Possible relationship between systemic side effects and sensitization to rPar j 2 in allergic patients submitted to an ultra-rush (20 min) sublingual immunotherapy and selected by component resolved diagnosis.

BACKGROUND: The pollen of Parietaria spp., a weed of the Urticaceae family, is a major cause of respiratory allergy in the Mediterranean area, where the most common species are Parietaria judaica and Parietaria officinalis. In this study, we evaluated the specific serum IgE-binding profiles to individual P. judaica pollen recombinant major allergen, and Phleum pratense cytoskeletal profilin and a 2-EF-hand calcium-binding allergen homologous to cross-reactive Parietaria pollen allergens, in patients allergic to pollen with positive skin test towards Parietaria spp. extract. METHODS: The present observation included 220 patients from the province of Cuneo, north-west Italy, all suffering from rhino-conjunctivitis and/or asthma selected on the basis of skin test positive to P. judaica extract. The sera were evaluated for specific IgE reactivity to P. judaica pollen major recombinant(r) allergen Par j 2, Phleum pratense pollen allergens rPhl p 7 (2-EF-hand calcium binding protein) and rPhl p 12 (profilin), both identified as cross-reactive Parietaria spp. allergens, using Pharmacia CAP System. Out of 220 patients, 37 patients with IgE reactivity to rPar j 2 and 105 patients sensitized to at least one timothy pollen major allergen (i. e. rPhl p 1, rPhl p 2, natural Phl p 4 and rPhl p 6) were submitted to an ultra-rush protocol of sublingual immunotherapy (SLIT). The occurrence of adverse reactions were evaluated in both groups. RESULTS: All 220 patients with pollinosis and positive in vivo skin prick tests had in vitro positive CAP results to P. judaica natural extract. On the contrary, in these patients the prevalence of Par j 2-specific IgE was only 33.2% (73/220). In fact, 116/220 (52.7%) patients with serum specific IgE to crude Parietaria pollen extract had specific IgE to Phl p 12, 18/220 (8.1%) subjects with specific IgE to rPhl p 12 also exhibited specific IgE to Phl p 7 and 26/220 (11.8%) subjects had specific IgE against rPhl p 7. Particularly, geometric mean (25th-75th percentile) of specific IgE to rPar j 2 were as follows: 2.87 kUA/l (1.005-7.465). Out of 73 patients with specific IgE to rPar j 2, 7 subjects (9.6%) had also specific IgE to rPhl p 7, 12 (16.4%) had specific IgE to rPhl p 12 and 4 (4.1%) patients had specific IgE to both recombinant allergens. Of 37 patients under an ultra-rush protocol of SLIT, 3 subjects (8.1%) experienced generalized urticaria, and 1 of them also had diarrhea 3 h after the last dose of Parietaria judaica extract oral-vaccine administration. On the contrary, no systemic reactions were observed in 105 patients after Phleum pratense extract oral intake after a similar ultra-rush SLIT protocol (p = 0.0046). CONCLUSIONS: In the light of present findings, allergen extract-based diagnosis, in vivo and in vitro, cannot discriminate allergic patients that are genuinely sensitized to Parietaria spp. major allergens or to other major allergens to which current immunotherapeutic allergy extracts are standardized. Therefore, in vitro component resolved diagnosis is the unique tool to define the disease eliciting molecule(s). Finally, during sublingual immunotherapy, not only the dose of allergen, but also the biochemical characteristic of the major allergen administered may be an important factor in determining possible systemic reactions.

Evaluation of recombinant allergens Bet v 1 and Bet v 2 (profilin) by Pharmacia CAP system in patients with pollen-related allergy to birch and apple.

Sixty-five patients presenting either rhinoconjunctivitis or asthma and sensitized to pollens of trees of the order Fagales were studied by the Pharmacia CAP system in order to assess specific IgE for the important birch pollen allergens Bet v 1 and Bet v 2. All 65 subjects reacted to at least one of the recombinant birch allergens: 43% to Bet v 1, 30.7% to Bet v 2, and 26% to both. Patients monosensitized to birch did not react to Bet v 2. Of patients with a history of oral allergy syndrome after eating apples, 16/28 (57%) reacted to Bet v 1; among 20 polysensitized subjects presenting oral allergy syndrome after consumption of apple, four reacted to Bet v 2 (20%). Among patients with IgE against both recombinant allergens, six (35.30%) presented symptoms of allergy after eating apples. Our results indicate that sensitization to Bet v 1 is specific for birch and apple allergies, whereas sensitization to Bet v 2 is common in polysensitized patients.

A comparative study of the tryptase release test and the cellular allergen stimulation test (CAST) in mite sensitive patients.

