Comparison of ABO Antibody Titers on the Basis of the Antibody Detection Method Used

BACKGROUND: Detection methods for ABO antibody (Ab) titers vary across laboratories, and the results are different depending on the method used. We aimed to compare titer values using different detection methods for the measurement of ABO Ab titers. METHODS: For ABO Ab detection, pooled group A or B red blood cells (RBCs) were reacted with each of 20 sera from blood groups A, B, or O without dithiothreitol treatment. The room-temperature (RT) incubation technique and the indirect antiglobulin test (IAT) were used in the tube test and gel card test. Flow cytometry (FCM) was performed by using anti-IgM and anti-IgG Abs. RESULTS: Regardless of the blood groups tested, the FCM assay with anti-IgM showed the highest titer compared to the tube test and gel card test with RT incubation in both. The tube test with IAT showed a higher titer than the gel card test with IAT (Gel-IAT) or FCM with anti-IgG in blood group A and B, while Gel-IAT showed the highest titer relative to the other tests, only for the anti-A Ab in blood group O. CONCLUSIONS: There were significant differences in the titers depending on the detection method used, and each method showed a different detection capacity for each ABO Ab depending on the ABO blood group tested. Therefore, caution should be exercised in interpreting ABO Ab titer results, taking into consideration the detection method used and the blood group.

Development of a novel enzyme-linked immunosorbent assay to detect anti-IgG against swine hepatitis E virus

Swine hepatitis E virus (HEV) is widespread throughout pigs in both developing and industrialized countries. This virus is an important zoonotic agent and a public concern worldwide. Infected pigs are asymptomatic, so diagnosing swine HEV relies on detection of the virus or antibodies against the virus. However, several obstacles need to be overcome for effective and practical serological diagnosis. In this study, we developed an enzyme-linked immunosorbent assay (ELISA) that used a purified recombinant capsid protein of swine HEV. The potential clinical use of this assay was evaluated by comparing it with a commercial kit (Genelabs Technologies, Diagnostics, Singapore). Results of the ELISA were highly correlated with those of the commercial kit with a sensitivity of 97% and specificity of 95%. ROC (receiving operator characteristic) analysis of the ELISA data produced a value of 0.987 (95% CI, 0.977~0.998, p < 0.01). The cut-off value for the ELISA was also determined using negative pig sera. In summary, the HEV-specific ELISA developed in the present study appears to be both practical and economical.

Detection of antibody in serum and secretion for the diagnosis of Helicobacter pylori infection.

Helicobacter pylori plays a major role in chronic gastritis and peptic ulcer. In addition, it has been shown to be associated with gastric carcinoma. In this study, the authors compared the detection of IgG antibodies specific to H. pylori by enzyme-immunoassay with culture, histology and a CLO test as tools for diagnosis of H. pylori infection. If the criteria that patients will be considered as H. pylori infected only when their samples are positive by culture or CLO test and histology were used, the sensitivity and specificity of detecting IgG in sera were 96.84 and 72.04 per cent respectively. The use of serological test will be useful as a screening test for H. pylori infection without the need of endoscopy. The authors also performed the assay for detecting IgA antibodies in saliva and gastric juice. The sensitivity and specificity of IgA detection in saliva were 26.79 per oent and 75.00 per cent. As for the assay in gastric juice, although the specificity was as high as 91.67 per cent, the sensitivity is very low (22.22%).

Humoral immune responses in different clinical forms of tuberculosis.

To assess the antibody responses in different clinical forms of tuberculosis in an attempt to ascertain the specificity of such a response, so that it may be used as a diagnostic tool, 93 tuberculosis cases and 62 normal healthy controls were included in the study. All the cases were diagnosed as tuberculosis by clinical picture including radiological findings, blood picture, fine needle aspiration cytology (FNAC) or histopathological features, sputum examination or urine culture for acid-fast bacilli. IgM and IgG antibodies in the cases and controls were detected by ELISA using A60 antigen from M. bovis and compared with common diagnostic parameters of tuberculosis like presence of acid-fast bacilli in smear and tuberculin response. Antibody responses with A60 antigen has not been found to be specific and often failed to detect a new case.

