Twenty-eight mite asthmatics were given either mPEG (n 14) or Der.p. (n 14) in a double-blind man... more Twenty-eight mite asthmatics were given either mPEG (n 14) or Der.p. (n 14) in a double-blind manner for one year. Allergen preparations were freeze-dried and reconstituted on the day of diagnostic tests with 0.03% albumin-saline, mPEG with albuminsaline and Der.p. with Al(OH)3 0.2% for IT. Increasing doses with 2-fold increments were given weekly, 50 -40 000 BU, i.e. 300 -270 000 IU. The changes in sensitivity as measured by bronchial (BPT) and conjunctival provocation tests (CPT) and skin prick test (SPT) were evaluated before and after 3 and 12 months of IT. Severe general reactions occured in 3 cases given Der.p., but none given mPEG. The BPT improved (n.s.) and CPT increased (p < 0.05) in mPEG, but not in Der.p.. SPT decreased (p < 0.01) in both groups. Conclusion: IT with mPEG is at least as effective as with Der.p..
... Titre du document / Document title. Clinical assessment of the inflammatory component of asth... more ... Titre du document / Document title. Clinical assessment of the inflammatory component of asthma with emphasis on the eosinophils. Auteur(s) / Author(s). AHLSTEDT S. ; ENANDER J. ; PETERSON C. ; RAK S. ; VENGE P. ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). ...
BackgroundB‐lymphocytes play an important part in the allergic reaction as producers of IgE antib... more BackgroundB‐lymphocytes play an important part in the allergic reaction as producers of IgE antibodies.ObjectiveTo investigate the cell surface expression of the activation antigens CD23, CD40 and HLA‐DR on B‐lymphocytes in birch pollen allergic patients before and during birch pollen season and to study the effect of immunotherapy.MethodsThe study included 24 birch pollen allergic patients half of whom were treated with immunotherapy against birch pollen before the start of the season. Eleven of the 24 patients had asthma. Blood samples were taken and lung function was registered before the season began and before the immunotherapy treatment in January to February and during the season in May. The relative number of B‐lymphocytes (CD19+) of the lymphocyte population and the cell surface expression of CD23, CD40 and HLA‐DR on B‐lymphocytes was measured by the use of flow cytometry.ResultsIn the control group of patients the relative number and concentration of B‐lymphocytes, the cel...
Background: Reeent in vitro findings show that glucoeorticoids in combination with IL-4 can induc... more Background: Reeent in vitro findings show that glucoeorticoids in combination with IL-4 can induce the synthesis of IgE, indicating that glucocorticoids may promote allergy. Objective: A double-blind, placebo-controlled study was performed to evaluate the effect of an intranasal glucocorticoid an the levels of birch pollen-specific IgE antibodies in serum from patients with allergic rhinitis. Methods: Eighteen patients with allergie rhf:nitis received treatment with an intranasal glucocorticoid (beclomethasone dipropionate, 400 p~g/day) or placebo for 5 weeks, startiug from the beginning of the birch pollen season. Blood samples for antibirch IgE evaluation were taken before treatment was initiated and at 2 and 5 weeks after the beginning of the study. Results: The beclomethasone group (n = 9) had significantly Iower symptom scores when compared with the placebo group (n = 9) (0.86 _+ 0.26 vs 2.79 -+ 0.76, p value = 0.01). Both the treatment group and the placebo group showed a tren...
