Detection of serum IgE antibodies that react with alcuronium and tubocurarine after life-threatening reactions to muscle-relaxant drugs

Basophil Reactivity as Biomarker in Immediate Drug Hypersensitivity Reactions-Potential and Limitations

Immediate drug hypersensitivity reactions (DHRs) resemble typical immunoglobulin E (IgE)-mediated symptoms. Clinical manifestations range from local skin reactions, gastrointestinal and/or respiratory symptoms to severe systemic involvement with potential fatal outcome. Depending on the substance group of the eliciting drug the correct diagnosis is a major challenge. Skin testing and in vitro diagnostics are often unreliable and not reproducible. The involvement of drug-specific IgE is questionable in many cases. The culprit substance (parent drug or metabolite) and potential cross-reacting compounds are difficult to identify, patient history and drug provocation testing often remain the only means for diagnosis. Hence, several groups proposed basophil activation test (BAT) for the diagnosis of immediate DHRs as basophils are well-known effector cells in allergic reactions. However, the usefulness of BAT in immediate DHRs is highly variable and dependent on the drug itself plus its capacity to spontaneously conjugate to serum proteins. Stimulation with pure solutions of the parent drug or metabolites thereof vs. drug-protein conjugates may influence sensitivity and specificity of the test. We thus, reviewed the available literature about the use of BAT for diagnosing immediate DHRs against drug classes such as antibiotics, radio contrast media, neuromuscular blocking agents, non-steroidal anti-inflammatory drugs, and biologicals. Influencing factors like the selection of stimulants or of the identification and activation markers, the stimulation protocol, gating strategies, and cut-off definition are addressed in this overview on BAT performance. The overall aim is to evaluate the suitability of BAT as biomarker for the diagnosis of immediate drug-induced hypersensitivity reactions.

Drug-specific cyclodextrins with emphasis on sugammadex, the neuromuscular blocker rocuronium and perioperative anaphylaxis: implications for drug allergy

Cyclodextrins, oligosaccharides linked in a circular arrangement around a central cavity, are used extensively in the pharmaceutical industry to improve drug delivery. Their usefulness depends on their capacity to form a drug inclusion, or host-guest, complex within the cavity. In an attempt to improve the delivery of the widely used neuromuscular blocking drug (NMBD) rocuronium, a rocuronium inclusion complex was formed with a chemically modified γ-cyclodextrin. The high binding affinity and specificity of the modified carrier (named sugammadex) for rocuronium (and other aminosteroid NMBDs) led to its use in anaesthesia as an innovative and useful agent for rapid reversal of rocuronium-induced neuromuscular block by sequestering the drug as an inclusion complex. This, in turn, led to the suggestion that sugammadex might be useful to remove the NMBD from the circulation of patients experiencing rocuronium-induced anaphylaxis, a suggestion subsequently supported in case reports where traditional treatment had failed. Successful resuscitations suggested that sugammadex might be a valuable new treatment for such intractable cases but, given the inappropriateness of clinical trials, confirmation or refutation will have to await the slow accumulation of results of individual case reports. Important questions related to antibody accessibility of drug allergenic structures on the rocuronium-sugammadex inclusion complex, and the competition between sugammadex and IgE antibodies (both free and cell bound) for rocuronium, also remain and can be investigated in vitro. The sugammadex findings indicate that the use of carrier molecules such as the cyclodextrins to improve drug delivery will sometimes give rise to changed immunologic and allergenic behaviour of some drugs and this will have to be taken into account in preclinical drug safety assessments of drug-carrier complexes. The possibility of encapsulating and removing other allergenic drugs, e.g., penicillins and cephalosporins, in cases of difficult-to-reverse anaphylaxis to these drugs is discussed.

