Gene polymorphisms within the immune system that may underlie drug allergy

Investigation of cross-reactivity between phenobarbital and levetiracetam in children with epilepsy: A prospective, observational multicenter study

Objectives

Pharmaceutical allergic reactions due to antiseizure medications (ASMs) are one of the major concerns in the management of patients. Finding an alternative ASM which does not cause allergic reactions and has acceptable effectiveness can be difficult. In this regard, the present study attempts to investigate the cross-reactivity between phenobarbital and levetiracetam in children under treatment for seizure control.

Materials & Methods

The present study is a prospective, observational independent assessor study. 30 children with epilepsy who were hypersensitive to phenobarbital therapy were studied. In order to evaluate the cross-reactivity of the drugs, levetiracetam replaced phenobarbital to control seizure. Within 6 months, any allergic reactions and seizure recurrences were evaluated in the patients.

Results

53 % of the children in this study were female. The mean age of patients was 42.4 months. In patients' follow up no cross-reactive responses were observed in any of the patients. Seizure recurrence rate was 30 % in the first six months of follow up that with increasing dosage in the second six months of follow-up, decreased to 10 %.

Conclusion

Based on the results of this study, in children with epilepsy controlled by phenobarbital if allergic reactions to phenobarbital occur, levetiracetam may be used as a suitable alternative medicine.

Polymorphisms in GRIA1 gene are a risk factor for asparaginase hypersensitivity during the treatment of childhood acute lymphoblastic leukemia

l-asparaginase is an effective antineoplastic agent used in chemotherapy of acute lymphoblastic leukemia. The drug effect may be compromised by an elicited immune response, resulting in the production of anti-asparaginase antibodies causing an anaphylactic reaction or silent inactivation of the enzyme. To elucidate possible genetic predisposition for inter-individual differences in asparaginase hypersensitivity, we studied single nucleotide polymorphisms (SNPs) in the GRIA1 gene in 146 pediatric patients treated with l-asparaginase. Allergic reaction to l-asparaginase occurred in 49.3% of patients. We observed a statistically significant association between SNPs in the GRIA1 gene and the occurrence of asparaginase allergy: rs4958351 with p = 0.003, rs4958676 with p = 0.005, rs6889909 with p = 0.005, rs6890057 with p = 0.005 and rs10070447 with p = 0.006. We found a statistically significant correlation between asparaginase allergy and event-free survival (p-value 0.005).

Allergy to betalactams and nucleotide-binding oligomerization domain (NOD) gene polymorphisms

BACKGROUND

Polymorphisms of interleukin genes related to IgE production and inflammation are predictors of hypersensitivity to betalactam, but nothing is known on the influence of NOD genes, despite their association with inflammation and atopy.

OBJECTIVE

To evaluate the association of NOD2 and NOD1 polymorphisms with betalactam allergy.

METHOD

We genotyped 3 polymorphisms of NOD2 and 1 of NOD1 in 368 Italian and 387 Spanish patients, compared with 368 and 326 controls, respectively.

RESULTS

CT/TT genotypes of rs2066845 of NOD2 predicted a lower risk in Italy (P = 0.003), while WT/insC genotype of rs5743293 (also in leucine-rich repeat domain) predicted a higher risk in Spain (P = 0.007). G allele of rs2066845 was associated with a higher level of IgE in the Italian population.

CONCLUSION

The mirrored influence of these NOD2 polymorphisms on betalactam allergy in two populations suggests a link with pathways of inflammation and/or atopy through mechanisms, which need to be clarified.

Genetic variations in GRIA1 on chromosome 5q33 related to asparaginase hypersensitivity

The genetic variations that result in allergy to asparaginase are as yet undetermined. We interrogated more than 500,000 single-nucleotide polymorphisms (SNPs) in 485 children with acute lymphoblastic leukemia (ALL), 322 in a discovery cohort, and 163 in a validation cohort. In the top 100 SNPs associated with allergy in the discovery cohort, chromosome 5 was overrepresented as compared with other chromosomes (P = 0.00032), hosting 10 SNPs annotated to genes. Among these 10 SNPs, one SNP (rs4958351) [corrected], in GRIA1 on chromosome 5q33, was replicated in the validation cohort (P = 1.8 x 10(-5), 2.9 x 10(-3), and 3.5 x 10(-7) in the discovery, validation, and combined cohorts, respectively). Four additional SNPs annotated to GRIA1 were also significantly associated with allergy (P < 0.05) in both cohorts. Chromosome 5q33 has previously been associated with asthma and atopy. These data contribute to the growing body of evidence that there is an inherited component to predisposition to drug allergy.

Genetics of Nickel Allergic Contact Dermatitis

Nickel sulfate is the most frequently detected cause of allergic contact dermatitis in the world; the prevalence of nickel allergic contact dermatitis is between 8 and 11% in the general female population. Although it is well recognized that environmental factors are important in the pathogenesis of this dermatitis, some investigators have hypothesized that genetic factors are important as well. This review summarizes animal and human studies evaluating genetic factors in the development of allergic contact dermatitis from nickel.

Evaluation of the incidence of carboplatin hypersensitivity reactions in cancer patients

OBJECTIVES

Although the reported incidence of carboplatin hypersensitivity is low, its occurrence is important to characterize because of potential fatal complications. The purpose of this study was to determine the current incidence of carboplatin hypersensitivity in the ovarian cancer patients compared to other oncology patients and identify potential risk factors that may contribute to development of carboplatin hypersensitivity reactions.

METHODS

This was a retrospective chart review analyzing all hospital records at an academic tertiary oncology center between July 2002 and September 2003. Data collected included patient demographics, past medical histories, and detailed carboplatin administration information. Patients that had received carboplatin were identified from pharmacy dispensing records. Positive carboplatin hypersensitivity reactions were identified from the documentation provided in the patient medical record.

RESULTS

The incidence of carboplatin hypersensitivity for all cancer patients compared to ovarian cancer patients receiving carboplatin at our institution was 2.6% and 7.9%, respectively. Statistically significant risk factors (P < 0.05) included prior carboplatin exposure and history of drug allergies. There was also a trend to suggest premedication with histamine1 (H1) and histamine(2) (H2) blocker decreases the risk of developing carboplatin hypersensitivity reactions.

CONCLUSION

This study confirmed a similar incidence of carboplatin hypersensitivity reactions to previous reports. However, we found that the higher incidence associated with ovarian cancer patients can be attributed to the prolonged carboplatin exposure or history of drug allergies. This is the first study to observe that the administration of H1 and H2 antagonists is associated with a decrease risk of carboplatin hypersensitivity reaction.

Genetic aspects of immune-mediated adverse drug effects

Adverse drug effects (ADEs) are of great importance in medicine and account for up to 5% of all hospital admissions. ADEs can arise from several mechanisms and a wide range of drugs can cause immune-mediated ADEs (IMADEs). For a drug to elicit an IMADE, it must be both immunogenic (that is, able to sensitize the immune system) and antigenic (that is, able to evoke a response from a sensitized immune system). Unlike protein therapeutics, small-molecule drugs (or xenobiotics) are usually neither immunogenic nor antigenic. IMADEs are therefore the result of complex interactions between drug-metabolizing enzymes, immune sensitization and immune effectors. The genetic aspects of this interplay are discussed in this review.