In vitro evaluation of IgE-mediated hypersensitivity reactions to quinolones

BACKGROUND

  Hypersensitivity IgE-mediated reactions to quinolones are not easy to diagnose, with skin testing inducing false positive results. The aim of the study was to evaluate the in vitro-specific IgE response in patients with immediate allergic reactions to quinolones.

METHODS

  We evaluated 38 patients with confirmed immediate allergic reactions to quinolones. Those with anaphylaxis were considered allergic by clinical history, once other possible causes were ruled out, and those with urticaria by drug provocation. Sepharose-radioimmunoassay (RIA) and basophil activation test (BAT) with ciprofloxacin, moxifloxacin and levofloxacin were performed.

RESULTS

  The quinolones involved were moxifloxacin (N = 24), ciprofloxacin (N = 11) and levofloxacin (N = 3). Sepharose-RIA was positive in 12 cases (31.57%) and BAT in 27 (71.05%). With Sepharose-RIA, 8 (21%) were positive to ciprofloxacin, 7 (18.4%) to moxifloxacin and 7 (18.4%) to levofloxacin. With BAT, 23 (60.5%) were positive to ciprofloxacin, 12 (31.6%) to moxifloxacin and 8 (21%) to levofloxacin. The specificity of the Sepharose-RIA was demonstrated by inhibition tests. To confirm that the BAT results observed were IgE mediated, the PI3K inhibitor wortmannin was used, with this compound inhibiting the BAT when stimulated with anti-IgE and the different quinolones, but not when fMLP was used as the basophil stimulator. Sepharose-RIA and BAT were repeated in positive cases 1 year later, detecting a decrease in all cases, with four becoming negative.

CONCLUSION

  Immediate hypersensitivity reactions to quinolones do occur, with moxifloxacin being the drug most frequently involved. The BAT is a useful method for diagnosing patients. Specific IgE was demonstrated by Sepharose-RIA and inhibition assay.

Natural killer-dendritic cell interaction in lymphocyte responses in hypersensitivity reactions to betalactams

BACKGROUND

Betalactams are the commonest cause of allergic reactions mediated by either IgE or T lymphocytes in which innate and adaptive immune systems mediate the earlier stages of immunological responses. One of the links between these systems is related to the interaction between natural killer (NK) and dendritic cells (DC). We have evaluated the role of NK cells and NK-DC interaction in the immunopathological mechanisms of nonimmediate reactions to betalactams.

METHODS

Patients allergic to amoxicillin (AX) (N = 17) and tolerant controls (N = 13) were included. Changes in phenotype (CD69, IFNγ, perforin, and granzyme B) in AX-stimulated NK cells, the cytotoxic activity on mature or immature DC (imDC), and the proliferation and phenotype of NK lymphocytes after culture with AX and DC were determined by flow cytometry.

RESULTS

Amoxicillin induced activation and increases of perforin and granzyme B (P = 0.007 and P = 0.041 respectively) but not IFNγ production in NK cells from patients. In NK subpopulations, AX induced a significant enhancement of perforin and granzyme B in CD56(dim) (P = 0.005 and P = 0.002 respectively) and of IFNγ in CD56(bright) (P = 0.001). The cytotoxic phenotype was demonstrated by an increase of annexin V only in imDC (P < 0.001). Amoxicillin also induced an increased NK proliferation with different patterns, cytotoxic or proinflammatory, depending on the presence of imDC or mature DC, respectively. No differences were observed in NK cells from tolerant controls.

CONCLUSION

These data could demonstrate the involvement of NK cells in the immunopathological mechanisms of nonimmediate allergic reactions to AX, showing that both the innate and adaptive immune systems are involved and crosstalk, producing amplification of the harmful effects observed in these drug reactions.

General considerations on rapid desensitization for drug hypersensitivity - a consensus statement