Drug allergy: an updated practice parameter

Adverse drug reactions (ADRs) result in major health problems in the United States in both the inpatient and outpatient setting. ADRs are broadly categorized into predictable (type A and unpredictable (type B) reactions. Predictable reactions are usually dose dependent, are related to the known pharmacologic actions of the drug, and occur in otherwise healthy individuals, They are estimated to comprise approximately 80% of all ADRs. Unpredictable are generally dose independent, are unrelated to the pharmacologic actions of the drug, and occur only in susceptible individuals. Unpredictable reactions are subdivided into drug intolerance, drug idiosyncrasy, drug allergy, and pseudoallergic reactions. Both type A and B reactions may be influenced by genetic predisposition of the patient

Diagnosis of neuromuscular blocking agent hypersensitivity reactions using cytofluorimetric analysis of basophils

BACKGROUND

Immunoglobulin E (IgE)-mediated hypersensitivity reactions to neuromuscular blocking agents (NMBA) are common and life threatening. Basophil activation based upon the expression of CD63 in the presence of specific allergens was found to be of importance for the diagnosis of IgE-mediated hypersensibility.

METHODS

The Basotest was evaluated for the diagnosis of NMBA in 47 patients with proven NMBA anaphylaxis, 40 atopic subjects nonallergic to NMBA and five healthy volunteers. Diagnosis of NMBA was made according to international standards on clinical history, skin tests and provocation tests when needed.

RESULTS

In the NMBA allergic patients, sensitivity of Basotest was 36.1%, but it increased to 85.7% for reactions which occurred within the last 3 years. The specificity was 93.3%.

CONCLUSION

Basotest may be useful for the diagnosis of NMBA allergy in patients with a suspicion of recent IgE-mediated hypersensitivity reaction to NMBA.

Studies on the mechanism of multiple drug allergies. Structural basis of drug recognition

The multiple drug allergy syndrome, that is, allergic recognition of a variety of drugs that may be both pharmacologically and structurally different, has been little studied and, consequently, the underlying mechanism(s) is unknown. The molecular basis of drug recognition by IgE antibodies found in the sera of subjects exhibiting multiple allergic drug sensitivities was studied by direct binding and quantitative hapten inhibition assays in experiments employing a wide range of carefully selected drugs and other chemicals. Drug recognition was shown to be related to the presence of tertiary and quaternary mono-, di- and trialkyl amino groups, but only if the alkyl groups were 'small' viz., methyl or, perhaps, ethyl. Primary, secondary, and tertiary (with R = 'large' alkyl) groups showed no direct antibody binding or antibody inhibitory activities. Near-neighbour effects of amide and hydroxyl groups appeared to promote weaker antigenic recognition. Results indicate that the antibody recognition and clinical drug allergy spectra of at least some subjects with multiple drug allergies are due to wide ranging immunological cross-reactivities with drugs containing tertiary amino and quaternary ammonium groups which are present in many different pharmacologically active agents. Separate populations of antibodies to other non-cross reacting drugs, for example, beta-lactam antibiotics, may also be present in the sera of such subjects.

Drug metabolism, danger signals, and drug-induced hypersensitivity

One of the most difficult challenges for the practicing allergist/immunologist today is that of evaluating and managing patients who present with histories of drug-induced reactions. Adverse drug reactions are heterogeneous, and a single drug can often cause a multitude of reactions. Because the mechanisms responsible for many of these reactions are not known, they can be, and often are, difficult to classify. Moreover, for those that have features consistent with immune-mediated mechanisms, our diagnostic tools remain limited, because little is known about the relevant immunogenic determinants of most drugs. Despite these challenges, management approaches must be devised for patients who present with histories of drug-induced disease. Simply telling such a patient to avoid all drugs that have been associated with previous adverse events leaves both the patient and the referring physician frustrated. The initial part of this review focuses on exciting current research that is furthering our understanding of the mechanisms responsible for drug-induced reactions. Because it will take time to translate this new information into clinical practice, the latter part of the review focuses on ways to evaluate and manage patients who present with drug-induced reactions using the tools and the knowledge that are currently available.

