J ALLERGY CLIN IMMUNOL Abstracts S203 VOLUME 109, NUMBER 1 used as control. These patients only received pharmacological treatment. The study was open and controlled. The main objective of this study was to evaluate efficacy using objective criteria, such as an improvement in specif- ic bronchial hyperreactivity, as confirmed by allergen specific bronchial challenges and a reduction in skin test reactivity. Each patient received a build-up phase of 6 injections in 6 weeks, followed by 5 injections of the maintenance dose, which consisted of 55 micrograms of depigmented, polymerized extract. The total accumulated dose was 370 micrograms. No serious side effects were registered. The Wilcoxon signed rank test was used to compare the results of the specific bronchial challenges at the beginning and after six months of treatment. In the group that received Depigoid ®, there was a significant difference in the amount of native extract needed to produce a drop of 20% in the FEV1 (p = 0.0018). The median allergen potency needed at the beginning was 0.89 HEP (22.5 micrograms) vs. 4.26 HEP (106.5 micrograms) at the end. However, there was no difference (median at the beginning 5.04 vs. 4.11 HEP) in the con- trol group. There was also a significant change in skin test reactivity. In the group that received Depigoid ®, there was a significant increase in the quan- tity of allergen required to produce the same wheal size as the histamine control (p = 0.039). There was no change in the control group. Depigment- ed polymerized extracts of D. pteronyssinus are safe and effective in the treatment of mite allergic asthmatic patients, and provide clinical benefit in the shock organ after 6 months of treatment. Depigmented polymerized extracts of D. pteronyssinus induce clinical protection against a native extract as verified by specific bronchial challenges. 607 Clinical Tolerance of a Modified (Depigmented and Glotaralde- hyde Polymerized) Allergenic Extract of Phleum Pratense Magdalena Lluch*, Ana Novalbos*, Joaquln Sastre*, Maria Jos~ G6mez§, Enrique Ferndndez-Caldas§, Miguel Casanovas§ *Fundaci6n Jimdnez Diaz, Madrid, Spain §CBF Leti S A, Tres Cantos (Madrid), Spain The physicochemical modification of allergens to reduce allergenicity, while retaining immunogenicity, provides a chance for the administration of higher doses of immunotherapy, with a decreased risk of systemic reac- tions. Depigmented and glutaraldehyde polymerized allergens have, at least, a 95% reduction in specific IgE binding capacity, while retaining spe- cific IgG recognition. The objective of this study was to evaluate the clini- cal tolerance of a depigmented and glutaraldehyde polymerized extract of Phleum pratense. The maximum concentration used was the equivalent of chemically modifying 100 times the maximum concentration used for treatment with the native extract. The tolerance was evaluated recording all the side reactions related to immunotherapy and quantified following the recommendations of the EAACI. Twenty-three adult patients, clinically sensitive to the grasses, were entered in a double-blind trial, comparing the safety of modified and unmodified standardized allergenic extracts of Phleum pratense. The study was conducted following Good Clinical Prac- tices and appropriate consent forms were signed. Patients were treated in 9 weekly visits for the build-up phase and 2 weeks of maintenance dose (11 injections per patient). Twelve patients received unmodified allergenic extract. The maximum concentration was 308 micrograms/ml (a potency of 100 HEPL/ml ). Two immediate local reactions were recorded, evaluated as mild. Two immediate systemic reactions were recorded and evaluated as mild. The delayed reactions recorded were 13 local (3 mild, 8 moderate and 2 severe), and 5 systemic (2 evaluated as moderate and 3 as severe). All the systemic reactions were produced by the highest doses. Three patients abandoned the study due to a severe delayed systemic reactions, and I due to moderate immediate systemic reaction (urticaria). Eleven patients received immunotherapy with the modified allergenic extract. The maxi- mum concentration was 2.5 mg of freeze-dried material/ml. A total of 6 immediate local reactions were recorded, being all evaluated as mild. One immediate systemic reaction was recorded and evaluated as mild. The delayed reactions recorded were 12 local (11 mild and 1 moderate) and 2 systemic (1 mild and 1 moderate). These systemic reactions were produced by the highest concentration used. All the patients treated with this modi- fied extract concluded the trial. The modified allergenic preparation of P. pratense demonstrated to be safer than the unmodified extract, even at doses that are significantly higher than the used in normal clinical condi- tions. It confirms a wide therapeutic margin for this chemically modified allergen vaccine. 6~r~Q Expression of Selected Surface Proteins on Peripheral Blood V q , JI Monocytes of Asthma Patients Treated With Specific Immuno- therapy With House Dust Mite Allergen Extracts K Kowal*, A Pampuch*, 1 Zlotnik*, LM Dubuske§, A BodzentaLuzaszyk* *University Medical School, Bialystok, Poland §Immunology Research Institute of New England, Fitchburg, MA Monocytes have been shown to actively participate in airway inflamma- tion in bronchial asthma patients. The aim of this study was to evaluate expression of several surface receptors on peripheral blood monocytes in patients with bronchial asthma who were treated with house dust mite aller- gen extracts. The study was performed on 20 asthma patients mean age 26.7 +/-7.6 years and on 10 healthy subjects mean age 24.5 +/-3.6 years. The patients were selected on the basis of typical clinical history, positive skin prick tests with house dust mite allergens and positive bronchial challenge test with Dermatophagoides pteronyssinus (Dp) extracts. Specific immunotherapy (SIT) was performed using Novo Helisen Depot (Aller- gopharma Germany). The initial dose in all patients was 5 therapeutic units (TE). The dose was doubled every week until maintenance dose (5000 TE) was achieved. Blood was collected before therapy and one week after injec- tion of the first maintenance dose. Flow cytometry analysis was performed on the whole blood samples using labeled monoclonal antibodies against CD14, CD 16 (DAKO, Denmark), CD36 (Serotec, UK) and CD54 (Pharmingen, USA). The results of flow cytometry analysis are presented in the table. No statistically significant difference was found in the absolute number of monocytes between the control group and asthma patients (378+/-103 cells/gl vs 339+/-71 cells/l.tl respectively, p=0.73). A higher percentage of CD 16+, CD36+, CD54+ and CD 14+/CD 16+ monocytes was found in asthma patients, but only for CD54+ (p<0.001 ) and CD 14+CD 16+ (p<0.001) monocytes were the differences statistically significant. There were no significant changes in absolute number ofmonocytes in the periph- eral blood after SIT (339+/-71 cells/t.tl vs 360+/-114 cells/gl, before and after SIT respectively, p=0.5). The percentage of CD36+, CD54+ and CD 14+/CD 16+ monocytes decreased after SIT, although the percentage of CD 14+/CD 16+ monocytes was still significantly higher than in the control group (p=0.01). SIT with house dust mite allergen extracts is associated with significant changes in expression of adhesion molecules on the periph- eral blood monocytes. Significant reduction in CD36+ and CD54+ were noted in this investigation. These changes in monocyte surface receptors may be at least partially responsible for the beneficial effect of SIT in asth- ma patients. CD14+ (%) CD16+ (%) CD36+(%) CD14+/16+ (%) CD54+ (%) Controls 86.4+/-7.2 35.6+/-19.2 74.3+/-16.8 7.5+/-5.8 22.4+/-17.2 Before SIT 88.3+/-4.2 52.4+/-17.5 81.7+/-15.6 46.7+/-11.4" 63.2+/-21.1" After SIT 88.2+/-4.1 49.5+/-12.4 71.4+/-18.7"* 35+/-9.6** 38.5+/-16.7"* *p<0.05 between asthma patients and control. **p<0.05 between asthma patients before and after SIT.