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Background The diagnostic approach for beta-lactam (BL) drug hypersensitivity reactions (DHR) is based on the history, clinical signs, skin tests (ST), in vitro tests, and drug provocation tests (DPT). The aim of this study was to assess the performance of an allergy workup with ST in a real-world use. Methods In this cross-sectional study the rate of positive ST in subjects with suspected DHR to penicillins and cephalosporins was investigated. Of special interest were correlations of ST positivity: 1) to the time intervals between index reaction and the allergic work-up, 2) time interval from drug exposure to the onset of signs, 3) pattern of manifestation in delayed DHR and involvement of test area in the index reaction, and 4) potential advantage of patch testing in delayed DHR. Results 175 patients were included between January 2018 and April 2019 (63.4% female), 45 (25.7%) with immediate DHR manifestation and 130 with delayed DHR manifestation (74.3%). A total of 44 patients (25.1%) had a positive ST (immediate DHR 37.8% versus 20.0% in delayed DHR). ST positivity decreased in both groups after 3 years from 47.8% [95%CI 29.2–67] to 23.5% [95%CI 9.6–47.3] in immediate DHR and 23.0% [95%CI 15-4-32.9] to 12.9% [95%CI 5.1–28.9] in delayed DHR. The proportion of positive ST was higher in patients with more severe forms of delayed DHR, and in subjects with a shorter latency period of onset of symptoms after drug exposure: 0-3d: 29.5% [95%CI 19.6–41.9] vs. >3d: 11.6% [95%CI 6.0–21.2]). No sensitization was shown in delayed urticaria or angioedema. ST done outside the skin area involved during the index reaction were negative in all cases (0/38 vs. 26/84 in cases with involved area). The combination of patch test and intradermal test (IDT) revealed an additional positive result in 2/77 cases. Additional in vitro testing reduced the proportion of negative test results to 72%. Conclusion In most patients with negative test results, we could not clarify the cause of the BL-associated adverse events even with further investigations (including DPT). How to prevent new drug-induced adverse events in such patients has hardly been investigated yet. Corresponding cohort studies could improve the data situation.

Previously positive lymphocyte transformation test (LTT) results changed to negative during influenza infection. As observed in the current article, results of LTT may be influenced by infection; therefore, it is crucial to consider the timing of LTT.

Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening severe cutaneous adverse drug reactions, and SJS/TEN in infancy is rare. Here, we present a case of a 4-month-old infant with generalized exanthema, flaccid blisters, and mucosal erosions. He was diagnosed with TEN within 2 days using a granulysin quick screen test and subsequently verified with histopathologic findings. Transmission of cephalexin through breastfeeding was suspected to be a possible cause based on drug history, breastfeeding history, and lymphocyte transformation test. The patient survived with only skin hyperpigmentation remaining.

Drug-induced hypersensitivity reactions encompass a variety of different clinical phenotypes ranging from harmless rashes to fatal reactions. They can be classified into allergic (i.e. drug allergy) and non-allergic reactions (i.e. non-allergic hypersensitivity). Drug allergies in turn can either be antibody (e.g. IgE) or T cell-mediated. One of the diagnostic tools for the in vitro detection of drug allergy is the lymphocyte transformation test (LTT) which is based on the activation and expansion of the drug-specific memory T cells following co-incubation of the patient's peripheral mononuclear cells (PMBC) with the suspected drug in vitro. The read-out parameter in the classical LTT is T cell proliferation which can be measured as counts per minute following the addition of radiolabeled thymidine to the cell culture. However, in the course of time different modifications of the classical LTT with regard to the read-out parameters and methods have been proposed. Likewise, variations of the LTT platform itself have been described in the literature. This review article describes the development of the classical LTT and its use in the context of drug allergy detection and summarizes the modifications which have been published over time.

