Atopy patch test (APT) in the diagnosis of food allergy in children with atopic dermatitis / Teste de contato atópico (TCA) no diagnóstico de alergia alimentar em crianças com dermatite atópica

BACKGROUND: Atopic Dermatitis is a chronic inflammatory skin disease. Food allergens are important in the pathogenesis in 1/3 of the cases. Several mechanisms are involved in the pathogenesis of Atopic Dermatitis. Immediate reactions are identified by both measurement of specific IgE and skin prick test. Atopy Patch Test seems to be relevant in the investigation of patients with suspected delayed-type reactions. OBJECTIVES: To evaluate the standardization of this method concerning allergen concentration, occlusion time and interpretation, and determine the specificity and sensitivity of the Atopy Patch Test according to the skin prick test and specific IgE levels in food allergy diagnosis in children with Atopic Dermatitis. METHODS: Seventy-two children, aged 2-12 years were selected and followed at the allergy clinic of the Hospital São Zacharias. Skin prick test, specific IgE and food Atopy Patch Test (cow's milk, egg, soy and wheat) were carried out. Three groups were submitted to the Atopy Patch Test: (1) Atopic Dermatitis with or without Rhinitis and Asthma; (2) Rhinitis and or Asthma without AD; (3) Healthy individuals. RESULTS: In group 1, 40% of the patients presented positive reactions. The longer the exposure time (48h and 72h), the higher the sensitivity. In group 2, the test was more specific than sensitive for all the extracts, with increased sensitivity the longer the time of exposure (72h). In group 3, 8.3% presented positive tests. CONCLUSION: APT evidenced a great diagnostic value in late-phase reactions to food, with high specificity. It showed to be a specific and reliable tool in comparison with the healthy group's results.

FUNDAMENTOS: A Dermatite Atópica é uma doença inflamatória crônica da pele. Os alimentos são importantes na patogênese da doença em 1/3 dos casos. Diversos mecanismos estão envolvidos na fisiopatogenia da dermatite Atópica. As reações imediatas são identificadas pela dosagem de IgE específica e teste de puntura. O teste de contato atópico parece ter relevância na investigação de pacientes com suspeita de reação tardia. OBJETIVOS: Avaliar a padronização do método com relação à concentração do alérgeno, tempo de oclusão e de interpretação; e determinar a especificidade e a sensibilidade do teste de contato atópico em relação ao teste de puntura e a dosagem de IgE específica, no diagnóstico de alergia alimentar em crianças com dermatite Atópica. MÉTODOS: Setenta e duas crianças com 2 a 12 anos foram submetidas a teste de puntura e dosagem de IgE específicas para alimentos (leite de vaca, ovo, soja, trigo). O teste de contato atópico foi aplicado em 3 grupos: (1) Dermatite Atópica com ou sem Rinite e Asma; (2) Rinite e ou Asma sem Dermatite Atópica; (3) Saudáveis. RESULTADOS: No grupo 1, 40% dos pacientes apresentaram reação positiva. Quanto maior o tempo de exposição, maior foi a sensibilidade. No grupo 2, o teste foi mais específico que sensível para todos os extratos; com aumento da sensibilidade com maior tempo de exposição (72h). No grupo 3, 8.3% apresentaram testes positivos. CONCLUSÃO: O teste de contato atópico mostrou ter valor diagnóstico em relação às reações de fase tardia a alimentos, com elevada especificidade. Mostrou-se um teste específico e confiável ao comparar com os resultados do grupo controle.

Teste de desencadeamento alimentar oral na confirmação diagnóstica da alergia à proteína do leite de vaca / Oral food challenge test to confirm the diagnosis of cow's milk allergy