American Journal of Respiratory Cell and Molecular Biology, 1993
We have investigated the phenotype of interleukin-5 (IL-5) mRNA+ cells in the nasal mucosa of sub... more We have investigated the phenotype of interleukin-5 (IL-5) mRNA+ cells in the nasal mucosa of subjects with allergic rhinitis. Serial cryostat sections were cut from paraformaldehyde-fixed snap-frozen nasal biopsies from six patients, before and 24 h after local allergen provocation with grass pollen. Immunocytochemistry (APAAP) was followed by in situ hybridization on the same sections. For immunocytochemistry, antibodies against CD3, tryptase, and major basic protein (MBP) were used to identify T cells, mast cells, and eosinophils, respectively. Hybridization studies were performed using a Digoxigenin-labeled IL-5 riboprobe. Nitroblue tetrazolium (NBT) and X-phosphate-5-bromo-4-chloro-3- indoly phosphate (BCIP) served as chromogens to detect hybridized IL-5 mRNA signals. The majority of IL-5 mRNA+ cells were CD3+ (83.2%), whereas the remainder were either tryptase+ (11.3%) or MBP+ (5.4%). In contrast, only a few IL-5 mRNA+ cells were observed in nasal biopsies before challenge, all of which were co-localized to CD3+ cells. These results indicate that CD3+ cells are the principal cellular source of IL-5 transcripts in the nasal mucosa 24 h after allergen-induced late-phase nasal responses.
We have studied the influence of substance P (SP) on the proliferative response of concanavalin A... more We have studied the influence of substance P (SP) on the proliferative response of concanavalin A (ConA)-activated peripheral blood lymphocytes from 16 birch pollen-allergic patients, sampled before and during the pollen season, and from 15 normal individuals. The median response to ConA 3 micrograms/ml in the presence of SP 10(-11)-10(-6) M, was in most instances within +/- 10% of the control value for cells from both healthy and atopic individuals. However, the individual differences were considerable. Analysis of the proliferative responses to ConA of the cells from the allergic patients sampled before and during season, revealed higher responses in the presence of 10(-6) than of 10(-7) M SP. This was in contrast to the findings in the normal individuals: only half of their cells showed such increased responses. This difference in response frequency was statistically significant between allergic patients before season and normal individuals (P less than 0.05) and between allergic patients during season and normal individuals (P less than 0.01). The difference in proliferation rate in the SP concentration interval, 10(-6) to 10(-7) M, for the cells from allergic patients, sampled both before and during season, was significantly different from the cells from healthy individuals (P less than 0.03 and P less than 0.001 respectively). The cells sampled from four allergic subjects during the birch pollen season showed a more profoundly decreased response to ConA in the presence of SP 10(-8) M, compared with their cells sampled before season. Such responses were never seen with cells sampled before season and with cells from normal individuals. The results suggest an involvement of SP in the immunoregulation, particularly in patients exhibiting allergic reactions to birch pollen.
Mast cells are known to accumulate in tissue during allergic inflammation. However, the chemotaxi... more Mast cells are known to accumulate in tissue during allergic inflammation. However, the chemotaxins responsible are undefined. Using a modified Boyden chamber and the human mast-cell line HMC-1, we first identified mast-cell chemotactic activity in nasal lavage fluid collected before the pollen season after allergen provocation of allergic patients (n=29) (mean migratory response compared to medium control was 121%, range 85-198%). Mast-cell chemotactic activity was also detected in lavage fluid collected after allergen provocation at the end of a Swedish birch-pollen season from three different treatment groups: topical steroid treatment with budesonide; the topical antihistamine, levocabastine; and placebo. There was no significant difference in mast-cell chemotactic activity between nasal lavage fluid collected from the placebo group (mean=102%), the budesonide-treated group (mean=114%), or the levocabastine group (mean=125%). Stem cell factor (SCF), a known mast-cell chemotaxin, was present in the nasal lavage fluids from all three groups, and correlated with the mast-cell chemotactic activity (r=0.67, P&lt;0.01). The mast-cell chemotactic activity was inhibited (range 5-100%) in some, but not all, nasal lavage fluids by a polyclonal antibody directed against SCF. This report describes the presence of mast-cell chemotactic activity in nasal lavage fluid during an allergic reaction. These findings show that SCF may play a pivotal role in the recruitment of mast cells in allergic rhinitis.
