Mortality after transcatheter versus surgical aortic valve replacement: an updated meta-analysis of randomised trials.

BACKGROUND: To determine whether transcatheter aortic valve implantation (TAVI) improves early (30-day) and midterm (1-year) mortality compared with surgical aortic valve replacement (SAVR), we performed an updated meta-analysis of all the currently available randomised controlled trials (RCTs). METHODS: To identify all RCTs providing both 30-day and 1­year mortality after TAVI versus SAVR, PubMed and ClinicalTrials.gov were searched up to and including July 2019. A risk difference (RD) and its 95% confidence interval were generated using data of prespecified outcomes in both the TAVI and SAVR groups. Study-specific estimates were pooled using inverse variance-weighted averages of RDs in the random-effects model. RESULTS: We identified seven eligible high-quality RCTs including a total of 7631 as-treated patients. Pooled analyses demonstrated significantly lower 30-day (RD -0.60%; p = 0.046) and 1­year all-cause mortality (RD -1.12%; p = 0.03) after TAVI than after SAVR. No funnel plot asymmetry was detected for 30-day and 1­year mortality. Meta-regression analyses indicated that RDs of 30-day and 1­year mortality between TAVI and SAVR were not modulated by mean Society of Thoracic Surgeons Predicted Risk of Mortality score. Bleeding complications at 30 days and 1 year and stage 2/3 acute kidney injury at 30 days were significantly less frequent after TAVI than after SAVR, whereas major vascular complications and new permanent pacemaker implantation at 30 days and 1 year were significantly more frequent after TAVI than after SAVR. CONCLUSION: The best evidence from the present meta-analysis of all the currently available RCTs suggests that TAVI may reduce 30-day and 1­year all-cause mortality compared with SAVR.

Identification and fine-mapping of Xa33, a novel gene for resistance to Xanthomonas oryzae pv. oryzae.

Broadening of the genetic base for identification and transfer of genes for resistance to insect pests and diseases from wild relatives of rice is an important strategy in resistance breeding programs across the world. An accession of Oryza nivara, International Rice Germplasm Collection (IRGC) accession number 105710, was identified to exhibit high level and broad-spectrum resistance to Xanthomonas oryzae pv. oryzae. In order to study the genetics of resistance and to tag and map the resistance gene or genes present in IRGC 105710, it was crossed with the bacterial blight (BB)-susceptible varieties 'TN1' and 'Samba Mahsuri' (SM) and then backcrossed to generate backcross mapping populations. Analysis of these populations and their progeny testing revealed that a single dominant gene controls resistance in IRGC 105710. The BC(1)F(2) population derived from the cross IRGC 105710/TN1//TN1 was screened with a set of 72 polymorphic simple-sequence repeat (SSR) markers distributed across the rice genome and the resistance gene was coarse mapped on chromosome 7 between the SSR markers RM5711 and RM6728 at a genetic distance of 17.0 and 19.3 centimorgans (cM), respectively. After analysis involving 49 SSR markers located between the genomic interval spanned by RM5711 and RM6728, and BC(2)F(2) population consisting of 2,011 individuals derived from the cross IRGC 105710/TN1//TN1, the gene was fine mapped between two SSR markers (RMWR7.1 and RMWR7.6) located at a genetic distance of 0.9 and 1.2 cM, respectively, from the gene and flanking it. The linkage distances were validated in a BC(1)F(2) mapping population derived from the cross IRGC 105710/SM//2 × SM. The BB resistance gene present in the O. nivara accession was identified to be novel based on its unique map location on chromosome 7 and wider spectrum of BB resistance; this gene has been named Xa33. The genomic region between the two closely flanking SSR markers was in silico analyzed for putatively expressed candidate genes. In total, eight genes were identified in the region and a putative gene encoding serinethreonine kinase appears to be a candidate for the Xa33 gene.

Inheritance of bacterial blight resistance in the rice cultivar Ajaya and high-resolution mapping of a major QTL associated with resistance.

