The controversy of drug hypersensitivity in patients with cystic fibrosis and review of the literature

Lymphocyte transformation tests predict delayed-type allergy to piperacillin/tazobactam in patients with cystic fibrosis

BACKGROUND

Antibiotic treatment is crucial for patients with chronic bacterial infections. Suspected drug allergies often lead to inconsistent therapies and challenging clinical management for patients and caregivers. The objective of this study was to evaluate the value of lymphocyte transformation tests in comparison to skin tests for the prediction of delayed-type allergic reactions.

METHODS

This prospective, observational study tested the diagnostic value of skin prick tests, intradermal tests (reading: 15 min and 72 h) and lymphocyte transformations tests for the prediction of allergic reactions in CF patients with physician reported allergy to piperacillin/tazobactam, meropenem and ceftazidime. The tests were performed directly before a 14d intravenous drug challenge.

RESULTS

We performed 33 drug challenges in 29 subjects. 21 drug challenges were negative (63 %); 12 lead to a reaction (37 %), of those 2 were immediate and 10 were delayed-type. 100 % of the skin prick tests were negative. 97 % (33/34) of the intradermal tests with early reading and 100 % of the intradermal tests with late reading yielded negative results. 5/11 patients who experienced a delayed-type reaction during the drug challenge had a positive lymphocyte transformations test. All 17 patients who did not react had a negative lymphocyte transformations test. For piperacillin/tazobactam, 4/5 patients who experienced a delayed-type reaction during the drug challenge had positive lymphocyte transformations tests. Hence, for piperacillin/tazobactam, the sensitivity of the lymphocyte transformation test for prediction of reactions was 80.0 % and the specificity 100 %.

CONCLUSION

We demonstrate that the lymphocyte transformation test predicts delayed-type allergy to piperacillin/tazobactam in contrast to skin tests.

"Antibiotic hypersensitivity reactions in Cystic Fibrosis: A thorough inspection on a stumbling block in patient care"

One hurdle in the management of CF, a disease characterized by progressive endobronchial infection, is the presence of hypersensitivity reactions to antimicrobials due to prolonged and repetitive treatment courses. The aim of this review is to compile existing data and provide insight to medical professionals on a long-debated topic for optimum patient care. Clinical studies were inducted from the last 15 years and filtered based on their relativity to drug hypersensitivity reactions (DHRs), antibiotics and CF. After completing the selection process, 10 clinical studies were thoroughly examined. The most frequent antibiotic group related to DHRs were beta-lactams. Frequency of the most common overall type of reaction (immediate or nonimmediate) differed among clinical studies. Although severe reactions seem rare comparatively, they do occur during and even after completion of treatment regimens. The prevalence of true drug allergies should be confirmed using a variety of tests available, however, should not be confused with overall DHR rates. Genetic mutations, gender and lifetime antibiotic dose were not related with an increased risk for DHR development. On the contrary, the most important factor according to most studies was the cumulative antimicrobial dose in a given period of time, especially when delivered parenterally. DHRs are an indisputable problem in the management of CF patients. Understanding possible risk factors and increased awareness is vital in both hospital and outpatient settings as early detection can decrease the severity of the reactions.

Skin testing as a biomarker in drug allergy

Despite the significant negative impact drug allergies can have on patient care, the diagnosis is largely based on clinical history, and there are limited diagnostic tests that can be done at the time of a reaction. Biomarkers are needed to improve the diagnosis and the identification of the culprit medication. Skin testing is the most useful biomarker for immediate- and delayed-type reactions available, but it is limited by its low sensitivity. To improve its accuracy and reproducibility, a standardized procedure must be used. For immediate-type reactions, penicillin skin testing is the most widely studied, and it can be used in patients with history of anaphylaxis or recent immunoglobulin E-mediated reaction or for whom there is a significant risk if a reaction were to occur, such as pregnancy. Skin testing is also important in allergy to platinum agents allowing for continued first-line therapy. For delayed-type reactions, patch testing and delayed intradermal testing, used in conjunction with clinical history, can help to improve identification of the culprit medication depending on the type of reaction. Other biomarkers including in vitro testing for specific immunoglobulin E, basophil activation test, lymphocyte transformation test, ELISpot, and genetic factors that increase the likelihood of reaction are under investigation, and they may be most helpful when used in combination with the clinical history and skin testing results.

Evaluation of Frequency and Characteristics of Drug Allergy in Pediatric Patients with Cystic Fibrosis

Background: Previous studies reported that the prevalence of drug allergy is higher in patients with cystic fibrosis (CF) than in the general population. It is important to exclude or confirm the drug allergy diagnosis with detailed allergic evaluation for preventing drug allergy overdiagnosis. Our study aims to determine the actual frequency of drug allergy proven by diagnostic tests in children with CF and to compare it with the control group. Methods: Patients diagnosed with CF who were followed up in the Pediatric Pulmonology Clinic were included in the study group. Children with similar gender and age characteristics who did not have any chronic diseases and who applied to the Pediatric Polyclinics were included in the control group. We reviewed the medical data of patients with CF. Also, we evaluated the parents of the patients via phone conversation and/or during the control of the outpatient clinic and questioned them in terms of drug allergy. In addition, we assessed those with suspected drug allergies in the pediatric allergy clinic for diagnostic tests and compared it to the control group. Results: CF patients (n = 44) and control group (n = 100) were included in the study. Only 1 patient (2.2%) out of the 44 patients in the study group had a suspicion of drug-related hypersensitivity history. In the control group, 1 patient had a history of rash, provocation test was performed to rule out drug hypersensitivity reaction, and it was evaluated as a negative result. Conclusions: The result of our study showed that the frequency of drug allergy in children diagnosed with CF was not different from the control group. However, it will be useful to confirm the data of pediatric patients with CF in larger groups. In the presence of suspicion of drug allergy, a diagnostic evaluation can prevent unnecessary drug allergy diagnoses.