The causes of nonischemic dilated cardiomyopathy are classified as genetic or nongenetic, but environmental factors such as metal pollutants may interact with genetic susceptibility. The presence of metal particles has been detected in the myocardium, including in those patients with dilated cardiomyopathy. It is also known that hypersensitivity reactions can induce inflammation in tissue. The present study aimed to verify if metal-induced delayed-type hypersensitivity is present in patients with nonischemic dilated cardiomyopathy. The patient group consisted of 30 patients with newly diagnosed dilated cardiomyopathy; the control group comprised 41 healthy subjects. All patients and control subjects provided blood samples for lymphocyte transformation testing (MELISA®) to assess possible hypersensitivity to seven common metals. Specific exposure to metals was based on interview data. Results showed that exposure to cadmium and lead (p = 0.0002), aluminum (p = 0.0006), nickel (p = 0.0012), and chromium (p = 0.0065) was more often reported by patients than controls. The patients also had significantly more frequent hypersensitivity reactions to mercury (26.7% vs. 7.3%, p = 0.014624), nickel (40% vs. 12.2%, p = 0.02341), and silver (20% vs. 4.8%, p = 0.025468) than the control group. Patients with dilated cardiomyopathy had greater exposure to certain metals compared with healthy controls. Hypersensitivity to metals was more frequent in patients with dilated cardiomyopathy, suggesting a possible association that warrants further investigation.

Background and objective Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a complex multisystemic severe drug hypersensitivity reaction whose diagnosis and management are troublesome. DRESS syndrome requires management by various specialists. The correct identification of the culprit drug is essential to ensure safe future therapeutic options for the patient. There are no previous Spanish guidelines or consensus statements on DRESS syndrome. Objective: To draft a review and guidelines on the clinical diagnosis, allergy work-up, management, treatment, and prevention of DRESS syndrome in light of currently available scientific evidence and the experience of experts from multiple disciplines. Methods These guidelines were drafted by a panel of allergy specialists from the Drug Allergy Committee of the Spanish Society of Allergy and Clinical Immunology (SEAIC), together with other medical specialists involved in the management of DRESS syndrome and researchers from the PIELenRed consortium. A review was conducted of scientific papers on DRESS syndrome, and the expert panel evaluated the quality of the evidence of the literature and provided grades of recommendation. Whenever evidence was lacking, a consensus was reached among the experts. Results The first Spanish guidelines on DRESS syndrome are now being published. Important aspects have been addressed, including practical recommendations about clinical diagnosis, identification of the culprit drug through the Spanish pharmacovigilance system algorithm, and the allergy work-up. Recommendations are provided on management, treatment, and prevention. Algorithms for the management of DRESS in the acute and recovery phases have been drawn up. Expert consensus-based stepwise guidelines for the management and treatment of DRESS syndrome are provided.

Furosemide is the most commonly prescribed loop diuretic worldwide. Although, its extended use, furosemide rarely induces allergic reactions. Until 2013, only 49 cases of furosemide allergy had been described.We have reported on a patient who developed a delayed, erythematous and pruritic skin eruption after the ingestion of furosemide. The implication of furosemide in the reaction was established by a positive lymphocyte transformation test (LTT).This is the first reported case of hypersensitivity to furosemide in which this drug was confirmed as the trigger by a positive LTT. LTT could become a decent diagnostic alternative for patients who experience delayed reactions to furosemide.Antecedentes: La furosemida es el diurético de asa más comúnmente prescrito en todo el mundo. A pesar de su amplio uso, rara vez induce reacciones alérgicas. Hasta 2013 solo se habían descrito 49 casos de alergia a la furosemida. Caso clínico: Mujer de 68 años con hipertensión tratada con amlodipina, así como rinoconjuntivitis alérgica. Después del consumo de 40 mg de furosemida por cinco días debido a edema bilateral maleolar presentó exantema cutáneo maculopapular, eritematoso y pruriginoso. Los resultados positivos en la prueba de transformación de linfocitos confirmaron la implicación de la furosemida en la reacción. Conclusión: El caso que se reporta es el primero de hipersensibilidad a la furosemida en el que se confirma la implicación del fármaco por medio de una prueba de transformación de linfocitos positiva, la cual podría convertirse en una alternativa diagnóstica para los pacientes que experimentan reacciones adversas tardías a la furosemida.

