In vitro diagnostics of drug allergies.

In vitro diagnostics for drug hypersensitivity reactions distinguish between serological and cellular-based tests. A serological test used for the diagnosis of immediate type reactions is the detection of specific IgE antibodies. The cellular tests include the basophil activation test for immediate type reactions and the lymphocyte transformation test, which is mainly used to detect delayed type hypersensitivity reactions. Further cellular-based tests are the CAST-ELISA and the mast cell activation test. None of the above-mentioned tests can definitively exclude an allergy if the result is negative. In addition, it is important to note that even a positive test result is not necessarily associated with an allergy but has to be interpreted in the clinical context.

Simultaneous distinct cutaneous fungal infections with chromoblastomycosis due to Exophiala xenobiotica and hyalohyphomycosis due to Scedosporium apiospermum in a patient with severe cellular immunodeficiency.

Deep-seated dermatomycosis is a rare disease that is often caused by trauma and/or systemic immunodeficiency. We describe a case of chromoblastomycosis complicated by hyalohyphomycosis that occurred simultaneously at different sites. A 92-year-old Japanese man who had been taking oral prednisolone for an IgG4-related respiratory disease visited our clinic. He developed brownish plaques with grayish-white scales with pseudo-carcinomatous hyperplasia and numerous brownish muriform cells developing in the dermis of his right hand, and multiple painful abscesses with pustules and papules and numerous hyphae within and around the histiocytes in the dermis of his right lower leg. Upon skin tissue culture and DNA sequencing, Exophiala xenobiotica and Scedosporium apiospermum were detected separately. He had severe cellular immunodeficiency indicated by low levels in the phytohemagglutinin (PHA)-stimulated lymphocyte transformation test (LTT) and serum interferon-gamma (IFN-γ), although his humoral immunity was normal. The patient died of bacterial pneumonia, despite antifungal drug treatment for 2 months. IFN-γ producing type 1 T helper (Th1) cells play an important role in the defense against fungal infections, however, corticosteroids specifically suppress Th1 cell responses and promote the induction of fungal infection. Measurement of PHA-stimulated LTT and serum IFN-γ may be useful in determining the severity and prognosis of deep-seated dermatomycosis in patients undergoing corticosteroid treatment.

A Case Report of Pembrolizumab-Induced Allergic Hepatitis.

The immune checkpoint inhibitor pembrolizumab is now considered a first-line treatment for recurrent or metastatic head and neck squamous cell cancer. Pembrolizumab is less toxic than conventional chemotherapy but may result in immune-related adverse events. We report a case in which liver injury occurred just two days after the administration of pembrolizumab plus chemotherapy. A 48-year-old woman achieved a complete response after chemoradiotherapy for cT2N3bM0 squamous cell carcinoma of the oropharynx with multiple lymph node metastases. However, the tumor recurred one year later, and she was started on pembrolizumab plus chemotherapy. On day 3, her alanine aminotransferase and aspartate transaminase concentrations markedly increased. She was initially diagnosed with drug-induced liver injury and all medications were withdrawn. Her liver function recovered within two weeks without intervention. The lymphocyte transformation test was only positive for pembrolizumab. Clinicians should consider pembrolizumab-induced allergic hepatitis as a possible cause of liver injury after excluding liver metastasis and immune-related adverse events.

Nickel allergy does not correlate with function after total knee arthroplasty.