Determinación de la actividad anti-C3d en reactivos antiglobulina humana / Determination of the anticomplement activity in human antiglobulin reagent

La evaluación de la actividad de anti-C3d en reactivos de Coombs poliespecíficos, con los procedimientos clásicos presenta, según la experiencia de los autores, dificultades técnicas y falta de reproductibilidad. El objetivo de este trabajo fue describir una técnica para controlar la actividad de los reactivos antiglobulina humana (AGH) poliespecíficos y monoespecíficos anti-C3d, utilizando glóbulos rojos de carnero (GRc) sensibilizados con fragmentos de complemento (C'). La obtención de GRc sensibilizados con C3d, se evaluó con reactivos de calidad certificada por la firma comercial. Se obtuvieron reacciones de aglutinación francamente positivas con reactivos de Coombs poliespecíficos y con reactivos anti-C3d, -C3d monoespecíficos. La sensibilidad, especificidad y sencillez de esta técnica induce a proponerla dentro del protocolo de Control de Calidad de los antisueros AGH poliespecíficos y anti-C3d, -C3d, utilizados de rutina en los Servicios de Medicina Transfusional

Serological diagnosis of celiac disease.

In developing countries like India, unlike in the West, diagnosis of celiac disease is a dilemma because the histological changes consistent with celiac disease may not be pathognomonic of the disease. We need clarity on how to use one or more of the serological antibodies, namely IgG and IgA anti-gliadin and IgA anti-endomysial antibodies as independent disease markers or as adjuncts to clinico-histological diagnosis. In this review, various possible algorithms have been discussed. The serological antibodies can be used as reliable screening tests to decide whom to biopsy and to interpret histological changes in our settings where malnutrition and intercurrent enteric infection are common.

IgE production from the nasal polyp tissue: comparison between atopic and non-atopic subjects

OBJECTIVES AND METHODS: To confirm the local production of IgE antibody from the nasal polyp tissue, and to evaluate the difference between atopics and non-atopics, nasal polyp tissues were taken from both 10 atopic and 10 non-atopic subjects. The tissue total IgE (tlgE) level was measured by enzyme-linked immunosorbent assay (ELISA) and serum tlgE level by radio-immunoassay. The tissue albumin level was measured by nephelometry, and serum albumin level by Bromocresol green method. RESULTS: The polyp tissue tlgE/albumin as well as serum tlgE/albumin ratio were significantly higher in atopics than in non-atopics (p 0.05). Three non-atopic subjects had high polyp tissue tlgE/albumin (> 10). A significant correlation was noted between serum tlgE/albumin and polyp tlgE/albumin (r = 0.46, p = 0.04). The ratio of polyp tlgE/albumin to serum tlgE/albumin was greater than 1 in all of the non-atopic subjects and 7 of 10 atopic subjects. CONCLUSION: These findings support the hypothesis that IgE antibody could be locally produced from the nasal polyp tissue of non-atopic subjects as well as atopic subjects. The possibility of an isolated local production of IgE antibody was suggested.