OBJETIVO: Verificar a prevalência de alergia à proteína do leite de vaca em crianças com sintomas atribuídos à ingestão do leite de vaca. MÉTODOS: Foram estudadas 65 crianças com sintomas atribuídos à ingestão do leite de vaca. A definição diagnóstica ocorreu após teste de desencadeamento alimentar oral aberto, realizado no mínimo 15 dias após dieta de exclusão e ausência de sintomas, com período de observação de até 4 semanas após o teste. Considerou-se caso (alergia à proteína do leite de vaca positiva; n = 35) criança com reaparecimento do sintoma que motivou a realização do teste, e comparação (alergia à proteína do leite de vaca negativa; n = 30) aquela sem sintomas após o período de observação do teste. RESULTADOS: A mediana de idade foi 5 meses (P 25-75 por cento 2-9 meses) no grupo caso e 7 meses (P 25-75 por cento 4-11 meses) no grupo comparação (p = 0,05). O teste não confirmou alergia à proteína do leite de vaca em 46,8 por cento dos pacientes com sintomas atribuídos à ingestão de leite de vaca. Reação tardia ocorreu em 77,1 por cento (27/35) dos casos com teste positivo, sendo 18/27 na primeira, 3/27 na segunda e 6/27 na terceira semana de observação. Encontrou-se associação estatística significante entre manifestações cutâneas e teste positivo (p = 0,04), mas não com sintomas digestivos e respiratórios. CONCLUSÃO: Os resultados corroboram a necessidade do teste de desencadeamento alimentar oral para determinar os pacientes que realmente têm alergia à proteína do leite de vaca e se beneficiarão com dieta de exclusão de leite de vaca.

OBJECTIVE: To determine the prevalence of cow's milk protein allergy in children with symptoms attributed to cow's milk intake. METHODS: Sixty-five children with symptoms attributed to cow's milk intake were studied. Diagnosis was established after an open oral food challenge test carried out at least 15 days after an elimination diet and absence of symptoms, with a follow-up period of up to 4 weeks after the test. The children who remained asymptomatic after this period were considered negative for cow's milk protein allergy (n = 30), while those whose symptoms reappeared were considered positive (n = 35). RESULTS: The median age was 5 months (P 25-75 percent 2-9 months) in the case group and 7 months (P 25-75 percent 4-11 months) in the comparison group (p = 0.05). The test did not confirm cow's milk protein allergy in 46.8 percent of the patients with symptoms attributed to cow's milk intake. A delayed reaction occurred in 77.1 percent (27/35) of the cases testing positive, 18/27 in the first week, 3/27 in the second week, and 6/27 in the third week of follow-up. A statistically significant association was found between cutaneous manifestations and positive test result (p = 0.04). However, there was no association with digestive and respiratory symptoms. CONCLUSION: Our results confirm the need of an oral food challenge test to determine which patients really have cow's milk protein allergy and may therefore benefit from a diet free of cow's milk.

Three suitable antigens for delayed-type hypersensitivity skin testing in a tropical country like Thailand.

Delayed type hypersensitivity (DTH) skin test is a standard tool to assess in vivo cell-mediated immunity. Mantoux method using 4-5 common recalled antigens is recommended. However, not all antigens are widely available and appropriate antigens for tropical countries are not known. The objective of this study is to investigate what and how many antigens should be included in the DTH testing panel that suitable for Thailand and may be for this region. The DTH skin tests were done by Mantoux method in a double blinded fashion. Average induration size of > or = 5 mm defined as a positive test. Antigens included purified protein derivative (PPD), Candida albicans, tetanus toxoid (TT), Trichophyton mentagrophytes and hepatitis B vaccine (HBV). The negative control was normal saline. Of 95 healthy subjects, all showed DTH positive to > or = 1 antigen. The positivity to C. albicans, tetanus toxoid, PPD, T. mentagrophytes, and HBV was 92.6%, 83.2%, 82.1%, 50.5%, and 5.3%, respectively. When three antigens: PPD, TT and C. albicans were analyzed, 100% of subjects showed a positive response to > or = 1 antigen and 96.8% showed a positive response to > or = 2 antigens. When only PPD and TT were analyzed, 100% of subjects showed > or = 1 antigen positive and 68.4% showed both antigens positive. C. albicans antigen at 1:100 was associated with a high incidence of fever (2/20) and large local reaction (7/20), 1:500 was found to be the optimal concentration. PPD, TT and C. albicans are suitable to be included in a DTH skin testing in a tropical country like Thailand. However, in a setting where C. albicans extract is not available, testing with only two antigens of PPD and tetanus toxoid may be an alternative, but with a lower sensitivity.

Delayed hypersensitivity skin testing in the Thai adult population.