The cultivar Ajaya (IET 8585) exhibits durable broad-spectrum resistance to bacterial blight (BB) disease of rice and is widely used as a resistance donor. The present study was carried out to decipher the genetics of BB resistance in Ajaya and map the gene(s) conferring resistance. Genetic analysis in the F2 indicated a quantitative/additive nature of resistance governed by two loci with equal effects. Linked marker analysis and allelic tests revealed that one of the resistance genes is xa5. Sequence analysis of a 244 bp region of the second exon of the gene-encoding Transcription factor IIAγ (the candidate gene for xa5) confirmed the presence of xa5. Bulked-segregant analysis (BSA) revealed the putative location of the two quantitative trait loci (QTLs)/genes associated with resistance on chromosomes 5 and 8. Composite interval mapping located the first locus on Chr. 5S exactly in the genomic region spanned by xa5 and the second locus (qtl BBR 8.1) on Chr. 8L. Owing to its differential disease reaction with a set of seven hyper-virulent isolates of Xanthomonas oryzae, a map location on Chr. 8L, which was distinct from xa13 and data from allelism tests, the second resistance locus in Ajaya was determined to be novel and was designated as xaAj. A contig map spanning xaAj was constructed in silico and the genomic region was delimited to a 13.5 kb physical interval. In silico analysis of the genomic region spanning xaAj identified four putatively expressed candidate genes, one of which could be involved in imparting BB resistance in Ajaya along with xa5.

Cytotoxic mechanisms in different forms of T-cell-mediated drug allergies.

BACKGROUND: Cytotoxic mechanisms are involved in different forms of drug induced exanthems. METHODS: Here we compare the killing pathways of CD4+, CD8+ and CD4/CD8+ T-cell lines (TCL) and clones derived from patients suffering from maculopapular, bullous and pustular drug eruptions. In vitro, perforin and Fas-mediated killing was analysed in cytotoxicity assays against autologous Epstein-Barr virus (EBV)-transformed B-cell lines, Fas-transfected mouse lymphoblasts and natural killer (NK)-target cells. In addition, affected skin lesions and the TCL and clones were stained for perforin and FasL-expression. RESULTS: We detected perforin and some FasL-mediated killing in all three types of exanthems. Some of the drug-specific T-cell clones analysed exerted mainly perforin-, other more FasL-mediated killing showing no strict relationship between their perforin- and Fas-mediated cytotoxic capacity. Using a cell culture method focusing on the generation of cytotoxic T cells, we detected drug-specific CD8+, TCRalphabeta+ T cells, which failed to proliferate to drug presentation by antigen presenting cells but killed in a drug dependent way. Interestingly, these cells had substantial natural killer-like T cell(s) like features as they were CD56+ and CD94+ and had the ability to kill the NK-sensitive cell line K562. CONCLUSION: Our data underline the important role of cytotoxic mechanisms in different forms of drug induced exanthems and suggest that even some T cells with NK-like characteristics may be involved in drug hypersensitivity.

T cell involvement in cutaneous drug eruptions.

BACKGROUND: The most frequent side-effects of drug therapy are skin eruptions. Their pathomechanism is rather unclear. OBJECTIVE: In this prospective study we investigated the T cell activation and drug specificity in different forms of drug-induced exanthemas from 22 patients. METHODS: During acute drug allergy, liver parameters and T cell subset activation in the circulation (up-regulation of CD25 and HLA-DR) were evaluated and skin biopsies of the acute lesion performed. After recovery, the causative drug was identified by lymphocyte transformation (LTT) and scratch-patch tests. RESULTS: Seventeen of 22 (17/22) patients had maculo-papular exanthema, 4/22 bullous exanthema and 1/22 urticaria. The causative drugs were mainly antibiotics, anti-epileptics and anti-hypertensives. Up-regulation of HLA-DR on circulating CD4(+) and/or CD8(+) T cells was detected in 17 patients, being most marked in patients with bullous reactions or hepatic involvement. The LTT was positive in 14/21 analysed and the patch test in 7/15. All patients showed lymphocytic infiltration in the skin biopsy of the acute lesion. Generally CD4(+) T cells dominated; a higher percentage of circulating CD8(+) T cells was found in patients with bullous skin reactions or hepatic involvement. CONCLUSION: Our data demonstrate activation and drug specificity of T cells in drug-induced skin eruptions. A predominant CD8(+) T cell activation leads to more severe (bullous) skin symptoms or liver involvement, while predominant activation of CD4(+) cells elicits mainly maculo-papular reactions.