Role of specific IgE, IgG and IgG4 antibodies to corn dust in exposed workers

BACKGROUND AND METHODS: To evaluate the role of specific antibodies to corn dust (CD) and their relationship to respiratory dysfunction, we detected serum specific IgE(slgE) and IgG4(slgG4) antibodies by ELISA in 42 employees working in the animal feed industry and 27 unexposed controls. RESULTS: Our survey revealed that 15 (34.9%) subjects had work-related respiratory dysfunction associated with or without nasal symptoms. Among these subjects, eight had airway hyper-responsiveness to methacholine. Significant differences were noted in slgE and slgG4 between exposed and unexposed groups (p = 0.04, p = 0.00 respectively), but no difference was noted in slgG (p = 0.1). Although there was no significant differences in the prevalence of specific IgE antibody between symptomatic (29%) and asymptomatic groups (19%, p = 0.55), the specific IgE levels were significantly higher in symptomatic workers than in asymptomatic workers (p = 0.03). Specific IgG antibody was detected in 1 (6%) symptomatic and 4 (15%) asymptomatic workers (p = 0.46). Specific IgG4 antibody was detected in 11 (73%) of symptomatic and 21 (78%) of asymptomatic workers (p = 0.90). The higher prevalence of slgG4 antibody was noted in workers with slgE antibody (p = 0.001). The correlation between slgG and exposure duration was significant (r = 0.36, p = 0.02). There was no association between the prevalence of slgE, slgG, and slgG4 to exposure intensity, smoking or atopic status. CONCLUSION: These results suggested that the existence of slgG and slgG4 might represent a response to CD exposure, and that some unexposed subjects had slgG to CD. Specific IgE might play a role in the development of respiratory symptoms.

UltramicroELISA indirecto para la detección de anticuerpos IgG en pacientes con fascioliasis / Indirect ultramicroELISA for the detection of IgG antibodies in patients with fascioliasis

Se describe la normalización de un ultramicroELISA para la detección de anticuerpos IgG anti-antígenos de excreción-secreción de Fasciola hepatica (UME-Fasciola). Se estudió un numeroso grupo de sueros entre los cuales 56 eran de pacientes con fascioliasis, 168 eran de pacientes con otras enfermedades parasitarias y 300 procedían de personas sanas, las cuales fueron utilizadas como controles negativos. Respecto al examen parasitológico considerado como "Regla de Oro", el UME-Fasciola mostró una sensibilidad del 100 por ciento, especificidad de 98 por ciento y valores predictivos para positivos y negativos de 90,3 y 100 por ciento, respectivamente. Sólo se observó reacción cruzada con los sueros de pacientes infectados con Opistorchis felineus. Al comparar el UME-Fasciola con el ELISA convencional se obtuvo un índice de concordancia de 95,5 por ciento

Estimacion de titulos de anticuerpos IgG a Adenovirus utilizando una curva patron y un ensayo de ultramiocroELISA indirecto / Estimation of the titre of IgG antibodies to Adenovirus using a standard curve and an indirect ultramicroELISA assay

Se logro normalizar un procedimiento que combinaba un ensayo de ultramicroELISA indirecto con una curva patron y que permitio estimar el titulo de anticuerpos IgG a Adenovirus en muestras de suero humano utilizando una sola dilucion de estos. Basandose en el titulo a punto final previamente determinado para un panel de 117 muestras de suero, se seleccionaron 90 de estas (r2 = 0,98) para construir 4 curvas patrones que relacionaron el logaritmo natural de las respuestas de fluorescencia y el logaritmo natural del titulo a punto final para un rango amplio de diluciones del suero (1:40 hasta 1:320). Se selecciono la curva correspondiente a la dilucion 1:40 del suero (r2 = 0,81), la cual posibilito una optima utilizacion de los accesorios disenados para la manipulacion de los volumenes en el rango ultramicro y, por tanto, la automatizacion de todo el procedimiento. Los resultados obtenidos con respecto a la tecnica de fijacion del complemento (100 por ciento de sensibilidad y 97,3 por ciento de especificidad) respaldan la utilizacion de este metodo como una herramienta complementaria en la ejecucion de estudios seroepidemiologicos a gran escala y con fines diagnosticos

Reverse single radial immunodiffusion for estimation of titre of anti IgG antibody.

