Antifungal activity of terpenes isolated from the Brazilian Caatinga: a review.

Terpenoids, also named terpenes or isoprenoids, are a family of natural products found in all living organisms. Many plants produce terpenoids as secondary metabolites, and these make up a large part of essential oils. One of most important characteristic is that the compounds are volatile, have odor and can be used in a variety of applications in different industrial segments and traditional medicine. Brazil has a rich and diverse flora that can be used as a source of research for obtaining new molecules. Within the Brazilian flora, it is worth mentioning the Caatinga as an exclusively Brazilian biome where plants adapt to a specific series of weather conditions and therefore become a great storehouse of the terpenoid compounds to be described herein. Fungal infections have become increasingly common, and a great demand for new agents with low toxicity and side effects has thus emerged. Scientists must search for new molecules exhibiting antifungal activity to develop new drugs. This review aims to analyze scientific data from the principal published studies describing the use of terpenes and their biological applications as antifungals.

Brugada syndrome trafficking-defective Nav1.5 channels can trap cardiac Kir2.1/2.2 channels.

Cardiac Nav1.5 and Kir2.1-2.3 channels generate Na (INa) and inward rectifier K (IK1) currents, respectively. The functional INa and IK1 interplay is reinforced by the positive and reciprocal modulation between Nav15 and Kir2.1/2.2 channels to strengthen the control of ventricular excitability. Loss-of-function mutations in the SCN5A gene, which encodes Nav1.5 channels, underlie several inherited arrhythmogenic syndromes, including Brugada syndrome (BrS). We investigated whether the presence of BrS-associated mutations alters IK1 density concomitantly with INa density. Results obtained using mouse models of SCN5A haploinsufficiency, and the overexpression of native and mutated Nav1.5 channels in expression systems - rat ventricular cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) - demonstrated that endoplasmic reticulum (ER) trafficking-defective Nav1.5 channels significantly decreased IK1, since they did not positively modulate Kir2.1/2.2 channels. Moreover, Golgi trafficking-defective Nav1.5 mutants produced a dominant negative effect on Kir2.1/2.2 and thus an additional IK1 reduction. Moreover, ER trafficking-defective Nav1.5 channels can be partially rescued by Kir2.1/2.2 channels through an unconventional secretory route that involves Golgi reassembly stacking proteins (GRASPs). Therefore, cardiac excitability would be greatly affected in subjects harboring Nav1.5 mutations with Golgi trafficking defects, since these mutants can concomitantly trap Kir2.1/2.2 channels, thus unexpectedly decreasing IK1 in addition to INa.

Green tea and glycine aid in the recovery of tendinitis of the Achilles tendon of rats.

PURPOSE: Green tea (GT) is widely used due to its anti-inflammatory properties. Previous studies have shown beneficial effects of a glycine diet on the remodeling process in inflamed tendons. Tendinitis is commonly observed in athletes and is of concern to surgeons due to the slowness of the recovery process. Our hypothesis is that GT + a glycine diet may improve tendinitis. AIM OF THE STUDY: To analyze the effect of GT and/or glycine in the diet on tendinitis. MATERIALS AND METHODS: Wistar rats were divided into seven groups (G): control group (C); G1 and G4, tendinitis; G2 and G5, tendinitis supplied with GT; and G3 and G6, tendinitis supplied with GT and a glycine diet for 7 or 21 days, respectively. We performed zymography for metalloproteinase, biochemical, morphological and biomechanics tests. RESULTS: G2, G3 and G5 showed high levels of hydroxyproline in relation to G1, while G4 showed high levels of glycosaminoglycans. High activity of metalloproteinase-2 was detected in G3. The organization of collagen bundles was better in G2 and G3. G5 showed similar birefringence measurements compared with C. G5 withstood a larger load compared with G4. CONCLUSIONS: The presence of metalloproteinase-2 indicates that a tissue is undergoing a remodeling process. High birefringence suggests a better organization of collagen bundles. After 21 days, G5 sustained a high load before rupture, unlike G4. The results suggest that GT + a glycine diet has beneficial effects that aid in the recovery process of the tendon after tendinitis.

Lolium perenne pollen from a polluted city shows high allergenic potency and increased associated enterobacteriaceae counts

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Trends in food availability in Switzerland, 1961-2007.