Degeneracy and additional alloreactivity of drug-specific human alpha beta(+) T cell clones.

It has been well established that T cells can recognize small mol. wt compounds such as drugs. Results from previous studies revealing a high heterogeneity and cross-reactivity of drug-specific T cell clones (TCC) in individual patients prompted us to analyze the degeneracy of drug-reactive TCR in detail. Hence, we analyzed the MHC restriction pattern of a panel of 100 drug-specific TCC isolated from different drug-allergic donors. We found that 28 of the tested clones showed an MHC allele-unrestricted drug recognition. Most of these clones were at the same time highly drug specific, i.e. they could only be stimulated by the original drug and not by any drug derivatives. In contrast, TCC with the ability to interact with different drug derivatives displayed a clearly MHC allele-restricted drug recognition. Therefore, we concluded that the TCR of these clones is mainly interacting with side chains of the appropriate drug molecules and hence able to tolerate alterations in the MHC molecule. Moreover, we tested all clones for additional alloreactivity and found that 27 clones could be stimulated by a self-MHC--peptide--drug complex as well as by a non-self-MHC--peptide complex. This cross-reactivity with allogeneic MHC molecules was substantially higher in drug-specific TCC compared to tetanus toxoid-specific clones from the same donors. This suggests that from the point of view of drug-specific TCR, non-self-MHC--peptide complexes have a higher incidence to mimic the 'original' self-MHC--peptide-drug complex and this may occur for TCR recognizing self-MHC--pathogen-derived peptide complexes. Finally, the biological functions of bispecific TCC were not influenced by the nature of the stimulating ligand. Both drug as well as allogeneic stimulation led to similar reaction patterns in the analyzed TCC.

Premedication with antihistamines may enhance efficacy of specific-allergen immunotherapy.

BACKGROUND: Antihistamine premedication has been used to increase safety of specific-allergen immunotherapy. Its influence on the efficacy of this treatment has not been studied so far. OBJECTIVE: The goal was to analyze the influence of antihistamine premedication on long-term efficacy of specific-allergen immunotherapy. METHOD: Patients included in a double-blind, placebo controlled trial who received premedication with terfenadine or placebo during initial rush immunotherapy with honeybee venom in 1988/1989 were assessed in a retrospective analysis for the long-term protective effect, as indicated by the tolerance of a bee sting challenge or field sting during immunotherapy. RESULTS: Of the 52 patients who had participated in the 1988/1989 trial, 47 could be reassessed after an average of 3 years. Of these, 45 were still receiving bee venom immunotherapy. A total of 41 patients were stung by bees while receiving immunotherapy (20 of the terfenadine-premedicated group and 21 of the placebo-premedicated group), 17 with in-field stings and 24 with in-hospital sting challenge. Six (29%) of the patients receiving placebo had a mild-to-moderate systemic allergic reaction, whereas none of the patients receiving terfenadine reacted to the bee sting (P =.012). CONCLUSIONS: These results indicate that antihistamine premedication during the initial phase of specific-allergen immunotherapy may enhance the efficacy of this treatment.

2',4'-BNA bearing unnatural nucleobases: toward the expansion of the target sequence of double-stranded DNA in triplex formation.

It is absolutely necessary for practical application of antigene strategy to create nucleoside analogues recognizing pyrimidine.purine interruption in dsDNA. To develop a nucleoside analogue to interact with T.A interruption, we designed and synthesized a novel 2',4'-BNA monomer (HBB), 2-(2'-O,4'-C-methyleneribofuranosyl)phenol, and it was introduced into a triplex-forming oligonucleotide (TFO). On melting temperature (Tm) measurements, HBB was found to interact with T.A interruption with moderate binding affinity, and unprecedented dU.A base pair recognition ability of HBB was also observed.