Drug hypersensitivity reactions can occur with most drugs, are unpredictable, may affect any organ or system, and range widely in clinical severity from mild pruritus to anaphylaxis. In most cases, the suspected drug is avoided in the future. However, for certain patients, the particular drug may be essential for optimal therapy. Under these circumstances, desensitization may be performed. Drug desensitization is defined as the induction of a temporary state of tolerance of a compound responsible for a hypersensitivity reaction. It is performed by administering increasing doses of the medication concerned over a short period of time (from several hours to a few days) until the total cumulative therapeutic dose is achieved and tolerated. It is a high-risk procedure used only in patients in whom alternatives are less effective or not available after a positive risk/benefit analysis. Desensitization protocols have been developed and are used in patients with allergic reactions to antibiotics (mainly penicillin), insulins, sulfonamides, chemotherapeutic and biologic agents, and many other drugs. Desensitization is mainly performed in IgE-mediated reactions, but also in reactions where drug-specific IgE have not been demonstrated. Desensitization induces a temporary tolerant state, which can only be maintained by continuous administration of the medication. Thus, for treatments like chemotherapy, which have an average interval of 4 weeks between cycles, the procedure must be repeated for every new course. In this paper, some background information on rapid desensitization procedures is provided. We define the drugs and drug reactions indicated for such procedures, describe the possible mechanism of action, and discuss the indications and contraindications. The data should serve as background information for a database (accessible via the EAACI-homepage) with standardized protocols for rapid desensitization for antibiotics, chemotherapeutic agents, monoclonal antibodies/fusion proteins, and other drugs.

IgE-mediated hypersensitivity reactions to methylprednisolone

BACKGROUND

Allergic reactions to systemically administered corticosteroids seem to be infrequent considering their extensive use. The aim of the study was to evaluate the IgE response in patients with immediate allergic reactions to methylprednisolone (MP).

METHODS

Four subjects who developed immediate reactions after MP administration and ten controls with good tolerance to MP administration were evaluated. Skin prick and intradermal testing were done using MP, hydrocortisone (HC), and dexamethasone (DX). If negative, a drug provocation test (DPT) was done to confirm the diagnosis and assess cross-reactivity. The in vitro IgE response was evaluated by the basophil activation test (BAT) and ImmunoCAP.

RESULTS

Three patients were diagnosed by the presence of a positive skin test in the immediate reading with MP, two by prick and one by intradermal testing, and one patient was skin test negative and diagnosed by DPT. All four patients had good tolerance to HC and DX. The BAT was positive for just MP in those patients with positive skin tests, with all patients being negative for HC and DX. Two patients were also ImmunoCAP positive to MP.

CONCLUSIONS

This study confirms the existence of immediate allergic reactions to MP and that some are mediated by specific IgE antibodies. Skin testing, ImmunoCAP and the BAT are useful to confirm the diagnosis.

Role of effector cells (CCR7(-)CD27(-)) and effector-memory cells (CCR7(-)CD27(+)) in drug-induced maculopapular exanthema

Maculopapular exanthema (MPE) induced by drugs is a T-cell mediated reaction and effector cells may play an important role in its development. We assessed the effector and cutaneous homing phenotype in peripheral blood cells from allergic patients after drug stimulation. This study included 10 patients and 10 controls. The effector phenotype (CCR7(-)CD27(+/-)), chemokine receptors (CCR4 and CCR10), and activation (CD25(low)) and regulatory markers (CD25(high)) were measured by flow cytometry in both peripheral blood mononuclear cells (PBMCs) and CD4-T-lymphocytes. Proliferation was determined by 5-(-6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) assay and the migratory capacity by a chemotaxis assay using CCL17 and CCL27. Compared to controls, CCR7(-)CD27(-) cells were increased in patients without (p=0.003) and with drug stimulation (p less than 0.001) and had significantly higher proliferation (p=0.010). CCR10 expression was increased in patients after drug stimulation in total and memory CD27(+) T-cells. Lymphocyte migration with CCL27 was higher in patients with drug stimulation (p=0.048), with a decrease in CCR7(-)CD27(-) (p less than 0.0001) and an increase in CCR7(-)CD27(+) (p=0.017). In patients, CD4-T-lymphocytes were significantly activated after drug stimulation (p less than 0.001). In conclusion, we show that effector memory CD4(+) T-cells (CCR7(-)CD27(+)) respond specifically to the drug responsible for MPE and confirm previous data about the involvement of CCR10 in cell trafficking to the skin.

Universal versus selective screening for the detection, control and prognosis of gestational diabetes mellitus in Argentina

In all, 1,702 unselected pregnant women from the city of La Plata were tested for gestational diabetes mellitus (GDM) and evaluated to determine GDM prevalence and risk factors. In women with GDM, we evaluated compliance with guidelines for GDM management, and perinatal complications attributable to GDM. GDM prevalence was 5.8%, and its risk factors were pre-gestational obesity, previous hyperglycaemia, age > 30 years, previous GDM (and its surrogate markers). In primi-gravida (PG) subjects, GDM was equally prevalent in the presence (4.2%) or absence (4.0%) of risk factors. In multi-gravida (MG) women, although risk factors doubled the prevalence of GDM (8.6%), in the absence of risk factors GDM prevalence was similar to that of PG women (3.9%). Half of all women with GDM received inadequate post-diagnosis obstetric control, and this induced a fourfold increase in infant perinatal complications. In conclusion, all non-hyperglycaemic 24-28-week pregnant women should be tested for GDM, although particular attention must be paid to MG women with risk factors.