Immunotherapy. Designing the future of allergen specific immunotherapy in the foreseeable future,... more Immunotherapy. Designing the future of allergen specific immunotherapy in the foreseeable future, it is imperative that steps are taken to develop, strengthen and optimize preventive and Calderon et al. Clinical and Translational Allergy 2012, 2:20
Background: Previous clinical trials with birch pollen subcutaneous immunotherapy have been condu... more Background: Previous clinical trials with birch pollen subcutaneous immunotherapy have been conducted over a 1-to 2-year treatment period and involved mostly a single geographic location. Objective: This study (EudraCT-Number: 2005-000025-35) intended to evaluate the effect of subcutaneous immunotherapy with high-dose hypoallergenic birch pollen allergoid in patients with confirmed moderate to severe seasonal allergic rhinitis/ rhinoconjunctivitis over a 3-year course in 19 European centres. Methods: Adults with confirmed birch pollen allergy (n = 253) were randomized to preseasonal placebo (n = 129) or active treatment (n = 124). Primary endpoint was change in Symptom Medication Score after 2 years treatment (2007). Results: The change in Symptom Medication Score of active-vs placebo-treated patients for the Full Analysis Set (n = 227, 15.2% reduction, P = 0.0710) and Per-Protocol Set (n = 216, 16.7% reduction, P = 0.0523) showed a positive trend, although significance was not achieved. The primary endpoint, assessed in 2007, coincided with the lowest pollination during the study period. In a subgroup analysis of patients in the northeastern region (n = 102), where birch is the major tree and consequently patients' exposure is higher, changes in Symptom Medication Score (32.7% reduction, P = 0.0034) and median number of well days (P = 0.0232) were highly significant in favour of the active group. During the open-label third year of treatment, the mean Symptom Medication Score of active-treated patients was further reduced despite an increased pollen count. Subcutaneous immunotherapy was well tolerated and consistent with the known safety profile. Conclusions and clinical relevance: Although the primary endpoint was not reached for the Full Analysis Set, a significant and clinically relevant effect on Symptom Medication Score was clearly demonstrated for the subgroup of patients in the northeastern region of Europe, where birch is the predominant tree species.
Background: The distribution of Pooideae species varies across Europe. Especially, Timothy is les... more Background: The distribution of Pooideae species varies across Europe. Especially, Timothy is less represented in Southern than in Northern Europe. Since allergenic cross-reactivity between pollens from different grasses is only partial, grass pollen-allergic patients are expected to display different sensitization profiles, with specific IgE directed against different combinations of allergenic epitopes, depending on their living places in Europe and the grasses they are exposed to. In this context, this study aimed at comparing two tablets commercially available for allergy immunotherapy, namely a 5-grass (Cocksfoot, Meadow-grass, Rye-grass, Sweet vernal-grass and Timothy) and a 1-grass (Timothy) pollen tablets, for their ability to represent the sensitization profiles of patients, depending on whether they live in Southern or Northern Europe. Methods: Sera were collected from adult patients living in Spain (n = 19) and Sweden (n = 22). Tablets were compared for their ability to inhibit the binding of patient serum IgE to pollen allergens from twelve grasses commonly distributed throughout Europe, as determined by the areas under the curves obtained by ELISA-inhibition. Tablets were adjusted to an equivalent allergenic activity, based on the CBER/FDA bioequivalent allergy unit. Results: Inhibition of the IgE binding to pollen allergens from twelve grasses was significantly stronger with the 5-grass than with the 1-grass pollen tablet (p < 0.0001), regardless of whether patients were considered as a whole or by geographical area. This difference between tablets was significantly greater for Southern than Northern European patients (p < 0.05). Conclusions: Compared to the 1-grass tablet, the 5-grass tablet generally covers better the sensitization profiles of European patients, especially patients from Southern Europe, in principle less exposed to pollen from Timothy than from other grasses. The 5-grass tablet is therefore expected to elicit larger spectra of blocking antibodies, which might have implications in light of the generally accepted mechanisms of allergy immunotherapy.