Triplex formation involving 2',4'-BNA with 2-pyridone base analogue: efficient and selective recognition of C:G interruption.

We examined the thermodynamic properties of 2',4'-bridged nucleic acid containing 2-pyridone as a nucleobase (PB) to recognize a C interruption in the homopurine strand of the target duplex for pyrimidine motif triplex formation at neutral pH. The triplex formation involving triplex-forming oligonucleotide with PB is highly sequence-selective to specifically recognize C:G target base pair rather than the other G:C, T:A, or A:T base pairs. PB.C:G triad gives significantly larger binding constant than T.C:G triad, which has been known to be the most stable combination in natural base.C:G triad. Our results certainly support the idea that PB could be a key nucleoside to recognize a C interruption in the homopurine strand of the target duplex with high binding affinity and selectivity, and reduce the restriction of target sequences for triplex formation.

2'-O,4'-C-methylene bridged nucleic acid modification promotes pyrimidine motif triplex DNA formation at physiological pH: thermodynamic and kinetic studies.

Extreme instability of pyrimidine motif triplex DNA at physiological pH severely limits its use in an artificial control of gene expression in vivo. Stabilization of the pyrimidine motif triplex at physiological pH is, therefore, crucial in improving its therapeutic potential. To this end, we have investigated the thermodynamic and kinetic effects of our previously reported chemical modification, 2'-O,4'-C-methylene bridged nucleic acid (2',4'-BNA) modification of triplex-forming oligonucleotide (TFO), on pyrimidine motif triplex formation at physiological pH. The thermodynamic analyses indicated that the 2',4'-BNA modification of TFO increased the binding constant of the pyrimidine motif triplex formation at neutral pH by approximately 20 times. The number and position of the 2',4'-BNA modification introduced into the TFO did not significantly affect the magnitude of the increase in the binding constant. The consideration of the observed thermodynamic parameters suggested that the increased rigidity itself of the 2',4'-BNA-modified TFO in the free state relative to the unmodified TFO may enable the significant increase in the binding constant at neutral pH. Kinetic data demonstrated that the observed increase in the binding constant at neutral pH by the 2',4'-BNA modification of TFO resulted from the considerable decrease in the dissociation rate constant. Our results certainly support the idea that the 2',4'-BNA modification of TFO could be a key chemical modification and may eventually lead to progress in therapeutic applications of the antigene strategy in vivo.

Evidence for a role for IL-5 and eotaxin in activating and recruiting eosinophils in drug-induced cutaneous eruptions.

BACKGROUND: Cutaneous drug reactions may be associated with increased numbers of eosinophils in the blood and tissue. However, the factors leading to the generation of eosinophilia have not been fully delineated. OBJECTIVE: The aim of this study was to investigate the in situ expression of IL-5, eotaxin, RANTES, monocyte chemoattractant protein 3, and IL-8 together with the appearance of eosinophils in acute cutaneous drug reactions. METHODS: Skin biopsy specimens were obtained from drug-induced maculopapular exanthems (n = 9), from normal skin of control subjects (n = 9), and from the skin of patients with psoriasis (n = 8). The in situ expression of IL-5, eotaxin, RANTES, monocyte chemoattractant protein 3, and IL-8 was analyzed by using immunohistochemistry. Furthermore, the corresponding numbers of eosinophils were determined in the blood and skin sections. RESULTS: Compared with normal skin and psoriatic skin, a significantly higher number of eosinophils was found both in the blood and tissue of patients with a drug-induced exanthem. In comparison with normal skin, immunoreactivity for IL-5 and all the chemokines was also significantly enhanced in drug-induced exanthem, whereas significant differences in psoriatic were only observed for IL-5 and eotaxin. CONCLUSION: Our data indicate that IL-5 and eotaxin may particularly contribute to the activation and recruitment of eosinophils and thereby play an important pathogenic part in the development of skin inflammation in drug-induced maculopapular exanthems.

T cells isolated from positive epicutaneous test reactions to amoxicillin and ceftriaxone are drug specific and cytotoxic.