OBJECTIVE: The present study was carried out in healthy Thai subjects to determine the types and concentrations of standard antigens used in delayed-type hypersensitivity (DTH) skin testing as an evaluation of cell-mediated immunity. MATERIAL AND METHOD: One hundred subjects were tested with three antigens including tuberculin (purified protein derivative), tetanus toxoid, 1:10 and 1:100 dilutions, and Candida albicans, 1:10 and 1:100 dilutions. RESULTS: We found that 92% of the subjects responded to tuberculin and/or tetanus toxoid at a 1:10 dilution, 77% responded to tetanus toxoid at a 1:10 dilution, and 35% responded to a 1:100 dilution. There was only one subject who responded to Candida albicans at a 1:10 dilution, and none to a 1:100 dilution. The size of tuberculin reactions varied from 5 mm to over 20 mm without any evidence of active tuberculosis. CONCLUSION: Tuberculin and tetanus toxoid at a 1:10 dilution are probably sufficient to be used in DTH skin testing to evaluate T-cell function.

Tubercúlides: revisão sobre tema polêmico / Tuberculids: revision on controversial theme

Tubercúlides representam uma forma de reação de hipersensibilidade a antígenos bacterianos liberados de um foco de infecção distante. A maioria dos pacientes é caracterizada por apresentar PPD forte reator e evidência de passado de tuberculose pulmonar e(ou) contactante. O tratamento é baseado na terapia de dessensibilização com tuberculina, drogas antituberculosas e corticóides.

Tuberculids represent a form of hypersensitivity reaction to tuberculosis antigens released from a distant focus of infection. Most of patients are characterized by displaying a markedly positive Mantoux skin test and evidence of past tuberculosis infection or contacts of patient with tuberculosis. The treatment is based on tuberculin desensitizing therapy, antituberculous drugs and corticosteroids.

Rol de la hipersensibilidad retartada en el proceso inmunitario de defensa contra la tuberculosis

La hipersensibilidad retardada es un mecanismo importante del proceso inmunologico especifico de defensa del individuo infectado con el Mycobacterium tuberculosis. La hipersensibilidad retartada es una reaccion producidad por ciertos linfocitos T especificos, llamdos linfocitos citotoxicos, cuyo rol principal es la destruccion de los macrofagos alveolares inanctivos, por infectados con los bacilos de koch, produciendo asi la liberacion de los mismos al medio extracelular; el caseum, medio no favorable a la division del bacilo: fenomeno responsable del detenimiento de la reproduccion logaritmica del bacilo hasta la aparicion de la inmunidad mediada por celulas. El presente articulo analiza algunos de estos aspectos importantes dentro de este proceso inmunologico

Hipersensibilidad retardada a antígenos de evocación: valores normales en adultos jóvenes chilenos / Delayed hypersensitivity to evocation antigens: standard values in chilean young adults

Delayed hypersensitivity skin test are widely accepted as in vivo measure of cellular immunity. Since genetic and environmental factors may affect these tests, each population must establish its own normal values. The aim of this work was to study delayed hypersensitivity in chilean normal young adults. We studied the response to 8 antigens using the Multitest CMI (Rhodia Merieux) in 50 students (22 females, 28 males), aged 18 to 25 years old. Skin tests were read at 24, 48 and 72 hours. At 48 h, 60 percent of women responded to 3 and 68 percent of men to 4 antigens. A mean response to 3.6 antigens was observed. Total score in men and women were 19.5ñ7.3 and 12.2ñ6.5 mm respectively (p<0.05). These figures are different from these published abroad and confirm the need for national standards

Pruebas de hipersensibilidad retardada y niveles séricos de cinc en pacientes diabéticos / Delayed hypersensitivity tests and serum levels of Zinc in diabetic patients

Se procesaron datos de 90 personas de ambos sexos, quienes fueron dividias en 3 grupos para su estudio. Se clasificaron en anérgicos o reactivos de acuerdo al resultado obtenido al realizarles las pruebas de hipersensibilidad retardada. En el grupo anérgico se estudiaron 30 pacientes diabéticos con edades entre los 37 y 80 años. En el grupo reactivo se estudiaron igualmente 30 pacientes diabéticos entre 50 y 74 años de edad y el grupo control, entre los 21 y 57. Se les determinó la concentración sérica de cinc y las pruebas de hipersensibilidad retardada. Al realizar la prueba t de Student se encontraron diferencias significativas entre los grupos anérgicos-control y anérgico-reactivo y no entre reactivo-control. Se concluye que los pacientes que resultaron anérgicos a las pruebas de hipersensibilidad retardada tienen menores concentraciones de cinc en suero que los que resultaron reactivos y que el grupo control, esto pudiera estar relacionado con su disminuido sistema inmune

Airway provocation test with ragweed pollen extract in Chinese asthmatics.