Trends in food availability in Switzerland were assessed using the Food and Agricultural Organization food balance sheets for the period 1961-2007. A relatively stable trend in the daily caloric supply was found: 3545 kcal/day in 1961 and 3465 kcal/day in 2007. Calories associated with carbohydrates decreased (slope±s.e.: -1.1±0.2 kcal/day/year), namely regarding cereals (-2.9±0.6 kcal/day/year) and fruit (-1.5±0.1 kcal/day/year), while the availability of sugars increased (1.2±0.5 kcal/day/year). In 1961, protein, fat, carbohydrates and alcohol represented 10.6, 33.5, 50.0 and 5.9% of total caloric supply, respectively; in 2007, the values were 10.8, 40.3, 43.7 and 5.2%. In 1961, palm, groundnut and sunflowerseed oil represented 3.4, 30.7 and 5.3% of total vegetable oils, respectively; in 2007, the values were 10.4, 3.7 and 31.6%. We conclude that between 1961 and 2007 total caloric availability remained relatively stable in Switzerland; the health effects of the increased and differing fat availability should be evaluated.

Grass pollen, aeroallergens, and clinical symptoms in Ciudad Real, Spain.

BACKGROUND: In allergic individuals, onset of symptoms is related to atmospheric pollen grain counts and aeroallergen concentrations. However, this relationship is not always clear. OBJECTIVES: To analyze the correlation between grass pollen grain and aeroallergen concentrations in Ciudad Real, Spain, during the year 2004 and establish their association with symptoms in patients with allergic asthma, rhinitis, or both. METHODS: Two different samplers were used to assess allergen exposure: a Burkard spore trap to collect pollen grains and a high-volume air sampler to collect airborne particles. Individual filters were extracted daily in phosphate-buffered serum and analyzed by enzyme-linked immunosorbent assay based on serum containing high titers of specific immunoglobulin (Ig) E to grasses. The study population comprised 27 grass-allergic patients whose symptoms and medication were recorded daily. RESULTS: Grass pollens were detected between April 28 and July 18. There was a positive correlation between pollen grain counts and symptoms (r = 0.62; P > .001). Grass aeroallergens were detected not only during the grass pollination period, but also before and after this period. There was also a very significant correlation between aeroallergen levels and symptoms (r = 0.76; P < .0001). The threshold level for grass pollen was 35 grains/m3. CONCLUSIONS: Grass-related allergenic activity is present throughout the year, demonstrating the existence of aeroallergens outside the pollen season. Symptoms in allergic patients may be related to airborne particle concentrations. This fact should be taken into account in the clinical follow-up and management of allergic patients.

Degree of olive pollen exposure and sensitization patterns. Clinical implications.

BACKGROUND: Very high levels of exposure to olive pollen in the south of Spain lead to differential allergen sensitization profiles. Therefore, new approaches to allergen standardization, diagnosis, and vaccination are necessary. METHODS: Quantification of minor allergens in extracts, component-resolved patient diagnosis, and IgG4 individual allergen responses were used to evaluate new strategies in the management of olive pollen allergy. RESULTS: Allergen variability observed between different olive cultivars can be used to identify suitable allergen sources that can be combined to yield consistent allergen extracts for diagnosis and immunotherapy. Component-resolved diagnosis can provide a better patient classification. IgG4 levels to major allergens increase significantly, whereas specific IgG4 to minor allergens does not seem to increase, at least during the early phases of immunotherapy. CONCLUSION: Patients exposed to extreme olive pollen levels display a different severity of allergy from those exposed to normal levels, which makes it necessary to follow a different clinical approach. The use of component-resolved diagnosis, better standardized allergen extracts, and new efficacy monitoring techniques will lead to a significant improvement in the management of olive allergy disease.

Air pollution and seasonal asthma during the pollen season. A cohort study in Puertollano and Ciudad Real (Spain).