In order to investigate the function of T cells in cutaneous adverse drug reactions, skin-derived T cells were analyzed in two patients with a drug-induced exanthem. Skin biopsy specimens were obtained from positive epicutaneous test reactions to amoxicillin and ceftriaxone. Immunohistochemical analysis revealed that the majority of the cell infiltrate in both biopsy specimens was composed of activated T cells, of which some expressed perforin. By limiting dilution 36 amoxicillin-specific and 10 ceftriaxone-specific T cell clones were raised. All of these T cell clones expressed CD4/T cell receptor alphabeta. Cytokine analysis after antigen stimulation of the seven best proliferating T cell clones (four specific for amoxicillin and three for ceftriaxone) revealed that these cells secrete high amounts of interleukin-5 and mostly lower or no amounts of tumor necrosis factor alpha, interleukin-4, and interferon-gamma. A part of these CD4+ T cell clones were cytotoxic, i.e., two selected ceftriaxone-specific T cell clones killed target cells after antigen stimulation. The amoxicillin-specific T cell clones failed to show drug-specific cytotoxicity, but killed target cells in the presence of concanavalin A, indicating a principal ability to be cytolytic. In correlation with the in situ expression of perforin on T cells, the ceftriaxone-specific T cell clones also expressed perforin in vitro. In conclusion, a substantial part of the T cells in drug-induced epicutaneous test reactions are drug specific and are composed of a heterogeneous cell population. Drug-specific T cells producing interleukin-5 may contribute to eosinophilia, whereas cytotoxic CD4+ T cells may account for tissue damage. These data underline the role of T cells in delayed-type cutaneous adverse drug eruptions and drug-induced epicutaneous test reactions.

Infiltration of cytotoxic T cells in drug-induced cutaneous eruptions.

BACKGROUND: Previous in vitro data indicate that perforin containing drug-specific cytotoxic T cells are involved in cutaneous drug reactions. OBJECTIVE: The aim of this study was to investigate the in situ expression of perforin and granzyme B together with the nature of the inflammatory infiltrate in acute drug-induced exanthem. Furthermore, expression of interleukin (IL)-12 and interferon (IFN)-gamma, which are known to stimulate cytotoxic T cells, was investigated. METHODS: Skin biopsy specimens were obtained from 10 patients with a generalized maculopapular exanthem and from nine controls with normal skin. Expression of CD3, CD4, CD8, CD56, CD1a, CD68, CD25, HLA-DR, CD54, perforin, granzyme B, IL-12 and IFNgamma was analysed using immunohistochemistry. RESULTS: In contrast to the controls, the skin of patients with an exanthem was mainly infiltrated by T cells (CD4 > CD8) and showed a marked enhancement of perforin and granzyme B immunostaining. Double immunostaining revealed that perforin and granzyme B were expressed in both CD4+ and CD8+ cells, which were partly located at the dermoepidermal junction and in the epidermis. In addition, strong immunreactivity for IL-12 and IFNgamma was observed in the mononuclear cells infiltrate, indicating that these cytokines may be important in activation of these cytotoxic T cells. CONCLUSION: The increased numbers of perforin and granzyme B containing T cells infiltrating the dermoepidermal junction may contribute to the damage of epidermal cells, which is frequently observed as a typical feature of interface dermatitis in drug-induced exanthem. Our data provide further evidence that cytotoxic T cells play an essential role in cutaneous drug reactions.

Reduction of side-effects from ultrarush immunotherapy with honeybee venom by pretreatment with fexofenadine: a double-blind, placebo-controlled trial.

