Background: Previous reports suggest the usefulness of basophil activation testing (BAT) in Hymenoptera-allergic patients with negative venom-specific IgE antibodies. We sought to evaluate the diagnostic utility of this testing in a routine clinical laboratory setting. Materials and Methods: Twenty-one patients with anaphylactic reactions to Hymenoptera sting (median grade III) and negative venom-specific IgE were routinely and prospectively tested with BAT. Results: We were able to diagnose 81% (17 of 21) of patients with BAT and 57% (12 of 21) with intradermal skin testing. Three wasp venom-allergic patients showed IgE positivity to rVes v 5. Four patients (19%) were negative for all tests. In the case of double-positive BAT, the culprit insect correlated with the venom that induced a significantly higher basophil response. Conclusions: BAT allows the identification of severe Hymenoptera-allergic patients with negative specific IgE and skin tests. The routine use of this cellular test should facilitate prescription of venom immunotherapy in complex cases with inconclusive diagnostic results.
COBISS.SI-ID: 36694789
Background: Peanut sensitization is common in children. However, it is difficult to assess which children will react mildly and which severely. This study evaluated the relevance of basophil allergen sensitivity testing to distinguish the severity of peanut allergy in children. Methods: Twenty-seven peanut-sensitized children with symptoms varying from mild symptoms to severe anaphylaxis underwent peanut CD63 dose-response curve analysis with the inclusion of basophil allergen sensitivity calculation (CD-sens) and peanut component immunoglobulin E (IgE) testing. Results: Eleven children who had experienced anaphylaxis to peanuts showed a markedly higher peanut CD63 response at submaximal allergen concentrations and CD-sens (median 1,667 vs. 0.5; p ( 0.0001) than 16 children who experienced a milder reaction. Furthermore, a negative or low CD-sens to peanuts unambiguously excluded anaphylactic peanut allergy. Children with anaphylaxis have higher levels of Ara h 1, 2, 3 and 9 IgE, but comparable levels of IgE to Ara h 8 and whole-peanut extract. The diagnostic specificity calculated with a receiver operating characteristic analysis reached 100% for CD-sens and 73% for Ara h 2. Conclusions: We demonstrated that severe peanut allergy is significantly associated with higher basophil allergen sensitivity. This cellular test should facilitate a more accurate diagnosis of peanut allergy.
COBISS.SI-ID: 4854335
Background: Asthma is a heterogeneous disease, and asthmatic patients without rhinitis more commonly have fixed airway obstruction, a feature that is also typical of chronic obstructive pulmonary disease (COPD). The Dutch hypothesis suggests that both COPD and asthma have common genetic risk factors. The purpose of this study was to assess the association between the polymorphism rs4795405 in the known asthma candidate gene ORMDL3 and asthma with and without rhinitis. We also analyzed COPD in order to investigate whether, in addition to a clinical overlap, there might also be a genetic overlap between COPD and asthma. Methods: The population of this genetic association study comprised 493 Slovenian adults, distributed as follows: 131 patients with asthma (59 had asthma with rhinitis and 72 asthma without rhinitis), 59 patients with rhinitis only, 133 patients with COPD, and 170 controls. Genotypes for rs4795405 were determined using the TaqMan genotyping assay. Results: rs4795405 was specifically associated with asthma without rhinitis. Assuming a recessive genetic model, we found the CC genotype in 26% of healthy controls, in 24% of patients with asthma with rhinitis (P=.862), and in 44% of patients with asthma without rhinitis (P=.006). Polymorphism rs4795405 was also associated with COPD, for which the CC genotype was found in 37% of cases (P=.045). Conclusions: rs4795405 was strongly associated with asthma without rhinitis, a subtype of asthma for which a higher degree of airway obstruction was found. These results show the importance of analyzing different asthma phenotypes in genetic association studies. We also observed a genetic overlap between COPD and asthma without rhinitis.
COBISS.SI-ID: 36819717
Hereditary angioedema (HAE) is a rare autosomal dominant disease characterized by swelling of the face, lips, tongue, larynx, genitalia, or extremities, with abdominal pain caused by intra-abdominal edema. HAE is caused by mutations affecting the C1 inhibitor gene, SERPING1, resulting in low levels of C1 inhibitor (Type I HAE) or normal levels of ineffective C1 inhibitor (Type II HAE). A nationwide survey identified nine unrelated families with HAE in Slovenia, among whom 17 individuals from eight families were recruited for genetic analyses. A diagnosis of HAE was established in the presence of clinical and laboratory criteria (low C1 inhibitor antigenic levels and/or function), followed up by a positive family history. Genetic studies were carried out using PCR and sequencing to detect SERPING1 mutations in promoter, noncoding exon 1, the 7 coding exons, and exon-intron boundaries. Multiplex ligation-dependent probe amplification was performed in order to search for large deletions/duplications in SERPING1 gene. A mutation responsible for HAE was identified in patients from seven families with the disease. In HAE type I families, one previously reported substitution (Gln67Stop, c.265C.T) and four novel mutations were identified. The new mutations included two missense substitutions, Ser128Phe (c.449C.T), and Glu429Lys (c.1351G.A), together with two frameshift mutations, indel (c.49delGinsTT) and deletion (c.593_594delCT). Both families with HAE type II harbored the two well-known substitutions affecting the arginyl residue at the reactive center in exon 8, Arg444Cys (c.1396C.T) and Arg444His (c.1397G.A), respectively. In one patient only the homozygous variant g.566T.C (c.-21T.C) was identified. Our study identified four novel mutations in the Slovenian HAE population, highlighting the heterogeneity of mutations in the SERPING1 gene causing C1 inhibitor deficiency and HAE. In a single patient with HAE a homozygous variant g.566T.C (c.-21T.C) might be responsible for the disease.
COBISS.SI-ID: 4586815
Background: Histamine intolerance (HIT) is characterized by an imbalance between histamine intake and the capacity for histamine degradation. The main enzyme for metabolizing ingested histamine is diamine oxidase (DAO). Determining DAO activity in serum may be useful in diagnosing HIT. Methods: Over a period of 3.5 years we recruited 316 subjects with clinically suspectedHIT and 55 healthy controls. Serum DAO activity was measured with a quantitative enzyme immunoassay. Twenty patients with highly reduced DAO activity went on a histamine-free diet for 6-12 months. Afterwards, their DAO activity was determined again. Results: We found that DAO activity was significantly lower in patients than in healthy control subjects (P(0.0001). Furthermore, 54 patients had highly reduced serum DAO activity ((40 HDU/ml). Their main symptoms involved the skin, gastrointestinal tract, respiratory system, and eyes. In all the 20 patients with highly reduced DAO activity, the main clinical symptoms typical of histamine intolerance disappeared after they adopted a histamine-free diet. Furthermore, the serum DAO activity values measured increased significantly (P(0.0001). Conclusions: Our results suggest that determining DAO activity in serum is a useful tool in diagnosing HIT. Furthermore, our results showed the benefit of a histamine-free diet because after the diet the majority of symptoms disappeared and the serum DAO activity significantly increased.
COBISS.SI-ID: 36718341