PURPOSE: The purpose of this study is to determine if there is a relationship between clinical outcomes and nickel allergy by evaluating asymptomatic total knee arthroplasty (TKA) patients with well-functioning implants through quantitative metal allergy (MA) testing. METHODS: A prospective case series was performed on 50 patients with well-functioning TKA of various implant types. Inclusion criteria included primary TKA with a minimum 12-month follow-up and Oxford knee score (OKS) ≥ 40. A commercially available Lymphocyte Transformation Test measured the amount of a hypersensitivity lymphocyte immune response after exposure to a particular antigen. MA results were stratified based on the stimulation index (SI). The Cochran-Mantel-Haenzel test was used to test the homogeneity of metal reactivities. The Wilcoxon-Mann-Whitney test was used to compare individual metal SI by gender and the association of OKS and metal SI was ascertained with the Spearman correlation. RESULTS: Nickel, cobalt, and chromium do not have the same reactivity scores (p < 0.001), and only nickel showed reactive/highly reactive scores. Females were found to have 3.41 times the odds of males for higher Ni reactivity (p = 0.0295, odds ratio [OR], 95% confidence interval [CI] = 3.41 [1.13-10.3]) only. Clinically, there was no correlation between metal SI and OKS score by metal (Ni rho = -0.1779; Co rho = -0.0036; Cr rho = -0.1748). CONCLUSION: This is the first study looking at MA in well-functioning TKA. There is no correlation between clinical results and nickel reactivity. Surgeons should exercise caution when revising a painful or poorly functioning TKA based solely on a 'positive' Nickel Allergy test and look for other possible reasons for failure. LEVEL OF EVIDENCE: Level II.

Neurological manifestations of immune origin after COVID-19 vaccination: retrospective case study.

Objectives: To know the frequency and characteristics of neurological manifestations of probable immune origin occurring after exposure to COVID-19 vaccination. In addition, to pre-study the usefulness of the Spanish pharmacovigilance system and lymphocyte transformation test in establishing causality. Methods: Retrospective case study, including patients admitted to the Neurology department from January 2021 to May 2022 with a probable neuroimmune disorder. Demographic, clinical and COVID-19 vaccination antecedent data were collected from medical records. Results: From a total of 108 patients, 30 were excluded due to a different etiological diagnosis after follow-up. Thirty-six patients (46.2%) had received the COVID-19 vaccine in the previous 3 months (21.8% during the previous month). BioNTech-Pfizer vaccine was the most frequent in this group (63.9%). 69/108 were female and mean age 51.2 years (SD 22.59), with no significant difference with not recently-vaccinated (U-Mann Whitney, p = 0.256). The neurological syndromes found were (vaccinated/total): polyradiculoneuropathy (8/16), encephalitis (5/11), multiple sclerosis relapse (5/16), optic neuritis (1/4), myelitis (3/6), cranial neuropathy (6/10), aseptic meningitis (1/3) and others (7/11). Acute immunosuppressive treatment was administered in 61.1% of cases and 47.2% presented complete clinical improvement, without significant differences with non-vaccinated patients (chi-square, p = 0.570). Eleven vaccinated patients were studied in the pharmacovigilance office for possible adverse drug reaction. Causality according to the Spanish pharmacovigilance system (SPVS) algorithm was "Related" to COVID-19 vaccine (score ≥ 4) in 11 cases with positive in vitro study (lymphocyte transformation test) to polyethylene glycol-2000 and polysorbate-80 in 4 cases. Conclusion: Neuroimmune disorders appearing after administration of COVID-19 vaccine do not seem to present important differentiating clinical and/or evolutive features. Delayed hypersensitivity to vaccine excipients could be one of the pathophysiological mechanisms, and lymphocyte transformation test is a useful tool to identify it.

Unveiling the Role of Metal Ion Concentration versus Immune Sensitization in Orthodontic Patients-A Long-Term Prospective Evaluation.

Background: This longitudinal prospective study aimed to assess orthodontic patients' immune system response to metal ion release in saliva. Methods: Thirty adult patients (18-35 years) were equally divided into three groups: groups at the end (G1) and beginning (G2) of multibracket appliances (MBA) treatment and a non-treated control group (G3). Participants were evaluated at four timepoints within 21 days, with saliva samples being analyzed for metal ion concentrations and blood for the lymphocyte transformation test (LTT). Results: There were no significant differences between groups or timepoints for saliva. LTT analyses revealed hypersensitivity in one-third of all patients and 50% of G2 for nickel, with three developing sensitizations after MBA insertion. All nickel-sensitized patients exhibited varying elevated saliva nickel concentrations. The most nickel-sensitized patients had low ion saliva loads. In borderline nickel-sensitization cases, saliva ion concentrations were up to 20 times higher than the reference. Hypersensitivity to palladium, gold, and mercury was also observed. Conclusions: These findings indicate that increased MBA ion release was not inherently linked to the immune response (Type-IV sensitization), as reactions occurred even with ion levels below thresholds. This underlines the need for a comprehensive evaluation of the immune response to metal ion release in orthodontic patients.