BACKGROUND: Immunotherapy with Hymenoptera venoms is highly effective but causes allergic side-effects frequently, especially when honeybee venom is used. Therefore, our objective was to investigate the effect of pretreatment with the antihistamine fexofenadine on the incidence of allergic side-effects during ultrarush immunotherapy with bee venom. METHODS: In a double-blind, placebo-controlled trial, 57 patients with a history of systemic allergic reactions to honeybee stings and positive diagnostic tests (skin tests, serum specific IgE to honeybee venom) were investigated. Bee venom immunotherapy was started with an ultrarush protocol and patients were randomized to pretreatment with either fexofenadine 180 mg or placebo on days 1, 8, 22, and 50 of the protocol. Local and systemic allergic side-effects were registered. RESULTS: Fifty-four patients completed the study, 28 on fexofenadine and 26 on placebo pretreatment. On day 1, large local reactions were significantly reduced in both extension and duration by fexofenadine pretreatment (P<0.025). Systemic allergic side-effects on the whole were not reduced. However, the symptoms pruritus, urticaria, and angioedema occurred less frequently with fexofenadine (P<0.05). CONCLUSIONS: Pretreatment with fexofenadine during venom immunotherapy reduces local allergic reactions and generalized symptoms of the urticaria and angioedema type.

Synthesis and triplex forming ability of conformationally locked oligonucleotides containing unnatural nucleobases: efficient recognition of a C.G interruption.

In order to develop a novel nucleoside analogue which recognizes C.G interruption in homopurine.homopyrimidine DNA, we designed and synthesized a conformationally locked nucleoside analogue, 1-(2-O,4-C-methylene-beta-D-ribofuranosyl)pyridin-2-one (4), and introduced it into a triplex-forming oligonucleotide (TFO). On melting temperature (Tm) measurements, the unprecedented C.G base recognition ability of 4 was observed.

Distinct serum cytokine levels in drug- and measles-induced exanthema.

BACKGROUND: Macular or maculopapular skin reactions are frequent events in drug allergy as well as in viral infections. Clinically, the differentiation may be difficult in the absence of a clear relationship to drug intake or failure to detect virus-specific antibodies of the IgM class. Studies on drug-specific T cell lines and T cell clones isolated from drug-allergic patients have suggested that these cells may represent a significant source of IL-5. On the other hand, viral infections are frequently associated with elevated IFN-gamma levels. OBJECTIVE: Determination of serum-cytokine levels to differentiate between drug- and virally induced skin eruptions. PATIENTS: 18 patients suffering from acute drug allergy and 19 patients with acute measles, rubella or parvovirus infection. MEASUREMENTS: Cytokine-ELISA (IL-5, IL-4 and IFN-gamma) of sera collected during acute drug allergy or during acute measles, rubella or parvovirus infection. RESULTS: In 12/18 patients with drug allergy, IL-5 and/or IL-4 were elevated. A significant correlation (r(Spearman) = 0.84) between IL-5 serum levels and eosinophil counts in the blood was found. No correlation was detected between IL-4 and blood eosinophilia or between IL-4 and IL-5 levels. After remission, IL-5 and IL-4 decreased to undetectable levels. IFN-gamma on the other hand was not measurable in patients with drug allergy while elevated IFN-gamma serum levels were detected in 17/19 patients with measles, rubella or parvovirus infection; 2 patients with acute virus infection had elevated IL-5, and/or IL-4 and IFN-gamma levels. CONCLUSION: These data underline the distinct pathogenesis of these morphologically similar exanthemas and suggest that the combined analysis of eosinophilia in the blood, IL-4 and IFN-gamma might help in differentiating skin eruptions.

T-cell reaction to local anaesthetics: relationship to angioedema and urticaria after subcutaneous application--patch testing and LTT in patients with adverse reaction to local anaesthetics.

BACKGROUND: Local anaesthetics are known to elicit T-cell reactions after epicutaneous application, namely contact dermatitis. In addition, adverse reactions like urticaria and angioedema are rather common after submucosal or subcutaneous injection. The pathogenesis of these side-effects, which appear frequently hours after application, is unknown, but thought to be not immunoglobulin E-mediated, since immediate skin tests are mostly negative. OBJECTIVES: We investigated whether patients who developed urticaria and angioedema after subcutaneous application have a T-cell sensitization to local anaesthetics, which might be responsible for the symptoms. METHODS: Twenty patients with generalized and/or local cutaneous reactions after LA were examined with intradermal testing using a standard panel of six LAs and patch testing using between seven and nine LAs in vaseline and four LAs in PBS. In 10 patients, a lymphocyte transformation test (LTT) was performed. RESULTS: Only 2/20 patients had an immediate skin reaction (positive intradermal test), whereas 6/20 patients had a positive delayed skin reaction (positive patch test). In 6/10 subjects the LTT was positive. CONCLUSIONS: Delayed appearance of urticaria and angioedema after subcutaneous application of local anaesthetics may be related to a T cell- mediated sensitization, which might be detected by patch testing or LTT.