As ragweed becomes widespread over China, ragweed pollenosis tends to be more frequent. Incidence of ragweed pollenosis is about 1.04% in Qingdao district. To elucidate ragweed as an allergen in the development of bronchial asthma, ragweed pollen extract inhalation airway provocation tests (APT) were studied in 55 patients with ragweed pollenosis. A single dosage of 9,000 PNU ragweed pollen extract was applied and positive response was defined as more than 35% fall in SGrs at the dose of PT35-Grs. Among 55 patients, positive APTs were found in 27 cases (49%), dual late-phase responses in 11 patients, single late-phase responses in 2 patients in the complicated asthma group. Late-phase responses were related to the increased specific IgE and strong positive skin test response (wheal > 11 mm). The results suggested ragweed pollen was one of the important allergens causing bronchial asthma. There was airway hyperresponsiveness to ragweed pollen in some patients (20%) with ragweed pollenosis without asthmatic symptoms.

Síndrome de hiperreatividade tuberculínica: revisäo e estudo de novos casos / Tuberculinic hiperreativity syndrome: review and study of new cases

Os autores, baseados em experiência de 28 casos selecionados, abordam um tema bastante polêmico - as síndromes de hiperreatividade tuberculínica (SHT). Procuram enfocar dentro do contexto clínico-tuberculínico, as peculiaridades mais exuberantes e significativas, objetivando, com isto, conglomerar parâmetros patodiagnósticos destas entidades alergo-bacterianas, visando a um posicionamento clínico definitivo e a um tratamento hipossensibilizante à luz dos novos conhecimentos da quimioprevençao anti-tuberculose moderna.

Transferencia in vitro de inmunidad a PPD con extracto dializable de leucocitos de calostro humano / In vitro immunity transference of PPD with human dialysable colostral leukocyte extract

Se pretende demostrar la transferencia de hipersensibilidad a PPD en un modelo in vitro con extracto dializable de leucocitos de calostro de madres PPD- y PPD+ (EDLC PPD- Y PPD-), a través de la medición de la actividad del factor inhibidor de la migración de leucocitos (LIF) de sangre de cordón de recién nacidos de madre PPD+. En los resultados se observa que el EDLC PPD+ incubado con leucocitos de recién nacidos de madres PPD- tuvieron inhibición de la migración de los leucocitos, comprados con la migración de los leucocitos incubados con EDLC PPD-; lo que sugiere que en el modelo in vitro se transfiere hipersensibilidad a PPD con el EDLC.

Reacción tuberculínica en niños de uno a cuatro años de edad vacunados con BCG. Lambayeque-Perú / Tuberculinic reaction in BCG vaccinated children aged one to four years

Considerando las discrepancias existentes sobre la calidad de la vacuna BCG aplicada en nuestro medio y la utilidad del PPD como método de diagnóstico de la infección tuberculosa, se realizó la presente investigación con los objetivos de determinar la prevalencia de la reactividad tuberculínica en niños de 1 a 4 años de edad, vacunados con BCG y evaluar indirectamente la utilidad del PPD. Se efectuó un muestreo sistemático en toda la población de la ciudad de Lambayeque, captándose un total de 569 niños de 1 a 4 años de edad becegeizados, aplicándoseles PPD 2 UT según pautas estandarizadas de la OMS/OPS. Los resultados nos indican un alta prevalencia de respuesta negativa al PPD: 90 por ciento del total de niños. No existe diferencia significativa según grupo etáreo, hacinamiento o grado de nutrición en la respuesta tuberculínica. Se plantea la revaloración del criterio internacional oficial sobre la utilidad del PPD como método diagnóstico de infección tuberculosa natural, dado que la vacuna no ocasiona distorciones en nuestro medio, y por otro lado efectuar estudios para determinar la razón de la alta negatividad de respuesta en niños vacunados, que indicarían mala calidad de vacuna BCG aplicada o deficiencias de respuestas inmunológicas en nuestra población infantil