Purpose Reports evaluating diagnosis and cross reactivity of quinolone hypersensitivity have revealed contradictory results. Furthermore, there are no reports investigating the cross-reactivity between gemifloxacin (GFX) and the others. We aimed to detect the usefulness of diagnostic tests of hypersensitivity reactions to quinolones and to evaluate the cross reactivity between different quinolones including the latest quinolone GFX. Methods We studied 54 patients (mean age 42.31±10.39 years; 47 female) with 57 hypersensitivity reactions due to different quinolones and 10 nonatopic quinolone tolerable control subjects. A detailed clinical history, skin test (ST), and single-blind placebo-controlled drug provocation test (SBPCDPT), as well as basophil activation test (BAT) and lymphocyte transformation test (LTT) were performed with the culprit and alternative quinolones including ciprofloxacin (CFX), moxifloxacin (MFX), levofloxacin (LFX), ofloxacin (OFX), and GFX. Results The majority (75.9%) of the patients reported immediate type reactions to various quinolones. The most common culprit drug was CFX (52.6%) and the most common reaction type was urticaria (26.3%). A quarter of the patients (24.1%) reacted to SBPCDPTs, although their STs were negative; while false ST positivity was 3.5% and ST/SBPCDPTs concordance was only 1.8%. Both BAT and LTT were not found useful in quinolone hypersensitivity. Cross-reactivity was primarily observed between LFX and OFX (50.0%), whereas it was the least between MFX and the others, and in GFX hypersensitive patients the degree of cross-reactivity to the other quinolones was 16.7%. Conclusions These results suggest that STs, BAT, and LTT are not supportive in the diagnosis of a hypersensitivity reaction to quinolone as well as in the prediction of cross-reactivity. Drug provocation tests (DPTs) are necessary to identify both culprit and alternative quinolones.

Drug-induced liver injury (DILI) is a growing problem. Diagnostic methods to differentiate DILI caused by an adaptive immune response from liver injury of other causes or to identify the responsible drug in patients receiving multiple drugs, herbals and/or dietary supplements (polypharmacy) have not yet been established. The lymphocyte transformation test (LTT) has been proposed as a diagnostic method to determine if a subject with an apparent hypersensitivity reaction has become sensitized to a specific drug. In this test, peripheral blood mononuclear cells (PBMC) collected from a subject are incubated with drug(s) suspected of causing the reaction. Cell proliferation, measured by the incorporation of [3H]-thymidine into new DNA, is considered evidence of a drug-specific immune response. The objectives of the current studies were to: (1) develop and optimize a modified version of the LTT (mLTT) and (2) investigate the feasibility of using the mLTT for diagnosing DILI associated with an adaptive immune response and identifying the responsible drug. PBMC collected from donors with a history of drug hypersensitivity reactions to specific drugs (manifested as skin rash) were used as positive controls for assay optimization. Following optimization, samples collected from 24 subjects enrolled in the U.S. Drug-Induced Liver Injury Network (DILIN) were tested in the mLTT. Using cytokine and granzyme B production as the primary endpoints to demonstrate lymphocyte sensitization to a specific drug, most samples from the DILIN subjects failed to respond. However, robust positive mLTT responses were observed for two of four samples from three DILIN subjects with hepatitis due to isoniazid (INH). We conclude that the mLTT, as performed here on frozen and thawed PBMC, is not a reliable test for diagnosing DILI caused by all drugs, but that it may be useful for confirming the role of the adaptive immune response in DILI ascribed to INH.

Total joint arthroplasties are increasingly common orthopedic procedures performed throughout the United States. Implant failure after these procedures occurs due to a number of causes such as infection or mechanical problems, with metal hypersensitivity being an area of growing interest. The nature and mechanism of a causative relationship between metal hypersensitivity and implant failure have been unclear as it is not known whether implant failure occurs due to a previous metal allergy or metal allergy results from secondary sensitization via metal exposure in existing failing implants. Overall, there appears to be growing support and evidence for metal-hypersensitive patients having worse outcomes with regard to total hip and knee arthroplasties. However, there are conflicting recommendations (outside of Nuss procedures) for pre-implant testing for metal hypersensitivity as testing has not consistently been shown to change patient outcomes.