Resume Introduction La quasi-totalite des patients allergiques au pollen de bouleau presente des ... more Resume Introduction La quasi-totalite des patients allergiques au pollen de bouleau presente des IgE dirigees contre l’allergene Bet v 1, la majorite reagissant exclusivement contre cet allergene pertinent. Dans ce contexte, nous avons produit et formule l’allergene Bet v 1.0101 recombinant (rBet v 1) sous forme de comprimes, a des fins d’immunotherapie allergenique. Methodes L’allergene rBet v 1 exprime dans Escherichia coli a l’echelle 1500 L a ete caracterise par chromatographie liquide, spectrometrie de masse (MS) et diffraction aux rayons X . Cet allergene de qualite pharmaceutique (BPF) a ensuite ete evalue lors d’une etude clinique de phase II multicentrique, randomisee, en double aveugle, controlee contre placebo, conduite sur une cohorte de 483 patients europeens souffrant de rhino-conjonctivite allergique au pollen de bouleau. Resultats L’integralite de la sequence de rBet v 1 a ete confirmee en MS/MS. Neanmoins, la detection en MS de formes non-matures et de substitutions d’acides amines a necessite des optimisations successives des conditions de cultures cellulaires afin de reduire la concentration de ces impuretes. Le procede de purification a ete modifie de facon a exclure des proteines de la cellule hote identifiees en MS. Ce procede a egalement ete optimise afin d’eliminer un metabolite d’E. coli piege dans la cavite hydrophobe de Bet v 1. De plus, nous avons adapte les conditions de stockage de l’allergene afin de limiter son oxydation. Finalement, l’evaluation clinique a demontre que rBet v 1 administre par voie sublinguale presente une innocuite et une efficacite similaires a celles observees avec un extrait de pollen de bouleau. Conclusion Nous avons produit l’allergene rBet v 1 de qualite pharmaceutique a l’echelle industrielle. La caracterisation structurale detaillee a ete decisive afin d’accompagner les developpements et optimisations des procedes d’expression et de purification de cette molecule. Une formulation en comprimes a permis de realiser la premiere etude clinique de phase II par voie sublinguale avec un allergene recombinant et de confirmer sa bonne tolerance et son efficacite pour les patients souffrant d’une rhino-conjonctivite allergique au pollen de bouleau.
Twenty-eight mite asthmatics were given either mPEG (n 14) or Der.p. (n 14) in a double-blind man... more Twenty-eight mite asthmatics were given either mPEG (n 14) or Der.p. (n 14) in a double-blind manner for one year. Allergen preparations were freeze-dried and reconstituted on the day of diagnostic tests with 0.03% albumin-saline, mPEG with albuminsaline and Der.p. with Al(OH)3 0.2% for IT. Increasing doses with 2-fold increments were given weekly, 50 -40 000 BU, i.e. 300 -270 000 IU. The changes in sensitivity as measured by bronchial (BPT) and conjunctival provocation tests (CPT) and skin prick test (SPT) were evaluated before and after 3 and 12 months of IT. Severe general reactions occured in 3 cases given Der.p., but none given mPEG. The BPT improved (n.s.) and CPT increased (p < 0.05) in mPEG, but not in Der.p.. SPT decreased (p < 0.01) in both groups. Conclusion: IT with mPEG is at least as effective as with Der.p..
... Titre du document / Document title. Clinical assessment of the inflammatory component of asth... more ... Titre du document / Document title. Clinical assessment of the inflammatory component of asthma with emphasis on the eosinophils. Auteur(s) / Author(s). AHLSTEDT S. ; ENANDER J. ; PETERSON C. ; RAK S. ; VENGE P. ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). ...
BackgroundB‐lymphocytes play an important part in the allergic reaction as producers of IgE antib... more BackgroundB‐lymphocytes play an important part in the allergic reaction as producers of IgE antibodies.ObjectiveTo investigate the cell surface expression of the activation antigens CD23, CD40 and HLA‐DR on B‐lymphocytes in birch pollen allergic patients before and during birch pollen season and to study the effect of immunotherapy.MethodsThe study included 24 birch pollen allergic patients half of whom were treated with immunotherapy against birch pollen before the start of the season. Eleven of the 24 patients had asthma. Blood samples were taken and lung function was registered before the season began and before the immunotherapy treatment in January to February and during the season in May. The relative number of B‐lymphocytes (CD19+) of the lymphocyte population and the cell surface expression of CD23, CD40 and HLA‐DR on B‐lymphocytes was measured by the use of flow cytometry.ResultsIn the control group of patients the relative number and concentration of B‐lymphocytes, the cel...