Subsequent general anaesthesia in patients with a history of previous anaphylactoid/anaphylactic reaction to muscle relaxant

Of 151 patients with a possible anaphylactoid/anaphylactic reaction to a muscle relaxant investigated over a 20-year period, follow-up for any subsequent general anaesthesia was complete in 145 (96%). One hundred and twenty-two anaesthetics in 72 patients were documented. There were no anaesthetic-related deaths. No subsequent reactions were seen if muscle relaxants were not used in the subsequent anaesthetic, nor were they in patients with severe reactions if the original intradermal test had been equivocal or negative. In the patients with a severe reaction and a positive intradermal test to one or more muscle relaxants, six out of 40 later anaesthetics using muscle relaxants were associated with clinical problems, three being probable anaphylactic reactions, whilst three were minor. Intradermal testing should be performed prior to surgery in this group of patients for the muscle relaxant(s) planned, or an anaesthetic technique which avoids relaxants should be used. This review should encourage other centres to undertake similar follow-up.

Mechanisms in IgE-dependent anaphylaxis to anesthetic drugs

The discovery of IgE antibodies to neuromuscular blocking drugs, to thiopentone and narcotics, particularly morphine, reinforced earlier beliefs formed from skin test and other clinical findings that many "anaphylactoid" reactions to drugs were true type 1 immediate hypersensitivity reactions. Immunochemical studies established the fine structural specificities of the drug-reactive IgE antibodies and provided an explanation in molecular terms for a number of observed clinical cross-reactions. Subtleties in interpreting relationships between skin tests and IgE radioimmunoassays are pointed out and mechanisms of drug-induced mediator release, persistence of IgE antibodies and the nature of the sensitizing sources are discussed.

Diagnosis of IgE-dependent anaphylaxis to neuromuscular blocking drugs, thiopentone and opioids

Although allergenic cross-reactivity of neuromuscular blocking drugs (NMBDs) is recognised clinically and has been firmly established at the serological and immunochemical levels, interpretation of in vitro inhibition findings for clinical purposes is not always straightforward. Points to be taken into account when considering serum IgE direct binding and inhibition results and when determining which NMBDs a patient may be sensitive to, include the relationship between in vitro potencies and clinical findings and the nature of the drug solid phase used for testing. It should also be remembered that the stimulating antigenic source for the patients' NMBD-reactive IgE antibodies is almost always unknown. A comparison of skin and IgE radioimmunoassay (RIA) tests for NMBDs in 29 patients is presented and difficulties involved in interpreting the results of both tests are discussed. Methods for increasing the detection of NMBD-reactive IgE antibodies are outlined. In screening sera of patients for IgE antibodies to thiopentone and morphine as well as NMBDs, multiple drug reactivities have been detected in a few subjects. Attention is drawn to defects in the existing thiopentone RIA although it is clear that the test is specific in patients who react to the drug. Addition of the serum tryptase assay to skin tests and IgE RIAs for NMBDs, thiopentone and morphine provides a powerful combination of diagnostic tests for the investigation of anaphylactoid reactions to anaesthetic drugs.

Clinical evaluation of in vitro leukocyte histamine release in allergy to muscle relaxant drugs

We have evaluated the in vitro leukocyte histamine release tests for the diagnosis of allergy to muscle relaxant drugs in 40 patients (Group A) and a control group of 44 subjects with negative leukocyte histamine release (Group B). Non-IgE dependent histamine release, expressed as a percentage of the total blood histamine, was 3.94% +/- 0.49 in Group B. The upper limit of positivity was estimated to be 5% (mean + 2 SD). Leukocyte histamine release tests were positive in 65% of the patients from Group A. The concordance between LHR and QAS-RIA was 64%. The maximal histamine release was observed at dilutions of 10(-2)-10(-4) in 20 of the 26 positive cases. The maximal histamine release was 43.8% +/- 23.3. The spontaneous histamine release was as low as 1.7% +/- 1.1. Cross-reactivity among the 5 different muscle relaxant drugs has been investigated and compared by intradermal testing. The muscle relaxant drugs which gave the lower skin reaction (M2) and the drug responsible for shock (M1) were selected for the study of in vitro leukocyte histamine release. Of 20 M2. All of the 10 cases had negative ID tests with M2. Three of these patients subsequently underwent general anesthesia with the muscle relaxant chosen as harmless (M2) without any clinical reaction.