Background Metal sensitivity as a cause for painful joint replacement has become increasingly prevalent; however, there is a lack of reported clinical outcome data from total knee arthroplasty patients with metal allergies. The purpose of this study was to determine whether patients presenting with a painful total knee arthroplasty with a positive metal sensitivity have improved outcomes following revision to a hypoallergenic implant. Methods A retrospective review was conducted for patients that underwent a revision total knee arthroplasty after metal sensitivity testing over a 3-year period from January 1, 2015, to December 31, 2017. Based on the results of sensitivity testing, patients underwent revision total knee arthroplasty to a hypoallergenic component or a standard component. Following revision, patients returned to the clinic at an interval of 6 weeks, 5 months, and 12 months for functional, pain, and satisfaction assessment. Outcomes were compared within and between sensitivity groups. Results Of the included patients, 78.3% (39/46) were positive for metal sensitivity. The most common metal sensitivity was to nickel (79.5%, 32/39). Both non-reactive and reactive patients significantly improved in range of motion after revision arthroplasty. The reactive group saw a 37.8% decrease in pain at 6 weeks post-revision (p

Benznidazole (Bzn) from the nitroimidazole family and nifurtimox from nitrofurans family, are drugs used as first and second line treatment for acute and chronic phases of Chagas disease (CD). Even though skin reactions are frequent, confirmed allergy to Bzn is rare, and there are few cases reported in the literature. Since CD treatment is very restrained, the possibility of cross-reactivity between members of the same and other pharmacological families highlights the importance of an adequate diagnosis that allows alternative treatments in CD and other diseases. We report a series of 31 patients (69% women) referred to our Allergy unit with suspected hypersensitivity to Bzn, twenty three of them with mild reactions and eight of them with severe reactions. LTT with Bzn was performed in 31 patients and in 8 negative controls. LTT was also performed in 25 and 20 of these patients with nifurtimox and Mtn, respectively. Twenty-one out of thirtyone patients were Bzn prick tested, and all were negative. We obtained 2/19 positive results on patch tests to Bzn. LTT with Bzn was positive in 22/31 patients (Sensitivity 75.9% and specificity 100%). The test was considered positive with a stimulation index 2. There was a positive result in 7/25 patients for nifurtimox and in 7/20 patients with Mtn. After negative LTT and skin tests, oral provocation was performed in 4/9 patients, all negative. LTT is a safe test that seems to be more useful than skin tests (prick and patch test), particularly in severe reactions, in confirming delayed hypersensitivity to Bzn and detecting cross reactivity with other imidazoles such as Mtn and reactivity to other drugs like nifurtimox. Tests for these drugs need to be included in the workup of patients with hypersensitivity to Bzn in case they are needed as an alternative treatment for CD or to treat other frequent infectious diseases., This work was funded by FIS PI13/01768 to TB

Background Toxic epidermal necrolysis (TEN) is a rare life-threatening condition almost exclusively attributed to drugs. The main etiologic factors for TEN are sulphonamides, anticonvulsants, and antibiotics; however, there are no published reports of warfarin causing TEN. Case presentation We present the case of a 3-year-old patient who developed TEN while receiving treatment for Henoch–Schönlein purpura nephritis (HSPN). With multiple-drug therapy comprising prednisolone, mizoribine, dipyridamole, and warfarin, it is difficult to detect which drug is the causative agent. While in most cases, diagnosis of the causative drug is based on clinical history without a lymphocyte transformation test (LTT), we performed the test three times and identified the causative drug as warfarin at the late phase. We continued HSPN treatment without warfarin, and results showed good renal function without life-threatening complications. Conclusion To our knowledge, this is the first report about TEN caused by warfarin. Repeated LTTs could be useful for identifying TEN-causative drugs even in the late phase.

Aims To evaluate whether patients with late complications of pacemakers or implantable cardioverter-defibrillators have hypersensitivity reactions to some of the materials used in generators or in electrodes, or to environmental metal burden. Methods and results The cohort consisted of 20 men and 4 women (mean age: 62.3 ± 17.2 years) who had a history of late complications of implanted devices. The control group involved 25 men and 8 women (mean age: 64.6 ± 14.0 years) who had comparable devices, but no history of late complications. Lymphocyte transformation test was used to evaluate hypersensitivity to eight metal pollutants (antimony, manganese, mercury, molybdenum, nickel, platinum, tin, and titanium) selected by results of questionnaires on environmental burden, and by material analysis of generators and electrode surfaces. Exposures to metal pollutants were approximately the same in patients and in controls. Titanium alloy used in generators contained at least 99.32% of titanium and trace levels of other metals; higher levels of tin and platinum were detected in electrode surfaces. Hypersensitivity reactions to mercury and tin were significantly more frequent in patients than in controls (patients and controls: mercury: 68.2 and 31.1%, respectively; P = 0.022; tin: 25.0 and 3.2%, respectively; P = 0.035). In contrast, hypersensitivity to manganese was significantly more frequent in controls than in patients (patients and controls: 13.6 and 50.0%, respectively; P = 0.008). Conclusion Our findings suggest a possible relation between hypersensitivity to metals used in implantable devices or to environmental metal burden and the occurrence of their late complications.