BACKGROUND: Many studies have demonstrated a positive association between air pollutants and emergency visits for asthma. However, few studies have included pollen when analysing this relationship in mild-moderate asthmatic patients. OBJECTIVE: To determine the importance of the pollutants such as ozone (O(3)), particles (PM(10)), nitrogen dioxide (NO(2)) and sulphur dioxide (SO(2)) in the clinical course of mild-moderate pollen-allergic asthmatic patients from two Spanish towns in La Mancha: Puertollano (high pollution levels) and Ciudad Real (low pollution levels). METHODS: We used a Poisson regression model to study a cohort of 137 patients from Puertollano and Ciudad Real during two pollen seasons (2000-2001) and analysed the relationship between air pollutant and pollen levels and daily symptoms, the medication used and peak-flow measurements. RESULTS: The number of asthma symptoms and the mean values of the PM(10), SO(2) and NO(2) levels were higher in Puertollano than in Ciudad Real. In Puertollano, the risk of asthma increased by 6% with a 3-day lag for PM(10), by 8% with a 3-day lag for O(3), by 4% with a 1-day lag for SO(2) and by 15% with a 3-day lag for O(3) when its values exceeded the health threshold (P < 0.05). CONCLUSIONS: The air pollution levels in Puertollano were associated with an increased risk of asthma symptoms in pollen-allergic asthmatic patients com pared with a similar group from Ciudad Real.

Decompensation of pollen-induced asthma in two towns with different pollution levels in La Mancha, Spain.

BACKGROUND: Allergic diseases have increased in industrialized countries and this increase is associated not only with genetic factors but also with lifestyle and environmental factors such as air pollution. Our hypothesis was that asthma in pollen-allergic patients from two towns with very different pollution levels in La Mancha (Spain) could be affected to a very different degree. OBJECTIVE: Our objectives were to assess the risk factors associated with decompensation of pollen-induced asthma in the two towns and to perform a comparison between the patients from Puertollano (high pollution level) and Ciudad Real (low pollution level) with respect to daily symptoms, medication used and peak-flow measurements. METHODS: We designed a cohort study with 137 patients (66 from Puertollano and 71 from Ciudad Real), conducted over 3 years (1999-2001) and including two pollen seasons. The two populations presented similar demographic and clinical characteristics. The variables studied included: area of residence, sex, age, smoking status, asthma symptoms and positive prick tests. Clinical decompensation was monitored by symptoms recorded on diary cards, twice daily peak-flow measurements and the use of protocolized medication. RESULTS: There was a clinically relevant relationship between the place of residence and clinical decompensation. The risk of clinical decompensation in patients from Puertollano was up to three times higher than that of patients in Ciudad Real (P=0.034). Furthermore, patients from Puertollano and patients with moderate asthma presented more rapid decompensation compared with patients from Ciudad Real (P=0.020) and patients with mild asthma (P=0.049). CONCLUSION: In conclusion, pollen-allergic asthmatics in Puertollano present a poorer clinical course and become decompensated earlier than those from Ciudad Real and it could be due to air pollution.

Pollen allergy in Cordoba city: frequency of sensitization and relation with antihistamine sales.

The occurrence of symptoms in pollen allergy patients in urban areas may be affected by local environmental factors such as sources of pollution, natural and ornamental vegetation, local architecture impeding dispersion, etc. The aim of this study was to analyse the frequency of sensitization in pollen allergy patients and the relationship with antihistamine sales. For this study, a large number of clinical records, together with pharmaceutical and pollen data, were collected between 1999 and 2001 in the city of Córdoba, in the south of the Iberian Peninsula. Differences were observed in the symptoms suffered by pollen allergy patients in different areas of the city due to varying local emission of both biological and non-biological particles. Temporal distribution of symptoms over the three study years was influenced by meteorological factors, especially rainfall patterns; higher water supply to plants was associated with increased airborne pollen concentrations. Air pollution might be one of the main factors affecting the distribution of pollen allergy patients within the city. Recent years have seen a worsening of symptoms and increased sensitization to urban species such as plane-trees.

Airborne plane-tree (Platanus hispanica) pollen distribution in the city of Córdoba, South-western Spain, and possible implications on pollen allergy.

Plane-trees are widely grown in Spain as ornaments. This taxon releases large amounts of pollen into the air and this pollen type seems to have proved implications on pollinosis. The aim of this study was to analyse airborne Platanus pollen content in the air of C6rdoba (South-western Spain) over the last 10 years, and its distribution in different areas of the city, as well as to consider possible implications regarding pollen allergies. Results revealed that Platanus pollen concentrations have been at their highest over the last 5 years. Within the city, the lowest pollen concentrations were in Northern areas of the city. Nevertheless, concentrations high enough to be of risk are reached over the whole city. All the patients studied presented symptoms during the Platanus pollen season. We can therefore conclude that plane pollen presents a risk for the whole city although symptoms are more intense and persistent in districts with a higher number of plane-trees. Platanus allergy is a particular problem for city-dwellers, where these trees are commonly used as ornamentals.