Persistence of allergy to anaesthetic drugs

Intradermal testing and RIA testing for specific IgE antibodies to neuromuscular blocking drugs (NMBDs) were performed in patients referred to an Anaesthetic Allergy Clinic. Six patients were initially investigated four to 29 years after clinical anaphylaxis during anaesthesia and two of these patients and sixteen others were investigated by intradermal testing on two occasions at least four years apart. Seven patients had RIA tests for NMBD-specific IgE antibodies on two occasions at the time of skin testing. In all but two patients the evidence for drug-specific antibodies persisted 4-29 years after the reactions. In one patient all tests became negative and in another the skin test became negative but the positive RIA persisted. Evidence of antibodies to NMBDs persisted in 21 of 22 patients who had had anaphylactic reactions to these drugs during anaesthesia. In the absence of evidence of allergy diminishing with time in the majority of patients it would seem wise to avoid drugs responsible for reactions for the rest of the patient's life.

Evaluation of a new reactive solid phase for radioimmunoassay of serum specific IgE against muscle relaxant drugs

Until now, immunoassays for detection of anti-muscle relaxant IgE in serum have been performed with the drug coupled to epoxy-activated Sepharose or to RAST papers dics. In the present work we have used a quaternary ammonium-Sepharose in which the quaternary ammonium reactive group (choline chloride) was directly coupled to Sepharose via an ether linkage. 50 microliters of the quaternary ammonium solid phase (QAS) was incubated with 50 microliters of serum for 3 h, washed, incubated 18 h with 125I-anti-IgE and washed again. The results were expressed as the percentage of 125I-anti-IgE absorbed onto the solid phase. The results were at 1.3 +/- 0.5% for 20 control sera, with an upper normal limit estimated to 2.3%. The within-run reproducibility ranged from 3.2% to 10.0%. The results were significantly correlated with those obtained with either alcuronium-epoxy-Sepharose, choline-epoxy-Sepharose, the RAST-alcuronium or with the RAST-succinyl choline (respectively, r = 0.66, r = 0.80, r = 0.81, r = 0.40 and r = 0.85). The values obtained with the sera of 83 patients ranged from 0.3 to 38.5%. The sensitivity was estimated at 87.9%, 66.7% and 40.7% with the QAS-RIA, the RAST-succinyl choline and the RAST-alcuronium, respectively. The inhibition of adsorption of specific IgE onto the gel ranged from 13.0 to 90.6% in presence of 130 nmol of soluble muscle relaxants. In 83.3% of 30 cases, the highest inhibition was obtained with the muscle relaxant which was clinically incriminated.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoassays employing substituted ammonium compounds other than neuromuscular blocking drugs to increase the detection of IgE antibodies to these drugs

Subjects who experience life-threatening anaphylactic reactions to neuromuscular blocking drugs frequently have serum IgE antibodies that react with substituted ammonium groups on the drugs. Failure to detect drug-reactive antibodies may be due to the nature of the drug-solid support used for testing sera. With this in mind, solid phases of some selected compounds containing substituted ammonium groups, in particular triethylamine and morphine, were prepared and used to screen sera in an attempt to increase the frequency of detection of IgE antibodies complementary to tertiary and/or quaternary ammonium groups. For subjects who experienced an anaphylactic reaction to succinylcholine or gallamine, use of the supplementary assays increased the frequency of detection from 83 to 100%. For d-tubocurarine and alcuronium, detections increased from 92 to 100% and from 67 to 88%, respectively. Molecular models revealed a clear structural similarity between the conformations of the trialkylammonium groups on one face of the molecules of morphine and d-tubocurarine.

The molecular basis of IgE antibody binding to thiopentone. Binding of IgE from thiopentone-allergic and non-allergic subjects

Thiopentone-specific IgE antibodies from the sera of subjects who experienced a life-threatening anaphylactic reaction to the drug and IgE antibodies that cross-react with thiopentone via substituted ammonium groups in either cyclic or acyclic form, were studied by direct binding immunoassays and quantitative hapten inhibition methods. Findings provided an explanation for the apparent 'non-specific' nature of some IgE antibody reactions with thiopentone and reinforce the conclusion that the thiopentone IgE immunoassay is a valuable aid in the diagnosis of immediate allergic reactions to the drug.