Summary The focus of this review are allergic reactions to orthopaedic-surgical metal implants. The spectrum of metal implant associated potential allergic reactions encompasses eczema, impaired wound and fracture healing, infection-mimicking reactions, effusions, pain and loosening. Nickel, cobalt and chromium seem to be the predominant eliciting allergens. Despite the growing number of respective publications the topic „metal implant allergy“ remains a diagnostic challenge. Initially, differential diagnoses should always be excluded in cooperation with surgery collegues. It is recommended to perform a combined evaluation of medical history, clinical findings, patch testing and histology. The lymphocyte transformation test (LTT) can indicate metal sensitization, but it needs careful interpretation. Allergists can provide a substantial contribution to this interdisciplinary topic.

Tribenoside is a semisynthetic sugar derivative that is mainly indicated for treatment of chronic venous insufficiency. Up to 10% of patients treated by tribenoside can suffer from skin side effects. The adverse effects usually present as angioedema, urticaria, or maculopapular exanthema. The pathophysiology of the reaction has not as yet been elucidated. In this study, we examined 22 patients with drug eruptions caused by tribenoside. Patch tests were performed to investigate in vivo cellular reactions. Laboratory investigations were carried out by lymphocyte transformation tests and basophil activation tests. We found a positive patch test reaction to tribenoside in one patient. The lymphocyte transformation test elicited a borderline positive reaction in one patient, and the basophil activation test gave a clearly positive reaction in another patient. The diagnosis of drug hypersensitivity reactions is a challenge. Both delayed and immediate immunologic response may play a role in the etiology of tribenoside-induced exanthemas. Our investigation and results indicate that benzoic acid could be the antigenic determinant in drug hypersensitivity to tribenoside.

Cutaneous delayed reactions to antihypertensive drugs have been described in a limited number of case reports but the mechanisms remain mostly unknown. We report the case of a 60-year-old female patient with a 3-week history of an itchy erythematous maculopapular eruption. Although the patient was polymedicated, irbesartan was the most likely culprit. Patch tests and a lymphocyte transformation test to irbesartan were both positive, which was useful for diagnosis and suggested an immunological reaction. No new lesions appeared after irbesartan was stopped or after the introduction of candesartan. Despite its similar chemical structure, candesartan may be tried in patients allergic to irbesartan. LEARNING POINTS Irbesartan can induce immunological cell-mediated skin reactions. Allergy to irbesartan does not imply a class allergy. Patch tests and a lymphocyte transformation test were useful in the diagnosis of irbesartan allergy.

Borrelia-specific antibodies are not detectable until several weeks after infection and even if they are present, they are no proof of an active infection. Since the sensitivity of culture and PCR for the diagnosis or exclusion of borreliosis is too low, a method is required that detects an active Borrelia infection as early as possible. For this purpose, a lymphocyte transformation test (LTT) using lysate antigens of Borrelia burgdorferi sensu stricto, Borrelia afzelii and Borrelia garinii and recombinant OspC was developed and validated through investigations of seronegative and seropositive healthy individuals as well as of seropositive patients with clinically manifested borreliosis. The sensitivity of the LTT in clinical borreliosis before antibiotic treatment was determined as 89,4% while the specificity was 98,7%. In 1480 patients with clinically suspected borreliosis, results from serology and LTT were comparable in 79.8% of cases. 18% were serologically positive and LTT-negative. These were mainly patients with borreliosis after antibiotic therapy. 2.2% showed a negative serology and a positive LTT result. Half of them had an early erythema migrans. Following antibiotic treatment, the LTT became negative or borderline in patients with early manifestations of borreliosis, whereas in patients with late symptoms, it showed a regression while still remaining positive. Therefore, we propose the follow-up monitoring of dis-seminated Borrelia infections as the main indication for the Borrelia-LTT.