Contribuição ao estudo da reação à tricofitina nas dermatofitoses / Contribution to the study of the reaction to trichophyline in dermatophytoses

Os autores investigaram a competência imunológica específica de 31 indivíduos portadores de dermatofitose, utilizando o antígeno tricofitina. Destes, 54,8% mostraram-se reatores à fase tardia dessa prova (48 h) nas seguintes proporções: tinea inguinale, 75%; tinea pedis, 61,5%; tinea unguium, 50% e tinea corporis, 20%. 62,5% dos casos apresentaram positividade à fase imediata (30 m) da reação. A associação entre essas reações revelou que, embora a maioria dos pacientes com reação imediata positiva apresentasse negatividade à reação tardia, 20,8% apresentaram positividade para as duas fases da reação. Dos pacientes não reatores à fase tardia, oito foram submetidos a outros testes cutâneos: PPD, estreptoquinase, candidina, vacínia e DNCB, verificando-se imunidade celular conservada em 75% dos casos. Estes resultados sugerem que, quando da utilização dessa prova na avaliação imunológica de pacientes com dermatofitose, deve-se considerar o estado imune geral do paciente, a presença de hipersensibilidade imediata e a localização da infecção

The authors investigated the specific immunological competence of 31 patients with dermatophytosis using tricophytin antigen. Among them, 54.8% showed reaction to the delay phase (48 h) in the following proportions: tinea inguinale, 75%; tinea pedis, 61.5%; tinea unguium, 50% and tinea corporis, 20%. Other 62.5% showed positive result to the early phase (30 m). The association between these reactions revealed that, although the majority of cases with early positive reaction showed negativity to the delayed reaction, 20.8% presented positivity to both phases of the reaction. Out of the non-reactive patients to the delayed phase, 8 were submitted to the other cutaneous tests such as PPD, streptokinase, candidin, vaccinia and DNCB and showed preserved cellular immunity in 75%. These results suggest that, while using this reaction for immunological evaluation of patients with dermatophytosis, one should consider the overall immune status of the patient, the presence of early hypersensibility and the localization of the infection

Studies on lepromin and soluble antigens of M.leprae: their classification standardization and use.

Before the discovery of armadillo as a susceptible animal the source of M.leprae was limited and hence the use of lepromin was not common in the field. In recent times, the soluble antigens of armadillo-derived M.leprae have been used extensively in the field. Although the results of the study show that these antigens do not differentiate always a susceptible form from the resistant form, they are able to segregate the polar forms of leprosy. In a given field situation the criteria for diagnosis is so stressed that leprosy is overdiagnosed and within one year of follow up nearly half the number of cases are noted as not leprosy. Hence, in such situations lepromin reaction would be definitely a poor correlate with the type of leprosy. However, in hospital based studies the lepromin reaction has always been and would remain useful in confirming the classification (Sengupta et al 1984). Lepromins and M.leprae soluble antigens have gone through extensive standardization procedures. As these antigens contain mostly common mycobacterial antigens along with the M.leprae-specific antigens, these antigens are unable to specifically diagnose M.leprae infection. After purification of M.leprae from infected armadillo tissue, it was expected that the soluble antigen of M.leprae would probably be as useful as tuberculin. However, this was not found to be true in case of lepromin. Specificity for M.leprae has been noted in the epitopes (antigenic sites) on cross reacting molecules (12 kd, 18 kd, 28 kd, 35 kd, 36 kd) of mycobacteria (Ivanyi et al 1983; Watson 1989). These specific epitopes, if synthesized, could be of use as skin test antigens for determining M.leprae infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Factor inhibidor de la migración de leucocitos y degranulación de basófilos en las reacciones de medicamentos / Leukocyte migration-inhibitory factors and basophile degranulation in drug reactions

Se comunican los resultados de un estudio prospectivo realizado en 31 pacientes con historia de reacción adversa a medicamentos con el propósito de descartar fondo alérgico. Se4 comparo la sensibilidad y especificidad de las pruebas del factor inhibidor de la migración de leucocitos y degranulación de basófilos contra las pruebas de exposición . Los resultados se analizaron estadisticamente y se concluyó que las pruebas de laboratorio antes mencionadas tienen poca sensibilidad y especificidad. La prueba de exposición es el método más rápido, útil y sencillo para determinar alergia a medicamentos, teniendo presente que implica mayor riesgo.