Radioallergosorbent test (RAST) for specific IgE antibody to lidocaine, procaine and methylparaben

Although anaphylactoid reactions to local anesthetics are well known, a radioallergosorbent test (RAST) to detect specific drug reagin (IgE) anti-body has not been developed. We established RAST for local anesthetics by using carboxylic acid derivatives of lidocaine, procaine and methylparaben. Serum samples were taken from 100 volunteers who were regarded to be nonallergic to the drugs used. Negative RAST values obtained from these volunteers were 1653 +/- 254(SD) cpm (lidocaine), 2750 +/- 264 cpm (procaine), and 2805 +/- 336 cpm (methyl paraben).

[Predictive value of intradermal tests using muscle-relaxing drugs]

A retrospective postal inquiry was carried out to find out a possible relation between the results of intradermal tests carried out for a previous anaesthetic and the course of a second anaesthetic performed afterwards. This study included 350 patients who have had an intradermal test to vecuronium, alcuronium, suxamethonium, gallamine, pancuronium, thiopentone, fentanyl and droperidol between March 1984 and November 1986. Eighty-nine did not reply (25.4%), 183 (52.3%) did not undergo new general anaesthetic since the skin tests, whilst 78 (22.3%) did. The inquiry was then sent to the 73 anaesthetists corresponding to the last group of patients. The 51 complete answers included 62 anaesthetics. Twenty-four patients had negative intradermal tests before the new anaesthetic, the other 27 having had a test positive to at least one muscle relaxant. Of these latter, 16 were given a muscle relaxant during their general anaesthetic, selected among those resulting in a negative intradermal test. Thirteen had undergone skin testing because of an anaphylactic reaction during induction. No new anaphylactic reaction was observed. Three anaesthetists only were not aware of the results of the intradermal tests at the time of the new anaesthetic. These data tend to demonstrate that a muscle relaxant could be injected in a patient who has had a previous anaphylactic reaction with positive intradermal tests, provided that the drug chosen for the new anaesthetic does not give a positive intradermal reaction.

Fatal anaphylactic reaction to suxamethonium: new screening test suggests possible prevention

A 40-year-old woman suffered cardiovascular collapse, cardiac ischaemia and arrest during induction of anaesthesia. Severe cerebral ischaemic damage was sustained during this episode and the patient died 4 days later. This fatal reaction was shown to be anaphylactic in origin; the causative agent was suxamethonium. High levels of IgE antibodies specific to the quaternary ammonium group (two of which are present in suxamethonium) were detected by the radioallergosorbent test. Results of the leucocyte histamine release test were less clear, partly as a result of steroid treatment. The two most relevant points were the absence of a history of previous anaesthesia, and involvement of the heart as the principal target of the reaction. This unfortunate and extreme case indicates the necessity for allergy testing (screening) before anaesthesia, and the need for organisation and funding of this procedure, if these fatal or near-fatal reactions are to be prevented. It is a timely reminder that action should be taken, since neuromuscular blockers have been confirmed as the most common culprits, and that specific tests for IgE antibodies are now available against haptenic groups generally common to all neuromuscular blockers.

A pharmacologic study on the histamine releasing effect of atracurium and other muscle relaxants in rat isolated ileum

In this study, the effects of histamine, antihistamines (terfenadine and mepyramine), 5-hydroxytryptamine, and muscle relaxants, atracurium, vecuronium and gallamine, on the tone and contractility of rat ileum were studied and compared in vitro. The aim of the present investigation was to measure, pharmacologically, the histamine releasing effect of muscle relaxants, e.g atracurium, vecuronium and gallamine, by comparing their contractile response in the absence and presence of antihistamines and comparing their mechanical responses with those produced by histamine and 5-hydroxytryptamine (5-HT). The results showed that the antihistamines, triludan(terfenadine) and mepyramine produced opposite effects in rat ileum. Terfenadine (0.1-20 microM) produced concentration-dependent contractions in the rat ileum, whereas mepyramine (0.1-10 microM) relaxed the muscle, e.g. by 1.2 g tension. Atracurium (0.5-500 microM), vecuronium (0.2-200 microM), and gallamine (0.1-7.0 microM) produced marked contractions (1.5-4.0 g tension) in rat ileum, and these contractions were markedly reduced by mepyramine (1.3 microM) or terfenadine (5 microM), implicating histamine release in the generation of these contractions. However, there was some residual contraction which was not blocked by mepyramine, but by 5-HT antagonist, methysergide (1 microM), indicating that a mechanism other than histamine release may be responsible for the residual contraction, i.e. release of other mediators such as 5-HT, prostaglandins, or calcium. 5-HT (0.5-500 microM) and histamine (0.5-500 microM) produced contractions in the rat ileum, but 5-HT was more effective than histamine in producing these contractions. Similarly, gall amine was more effective than atracurium and vecuronium in contracting the rat ileum.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergy to suxamethonium: persisting abnormalities in skin tests, specific IgE antibodies and leucocyte histamine release