Tolerance and short-term effect of a cluster schedule with pollen-extracts quantified in mass-units.

We performed a prospective, multicenter study to assess the tolerance and possible short-term effects of allergen vaccines administered according to a cluster schedule in the months immediately preceding the onset of the pollen season. The study was carried out in eight centers and included 191 patients (children and adults) with allergic respiratory disease due to sensitization to olive tree and/or grass pollen. Of these, 34 patients acted as controls and the remaining patients received immunotherapy administered in the initiation phase according to a cluster schedule of eight doses injected on four visits. After 3 months of treatment, significant differences were found between the two groups in medication consumption (antihistamines in drops and oral formulations: p = 0.045 and p = 0.001, respectively; short-acting beta2-agonist treatments: p = 0.004) and respiratory symptoms (wheezing and coughing: p = 0.035 and 0.014, respectively). The cytokine profile (interleukin [IL]-4, 5, 10 and 2, interferon [IFN-gamma], and tumor necrosis factor [TNF-alpha]) was determined before the start of treatment and at the end of follow-up (4-5 months). Levels of IL-4, 5 and 10 (Th2 profile) decreased while those of IL-2, IFN-gamma, and TNF-alpha (Th1 profile) decreased. These differences were more marked in the active group than in the control group but were not statistically significant. No severe adverse effects were recorded. This study shows that the schedule tested had an acceptable tolerance profile and produced significant changes in symptom and medication scores after a few months of treatment. A double-blind, placebo-controlled study is needed to confirm these results.

Tolerance and short-term effect of a cluster schedule with pollen-extracts quantified in mass-units

We performed a prospective, multicenter study to assess the tolerance and possible short-term effects of allergen vaccines administered according to a cluster schedule in the months immediately preceding the onset of the pollen season. The study was carried out in eight centers and included 191 patients (children and adults) with allergic respiratory disease due to sensitization to olive tree and/or grass pollen. Of these, 34 patients acted as controls and the remaining patients received immunotherapy administered in the initiation phase according to a cluster schedule of eight doses injected on four visits. After 3 months of treatment, significant differences were found between the two groups in medication consumption (antihistamines in drops and oral formulations: p = 0.045 and p = 0.001, respectively; short-acting β2-agonist treatments: p = 0.004) and respiratory symptoms (wheezing and coughing: p = 0.035 and 0.014, respectively). The cytokine profile (interleukin [IL]-4, 5, 10 and 2, interferon [IFN-γ], and tumor necrosis factor [TNF-α]) was determined before the start of treatment and at the end of follow-up (4-5 months). Levels of IL-4, 5 and 10 (Th2 profile) decreased while those of IL-2, IFN-γ, and TNF-α (Th1 profile) decreased. These differences were more marked in the active group than in the control group but were not statistically significant. No severe adverse effects were recorded. This study shows that the schedule tested had an acceptable tolerance profile and produced significant changes in symptom and medication scores after a few months of treatment. A double-blind, placebo-controlled study is needed to confirm these results (AU)

Se ha llevado a cabo un estudio prospectivo y multicéntrico con el objetivo de valorar la tolerancia y posible efecto a corto plazo de las vacunas alergénicas administradas bajo pauta cluster en los meses inmediatamente anteriores al inicio de la estación polínica. El estudio se realizó en 8 centros, incluyéndose un total de 191 pacientes (niños y adultos) con enfermedad alérgica respiratoria por sensibilización a polen de olivo y/o gramíneas. De ellos, 34 actuaron como controles y a los pacientes restantes se les administró inmunoterapia bajo una pauta cluster, en la fase de iniciación, de 8 dosis administradas en 4 visitas. Tras 3 meses de tratamiento, se registraron diferencias significativas entre ambos grupos en el consumo de medicación (antihistamínicos en colirio y orales -p = 0,045 y p = 0,001 respectivamente- y ß2 de corta duración -p = 0,004-) así como en síntomas pulmonares (sibilancias y tos -p = 0,035 y 0,014 respectivamente-). Por otro lado, se determinó el perfil de citocinas (IL-4, 5, 10 y 2, IFN-gamma y TNF-a) de forma previa al inicio del tratamiento y al finalizar el seguimiento (4-5 meses). Se observaron descensos en los niveles de IL-4, 5 y 10 (perfil TH2) y aumento en los valores de IL-2, IFN-gamma y TNF-a (perfil TH1), más marcados en el grupo activo que en el control, sin alcanzar significación estadística. No se registraron efectos adversos severos. Por tanto, podemos observar que la pauta ensayada mostró un adecuado perfil de tolerancia, y tras pocos meses de tratamiento se registraron cambios significativos en la puntuación de síntomas y medicación, siendo necesaria la realización de un estudio con un diseño doble ciego frente a placebo para confirmar los resultados obtenidos (AU)

Immunotherapy with a depigmented, polymerized vaccine of Olea europaea pollen allergens. Significantly reduces specific bronchial and skin test reactivity in sensitized patients after one year of treatment.