Role of minor determinants of amoxicillin in the diagnosis of immediate allergic reactions to amoxicillin

BACKGROUND

Skin testing of subjects with immediate hypersensitivity to amoxicillin is performed using major and minor determinants of benzylpenicillin plus amoxicillin. However, sensitivity is not optimal, and other determinants need to be considered. We assessed the sensitivity of stable, well-characterized minor determinants of amoxicillin in subjects with immediate allergic reactions to amoxicillin to improve skin test sensitivity.

METHODS

Amoxicillin, amoxicilloic acid, and diketopiperazine were prepared and characterized by reverse-phase HPLC, tested in vivo by skin testing and in vitro by basophil activation test and RAST inhibition assay.

RESULTS

Patients with immediate hypersensitivity to amoxicillin were selected: Group A (n = 32), skin test positive just to amoxicillin; Group B (n = 19), skin test positive to benzylpenicillin determinants; Group C (n = 10), skin test negative and amoxicillin drug provocation test positive. In Group A, 27 subjects (81.8%) were skin test positive to amoxicillin, ten (30.3%) to amoxicilloic acid, two (6.1%) to diketopiperacine, and six (18.2%) negative. In Group B, nine (50%) were positive to amoxicillin, eight (42.1%) to amoxicilloic acid, none to diketopiperacine, and nine (50%) negative. In Group C, skin tests were negative. BAT was positive to amoxicillin in 26 patients (50.9%), to amoxicilloic acid in 15 (29.1%), and diketopiperazine in four (7.8%). RAST inhibition studies showed > 50% inhibition in all sera, with the highest concentration of amoxicillin and amoxicilloic acid.

CONCLUSIONS

The combination of minor determinants of amoxicillin, amoxicilloic acid, and diketopiperazine seems to be of no greater value than the use of amoxicillin alone. Further efforts are needed to find new structures to improve sensitivity in the diagnosis of immediate hypersensitivity to betalactams.

Immediate and dual response to nasal challenge with Dermatophagoides pteronyssinus in local allergic rhinitis

BACKGROUND

Local allergic rhinitis (LAR) is characterized by in situ production of specific IgE (sIgE) antibodies and a positive response to a nasal allergen provocation test (NAPT) in the absence of atopy.

OBJECTIVE

The aim of this study was to investigate the immunological mechanisms involved in the immediate and late responses after nasal exposure to Dermatophagoides pteronyssinus (DP) in patients with LAR.

METHODS

A total of 40 subjects with LAR to DP were studied and compared with 50 healthy controls. Immediate and late responses to NAPT-DP were assessed using a visual analogue scale of nasal symptoms and acoustic rhinometry. Tryptase, ECP, total and sIgE-DP were measured in the nasal lavage by immunoassay at baseline, 15 min, 1, 6 and 24 h after nasal challenge.

RESULTS

NAPT-DP was positive in all patients, with significant increases in tryptase (45%), ECP (65%) and sIgE-DP (25%) (P<0.05). Sixty percent of the LAR patients presented an immediate response to NAPT-DP and 40% a dual response. Immediate responders showed a fast release of tryptase with a peak at 15 min after NAPT-DP, and a progressive increase in nasal ECP and sIgE-DP from 1 to 24 h after challenge, with a peak at 24 h. Dual responders presented persistently higher levels of tryptase from 15 min to 6 h after challenge, and a similar pattern of nasal release of ECP and sIgE-DP to immediate responders. There were no isolated late responders. NAPT-DP was negative in all healthy controls, with no increases in tryptase, ECP, or total and sIgE-DP in nasal secretions.

CONCLUSIONS

The results demonstrated the existence of immediate and dual responses to a NAPT with DP in LAR patients, with the local presence of sIgE and mast cell/eosinophil activation.