Twenty-one patients, who had previously experienced an anaphylactic reaction to suxamethonium during general anaesthesia, were selected for this study. Initially, skin tests with muscle relaxants were carried out in the twenty-one patients, detection of specific anti-choline IgE in nineteen, and leucocyte histamine release in seventeen. These three tests were then repeated between 1 year and 4 years after the initial evaluation. In the majority of patients, sensitization to the muscle relaxants persisted for more than 1 year after the anaphylactic reaction. Only three patients out of twenty-one (4%) had negative skin tests when retested 1-4 years later. A reduction in leucocyte histamine release was noticed in one of the seventeen retested patients (6%). Modifications of anti-choline IgE were observed in five of nineteen patients (26%). The persistence of sensitization to suxamethonium may result from repeated stimulation by occasional contacts with quaternary ammonium compounds. This study demonstrates the reliability of skin tests, leucocyte histamine release and detection of anti-choline IgE to diagnose allergic reactions to suxamethonium, even when they are performed a long time after the initial anaphylactic reaction.

An immunoassay for the detection of IgE antibodies to trimethoprim in the sera of allergic patients

An immunoassay was developed to detect IgE antibodies to the widely used antibacterial drug trimethoprim. Significant levels of trimethoprim-reactive IgE antibodies were found in the sera of two patients who had experienced life-threatening allergic reactions following administration of a combination of trimethoprim and sulphamethoxazole. No IgE antibodies reactive with sulphamethoxazole were found in the sera of either patient. Inhibition experiments revealed that a high degree of cross-reactivity occurs between the drug-reactive IgE antibodies and two structural analogues of trimethoprim, 6-hydroxy- and 6-chlorotrimethoprim. These experiments also indicated that the combining sites of the trimethoprim-reactive IgE antibodies in the two sera were probably complementary to different parts of the trimethoprim molecule. The assay should supplement skin testing in determining the offending drug in patients with suspected allergic sensitivity to trimethoprim-sulphamethoxazole complex.

Detection of thiopentone-reactive IgE antibodies following anaphylactoid reactions during anaesthesia

A radioimmunoassay was developed to detect IgE antibodies to the anaesthetic induction agent thiopentone. Significant levels of thiopentone-reactive IgE antibodies were found in the sera of two patients who had experienced life-threatening anaphylactoid reactions following administration of the drug. Inhibition experiments revealed that cross-reactivity occurs between the drug-reactive IgE antibodies and four barbiturate analogues pentobarbitone, phenobarbitone, barbitone and methohexital. The assay should supplement skin testing for the detection of patients with potentially lethal sensitivity to thiopentone.

Antigenic similarity between the protein neurotoxin alpha-bungarotoxin and neuromuscular blocking drugs

The snake neurotoxins alpha-bungarotoxin (alpha-BGT) and beta-bungarotoxin (beta-BGT) which act at the neuromuscular junction, were found to bind to IgE antibodies directed against neuromuscular blocking (NMB) drugs in the sera of two patients who had experienced lifethreatening anaphylactic reactions to succinylcholine. alpha-BGT inhibited IgE-binding to a choline-Sepharose solid support in one patient better than the NMB drug alcuronium, choline, triethylcholine and beta-BGT. IC50s for alpha-BGT and succinylcholine were 16 and 10 nmol respectively for one patient and 34 and 6.0 nmol for the other. Recognition of the NMB drugs and alpha-BGT by the same antibody is the first demonstration of an antigenic similarity between these drugs and the protein toxin.

