Dermatophagoides pteronyssinus immunotherapy changes the T-regulatory cell activity

Subcutaneous specific immunotherapy (SCIT) has been shown to modify the Dermatophagoides pteronissinus (DP) allergic response, characterized by generation of Treg cells. However, studies have reported no changes in the proportion of Treg cells after immunotherapy, indicating that the effects may be due to modifications in their regulatory activities. We aimed to determine whether Tregs generated by DP-SCIT can switch the allergic response to tolerant and study the involvement of suppressive cytokines on it. Twenty-four DP-allergic rhinitis patients were recruited, 16 treated with DP-SCIT and 8 untreated. Treg and T effector cells were isolated before and after DP-SCIT, and cocultured in different combinations with α-IL-10, α-TGF-β blocking antibodies and nDer p 1. Treg cells after DP-SCIT increased Th1 and decreased Th2 and Th9 proliferation. Similarly, they increased IL-10 and decreased IL-4 and IL-9-producing cells. α-IL-10 affected the activity of Treg cells obtained after DP-SCIT only. Finally, DP-specific IgG4 levels, Treg percentage and IL-10 production were correlated after DP-SCIT. These results demonstrate that DP-SCIT induces Treg cells with different suppressive activities. These changes could be mediated by IL-10 production and appear to play an important role in the induction of the tolerance response leading to a clinical improvement of symptoms.

Basophil Histamine Release Induced by Amoxicilloyl-poly-L-lysine Compared With Amoxicillin in Patients With IgE-Mediated Allergic Reactions to Amoxicillin

BACKGROUND

Amoxicillin (AX) is the ß-lactam most often involved in IgE-mediated reactions. Diagnosis is based mainly on skin testing, although sensitivity is not optimal. We produced a new AX derivative, amoxicilloyl-poly-L-lysine (APL), and analyzed its recognition of IgE using the passive histamine release test (pHRT).

METHODS

The study population comprised patients (n=19) with confirmed AX allergy and specific IgE to AX and controls (n=10) with good tolerance to AX. pHRT was performed using "IgE-stripped" blood from a single donor that was sensitized in vitro by patient sera and incubated with AX or APL. Histamine release was determined and expressed as nanograms of histamine released per milliliter of blood.

RESULTS

The clinical symptoms were anaphylaxis (n=9), urticaria (n=7), erythema (n=2), and nondefined immediate reactions (n=1). The median (IQR) time interval between reaction and study was 90 (60-240) days and between drug intake and development of symptoms 24 (10-60) minutes. The median sIgE level was 3.37 (0.95-5.89) kUA/L. The sensitivity of pHRT to APL was 79% and the specificity 100%, which were higher than data obtained with pHRT to AX (63% sensitivity and 90% specificity). There was a positive correlation between maximal histamine release levels obtained with AX and APL (r=0.63).

CONCLUSIONS

In patients with immediate hypersensitivity reactions to AX, APL showed higher sensitivity and specificity than the culprit drug, AX, when tested in vitro by pHRT. This indicates that APL can improve the in vitro diagnostic accuracy of allergic reactions to AX. Further assessment of skin testing is necessary.

Hypersensitivity reactions to β-lactams: relevance of hapten-protein conjugates

β-Lactams (BL) are the drugs most frequently involved in allergic reactions. They are classified according to their chemical structure as penicillins, cephalosporins, monobactams, carbapenems, and clavams. All BL antibiotics have a BL ring that is fused to a 5-member or 6-member ring (except in monobactams) and has 1, 2 or 3 side chains (except in clavams). Differences in chemical structure mean that a wide range of BLs are recognized by the immune system, and patients may experience clinical reactions to one BL while tolerating others. Diagnosis is based on skin and in vitro testing, although both display low sensitivity, possibly because they are based on drugs or drug conjugates that are not optimally recognized by the immune system. BLs are haptens that need to bind to proteins covalently to elicit an immune response. These drugs have a high capacity to form covalent adducts with proteins through nucleophilic attack of amino groups in proteins on the BL ring. Allergenic determinants have been described for all BLs, although benzylpenicillin is the most widely studied. Moreover, formation of BL-protein adducts is selective, as we recently demonstrated for amoxicillin, which mainly modifies albumin, transferrin, and immunoglobulin heavy and light chains in human serum. Given the complexity of BL allergy, understanding the immunological mechanisms involved and optimization of diagnostic methods require multidisciplinary approaches that take into account the chemical structures of the drugs and the carrier molecules, as well as the patient immune response.