Reverse Single Radial Immunodiffusion (SRID) for estimating titre of anti IgG antisera is reported. Unlike the conventional radial immunodiffusion, the antigen (IgG) is held immobile in the gel while the antibody (Anti IgG) diffuses radially from the well (7 microliters) and the diameter of the resulting immuneprecipitates after immunodiffusion at 4 degrees C for 24 hr, represents a linear correlation with the antibody titre. The procedure was standardised by an extensive trial and error employing different concentrations of human IgG in the gel (60-240 micrograms) against varying dilutions of the standard antibody (titre: 3.8 mg/ml). The best results were obtained at 80 micrograms of IgG in the gel. The locally raised rabbit anti IgG antisera displayed a distinctive titre pattern under optimised conditions. Technical reproducibility, high-sensitivity threshold (0.25 mg/ml), simultaneous visual scrutiny of several antibody batches at a glance and ability to assess the shelf life of the stored antisera are its distinct assets.

Measurement of red blood cell antibodies in autoimmune hemolytic anemia

The enzyme-linked antiglobulin test (ELAT) was employed to measure the number of IgG molecules per red blood cell (IgG/RBC0 in 11 patients with autoimmune hemolytic anemia (AIHA). All patients with AIHA had high levels of red cell-associated IgG (110-3,650IgG/RBC). The control group consisted of normal volunteers (N=10) and patients with hereditary spherocytosis (N=1), ß--thalassemia (N=1), immunologic thrombocytopenic purpura (N=3) and IgG multiple myeloma (N=4). All control individuals presented low levels of red cell IgG (less than 38IgG/RBC) with the exception of one of four patients with myeloma who had a mildly elevated value (50 IgG/RBC). Since the multiple myeloma patients had > 2g/dl IgG, the possible nosnspecific uptake of IgG onto the RBCs of patients with elevated serum IgG values did not interfere with the results of ELAT. ELAT proved to be a useful method for accurate quantification of the amount of IgG specifically bound on the surface of RBC of patients with AIHA

Specific antibodies in mouse milk after ovalbumin ingestion

C57B1/6J mice received ovalbumin (Ova) orally, 20 mg/day, from day of parturition for 3,5, 7, 10 or 15 days. Anti-Ova antibodies were titrated in plasma and milk by passive hemagglutination, and Ova-specific plaque-forming cells (PFC) were counted in the spleen and mesenteric lymph nodes. Anti-Ova antiobodies in milk and antibody-secreting cells in mesenteric lymph nodes and spleen were detected on day 3, increased on day 5 and peaked on day 10. In contrast, anti-Ova antibodies in serum and PFC in spleen were low on day 7 and decreased on days 10 to 15. Although the oral administration of this antigen has been used to induce oral tolerance or secretory immune responses in the mouse the present study demonstrates that the repeated ingestion of ovlbumin results in the development of circulating and secretory antibodies

Serological diagnosis of dengue by an Elisa inhibition method (EIM)

An ELISA Inhibition Method (EIM) was proposed for the serologic diagnosis of dengue, comparing its results with the Hemagglutination Inhibition (HI) and the IgM capture-ELISA (MAC-ELISA). Advantages and disadvantages of both methods are discussed according to sensitivity, specificity, performance and usefulness. As a conclusion we recommend the complementary inclusion of the EIM and MAC-ELISA substituting the HI for laboratories engaged in the diagnosis and surveillance of dengue

Antyphospholipid antibodies in syphilis

1. An enzyme-linked immunosorbent assay was used to determine the phospholipid specificity of antibodies in sera from 35 syphilis patients. 2. Based on the cross-reaction obtained aginst a mixture of cardiolipin, phosphatidylcholine and holesterol that is standard for flocculation tests according to the Venereal Disease Research Laboratory (CECON, Säo Paulo, Brazil), all 35 patients tested positive for antibodies of the IgG class whereas 13 (37%) also had IgM antibodies for the same mixture of lipids. IgG antibodies to cardiolipin were demonstrated in 2 patients (6%) and IgM antibodies in 5 (15%). Significant levels of IgG anti-phosphatidylcholine were detected in 3 patients (9%) and IgM antibodies in 4(11%). IgG anti-phosphatidylethanolamine antibodies were found in 1 patient (3%) and IgM antibodies in 3(9%). Antibody binding to cardiolipin plus cholesterol or cardiolipin plus phosphatidycholine was as effective as when the standard mixture of all 3 lipids was used. 3. A comparison with serum from systemic lupus erythematosus patients and inhibition studies using liposomes o cardiolipin or the mixture of 3 lipids suggests that there are at least 3 groups of anticardiolipin antibodies