[Radioimmunoassay method for the detection of IgE antibodies specific to alcuronium]

A radio-immunoassay (RIA) was used to screen for specific IgE to myorelaxants. Alcuronium was coupled to epoxy-activated Sepharose. Sixteen patients with anaphylaxis to alcuronium (n = 2), gallamine (n = 2) or suxamethonium (n = 12) were studied. The diagnosis was established by intradermal tests (ID), passive cutaneous anaphylaxis tests and human basophil degranulation tests. The amount of non specific label retained by Sepharose-ethanolamine (with sera of patients) and Sepharose-alcuronium (with sera of 11 control subjects) was estimated. The RIA was positive 10/16 (8/14 patients having reacted to a muscle relaxant other than alcuronium). The RIA seemed to be useful in the diagnosis of anaphylaxis to muscle relaxants. Drug-reactive antibodies were specific of the quaternary ammonium radical, which was the common allergenic determinant of all molecules of muscle relaxants. This test accounted for in vitro cross-reactivity, but had no predictive value for the clinical risk of crossed-anaphylaxis. This risk was best assessed by ID; it was positive in three cases. Although it was not possible to compare ID and RIA, the interpretation of which was different, both tests should be recommended for the detection of sensitivity to muscle relaxants.

[Anaphylactic complications due to suxamethonium]

A study was carried out on 36 patients who had presented with an anaphylactic reaction when they had been received anaesthetic induction agents including suxamethonium. After having been examined, they were assessed with various immunoallergic tests (skin tests, LHL, a search for specific anticholine IgE antibodies). They were compared with a group of 120 control patients with the same age, sex and professional characteristics. This study confirmed the part played by specific IgE antibodies in accidents involving suxamethonium. The specificity of the tests that could be used for the diagnosis was excellent. However, as far as sensitivity of the tests went, skin tests and LHL were more sensitive than the search for specific IgE antibodies. There was no statistical relationship between the limit for skin reactions and the degree of histamine release of the level of anticholine IgE antibody.

Inhibition of histamine-N-methyltransferase activity by neuromuscular blocking drugs

On the basis of previous findings that histamine-N-methyltransferase (HMT) activity can be significantly enhanced or inhibited by a number of analogues of histamine and drugs containing dialkylaminoalkyl moieties, we investigated whether the neuromuscular blocking drugs alcuronium, d-tubocurarine, decamethonium, succinylcholine, gallamine and pancuronium each of which contain quaternary ammonium groups, influence the activity of HMT. Our findings showed that all six drugs significantly inhibited HMT activity in the concentration range 10(-7)-10(-3) M with alcuronium being the most potent inhibitor (I.D.50 = 2 X 10(-6) M). Activities at these concentrations reveals that alcuronium, pancuronium, d-tubocurarine and gallamine are more potent inhibitors than two of the most potent histamine analogue inhibitors, N tau-methylhistamine and 2-methylhistamine. Alcuronium proved to be of similar potency to the dimaprit analogue, SKF 91488 regarded as one of the most potent HMT inhibitors known. The structurally similar and chemically least complex straight chain neuromuscular blocking compounds, succinylcholine and decamethonium proved to be the least potent inhibitors.

Leukocyte histamine release to suxamethonium in patients with adverse reactions to muscle relaxants