Clinical manifestations after the inhalation of Olea europaea pollen are very frequent in Spain. Forty-five patients with a clinical history of asthma and sensitivity to O. europaea pollen were included in a randomized trial to evaluate the safety and the clinical efficacy of immunotherapy with a new chemically modified extract (depigmented and glutaraldehyde-polymerized) of Olea europaea. The study was conducted following good clinical practices and appropriate consent forms were signed. Patients were divided into three groups of 15 individuals: Group A received a maximum concentration of 44 micrograms/ml of the depigmented, polymerized allergen extract (equivalent to 100 HEPL of the native unmodified extract). Group B received 10 times less; Group C did not receive any specific immunotherapy. Any adverse event was recorded to assess safety. Efficacy was evaluated by measuring the amount of allergen needed to elicit a positive response in specific bronchial challenges before and after 12 months of immunotherapy. The treatment schedule consisted of an incremental phase of five injections and a maintenance dosage of 0.5 ml per month. Each patient received a total of 14 injections during this period. No moderate or serious adverse events related to immunotherapy were recorded. At the beginning of the study, no significant differences were observed between the three groups in specific bronchial hyperreactivity (p > 0.05). A significant difference (p < 0.05) was obtained after 12 months. Patients in Group A needed four times more native unmodified allergen than Group C to elicit the same degree of bronchoconstriction. The analysis of the individual groups before and after 12 months of treatment showed that patients in Groups B and C did not improve. Patients in Group A showed a significant improvement (p < 0.05) in specific bronchial hyperreactivity, and at the end of the study needed 5.5 times more native unmodified allergen to obtain the same degree of bronchial response as in the beginning. Depigmented and glutaraldehyde-polymerized vaccines of Olea europaea pollen are very safe for treating patients with asthma and clinical sensitivity to allergens of this pollen. The clinical efficacy of this new allergen vaccine seems to be dose-dependent as shown by specific bronchial challenges as well as by symptom and medication scores. These modified extracts induce protection against unmodified native allergens.

ent-Kaur-16-en-19-oic acid, a KB cells cytotoxic diterpenoid from Elaeoselinum foetidum.

Toxic and cytotoxic activities of the toxic plant Elaeoselinum foetidum (Apiaceae) were evaluated using the brine shrimp toxicity (BST) and KB cell cytotoxicity assays. The active chloroform extract was subjected to a bioactivity-directed fractionation, monitored by the BST assay, that led to the isolation of the diterpenoid ent-kaur-16-en-19-oic acid. This compound was potent against the brine shrimp (LC(50) = 4.8 microg/mL) and KB cells (IC(50) = 1.6 microg/mL).

Perfil asistencial de una pauta agrupada de inmunoterapia con extractos de pólenes absorbidos en hidróxido de aluminio / Assistential profile of a cluster immunotherapy schedule with aluminium hydroxide-absorbed pollen extracts

Fundamento: Las pautas convencionales de iniciación de inmunoterapia se utilizan ampliamente a causa de su seguridad bien conocida, pero no se ha demostrado que constituyan un procedimiento óptimo. En los últimos años se han publicado algunas experiencias que avalan la seguridad de pautas agrupadas. Objetivo: Conocer de forma práctica las ventajas asistenciales de una pauta agrupada para extractos de pólenes estandarizados biológicamente y absorbidos en hidróxido de aluminio, en las condiciones de administración controlada en unidades asistenciales de inmunoterapia. Métodos: 139 pacientes alérgicos a pólenes (Olea, gramíneas, Chenopodium, Plantago) se trataron con Pangramín Depot® (ALK-Abelló, España) mediante una pauta de 4 visitas y 10 dosis, siguiendo las recomendaciones de la EAACI en dos unidades de inmunoterapia de Andalucía. El 72 por ciento de ellos tenían rinoconjuntivitis y asma y el 28 por ciento restante sólo rinoconjuntivitis. Se perseguía alcanzar la dosis máxima recomendada por el fabricante. Resultados: Los pacientes hicieron un total de 585 visitas a las unidades de inmunoterapia y recibieron 1.433 dosis. Seis pacientes (4,3 por ciento) presentaron otras tantas reacciones locales inmediatas (0,4 por ciento de las inyecciones) y un paciente (0,7 por ciento) sufrió una reacción sistémica leve (0,07 por ciento de las dosis) consistente en exantema urticarial.Todos alcanzaron la dosis de mantenimiento propuesta por el fabricante, sin abandonos ni exclusiones. Conclusiones: La pauta analizada ahorra considerablemente visitas, es bien aceptada por los pacientes y muestra un perfil de seguridad que permite su utilización habitual. Se propone la realización de otros trabajos que investiguen su utilidad para mejorar la eficacia y conocer el mecanismo de acción (AU)