Background: Reeent in vitro findings show that glucoeorticoids in combination with IL-4 can induc... more Background: Reeent in vitro findings show that glucoeorticoids in combination with IL-4 can induce the synthesis of IgE, indicating that glucocorticoids may promote allergy. Objective: A double-blind, placebo-controlled study was performed to evaluate the effect of an intranasal glucocorticoid an the levels of birch pollen-specific IgE antibodies in serum from patients with allergic rhinitis. Methods: Eighteen patients with allergie rhf:nitis received treatment with an intranasal glucocorticoid (beclomethasone dipropionate, 400 p~g/day) or placebo for 5 weeks, startiug from the beginning of the birch pollen season. Blood samples for antibirch IgE evaluation were taken before treatment was initiated and at 2 and 5 weeks after the beginning of the study. Results: The beclomethasone group (n = 9) had significantly Iower symptom scores when compared with the placebo group (n = 9) (0.86 _+ 0.26 vs 2.79 -+ 0.76, p value = 0.01). Both the treatment group and the placebo group showed a tren...
American Journal of Respiratory Cell and Molecular Biology, 1993
We have investigated the phenotype of interleukin-5 (IL-5) mRNA+ cells in the nasal mucosa of sub... more We have investigated the phenotype of interleukin-5 (IL-5) mRNA+ cells in the nasal mucosa of subjects with allergic rhinitis. Serial cryostat sections were cut from paraformaldehyde-fixed snap-frozen nasal biopsies from six patients, before and 24 h after local allergen provocation with grass pollen. Immunocytochemistry (APAAP) was followed by in situ hybridization on the same sections. For immunocytochemistry, antibodies against CD3, tryptase, and major basic protein (MBP) were used to identify T cells, mast cells, and eosinophils, respectively. Hybridization studies were performed using a Digoxigenin-labeled IL-5 riboprobe. Nitroblue tetrazolium (NBT) and X-phosphate-5-bromo-4-chloro-3- indoly phosphate (BCIP) served as chromogens to detect hybridized IL-5 mRNA signals. The majority of IL-5 mRNA+ cells were CD3+ (83.2%), whereas the remainder were either tryptase+ (11.3%) or MBP+ (5.4%). In contrast, only a few IL-5 mRNA+ cells were observed in nasal biopsies before challenge, all of which were co-localized to CD3+ cells. These results indicate that CD3+ cells are the principal cellular source of IL-5 transcripts in the nasal mucosa 24 h after allergen-induced late-phase nasal responses.
We have studied the influence of substance P (SP) on the proliferative response of concanavalin A... more We have studied the influence of substance P (SP) on the proliferative response of concanavalin A (ConA)-activated peripheral blood lymphocytes from 16 birch pollen-allergic patients, sampled before and during the pollen season, and from 15 normal individuals. The median response to ConA 3 micrograms/ml in the presence of SP 10(-11)-10(-6) M, was in most instances within +/- 10% of the control value for cells from both healthy and atopic individuals. However, the individual differences were considerable. Analysis of the proliferative responses to ConA of the cells from the allergic patients sampled before and during season, revealed higher responses in the presence of 10(-6) than of 10(-7) M SP. This was in contrast to the findings in the normal individuals: only half of their cells showed such increased responses. This difference in response frequency was statistically significant between allergic patients before season and normal individuals (P less than 0.05) and between allergic patients during season and normal individuals (P less than 0.01). The difference in proliferation rate in the SP concentration interval, 10(-6) to 10(-7) M, for the cells from allergic patients, sampled both before and during season, was significantly different from the cells from healthy individuals (P less than 0.03 and P less than 0.001 respectively). The cells sampled from four allergic subjects during the birch pollen season showed a more profoundly decreased response to ConA in the presence of SP 10(-8) M, compared with their cells sampled before season. Such responses were never seen with cells sampled before season and with cells from normal individuals. The results suggest an involvement of SP in the immunoregulation, particularly in patients exhibiting allergic reactions to birch pollen.