In an earlier study we confirmed the usefulness of intradermal skin tests and histamine release in diagnosis of patients reactive to muscle relaxants, and we suggested an IgE-mediated reaction rather than an idiosyncratic mechanism. In a later study, we studied the relationship between (Formula: see text) that is one of the muscle relaxants producing the most frequent adverse reactions under anesthesia. Histamine release was measured in five patients with increasing concentrations of suxamethonium in the presence or absence of human serum albumin in Tris buffer. Suxamethonium by itself without any carrier in the buffer could, in vitro, act as a true allergen on target leukocytes in the sensitized patients' group. Acetylcholine (20 and 200 micrograms/ml) did not induce significant histamine release in five patients with positive histamine release in the presence of suxamethonium. Preincubation of leukocytes from 11 patients for 30 min with 20 and 200 micrograms of acetylcholine in Tris albumin CA++ Mg++ buffer decreased the histamine release induced by suxamethonium (10 micrograms/ml); mean maximal histamine release of 46% +/- 4.2 was reduced to 31.4 +/- 5.8 and 7% +/- 4 (p less than 0.001), respectively. However, in eight control subjects similar concentrations of acetylcholine did not change the maximal histamine release induced by anti-IgE (0.2 micrograms/ml). In the same way acetylcholine did not modify histamine release induced by Dermatophagoides pteronyssinus extract (1/10,000 w/v) in six patients allergic to this allergen. This study suggests that suxamethonium acts as a true allergen and that acetylcholine or one of its metabolites may act as a hapten inhibitor in the model of histamine release induced by suxamethonium.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro diagnosis and studies on the mechanism(s) of anaphylactoid reactions to muscle relaxant drugs

By covalently coupling alcuronium, d-tubocurarine and the pancuronium analogue, vecuronium, and using the resultant complexes in radioimmunoassays with patients' sera, we have found high levels of drug-reactive IgE antibodies in some subjects who reacted to these muscle relaxants. This is the first demonstration of IgE antibodies to such compounds. Assays were also developed for the detection of drug-reactive IgE antibodies to the muscle relaxant drugs succinylcholine, decamethonium and gallamine. They involved the coupling of choline and its ethyl analogue, triethylcholine to activated Sepharose. Results of direct binding and inhibition experiments and correlations with clinical findings demonstrated that the assays are relevant to the detection of succinylcholine-, decamethonium- and gallamine-reactive IgE antibodies in patients who experienced adverse reactions to these drugs. Quantitative inhibition studies revealed that IgE antibodies from most patients cross-reacted with all muscle relaxants tested, other quaternary ammonium compounds and some pharmacologically unrelated drugs including promethazine, morphine, neostigmine and pentolinium. Results showed that the specificities of the IgE antibodies are directed towards quaternary or tertiary ammonium ions on the drugs that bind the antibodies. As these ions occur widely in man's environment in drugs, cosmetics, disinfectants, foods and industrial materials, it seems possible that sensitization of patients may occur without previous exposure to muscle relaxant drugs. Thus, we now have assays that will detect antibodies to all six muscle relaxant drugs --alcuronium, d-tubocurarine, pancuronium, succinylcholine, decamethonium and gallamine-- and, for the first time since the work on penicillins, drug-specific IgE antibodies have been found in large numbers of patients and the allergenic determinants have been identified.

[Histamine liberation induced by anesthetics or their solvents: specific or non-specific?]

Histamine release is a frequent event in the perioperative period. The reasons for its occurrence are complex; they include pseudoallergic and allergic phenomena--and probably a mixture of both. Some drugs and solvents seem to modulate histamine release induced by other drugs. Thus the terms "specific and nonspecific" or "selective and nonselective" histamine release which have their well appreciated place in experimental immunology and pharmacology should be avoided in describing histamine release responses in clinical conditions. The clinical relevance of histamine release in the perioperative period is considerable and can be compared with that of perioperative thrombosis and thromboembolism. Far too many drugs and anaesthetic and surgical procedures give increased plasma histamine levels; premedication with H1- + H2-histamine receptor antagonists is therefore recommended in patients who have a history of hypersensitivity reactions to intravenous agents; a history of atopy, who are to be given the same drug a few days later, undergo surgery with a high risk of histamine release, are more than 70 years old or are poor risk patients with perioperative cardiac, respiratory or liver failure and shock.

Role of IgE in anaphylactoid reactions during anaesthesia

As diagnostic methods of detecting drug-specific IgE antibodies become more sophisticated, the evidence implicating specific IgE in anaesthetic allergy has increased. To implicate IgE in reactions, a history resembling anaphylaxis, the demonstration of drug-specific histamine release by intradermal testing and the demonstration of specific antibodies are necessary. Such evidence is seen in 70% of muscle relaxant reactors. Basophil histamine release studies suggest that histamine release is allergen-induced, not direct, and the final evidence necessary is to demonstrate the role of drug-specific antibodies in such histamine release.