Properties of different lactic acid bacteria isolated from Apis mellifera L. bee-gut

Eight strains belonging to Lactobacillus spp. and five to Enterococcus spp. were isolated from the gut of worker Apis mellifera L. bees. Studies based on 16S rRNA sequencing revealed that AJ5, IG9, A15 and CRL1647 strains had a 99% identity with Lactobacillus johnsonii, while SM21 showed a 99% similarity with Enterococcus faecium. L. johnsonii CRL1647, AJ5 and IG9 were high lactic acid producers (values were between 177 and 275 mM), and in vitro they inhibited different human food-borne pathogens and Paenibacillus larvae, the American foulbrood agent. This bacterium was the most sensitive to the lactic acid effect being inhibited by 44 mM of this metabolite. L. johnsonii CRL1647, AJ5 and IG9 also presented important surface properties. These cells showed between 77% and 93% of auto-aggregation. The preliminary study of the chemical nature of the aggregating factors revealed that the molecules involved in the surface of each L. johnsonii strain were quite complex; and something of a peptidic nature was mainly involved. E. faecium SM21 produced bacteriocin-like compounds with anti-Listeria effects. Furthermore, a band close to 6.0-7.5 kDA was detected by SDS-PAGE studies, and the entA, B and P structural genes were amplified by PCR reactions. For the first time, bee-gut associated L. johnsonii and E. faecium strains have been isolated, identified, cultivated and some of their functional properties reported.

Update on the evaluation of hypersensitivity reactions to betalactams

Hypersensitivity reactions to betalactams (BLs) are classified as immediate or nonimmediate. The former usually appear within 1 h of drug-intake and are mediated by specific IgE-antibodies. Nonimmediate reactions are those occurring more than 1 h after drug-intake, and they can be T-cell mediated. The diagnostic evaluation of allergic reactions to BLs has changed over the last 5 years, for several reasons. Major and minor determinants are no longer commercially available for skin testing in many countries. In immediate allergic reactions, the sensitivity of skin testing and immunoassays is decreasing and new in vitro methods, such as the basophil activation test, are gaining importance for diagnosis. For nonimmediate reactions, skin testing appears to be less sensitive than previous results, although more studies need to be carried out in this direction. Nevertheless, the drug provocation test is still necessary for diagnosis.

Negativization rates of IgE radioimmunoassay and basophil activation test in immediate reactions to penicillins

BACKGROUND

Skin test sensitivity in patients with immediate allergy to penicillins tends to decrease over time, but no information is available concerning in vitro tests. We analysed the negativization rates of two in vitro methods that determine specific immunoglobulin E (IgE) antibodies, the basophil activation test using flow cytometry (BAT) and the radioallergosorbent test (RAST), in immediate allergic reactions to penicillins.

METHODS

Forty-one patients with immediate allergic reactions to amoxicillin were followed up over a 4-year period. BAT and RAST were performed at 6-month intervals. Patients were randomized into groups: Group I, skin tests carried out at regular intervals; Group II, skin tests made only at the beginning of the study.

RESULTS

Differences were observed between RAST and BAT (P < 0.01), the latter showing earlier negativization. Considering different haptens, significant differences for the rate of negativization were only found for amoxicillin (P < 0.05). Comparisons between Groups I (n = 10) and II (n = 31) showed a tendency to become negative later in Group I with RAST.

CONCLUSIONS

Levels of specific IgE antibodies tended to decrease over time in patients with immediate allergic reactions to amoxicillin. Conversion to negative took longer for the RAST assay, although the differences were only detected with the amoxicillin hapten. Skin testing influenced the rate of negativization of the RAST assay, contributing to maintenance of in vitro sensitivity. Because of the loss of sensitivity over time, the determination of specific IgE antibodies to penicillins in patients with immediate allergic reactions must be done as soon as possible after the reaction.

Skin testing and drug provocation in the diagnosis of nonimmediate reactions to aminopenicillins in children

BACKGROUND

Nonimmediate allergic reactions (NIR) to aminopenicillin include several entities, the most common of which are urticaria-like and maculopapular exanthemas.

AIMS OF THE STUDY

To evaluate a group of children who developed one or more episodes of skin reactions suggestive of NIR after aminopenicillin administration.

METHODS

The inclusion criteria required negative immediate skin tests and absence of specific IgE antibodies to different penicillins. Intradermal and patch tests were carried out with delayed readings and, if negative, a drug-provocation test including a full therapeutic course of the drug was given. Two different groups were compared: A) children with positive skin testing or a positive drug-provocation test and B) children with negative skin testing and good tolerance after a drug-provocation test.

RESULTS

Group A was composed of 20 patients. Positive intradermal/patch tests were found in one patient and in the remaining 19, a positive response to a drug-provocation test confirmed the diagnosis. Group B (the control group) consisted of 19 patients with similar symptoms after aminopenicillin intake but good tolerance. No differences in age, dose or number of previous treatments were observed between the groups. The clinical entities were also similar in both groups.