In-vivo and ex-vivo tests for culprit drugs identification in severe cutaneous adverse drugs reactions.

Drug causality assessment in severe cutaneous adverse reactions (SCARs) remains challenging. We investigated the usefulness of in-vivo drug patch tests (PT), ex-vivo interferon (IFN)-γ enzyme-linked immunospot (ELISpot) assay, and lymphocyte transformation test (LTT) in 30 SCARs patients within the past 36 months. Drug PT yielded a 20% positivity rate (n = 6), while IFN-γ ELISpot and LTT showed positive rates of 56.67% (n = 17) and 41.38% (n = 12), respectively. Combining the three tests resulted in an overall positive rate of 66.67% (n = 20) of cases. IFN-γ ELISpot offered additional positivity, especially with oxypurinol. Employing a combined diagnostic approach may enhance the chances of obtaining a positive result.

Involvement of autologous myeloid dendritic cells in the evaluation of immediate hypersensitivity reactions to betalactams.

BACKGROUND: Amoxicillin (AX) and clavulanic acid (CLV) are the betalactam antibiotics (BLs) most used to treat bacterial infections, although they can trigger immediate hypersensitivity reactions (IDHRs). The maturation analysis of monocyte-derived dendritic cells (moDCs) and their capacity to induce proliferative response of lymphocytes are useful to test the sensitisation to a drug, although without optimal sensitivity. Nevertheless, this can be improved using directly isolated DCs such as myeloid DCs (mDCs). METHODS: mDCs and moDCs were obtained from 28 allergic patients (AP), 14 to AX, 14 to CLV and from 10 healthy controls (HC). The expression of CCR7, CD40, CD80, CD83, and CD86 was analysed after stimulation with both BLs. We measured the capacity of these pre-primed DCs to induce drug-specific activation of different lymphocyte subpopulations, CD3+, CD4+, CD8+, CD4+Th1, and CD4+Th2, by flow cytometry. RESULTS: Higher expression of CCR7, CD40, CD80, CD83, and CD86 was observed on mDCs compared to moDCs from AP after stimulating with the culprit BL. Similarly, mDCs induced higher proliferative response, mainly of CD4+Th2 cells, compared to moDCs, reaching up to 67% of positive results with AX, whereas of only 25% with CLV. CONCLUSIONS: mDCs from selective AP efficiently recognise the culprit drug which trigger the IDHR. mDCs also trigger proliferation of lymphocytes, mainly those with a Th2 cytokine pattern, although these responses depend on the nature of the drug, mimicking the patient's reaction.

Hypersensitivity to metals in metal-on-metal hip arthroplasty: a prospective study of one hundred and thirty five lymphocyte transformation tests.

BACKGROUND: Metal allergy remains a controversial topic in the orthopaedic community. It is not known if or to what degree metal sensitivity contributes to inflammatory soft tissue failures, unexplained residual pain, or clinical complications after total joint replacement with metal prostheses. METHODS: We investigated the efficacy of the lymphocyte transformation test (LTT) in predicting adverse outcomes in patients after receiving a metal joint replacement. Our study cohort consists of 135 metal-on-metal hip resurfacing arthroplasty cases performed between 2013 and 2015. All study patients had an LTT preoperatively. We retrospectively analyzed clinical outcomes and failures for our cohort. RESULTS: There was no difference in LTT reactivity between men and women. Of the 135 patients tested, 46 (34.1% of cohort) tested positive to at least one of the materials comprising their implant, and 78 patients (57.8%) had at least one reactive score to any component of the LTT. After a minimum follow-up of two years, we did not observe an allergic response to the implant in any patients. There were no failures requiring revision. We observed a 2.2% rate of moderate residual pain; no patients with residual pain tested positive for metal sensitivity. When patients with moderate-high LTT reactivity (30.4% of cohort) were compared to the remainder of the study group, there was no difference in HHS or UCLA activity score. There was no correlation between blood metal ion levels and LTT reactivity. CONCLUSION: We were unable to prove any predictive value of the LTT. We failed to identify hypersensitivity to metals in patients with metal-on-metal hip resurfacing arthroplasty.