Drug-induced linear IgA bullous dermatosis associated with ceftriaxone- and metronidazole-specific T cells.

BACKGROUND: Previous reports indicate that various drugs may induce linear IgA bullous dermatosis (LABD). The role of T cells and T-cell-derived cytokines in the pathomechanism of such skin lesions, however, has remained unclear. OBJECTIVE: To describe a case of LABD induced by ceftriaxone and metronidazole in an 80-year-old female suffering from cholelithiasis with concomitant cholecystitis and provide evidence that drug-specific T cells and their cytokines may contribute to the development of LABD lesions. METHODS: We performed flow cytometry analysis of peripheral blood T cells during LABD, epicutaneous testing (scratch-patch) and lymphocyte proliferation analysis (LTT) with the suspected drugs, routine histological and immunohistochemical examination of the acute skin lesions during LABD as well as of the positive epicutaneous test reactions and measurement of cytokines (IL-4, IL-5, IL-10, TNF-alpha, IFN-gamma) in the supernatant of the LTT cultures. RESULTS: An increased number mainly of activated CD8+ cells was detected in the peripheral blood during LABD. T cell sensitization to ceftriaxone and metronidazole was confirmed by epicutaneous testing and LTT, indicating that these methods may be useful in identifying the causative drugs. Enhanced cytokine levels, particularly of IL-5, were found in the supernatant of the LTT stimulated with ceftriaxone and metronidazole. Furthermore, in situ expression of IL-5 was confirmed in the patient's skin lesions by immunohistochemistry. CONCLUSION: Our findings suggest that in addition to IgA antibodies drug-specific T cells and their subsequent release of cytokines may play an important role in the pathogenesis of drug-induced LABD.

Preparation and properties of 2',5'-linked oligonucleotide analogues containing 3'-O,4'-C-methyleneribonucleosides.

Bicyclic nucleoside analogues, 3'-O,4'-C-methyleneuridine and -5-methyluridine, were successfully incorporated into oligonucleotides via connection with 2',5'-phosphodiester linkage, and hybridization behavior and nuclease stability of the modified oligonucleotides were investigated.

Recognition of local anesthetics by alphabeta+ T cells.

Patients with drug allergy show a specific immune response to drugs. Chemically nonreactive drugs like, for example, local anesthetics are directly recognized by alphabeta+ T cells in an HLA-DR restricted way, as neither drug metabolism nor protein processing is required for T cell stimulation. In this study we identified some of the structural requirements that determine cross-reactivity of T cells to local anesthetics, with the aim to improve the molecular basis for the selection of alternatives in individuals sensitized to a certain local anesthetic and to better understand presentation and T cell recognition of these drugs. Fifty-five clones (52 lidocaine specific, three mepivacaine specific from two allergic donors) were analyzed. Stimulatory compounds induced a down-regulation of the T cell receptor, demonstrating that these non-peptide antigens are recognized by the T cell receptor itself. A consistent cross-reactivity between lidocaine and mepivacaine was found, as all except one lidocaine specific clone proliferated to both drugs tested. Sixteen chemically related local anesthetics (including ester local anesthetics, OH- and desalkylated metabolites) were used to identify structural requirements for T cell recognition. Each of the four clones examined in detail was uniquely sensitive to changes in the structures of the local anesthetic: clone SFT24, i.e., did not recognize any of the tested OH- or desalkylated metabolites, while the clone OFB2 proliferated to all OH-metabolites and other differently modified molecules. The broadly reactive clone OFB2 allowed us to propose a model, suggesting that the structure of the amine side chain of local anesthetics is essential for recognition by the T cell receptor.