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Idiopathic hypereosinophilic syndrome (HES) characterized by unexplained and persistent hypereosinophilia is heterogeneous and comprises several entities: a myeloproliferative form where myeloid lineages are involved with the interstitial chromosome 4q12 deletion leading to fusion between FIP1L1 and PDGFRA genes, the latter acquiring increased tyrosine kinase activity. And a lymphocytic variant, where hypereosinophilia is secondary to a primitive T lymphoid disorder demonstrated by the presence of a circulating T-cell clone. We performed molecular characterization of HES in 35 patients with normal karyotype by conventional cytogenetic analysis. TCRgamma gene rearrangements suggesting T clonality were seen in 11 (31%) patients, and FIP1L1-PDGFRA by RT-PCR in six (17%) of 35 patients, who showed no evidence of T-cell clonality. An elevated serum tryptase level was observed in FIP1L1-PDGFRA-positive patients responding to imatinib, whereas serum IL-5 levels were not elevated in T-cell associated hypereosinophilia. Sequencing FIP1L1-PDGFRA revealed scattered breakpoints in FIP1L1-exons (10-13), whereas breakpoints were restricted to exon 12 of PDGFRA. In the 29 patients without FIP1L1-PDGFRA, no activating mutation of PDGFRA/PDGFRB was detected; however; one patient responded to imatinib. FISH analysis of the 4q12 deletion was concordant with FIP1L1-PDGFRA RT-PCR data. Further investigation of the nature of FIP1L1-PDGFRA affected cells will improve the classification of HES.

Objectives: Hypersensitivity reactions IgE-mediated (anaphylaxis) or non-IgE-mediated (anaphylactoid) reactions occurring during anaesthesia remain a major cause of concern for anaesthesiologists, since these reactions remain usually unpredictable, may be potentially life-threatening even when appropriately treated. The authors report the results of the last 2-year survey (2001, 2002) of such reactions conducted in France by the GERAP (groupe d'etude des reactions anaphylactoides peranesthesiques), and compare these results with their previous published surveys., Methods: Between January 1, 2001 to December 31, 2002, 712 patients who experienced immune-mediated (anaphylaxis) or non-immune-mediated (anaphylactoid) reactions were referred to one of the 40 allergo-anaesthesia centres members of the GERAP. Anaphylaxis was diagnosed on the basis of clinical history, tryptase measurements during the adverse reaction, and skin tests and/or specific IgE assay., Results: Anaphylactic and anaphylactoid reactions were diagnosed in 491 cases (69%) and 221 cases (31%), respectively. The most common causes of anaphylaxis were neuromuscular blocking agents (NMBA) (n=271, 55%), latex (n=112, 22.3%), and antibiotics (n=74, 14.7%). Succinylcholine (n=102, 37.6%) and rocuronium (n=71, 26.2%) were the most frequently incriminated NMBAs. Cross-reactivity between NMBAs was observed in 63.4 % of cases of anaphylaxis to a NMBA. No difference was observed between anaphylactoid and anaphylactic reactions when the incidences of atopy, food, or drug intolerance were compared. However atopy, asthma and food allergy were significantly more frequent in case of latex allergy, when compared with NMBA allergy. Clinical manifestations were more severe in anaphylaxis. The positive predictive value of tryptase measurement for the diagnosis of anaphylaxis was 95.3%, the negative predictive value 49%. The diagnostic value of specific neuromuscular blocking agent IgE assays was confirmed., Conclusion: Our results further corroborate the need for systematic screening in case of immediate hypersensitivity reaction during anaesthesia and for the constitution of allergo-anaesthesia centres to provide expert advice to anaesthesiologists and allergologists.

Background: Anaphylactic and anaphylactoid reactions occurring during anesthesia remain a major cause of concern for anesthesiologists. The authors report the results of a 2-yr survey of such reactions observed during anesthesia in France., Methods: Between January 1, 1999, and December 31, 2000, 789 patients who experienced immune-mediated (anaphylaxis) or nonimmune-mediated (anaphylactoid) reactions were referred to one of the 40 participating centers. Anaphylaxis was diagnosed on the basis of clinical history, skin tests, and/or specific immunoglobulin E assay., Results: Anaphylactic and anaphylactoid reactions were diagnosed in 518 cases (66%) and 271 cases (34%), respectively. The most common causes of anaphylaxis were neuromuscular blocking agents (NMBAs) (n = 306, 58.2%), latex (n = 88, 16.7%), and antibiotics (n = 79, 15.1%). Rocuronium (n = 132, 43.1%) and succinylcholine (n = 69, 22.6%) were the most frequently incriminated NMBAs. Cross-reactivity between NMBAs was observed in 75.1% of cases of anaphylaxis to an NMBA. No difference was observed between anaphylactoid and anaphylactic reactions when the incidences of atopy, asthma, or drug intolerance were compared. However, atopy, asthma, and food allergy were significantly more frequent in the case of latex allergy when compared with NMBA allergy. Clinical manifestations were more severe in anaphylaxis. The positive predictive value of tryptase for the diagnosis of anaphylaxis was 92.6%; the negative predictive value was 54.3%. The diagnostic value of specific NMBA immunoglobulin E assays was confirmed., Conclusions: These results further corroborate the need for systematic screening in the case of anaphylactoid reaction during anesthesia and for the constitution of allergoanesthesia centers to provide expert advice to anesthesiologists and allergists.