Contributions of pharmacogenetics and transcriptomics to the understanding of the hypersensitivity drug reactions

Hypersensitivity drug reactions (HDRs) represent a large and important health problem, affecting many patients and leading to a variety of clinical entities, some of which can be life-threatening. The culprit drugs include commonly used medications including antibiotics and NSAIDs. Nontherapeutical agents, such as contrast media, are also involved. Because the pathophysiological mechanisms are not well known and the current diagnostic procedures are somewhat insufficient, new approaches are needed for understanding the complexity of HDRs. Histochemical and molecular biology studies have enabled us to classify these reactions more precisely. Pharmacogenetics has led to the identification of several genes, involved mainly in T-cell-dependent responses, with a number of markers being replicated in different studies. These markers are now being considered as potential targets for reducing the number of HDRs. Transcriptomic approaches have also been used to investigate HDRs by identifying genes that show different patterns of expression in a number of clinical entities. This information can be of value for further elucidation of the mechanisms involved. Although first studies were performed using RT-PCR analysis to monitor the acute phase of the reaction, nowadays high-density expression platforms represent a more integrative way for providing a complete view of gene expression. By combining a detailed and precise clinical description with information obtained by these approaches, we will obtain a better understanding and management of patients with HDRs.

Trends in hypersensitivity drug reactions: more drugs, more response patterns, more heterogeneity

Hypersensitivity drug reactions (HDRs) vary over time in frequency, drugs involved, and clinical entities. Specific reactions are mediated by IgE, other antibody isotypes (IgG or IgM), and T cells. Nonspecific HDRs include those caused by nonsteroidal anti-inflammatory drugs (NSAIDs). beta-Lactams--the most important of which are amoxicillin and clavulanic acid--are involved in specific immunological mechanisms. Fluoroquinolones (mainly moxifloxacin, followed by ciprofloxacin and levofloxacin) can also induce HDRs mediated by IgE and T cells. In the case of radio contrast media, immediate reactions have decreased, while nonimmediate reactions, mediated by T cells, have increased. There has been a substantial rise in hypersensitivity reactions to antibiotics and latex in perioperative allergic reactions to anesthetics. NSAIDs are the most frequent drugs involved in HDRs. Five well-defined clinical entities, the most common of which is NSAID-induced urticaria/angioedema, have been proposed in a new consensus classification. Biological agents are proteins including antibodies that have been humanized in order to avoid adverse reactions. Reactions can be mediated by IgE or T cells or they may be due to an immunological imbalance. Chimeric antibodies are still in use and may have epitopes that are recognized by the immune system, resulting in allergic reactions.

Diagnosis of immediate hypersensitivity reactions to radiocontrast media

BACKGROUND

No consensus exists on the diagnostic approach for immediate hypersensitivity reactions (IHR) to radiocontrast media (RCM). We analyzed the diagnostic value of a skin test (ST), drug provocation test (DPT) and basophil activation test (BAT) in patients with symptoms compatible with IHR to RCM.

METHODS

Ninety patients with symptoms suggestive of IHR to RCM were evaluated. ST with a panel of RCM was performed, and if negative, DPT was carried out with the culprit RCM. If ST or DPT were positive, tolerance was assessed with an alternative RCM and BAT was carried out with the same panel used for ST.

RESULTS

Eight (8.9%) cases were confirmed as having IHR, 5 (62.5%) by ST and 3 (37.5%) by DPT. Five from those confirmed as IHR (62.5%) had a positive BAT.

CONCLUSIONS

Hypersensitivity to RCM was confirmed in 9%, by ST or DPT. BAT proved a valuable method for 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.

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.

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.

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.