a mean 25 +/- 26 min after the reaction, and a second one in thirteen a mean 120 +/- 65 min after the reaction. Ten patients had had a life-threatening reaction. Plasma histamine levels were increased in all these cases, and tryptase concentrations in 9 out of 10. Urinary methylhistamine rarely reached pathological levels (4 out of 10). Skin tests were positive in the four tested patients. Plasma histamine concentration was still high in 8 cases thirty minutes after the reaction, and remained increased for more than 2 h in two patients. Among the other eight patients with a moderate reaction, 3 had high histamine levels, with normal or weakly increased tryptase concentrations, and normal urinary methylhistamine. Two of these patients had positive skin tests. There were no abnormal findings in any of the investigations carried out in the other five patients, except for a slightly positive skin test to atracurium in one patient. Plasma histamine had a higher sensitivity than tryptase levels. Methylhistamine concentrations were only rarely of interest. There were no false positives with the three investigated markers.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of urinary N tau-methylhistamine excretion: correlation of a newly developed radioimmunoassay (RIA) with gas chromatography mass spectrometry (GCMS)

A newly developed radioimmunoassay (RIA, Y) for the determination of urinary N tau-methylhistamine concentrations was correlated with gas chromatography mass spectrometry (GCMS, X). In 34 urine samples, with histamine and N tau-methylhistamine levels within our reference values, the correlation was: Y = 1.47X -0.245 mumol/l (r = 0.92; p-slope less than or equal to 0.0001). In 14 pathological urine samples, derived from patients with mastocytosis and having upper reference values, the correlation was: Y = 1.75X - 1.02 mumol/l (r = 0.93; p-slope less than or equal to 0.001). In spite of the greater specificity of the monoclonal antibody for N tau-methylhistamine compared with that of histamine, relatively high urinary histamine concentrations gave a false positive influence on the RIA results, which was 100% when the histamine/N tau-methylhistamine ratio was about 19. Clear cases of mastocytosis can be diagnosed, using the RIA-kit, but for a more precise N tau-methylhistamine value GCMS analyses will remain necessary.