Estudio prospectivo de seguridad de inmunoterapia agrupada con extractos acuosos de pólenes / A prospective study of the safety of cluster immunotherapy with aqueous pollen extracts

Fundamento: Si la fase de iniciación de inmunoterapia convencional pudiera acortarse sensiblemente, con un nivel de seguridad similar al de las pautas convencionales actualmente en uso, se obtendrían numerosos beneficios para los pacientes y para el sistema sanitario. En el presente trabajo se monitoriza la seguridad de una pauta agrupada para extractos de pólenes administrados de forma controlada por alergólogos, y se analiza su perfil asistencial. Métodos: En tres Unidades de Inmunoterapia de España se han administrado tratamientos acuosos de Lolium perenne 100 por ciento, Olea europaea 100 por ciento o Lolium-Olea 50 por ciento de dos fabricantes, a 158 pacientes diagnosticados de rinoconjuntivitis y asma, mediante una pauta agrupada de 12 dosis y 4 visitas, siguiendo estrictamente la normativa de la EAACI. Resultados: Se administraron 2.009 dosis en 740 visitas, con un ahorro de 1.783 dosis y 3.052 visitas sobre un programa convencional acuoso. Diez pacientes (6,3 por ciento del total de pacientes) desarrollaron 12 reacciones sistémicas (0,6 por ciento del total de dosis), todas ellas leves, durante los 30 minutos protocolizados de observación. La respuesta al tratamiento ordinario fue excelente. Salvo 3 pacientes que abandonaron por propia iniciativa, los 155 restantes (98 por ciento) alcanzaron la dosis máxima convencional e iniciaron su mantenimiento adecuadamente. Treinta y dos pacientes (20 por ciento del total de pacientes) desarrollaron reacciones locales y 10 (6,3 por ciento del total), reacciones inespecíficas que motivaron algunos retrasos en la pauta. Conclusiones: La inmunoterapia agrupada es una alternativa a la convencional en la administración de rutina en las Unidades de Inmunoterapia. Es necesario ensayar nuevas pautas y conocer el comportamiento de extractos depot de pólenes (AU)

Allergens induce apoptosis in lymphocytes from atopic patients.

Repeated stimulation of immune cells may induce an "activation-induced cell death" (AICD) program. Allergy is characterized by the cyclic activation of allergen-reactive immune cells. To study the effects of allergen stimulation in cell proliferation and apoptosis in atopic subjects, peripheral blood mononuclear cells (PBL) from 40 atopic patients with positive reactivity to the allergens Olea Europaea (OE) and Lollium Perenne (LP) (20 without immunotherapy and 20 with specific immunotherapy) and 10 normal subjects were cultured with the allergens OE and LP. PBL from atopic patients proliferate more vigorously than cells from normal subjects after culture in vitro with both allergens, although PBL from atopic subjects without immunotherapy proliferate more than PBL from atopic subjects with immunotherapy. The study of cell proliferation shows that in atopic patients PBL mainly exhibit the CD4/CD45RO phenotype. This preferential proliferation is more evident in PBL from atopic patients treated without immunotherapy. Cell culture with specific allergens induces apoptosis in PBL from atopic patients. The percentage of apoptosis increased when atopic patients had been previously treated with immunotherapy. In addition to the observed increase in cell proliferation, apoptosis mainly occurs in the CD45RO cells that support the involvement of these cells in allergy. Furthermore, results obtained in cells from immunized patients suggest that an AICD process may partly at least explain the mechanism of action of allergen immunotherapy.