Characteristics of mild and severe apalutamide-related cutaneous adverse events in patients with prostate cancer: A review of the literature.

Apalutamide is an antiandrogen used to treat prostate cancer. Although it sometimes induces mild cutaneous adverse events and occasionally severe ones, clinical differences between severe and mild cases remain unclear. To assess the risks in patients experiencing apalutamide-related cutaneous adverse events (ARCAEs), we aimed to characterize severe and mild ARCAEs in terms of onset time and lymphocyte transformation test (LTT) for apalutamide. We reviewed 41 ARCAE cases: 24 from our institute and 17 from the literature, comprising (i) eight severe cases including six with toxic epidermal necrolysis, one with acute generalized exanthematous pustulosis, and one with drug reaction with eosinophilia and systemic symptoms, and (ii) 33 mild cases. Patients with evere cases developed ARCAEs significantly earlier than patients with mild cases (5.2 vs 9.6 weeks). No severe cases appeared ≥8 weeks after initiation of apalutamide. LTTs showed positive results in two of seven mild cases (28.6%) and four of four severe cases (100.0%). In conclusion, we found that severe ARCAEs are characterized by earlier onset and LTT positivity. Dermatologists and urologists should pay special attention to patients who develop ARCAEs <8 weeks after initiating apalutamide and/or show positive LTT results.

[Stevens-Johnson syndrome in a patient with positive lymphocyte transformation test]. / Síndrome de Stevens-Johnson en una paciente con prueba positiva de transformación linfocitaria.

BACKGROUND: Stevens-Johnson syndrome is a severe drug reaction. Sulfonamides have been associated with drug reactions, complications, sequelae, even death. CASE REPORT: A 40-year-old female patient with a medical history of endometriosis and recently diagnosed chronic inflammatory ulcerative colitis. She was treated at the Allergology service of the San Juan de Dios Hospital of the Costa Rican Social Security Fund, and after 20 days of treatment with sulfasalazine she had a severe drug reaction on the skin, compatible with Stevens-Johnson syndrome. The lymphocyte transformation test was positive, confirming sulfasalazine as the causative agent. CONCLUSION: The lymphocyte transformation test is a useful method that can confirm the causative agent and prevent important complications in the future.

ANTECEDENTES: El síndrome de Stevens-Johnson es una reacción medicamentosa severa. Las sulfamidas se han asociado con reacciones medicamentosas, complicaciones, secuelas, incluso la muerte. REPORTE DE CASO: Paciente femenina de 40 años, con antecedentes médicos de endometriosis y colitis ulcerativa crónica inflamatoria de reciente diagnóstico. Fue atendida en el servicio de Alergología del Hospital San Juan de Dios de la Caja Costarricense del Seguro Social, y luego de 20 días de tratamiento con sulfasalazina tuvo una reacción medicamentosa severa en la piel, compatible con síndrome de Stevens-Johnson. La prueba de transformación linfocitaria resultó positiva, con lo que se confirmó la sulfasalazina como el agente causal. CONCLUSIÓN: La prueba de transformación linfocitaria es un método útil que puede confirmar el agente causal y prevenir complicaciones importantes a futuro.

IFN-γ secretion of PBMC from non-drug-allergic control persons: Considerations for the validity of a positive lymphocyte transformation test.