Mast cells are known to accumulate in tissue during allergic inflammation. However, the chemotaxi... more Mast cells are known to accumulate in tissue during allergic inflammation. However, the chemotaxins responsible are undefined. Using a modified Boyden chamber and the human mast-cell line HMC-1, we first identified mast-cell chemotactic activity in nasal lavage fluid collected before the pollen season after allergen provocation of allergic patients (n=29) (mean migratory response compared to medium control was 121%, range 85-198%). Mast-cell chemotactic activity was also detected in lavage fluid collected after allergen provocation at the end of a Swedish birch-pollen season from three different treatment groups: topical steroid treatment with budesonide; the topical antihistamine, levocabastine; and placebo. There was no significant difference in mast-cell chemotactic activity between nasal lavage fluid collected from the placebo group (mean=102%), the budesonide-treated group (mean=114%), or the levocabastine group (mean=125%). Stem cell factor (SCF), a known mast-cell chemotaxin, was present in the nasal lavage fluids from all three groups, and correlated with the mast-cell chemotactic activity (r=0.67, P&lt;0.01). The mast-cell chemotactic activity was inhibited (range 5-100%) in some, but not all, nasal lavage fluids by a polyclonal antibody directed against SCF. This report describes the presence of mast-cell chemotactic activity in nasal lavage fluid during an allergic reaction. These findings show that SCF may play a pivotal role in the recruitment of mast cells in allergic rhinitis.
Immunotherapy. Designing the future of allergen specific immunotherapy in the foreseeable future,... more Immunotherapy. Designing the future of allergen specific immunotherapy in the foreseeable future, it is imperative that steps are taken to develop, strengthen and optimize preventive and Calderon et al. Clinical and Translational Allergy 2012, 2:20
Background: Previous clinical trials with birch pollen subcutaneous immunotherapy have been condu... more Background: Previous clinical trials with birch pollen subcutaneous immunotherapy have been conducted over a 1-to 2-year treatment period and involved mostly a single geographic location. Objective: This study (EudraCT-Number: 2005-000025-35) intended to evaluate the effect of subcutaneous immunotherapy with high-dose hypoallergenic birch pollen allergoid in patients with confirmed moderate to severe seasonal allergic rhinitis/ rhinoconjunctivitis over a 3-year course in 19 European centres. Methods: Adults with confirmed birch pollen allergy (n = 253) were randomized to preseasonal placebo (n = 129) or active treatment (n = 124). Primary endpoint was change in Symptom Medication Score after 2 years treatment (2007). Results: The change in Symptom Medication Score of active-vs placebo-treated patients for the Full Analysis Set (n = 227, 15.2% reduction, P = 0.0710) and Per-Protocol Set (n = 216, 16.7% reduction, P = 0.0523) showed a positive trend, although significance was not achieved. The primary endpoint, assessed in 2007, coincided with the lowest pollination during the study period. In a subgroup analysis of patients in the northeastern region (n = 102), where birch is the major tree and consequently patients' exposure is higher, changes in Symptom Medication Score (32.7% reduction, P = 0.0034) and median number of well days (P = 0.0232) were highly significant in favour of the active group. During the open-label third year of treatment, the mean Symptom Medication Score of active-treated patients was further reduced despite an increased pollen count. Subcutaneous immunotherapy was well tolerated and consistent with the known safety profile. Conclusions and clinical relevance: Although the primary endpoint was not reached for the Full Analysis Set, a significant and clinically relevant effect on Symptom Medication Score was clearly demonstrated for the subgroup of patients in the northeastern region of Europe, where birch is the predominant tree species.