CONCLUSIONS

Reproducible nonimmediate skin reactions to aminopenicillins may occur in children in spite of negative skin testing. The value of this diagnostic procedure seems to be limited in this type of reaction, with drug-provocation tests (DPT) being a reasonable and safe alternative if the diagnosis has to be confirmed.

Pharmacovigilance of drug allergy and hypersensitivity using the ENDA-DAHD database and the GALEN platform. The Galenda project

Nonallergic hypersensitivity and allergic reactions are part of the many different types of adverse drug reactions (ADRs). Databases exist for the collection of ADRs. Spontaneous reporting makes up the core data-generating system of pharmacovigilance, but there is a large under-estimation of allergy/hypersensitivity drug reactions. A specific database is therefore required for drug allergy and hypersensitivity using standard operating procedures (SOPs), as the diagnosis of drug allergy/hypersensitivity is difficult and current pharmacovigilance algorithms are insufficient. Although difficult, the diagnosis of drug allergy/hypersensitivity has been standardized by the European Network for Drug Allergy (ENDA) under the aegis of the European Academy of Allergology and Clinical Immunology and SOPs have been published. Based on ENDA and Global Allergy and Asthma European Network (GA(2)LEN, EU Framework Programme 6) SOPs, a Drug Allergy and Hypersensitivity Database (DAHD((R))) has been established under FileMaker((R)) Pro 9. It is already available online in many different languages and can be accessed using a personal login. GA(2)LEN is a European network of 27 partners (16 countries) and 59 collaborating centres (26 countries), which can coordinate and implement the DAHD across Europe. The GA(2)LEN-ENDA-DAHD platform interacting with a pharmacovigilance network appears to be of great interest for the reporting of allergy/hypersensitivity ADRs in conjunction with other pharmacovigilance instruments.

Nonimmediate allergic reactions induced by drugs: pathogenesis and diagnostic tests

Nonimmediate allergic reactions (NIRs) to drugs, which are the most common reactions induced by specific immunologic mechanisms, can be induced by all commercially available drugs. NIRs can appear hours, days, or even weeks after drug intake. They elicit a spectrum of manifestations, mostly affecting the skin, ranging from maculopapular exanthema and urticaria to other less common but more severe entities such as acute generalized exanthematic pustulosis, drug rash with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome, Stevens-Johnson syndrome, and toxic epidermal necrolysis. The main pathologic event involved in NIRs is a T-cell effector response and the wide heterogeneity of clinical symptoms may reflect differences in the underlying immunologic mechanisms. Despite their clinical heterogeneity, NIRs share certain aspects such as the activation of T cells with increased expression of CD25 and HLA-DR. NIRs are classified as type 1 helper (T(H)1) T-cell responses, characterized by the production of interferon-gamma, tumor necrosis factor-alpha, interleukin 2, T-bet, and the cytotoxic markers perforin and granzyme B. Diagnosis is often complicated because of the difficulty of obtaining a reliable clinical history, the important role played by cofactors such as viral diseases, and the low sensitivity of skin tests and in vitro tests. Further studies are thus required in order to improve our understanding of NIRs and refine our diagnostic criteria.

Diagnosis of immediate-type beta-lactam allergy in vitro by flow-cytometric basophil activation test and sulfidoleukotriene production: a multicenter study

INTRODUCTION

This multicenter study aimed to evaluate the diagnostic value of 2 cellular tests based on basophil reactivity--the basophil activation test (BAT, Flow-CAST) and the sulfidoleukotriene release assay (CAST-ELISA)--in immediate-type beta-lactam allergy, particularly in patients with a clinical history of allergy and a negative skin test result.

MATERIAL AND METHODS

In a multicenter study encompassing 10 European centers, 181 patients with a history of immediate-type beta-lactam allergy, and 81 controls, we evaluated the diagnostic efficiency of specific IgE determinations and of 2 cellular tests based on basophil reactivity, the BAT and the sulfidoleukotriene release assay.

RESULTS

With Flow-CAST, sensitivity varied for individual beta-lactam allergens from 16% for penicilloyl-polylysine to 33% for amoxicillin, reaching 50% when all 5 allergens were considered. In beta-lactam-allergic patients with negative skin test results (22.8%), Flow-CAST showed positive results for at least 1 of the 5 allergens in 37%. Specificity varied from 89% to 97%, depending on the allergens used. In CAST-ELISA, the overall sensitivity in skin test-positive patients was 41.7%; in patients with negative skin test results it was 27.9%. Both tests were not absolutely correlated, so that when all the results were considered together, sensitivity increased to 64.3% and specificity varied for both tests combined from 73% to 92%. In contrast, specific IgE determinations in the same population yielded a lower sensitivity (28.3%).