BACKGROUND: The lymphocyte transformation test (LTT) is used for the in vitro detection of a drug sensitization in assumed drug allergic patients. It is based on the detection of antigen (drug)-specific activation of T cells indicated by e.g. proliferation or cytokine secretion. However, occasional stimulatory effects of the drug unrelated to specific drug-allergic mechanisms can only be detected if a larger number of non-drug allergic control persons are tested with this specific drug. In this respect, the overall specificity of the LTT with ELISA read-out is summarized in several review articles, but the impact of a specific drug on the specificity has not yet been analyzed in a larger set of control persons. OBJECTIVE: Do amoxicillin, cefuroxime and clindamycin induce an interferon (IFN)-y or interleukin (IL)-5 secretion of PBMC from control persons using the LTT with ELISA read-out? METHODS: We performed LTTs with amoxicillin, cefuroxime and clindamycin and determined drug-specific IFN-γ and IL-5 secretion measured by ELISA read-out. We included PBMC from 60 non-drug allergic control persons, who were unexposed to the tested drug at the time of blood donation. RESULTS: PBMC from 12 out of 23 control persons tested with amoxicillin gave a positive stimulation index (SI > 3.0) for IFN-γ resulting in a specificity of 47.8%. The corresponding specificity was 75% for cefuroxime (5/20 if SI > 3.0) and 58.8% for clindamycin (7/17, if SI > 2.0), respectively. In a next step, we calculated the Δ IFN-γ concentration by subtracting the background IFN-γ concentration in the unstimulated sample from the stimulated sample. After stimulation with amoxicillin, a mean concentration of 21.0 pg/mL IFN-γ was secreted. The less outlier prone median concentration was 7.4 pg/mL and much higher than for cefuroxime (1.7 pg/mL) and clindamycin (1.0 pg/mL). Remarkably, IL-5 concentrations were below the detection limit (< 1 pg/mL) for all drugs in all control persons who responded to TT. CONCLUSION: Consideration of these observations may be helpful since a positive LTT result in a control patient may challenge the validity of a positive LTT result in the same experiment for a patient with assumed drug allergy.

Immune-Mediated Organ-Specific Reactions to COVID-19 Vaccines: A Retrospective Descriptive Study.

Severe acute respiratory syndrome coronavirus 2 caused the global COVID-19 pandemic and public health crisis, and it led to the rapid development of COVID-19 vaccines, which can cause rare and typically mild hypersensitivity reactions (HRs). Delayed HRs to COVID-19 vaccines have been reported, and the excipients polyethylene glycol (PEG)2000 and polysorbate 80 (P80) are the suspected culprits. Skin patch tests do not help in diagnosing delayed reactions. We aimed to perform lymphocyte transformation tests (LTT) with PEG2000 and P80 in 23 patients with suspected delayed HRs. Neurological reactions (n = 10) and myopericarditis reactions (n = 6) were the most frequent complications. Seventy-eight percent (18/23) of the study patients were admitted to a hospital ward, and the median time to discharge was 5.5 (IQR, 3-8) days. Some 73.9% of the patients returned to baseline condition after 25 (IQR, 3-80) days. LTT was positive in 8/23 patients (5/10 neurological reactions, 2/4 hepatitis reactions and 1/2 rheumatologic reactions). All myopericarditis cases had a negative LTT. These preliminary results indicate that LTT with PEGs and polysorbates is a useful tool for identifying excipients as causal agents in HRs to COVID-19 vaccines and can play an important role in risk stratification in patients with HRs.

In vitro diagnostic testing for drug allergy in children.

Diagnosing Drug Hypersensitivity Reactions (DHRs) could be a complicated process especially in children, since allergic-like manifestation at this age is more often the expression of concomitant infections rather than a actual DHRs. In vivo tests are usually suggested as a first step; however, prick and intradermal tests could be painful and have shown different sensitivity and specificity among published studies. In some cases, in vivo tests such as Drug Provocation test (DPT) could be even contraindicated. Therefore, the need for in vitro testing is compelling, to add useful information along the diagnostic pathway and to limit the need of DPT. In this review, we analyze the different types of in vitro tests, focusing on those used more widely such as specific IgE and on those that are still for research settings, such as basophil activation test and lymphocyte transformation test, but that have shown some useful diagnostic potential.