Background All implant compounds undergo an electrochemical process when in contact with biological fluids, as well as mechanical corrosion due to abrasive wear, with production of metal debris that may inhibit repair processes. None of the commonly-used methods can diagnose implant allergies when used singly, therefore a panel of tests should be performed on allergic patients as pre-operative screening, or when a postoperative metal sensitisation is suspected. Methods We analysed patients with painful prostheses and subjects prone to allergies using the Patch Test in comparison with the Lymphocyte Transformation Test. Cytokine production was evaluated to identify prognostic markers for early diagnosis of aseptic loosening. Metal debris endocytosis and cytoskeletal rearrangement was visualised by confocal microscopy. Results Our results demonstrate that the Lymphocyte Transformation Test can identify patients who have a predisposition to develop allergic reactions and can confirm the diagnosis of hypersensitivity in patients with painful prostheses. The prevalence of a Th2-cytokine pattern may be used to identify predisposition to the development of allergic diseases, while the selective presence of osteoclastogenic cytokines may be used as predictor of a negative outcome in patients with painful prosthesis. The hypothesis of the prognostic value of these cytokines as early markers of aseptic loosening is attractive, but its confirmation would require extensive testing. Conclusions The Lymphocyte Transformation Test is the most suitable method for testing systemic allergies. We suggest that the combined use of the Patch Test and the Lymphocyte Transformation Test, associated with cytokine detection in selected patients, could provide a useful tool for preventive evaluation of immune reactivity in patients undergoing primary joint replacement surgery, and for clinical monitoring of the possible onset of a metal sensitization in patients with implanted devices.

The object of this work was to study the correlation between the lymphocyte proliferation and apoptosis in the cultures stimulated by specific inactivated Borrelia garinii antigen and the different clinical outcomes in Lyme borreliosis patients. It was found that borrelia antigen stimulation of the cultures obtained from chronic patients induced T helper type 1-like response as well as depression in lymphocyte apoptosis, which may provide the basis of persistent activated T cell immune response and chronic inflammatory in Lyme borreliosis.

Background: Culture filtrate proteins (CFPs) of Mycobacterium tuberculosis are potential vaccine candidates. Objective: The aim was to study the influence of iron levels on CFPs and assess the immuno-protective potential of defined antigenic fractions from high (8 μg Fe/mL) and low iron (0.02 μg Fe / mL) cultures of M. tuberculosis. Materials and Methods: The CFPs of M. tuberculosis from high (CFP-high) and low (CFP-low) iron conditions were first compared to identify iron-regulated proteins and then fractionated to obtain ten antigen pools (CF-Ags H1- H5 and L1-L5) that were used to assess the immune response of TB patients and normal healthy controls. Results: Iron limitation resulted in the up-regulation of two novel iron-regulated low-molecular-weight proteins Irp-1 (in CF-Ag L4) and Irp-2 (in CF-Ag L5) and repression of two ESAT proteins (identified with monoclonal antibody HYB 76.8). The median stimulation indices (SIs) against most of the CF-Ags were high in pulmonary TB patients. The CF-Ags L1 and L2 showed statistically significant SI (P values of 0.0027 and 0.0029 respectively); the % case recognition was high with these antigens as well as with L4 ( P = 0.0275). IFN-γ in response to these CF-Ags was significantly high in the endemic normals; maximal expression was seen with CF-Ag L5 (median value of 233 pg mL -1 ) that was higher than the corresponding H5 (140 pg mL -1 ) and H3 and L3 (205 and 206 pg mL -1 respectively). Conclusions: CF-Ags L5, H3 and L3 showed immuno-protective potential in this geographical location.