BACKGROUND: The stimulation of blood basophils to release mediators in vitro is widely used for diagnosis of allergic diseases. Tryptase release and sulphidopeptideleukotriene production are both triggered by cross-bridging of adjacent IgE molecules on the surface of IgE-bearing basophils. OBJECTIVE: We have compared the sensitivity of tryptase release test (TRT) and cellular allergen stimulation test (CAST) which, respectively, measure tryptase and sulphidopeptideleukotrienes that are produced upon cell stimulation by mite extracts. METHODS: Blood was taken from 247 patients with allergy to mites and 137 non-allergic control subjects. We measured tryptase release from basophils after allergen challenge in vitro by sandwich radioimmunoassay. The sulphidopeptideleukotrienes production was quantified by an ELISA test based on a monoclonal antibody which recognized leukotriene T4 (LTC4) and its metabolites LTD4 and LTE4. RESULTS: Our data show that both methods are equally effective to distinguish allergic patients from normal controls (P > 0.0001). There was a significant correlation between mite-specific serum IgE and CAST results (r = 0.69 for Dermatophagoides pteronyssinus; r = 0.73 for Dermatophagoides farinae). Correlations between IgE against mites and tryptase values appeared rather poor (r = 0.47 for Dermatophagoides pteronyssinus; 0.49 for Dermatophagoides farinae). Moreover, the data were used for the calculation of sensitivity, specificity, prevalence, and overall efficiency (Roc/Galen & Gambino analysis). The results were as follows: 71%, 87%, 64%, 76% (CAST results for Dermatophagoides farinae); 64%, 78%, 53%, 70% (TRT results for Dermatophagoides farinae). CONCLUSION: The partial discrepancies observed could be interpreted as a consequence of conditions that were technically not optimal. False-positive results may be due to the action of some non-specific cytotoxic agent, false-negative results may be due to hyporesponsive basophils or the low number of cells participating in the reaction and finally, in the case of TRT, to G4 monoclonal antibody to tryptase employed.

Evaluation of IgE antibodies to recombinant pollen allergens (Phl p 1, Phl p 2, and Phl p 5) in a random sample of patients with specific IgE to Phleum pratense.

BACKGROUND: We measured specific IgE levels against the recombinant allergens (RAs) rPhl p 1, rPhl p 2, and rPhl p 5 in patients allergic to grass pollen, and examined the existence of different patterns of IgE production to RAs. The seasonal variations of IgE levels to rPhl p 1, rPhl p 2, and rPhl p 5 were considered, too. METHODS: Blood was taken from 276 consecutive patients with allergy to grass pollen diagnosed by patient history and skin prick testing. Total and specific serum IgE was measured by the immunoenzymatic CAP FEIA System. Eosinophil cationic protein (ECP) and myeloperoxidase (MPO) were assessed by radioimmunoassay according to the instructions of the manufacturers. RESULTS: We observed eight different patterns of IgE production to rPhl p 1, rPhl p 2, and rPhl p 5 in patients with specific IgE to timothy grass. A significant difference between the values of IgE levels to timothy and the sum of each level of specific IgE to individual RAs was found (P = 0.039, Wilcoxon matched pairs test) in the whole population (n = 276 subjects). In four subgroups of patients, the sum of each level of specific IgE to individual RAs was equal to the levels of specific IgE to timothy grass extract. In one subgroup, the sum of IgE to RAs was lower than the levels of IgE to the natural counterpart (P = 0.013). A lack of subjects in two subgroups did not permit comparison at all. Finally, three subjects with specific IgE to timothy did not show specific IgE to RAs. Out of 276 patients, blood was taken from two different groups of subjects at different time points: November-January and May-July, respectively. The median values were as follows: total IgE = 139 kU/l, IgE to timothy = 10.2 kUA/l; IgE to rPhl p 1 = 3.6 kUA/l, to rPhl p 2 = <0.35 kUA/l, and to rPhl p 5 = 1.1 kUA/l; ECP = 8.25 microg/l; MPO = 303.08 microg/l (before exposure to grass pollen); total IgE = 159 kU/l, IgE to timothy = 57.2 kUA/l; IgE to rPhl p 1 = 22.1 kUA/l, to rPhl p 2 = 5.9 kUA/l, and to rPhl p 5 = 3.9 kUA/l; ECP = 16.21 microg/l; MPO = 413.09 microg/l (during the pollen season). There were significant variations of specific IgE levels between the patients exposed to pollen and the unexposed patients. Moreover, there were statistical differences in the IgE, ECP, and MPO levels in sera before and during the pollen season P<0.035, P<0.017, and P<0.0062, respectively. CONCLUSIONS: The results suggest that RAs allow establishment of the patient's IgE-reactivity profile, encourage future research, and encourage manufacturers to produce further RAs for precise diagnosis and substantially improved immunotherapy injection of only those allergens against which significant amounts of specific IgE are produced.