Background: The distribution of Pooideae species varies across Europe. Especially, Timothy is les... more Background: The distribution of Pooideae species varies across Europe. Especially, Timothy is less represented in Southern than in Northern Europe. Since allergenic cross-reactivity between pollens from different grasses is only partial, grass pollen-allergic patients are expected to display different sensitization profiles, with specific IgE directed against different combinations of allergenic epitopes, depending on their living places in Europe and the grasses they are exposed to. In this context, this study aimed at comparing two tablets commercially available for allergy immunotherapy, namely a 5-grass (Cocksfoot, Meadow-grass, Rye-grass, Sweet vernal-grass and Timothy) and a 1-grass (Timothy) pollen tablets, for their ability to represent the sensitization profiles of patients, depending on whether they live in Southern or Northern Europe. Methods: Sera were collected from adult patients living in Spain (n = 19) and Sweden (n = 22). Tablets were compared for their ability to inhibit the binding of patient serum IgE to pollen allergens from twelve grasses commonly distributed throughout Europe, as determined by the areas under the curves obtained by ELISA-inhibition. Tablets were adjusted to an equivalent allergenic activity, based on the CBER/FDA bioequivalent allergy unit. Results: Inhibition of the IgE binding to pollen allergens from twelve grasses was significantly stronger with the 5-grass than with the 1-grass pollen tablet (p < 0.0001), regardless of whether patients were considered as a whole or by geographical area. This difference between tablets was significantly greater for Southern than Northern European patients (p < 0.05). Conclusions: Compared to the 1-grass tablet, the 5-grass tablet generally covers better the sensitization profiles of European patients, especially patients from Southern Europe, in principle less exposed to pollen from Timothy than from other grasses. The 5-grass tablet is therefore expected to elicit larger spectra of blocking antibodies, which might have implications in light of the generally accepted mechanisms of allergy immunotherapy.
Resume Introduction La quasi-totalite des patients allergiques au pollen de bouleau presente des ... more Resume Introduction La quasi-totalite des patients allergiques au pollen de bouleau presente des IgE dirigees contre l’allergene Bet v 1, la majorite reagissant exclusivement contre cet allergene pertinent. Dans ce contexte, nous avons produit et formule l’allergene Bet v 1.0101 recombinant (rBet v 1) sous forme de comprimes, a des fins d’immunotherapie allergenique. Methodes L’allergene rBet v 1 exprime dans Escherichia coli a l’echelle 1500 L a ete caracterise par chromatographie liquide, spectrometrie de masse (MS) et diffraction aux rayons X . Cet allergene de qualite pharmaceutique (BPF) a ensuite ete evalue lors d’une etude clinique de phase II multicentrique, randomisee, en double aveugle, controlee contre placebo, conduite sur une cohorte de 483 patients europeens souffrant de rhino-conjonctivite allergique au pollen de bouleau. Resultats L’integralite de la sequence de rBet v 1 a ete confirmee en MS/MS. Neanmoins, la detection en MS de formes non-matures et de substitutions d’acides amines a necessite des optimisations successives des conditions de cultures cellulaires afin de reduire la concentration de ces impuretes. Le procede de purification a ete modifie de facon a exclure des proteines de la cellule hote identifiees en MS. Ce procede a egalement ete optimise afin d’eliminer un metabolite d’E. coli piege dans la cavite hydrophobe de Bet v 1. De plus, nous avons adapte les conditions de stockage de l’allergene afin de limiter son oxydation. Finalement, l’evaluation clinique a demontre que rBet v 1 administre par voie sublinguale presente une innocuite et une efficacite similaires a celles observees avec un extrait de pollen de bouleau. Conclusion Nous avons produit l’allergene rBet v 1 de qualite pharmaceutique a l’echelle industrielle. La caracterisation structurale detaillee a ete decisive afin d’accompagner les developpements et optimisations des procedes d’expression et de purification de cette molecule. Une formulation en comprimes a permis de realiser la premiere etude clinique de phase II par voie sublinguale avec un allergene recombinant et de confirmer sa bonne tolerance et son efficacite pour les patients souffrant d’une rhino-conjonctivite allergique au pollen de bouleau.
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