The introduction of ribavirin to hepatitis C combination therapy with pegylated interferon (PEG-IFN)-α2a has improved sustained responses, but it has been accompanied by an increased incidence of cutaneous side effects. Most cases of drug eruption caused by ribavirin and PEG-IFN-α2 or IFN-α combination therapy were not severe and we progressed without discontinuation of the antiviral treatment. We describe a 59-year-old Japanese woman with a chronic hepatitis C infection who developed erythema during PEG-IFN-α2a and ribavirin combination therapy. The eruption at the injection site of IFN occurred after each injection, and then, eruption on her exposed skin was observed. Twenty milligrams of prednisolone was administered. The eruption recurred after each administration of prednisolone and ribavirin. She finally had infiltrative erythema without any mucosal symptoms on her body. It seemed to be an erythema multiforme type drug eruption of PEG-IFN-α2a, ribavirin and/or fluvastatin sodium from the clinical course. The lymphocyte transformation test (LTT) of ribavirin was positive. This is the first case of a positive result of an LTT for ribavirin. A photosensitive type drug eruption with ribavirin treatment has been reported. We should not only consider IFN, but also ribavirin in case of a generalized eruption, especially on an exposed area with combination therapy for HCV.

Background Phenytoin can induce diversified adverse reactions including generalized eruptions and the hypersensitivity syndrome. Delayed-type allergic mechanisms have been postulated to underlie these reactions. The tests most widely used to detect T-cell sensitization to drugs are the patch test and the lymphocyte transformation test (LTT), but their sensitivity is not sufficient. Simultaneous assessment of both the frequencies and the cytokine-producing phenotypes of allergen-specific T cells has become possible with the recently introduced carboxyfluorescein succinimidyl ester (CFSE) assay. Methods Seven patients who presented with phenytoin-induced maculopapular exanthema with and without fever were included in this study. Peripheral blood mononuclear cells (PBMCs) were labeled with CFSE and cultured with phenytoin for seven days. The cells were stained with anti-CD4 and cytokine-specific monoclonal antibodies (MoAbs), and analyzed with FACSCalibur. Results The phenytoin-specific proliferation of CD4 + cells in patients was significantly higher than in the four controls exposed to phenytoin, and in seven healthy children with no previous phenytoin intake. A significant difference in the percentages of CD4 + IFN-γ + cells between patients and the seven healthy children was observed. The sensitivity and specificity of proliferation were 100% and 90.9%, and those of IFN-γ secretion were 71.4% and 100%, respectively. Conclusions Phenytoin-specific proliferation may be detected with greater sensitivity by the CFSE dilution assay than the conventional LTT. The assay revealed that both CD4 + and CD4 − T cells proliferated and produced IFN-γ and TNF-α after stimulation with phenytoin. The CFSE dilution assay might be useful for the diagnosis and understanding of drug hypersensitivity.

Sir, We would like to comment on the article “The lymphocyte transformation test for the diagnosis of Lyme borreliosis has currently not been shown to be clinically useful” by Dessau et al. in Clin Microbiol Infect. 2014 Feb 13. doi: 10.1111/ 1469-0691.12583. Mr. Dessau criticises in his article that the clinical inclusion criteria for the assignment of the 94 patients with clinical lyme borreliosis were not clearly defined and that the control group consisted only of seronegative patients. This leads him to the conclusion that due to this “selection bias” the specificity of the LTT for borreliosis antigens may be overestimated. We would like to give following comments: Our publication indicates the fact that clinical characterisation is difficult. This is in agreement with other studies and it is generally known that it is a problem to select a distinct characterised patient population. However, our study did not intend to distinguish between the immunological phenomena of different borrelia manifestations. The aim of this study was to investigate and confirm that the result obtained by LTT allows a statement on the borrelia specific immune response. As irrelevant for the study objective, we adopted clinical diagnoses, as for example Bannwarth Syndrome, from the patients’ health records. The investigation of seronegative patients was performed in order to show the specificity of the antigens used in the LTT as it is often criticised that the detected T-cell reactivity is not specific to borreliosis but simply a general T-cell reactivity of patients with other inflammatory diseases. For this reason, a seronegative healthy collective was used to investigate the analytical specificity and to ensure that those patients or rather probands have no borreliosis specific memory T-lymphocytes. It is certainly correct that the specificity is lower when also clinical healthy seropositive patients are included. To show this point, a clinically healthy seropositive control group (n = 48) was investigated as well, as shown in table 1. And indeed, with 91.6% the specificity was lower than the specificity of the seronegative group, however, this is clearly shown and also addressed in the discussion section. Despite the criticism regarding our patient selection, the quintessences should be accepted: 1. The fact that 1.3% of healthy seronegative (and therefore very likely not infected) and only 8.4% of healthy seropositive patients showed positive results speaks for a high analytical specificity. 2. The fact that 92.1% of patients in the early infection phase and 53.3% of patients with late manifestations forms showed a decline or negative LTT results under antibiotic treatment argues for the specificity of the analysis, because it is not explainable why antibiotic treatment should influence an unspecific T-cell reactivity.