CONCLUSIONS

A diagnostic algorithm including skin tests and specific IgE, followed by cellular tests in negative patients and controlled challenge enabled us to confirm beta-lactam allergy in 92% of cases. This procedure would also allow us to avoid two-thirds of the required controlled challenges.

Seasonal idiopathic rhinitis with local inflammatory response and specific IgE in absence of systemic response

BACKGROUND

Patients with idiopathic rhinitis (IR) are considered to be nonallergic because they have a negative skin prick test (SPT) and allergen specific-IgE in serum. The concept of localized mucosal allergy in the absence of atopy has recently been proposed. The immunological mechanisms involved in seasonal IR have not been sufficiently studied. We examined nasal mucosa inflammation, the presence of nasal specific-IgE and the response to nasal allergen provocation test (NAPT) in patients with seasonal IR who presented symptoms only in spring.

METHODS

We evaluated 32 patients with seasonal IR and 35 with persistent allergic rhinitis to pollen (PAR-P) and compared these with healthy controls and persons with PAR to house dust mite during the pollen season, as well as by NAPT out-of-season with grass and Olea europea. We measured the nasal leukocyte-lymphocyte phenotype (CD45, CD33, CD16, CD3, CD4 and CD8), eosinophil-cationic-protein, and total and specific-IgE to grass and olive pollen in serum and nasal lavage and performed NAPT.

RESULTS

In the IR group, 62.5% had a positive NAPT (IR-PosNAPT), 20/32 to grass, with four of these having a positive NAPT to olive pollen as well. IR-PosNAPT patients showed a similar nasal leukocyte-lymphocyte profile to the PAR-P patients and different to controls. We detected nasal specific-IgE in 35% of IR-PosNAPT patients.

CONCLUSIONS

These results support the hypothesis that a subgroup of patients with IR have seasonal symptoms with evidence of a nasal allergic immune reaction in the absence of a positive SPT or serum specific IgE.

Cytokine and chemokine expression in the skin from patients with maculopapular exanthema to drugs

BACKGROUND

Maculopapular exanthema (MPE) is the most frequent clinical manifestation of nonimmediate allergic reactions to drugs and T helper 1 (Th1) cytokines and CD4(+) T cells have been shown to play an important role in its pathogenesis. We assessed the role of cytokines and chemokines and their receptors in the pathogenesis of MPE.

METHODS

We evaluated skin biopsies and peripheral CD4(+) and CD8(+) T cells from 27 patients during the acute phase of the reaction and 26 exposed controls. Semiquantitative real-time PCR was performed to determine the expression of cytokines and chemokines and their receptors and immunohistochemistry was used to determine the same chemokines and their receptor proteins in skin.

RESULTS

There was a high expression of the Th1 cytokines interferon-gamma (P = 0.006) and tumor necrosis factor-alpha (P = 0.022) in skin and CD4(+) T cells (P = 0.007 and P = 0.005, respectively); and of the Th1 chemokines CXCL9 (P = 0.005) and CXCL10 (P = 0.028) in the skin, while their receptor CXCR3 was increased in skin (P = 0.006) and CD4(+) T cells (P = 0.03). Homing chemokine receptors were also increased: CCR6 in skin (P = 0.026) and CD4(+) T cells (P = 0.016), and CCR10 only in CD4(+) T cells (P = 0.016), as well as their ligands, CCL20 and CCL27, in skin alone. Immunohistochemistry confirmed these results.

CONCLUSIONS

These data show significant differences in the expression of chemokines and chemokine receptors, related with a Th1 profile, in both skin biopsies and peripheral CD4(+) T cells in patients with drug-induced MPE.