Hypersensitivity reactions to β-lactam and non-β-lactam antibiotics are commonly reported. They can be classified as immediate or nonimmediate according to the time interval between the last drug administration and their onset. Immediate reactions occur within 1 hour after the last drug administration and are manifested clinically by urticaria and/or angioedema, rhinitis, bronchospasm, and anaphylactic shock; they may be mediated by specific IgE-antibodies. Nonimmediate reactions occur more than 1 hour after the last drug administration. The most common manifestations are maculopapular exanthems; specific T lymphocytes may be involved in this type of manifestation. The diagnostic evaluation of hypersensitivity reactions to antibiotics is usually complex. The patient's history is fundamental; the allergic examination is based mainly on in vivo tests selected on the basis of the clinical features and the type of reaction, immediate or nonimmediate. Immediate reactions can be assessed by immediate-reading skin tests and, in selected cases, drug provocation tests. Nonimmediate reactions can be assessed by delayed-reading skin tests, patch tests, and drug provocation tests. However, skin tests have been well validated mainly for β-lactams but less for other classes of antibiotics.

Purpose Phenprocoumon-induced liver injury is a rare complication of oral anticoagulation. The mechanisms leading to this side effect are not entirely clear. Here we present data that at least in a subgroup of patients in whom phenprocoumon-induced liver disease was suspected, immunological processes may play an important role. Patients and methods Thirty patients with suspected phenprocoumon-induced liver disease from different hospitals in Germany were analyzed. Peripheral blood mononuclear cells (PBMC) of these patients were tested in the lymphocyte transformation test (LTT) for reactivity with phenprocoumon in vitro. As controls, PBMC were isolated from ten individuals treated with phenprocoumon but without any side effects, and from ten healthy individuals who have never received the drug. Results Fifteen of the 30 patients had sensitized lymphocytes toward phenprocoumon as shown by LTT. Four patients had taken the drug for more than 5 years; in one patient, liver disease appeared after 1 day of phenprocoumon intake. There was no correlation between a positive LTT and clinical/ laboratory parameters. None of the 20 controls had sensitized lymphocytes toward phenprocoumon. Conclusions Applying the LTT, we were able to unravel the cause of suspected phenprocoumon-induced liver injury as a drug allergic reaction in 15 out of 30 analyzed patients.

Allopurinol is one of the causative drugs that induce fixed drug eruption (FDE). The lymphocyte transformation test (LTT) is a safe and reliable diagnostic procedure for drug allergy, but is reported to be rarely positive in patients with FDE. In the current case, we performed an LTT and successfully confirmed allopurinol as the offending drug. This case report suggests that an LTT should be an optional diagnostic tool for FDE or delayed reaction due to allopurinol.

Titanium has gained immense popularity and has successfully established itself as the material of choice for dental implants. In both medical and dental fields, titanium and its alloys have demonstrated success as biomedical devices. Owing to its high resistance to corrosion in a physiological environment and the excellent biocompatibility that gives it a passive, stable oxide film, titanium is considered the material of choice for intraosseous use. There are certain studies which show titanium as an allergen but the resources to diagnose titanium sensivity are very limited. Attention is needed towards the development of new and precise method for early diagnosis of titanium allergy and also to find out the alternative biomaterial which can be used in place of titanium. A review of available articles from the Medline and PubMed database was done to find literature available regarding titanium allergy, its diagnosis and new alternative material for titanium.

We report a drug reaction with eosinophilia and systemic symptoms case of primary Epstein–Barr virus (EBV) infection, in which the diagnosis was first confirmed by lymphocyte transformation tests (LTT). LTTs were positive for cefditoren–pivoxil and acetaminophen. LTT, EBV load, and anti-EBV antibodies could allow early diagnosis of drug reaction with eosinophilia and systemic symptoms, which masquerades with the clinical features of infectious mononucleosis.