Monitoring non-immediate allergic reactions to iodine contrast media

Non-immediate reactions to iodine contrast media (ICM) affect 2-5% of patients receiving these agents. We studied the immunological mechanisms involved in patients with a confirmed non-immediate reaction, maculopapular exanthema, after administration of ICM. The diagnosis was carried out by skin testing or drug provocation test. The immunological study was performed in sequential peripheral blood mononuclear cells taken from the onset of the reaction by flow cytometry and in skin biopsy by immunohistochemistry, with specific recognition by the lymphocyte transformation test (LTT) with different ICM. Flow cytometry showed an increase in the different activation markers [CD69, CD25 and human leucocyte antigen D-related (HLA-DR)] and the skin homing receptor [cutaneous lymphocyte-associated antigen (CLA)] in CD4 lymphocytes, whereas perforin was higher in the CD8 lymphocytes. The skin biopsy showed a perivascular mononuclear infiltrate composed of CD4 lymphocytes, expressing CD25, HLA-DR and CLA, with eosinophils. Intradermal skin tests and the LTT were positive to several ICM, including the culprit agent in four and three patients, respectively, with negative results in all 10 tolerant controls. We showed that a specific immunological mechanism was implicated in patients with non-immediate reactions to ICM. Moreover, the positive results in skin tests and lymphocyte proliferation tests indicated that an important cross-reactivity exists.

Differential cytokine and transcription factor expression in patients with allergic reactions to drugs

BACKGROUND

Allergic drug reactions (ADR) can be either immediate reaction (IR) (IgE mediated) or delayed reaction (DR) (T-cell mediated). They follow the Th1/Th2 paradigm, with DR expressing interferon-gamma (IFN-gamma) with down-regulation of interleukin-4 (IL-4) and IR expressing IL-4 with down-regulation of IFN-gamma. We studied the extension of this polarization in DR and IR by examining the cytokine and transcription factor profile in T-cell subpopulations during the acute phase of an ADR.

METHODS

Expressions of cytokines [IL-4, IFN-gamma and tumor necrosis factor-alpha (TNF-alpha)] and transcription factors (c-maf, GATA-3 and T-bet) were analysed by semi-quantitative real time-polymerase chain reaction in peripheral blood mononuclear cells and in CD4 and CD8 subpopulations from ADR patients.

RESULTS

In DR, IFN-gamma, TNF-alpha and T-bet increased significantly in both CD4 and CD8 subpopulations, depending on the clinical severity. In IR, IL-4, c-Maf and GATA-3 were increased, but only significantly in CD4. A positive correlation existed between IFN-gamma and T-bet in DR and between IL-4 and c-Maf and GATA-3 in IR. In DR, IFN-gamma, TNF-alpha and T-bet were increased during the acute phase in CD4 and CD8. In IR, IL-4, c-Maf and GATA-3 were all increased in the acute phase, but only in CD4.

CONCLUSIONS

These results support the Th1/Th2 paradigm in ADR, confirming previous findings that include the expression in both CD4 and CD8 T cells, and extending the observation to the transcription factors involved in the polarization of the immune response. Monitoring the reactions in the cell populations implicated, could be an important tool for assessing the mechanisms involved in ADR.

Continued need of appropriate betalactam-derived skin test reagents for the management of allergy to betalactams

Immediate allergic reactions to betalactams (BLs) are due to IgE antibodies that recognize the ring-derived penicilloyl determinant or side-chain structures of common BLs. The presence of specific IgE antibodies can be demonstrated by skin testing, the determination of specific IgE antibodies in sera or their binding to basophils with subsequent activation upon contact with penicillins in vitro. Skin tests are still the most sensitive technique followed by in vitro tests, which may sometimes yield useful complementary information. The diversity of the response to BLs has meant that in some instances, in addition to benzylpenicillin-derived determinants, testing for amoxycillin, cephalosporins or other BLs may also be required to establish the diagnosis. The recent withdrawal from the market of BL-derived materials for skin testing will have a serious effect on public health, resulting in a return to the pre-1960 era before these reagents became available. Because of their greater sensitivity, these skin tests cannot yet be replaced by in vitro tests. Furthermore, skin tests are the most readily available form of allergy testing for physicians. This paper reviews the results of skin tests in BL allergy and provides evidence for their continued need.

Immediate Hypersensitivity Reactions to Penicillins and Other Betalactams

Immediate hypersensitivity reactions to betalactams are IgE mediated and constitute the most frequent allergic reactions mediated by specific immunological mechanisms. IgE responses to benzyl penicillin (BP), the first antibiotic producing the benzyl penicilloyl structure (BPO), are characterized by a quick release of inflammatory mediators, resulting in anaphylactic shock, urticaria and angioedema. With the progressive appearance of other structures, comprising cephalosporins, carbapenems, monobactams and clavulanic acid, IgE selective responses and cross-reactivity reactions were observed. The diagnosis of betalactam hypersensitivity, classically based on skin testing with major and minor determinants of benzyl penicillin or in vitro IgE antibodies to BP, has been modified by the inclusion of different determinants generated from these compounds, for which amoxicillin (AX) is the most relevant, followed by cephalosporins. Some subjects develop positive responses to several betalactams, mostly within the same family, but others develop a selective response. These are relevant for the appropriate selection of antimicrobial drugs in patients who have immediate hypersensitivity to betalactams.

Skin testing for immediate hypersensitivity to betalactams: comparison between two commercial kits

INTRODUCTION

Skin testing with major and minor determinants of benzylpenicillin is the recommended standard practice to evaluate subjects with immediate hypersensitivity to betalactams. The withdrawal of these products from the market has set us back to the early days, before the introduction of reagents for in vivo testing.

OBJECTIVES

To compare a recently released kit of benzylpenicillin conjugated to poly-l-lysine (PPL) and minor determinants mixture (MDM) with the previously existing kit in a positive control group of subjects sensitized to major and/or minor determinants of benzylpenicillin.

METHODS

Skin tests with both kits were made in a group of positive subjects previously diagnosed with immediate hypersensitivity to penicillins and with positive results to PPL and/or MDM and in a negative control group. Radioallergosorbent test (RAST) inhibition assays with a pool of sera and individual samples were carried out to compare the inhibition capacity of PPL and MDM of both kits.

RESULTS

Of 22 cases selected from our historical group, 14 were positive: eight to PPL, three to MDM and three to both. These results were equivalent for both kits. RAST inhibition studies showed similar potencies in the inhibition of PPL and MDM.

CONCLUSIONS

Both tests show similar results in terms of RAST inhibition assays and skin tests sensitivity and specificity in the groups selected. The new assay can be used for the same purpose and indications as the previous test.

IgE antibodies to betalactams: relationship between the triggering hapten and the specificity of the immune response

BACKGROUND

In immunoglobulin (Ig)E-mediated responses to betalactams (BL) the antibody is directed to the hapten inducing the response. For benzylpenicillin (BP) the determinant is benzylpenicilloyl (BPO) and for amoxicillin (AX), amoxicilloyl (AXO). Because of cross-reactivity, IgE from some patients reacts to both drugs whereas others have a drug-selective recognition. After an allergic episode, there is an increase in IgE that decreases over time. We analysed the response of patients allergic to BL after penicillin administration, with emphasis on IgE cross-reactivity.

METHODS

Subjects who developed an IgE antibody response were studied. Sequential follow-up samples were obtained at different times during the response. Changes in IgE specificity were analysed by competition immunoassays using different penicillin monomeric conjugates.

RESULTS

Two patterns of response were existed: one with IgE directed to the culprit penicillin and another with IgE mainly reactive to BPO. In both, a variable cross-reactivity with the hapten triggering the boosting response was found. This pattern was maintained with no change in specificity over time, even in subjects who experienced one boosting event.

CONCLUSION

The IgE response can be specific to the drug inducing the reaction or cross-reactive to the classical BPO determinant. This pattern is maintained throughout the whole period of the response, even if re-exposure occurs. The stability of the type of response can be explained by the phenomenon of original antigenic sin: in the presence of antibodies, memory B cells are more easily triggered than naive B cells.

Anti-oxidant enzyme activities and expression and oxidative damage in patients with non-immediate reactions to drugs

Adverse drug reactions with an immunological basis (ADRIB) may involve activation of other concomitant, non-specific mechanisms, amplifying the specific response and contributing to the severity and duration. One concomitant mechanism could be the generation of reactive oxygen species (ROS) and/or their detoxification by anti-oxidants, including anti-oxidant enzymes. We analysed the activity of the anti-oxidant enzymes Cu/Zn-superoxide dismutase (SOD), catalase (CAT) and cellular glutathione peroxidase (GPX), as well as certain markers of oxidative damage (thiobarbituric acid reactive substances (TBARS) and carbonyl content) in peripheral blood mononuclear cells from patients with non-immediate ADRIB using spectrophotometric methods and the anti-oxidant enzymes expression by quantitative real-time reverse transcription-polymerase chain reaction. SOD activity and expression were increased in all types of non-immediate reactions (urticaria, maculopapular exanthema and toxic epidermal necrolysis). Regarding oxidative damage, TBARS were increased in urticaria and maculopapular exanthema, and carbonyl groups in all types of reactions. Our observations indicate that oxidative damage occurs in non-immediate reactions. Carbonyl stress and the inadequacy of the anti-oxidant defences are probable causes.