Enzyme linked immunosorbent assay: determination of anti-adenovirus antibodies in an infant population

Com a finalidade de encontrar um ensaio preciso para a detecçäo de anticorpos anti-adenovírus, o teste ELISA recentemente padronizado foi compardo à inmunofluorescência indireta (IFI) e à fixaçäo de complemento (FC). Após testar 58 sóros, o ELISA demonstrou maior sensibilidade do que a IFI e a FC, que mostraram sensibilidades relativas de 94% e 63%, respectivamente. A falta de um padräo universal näo permitiu alcançar conclusöes definitivas quanto à especificidade dos ensaios. Além disso, o ELISA foi utilizado para estabelecer a prevalência de anticorpos anti-adenovírus em 116 crianças entre 1 e 24 meses de idade (média 7.28). Os dados mostraram que os anticorpos maternos desaparecem ao redor dos 5 a 6 meses de idade e que mais de 80% das crianças tinham sido infectadas antes dos 10 meses de idade

Fifth disease in children living in Belém, Brazil

Amostras de soro colhidas na fase aguda de doença exantemática, acometendo duas crianças, revelaram-se positivas quanto à presença de IgM específica para o vírus B 19, através do método de rádio-imuno-ensaio por mecanismo de captura. O primeiro paciente, um menino de dois anos, apresentou erupçäo cutânea com seis dias de duraçäo; o segundo foi uma menina de quatro anos de idade, irmä do primeiro paciente e que foi submetida a exame à mesma época em que se procedeu à avaliaçäo clínica do irmäo, e que exibia "rash" cutáneo que evoluía há três dias

Neuropsychiatric manifestations of systemic lupus erythematosus: the value of anticardiolipin, antigangliosides and antigalactocerebrosides antibodies

In an attempt to find a serological marker for neuropsychiatric manifestations (NPM) of SLE sera from 66 patients (classified in three groups, according to their NPM - defined, probable and without NPM) were analysed by ELISA for IgG and antigalactocerebrosides antibodies. A strong correlation was found between IgM antigangliosides and antigalactocerebrosides antibodies and NPM, but not with IgG class. IgM and IgG antibodies anticardiolipin were not correlated with BPM in this study. Both IgM antigangliosides and seven patients with definid NPM but clinically inactive. The analysis of these autoantibodies showed an important role predictive for NPM in SLE; the negative test decreases the chance of the NPM

Cuantificación de anticuerpos antiapolipoproteína- B humana por ensayo inmunoenzimático (ELISA) / Quantitation of human antiapolipoprotein- B antibodies by enzyme-linked immunosorbent assay (ELISA)

SE describen dos sistemas de ensayo inmunoenzimático para la cuantificación de anticuerpos contra apolipoproteína-B humana, con un rango de sensibilidad entre 0,5 y 8 microgramos por milímetro. En uno de los sistemas la fase sólida se recubre directamente con suero humano fresco y en el otro con anticuerpos específicos contra la apolipoproteína-B y posteriormente se añade el suero humano. Con este último sistema se obtienen curvas de mayor pendiente que con el primero. Ambos sistemas tienen la ventaja de utilizar la apo-B de recubrimiento sin procedimientos previos de purificación que puedan afectar los determinantes antigénicos de las particulas lipoproteínas que la contienen

Primeiro registro de epidemias causadas pelo vírus Oropouche nos estados do Maranhäo e Goiás, Brasil / 1st register of an epidemic caused by Oropouche virus in the states of Maranhäo and Goiás, Brazil

Os autores descrevem a ocorrência de epidemias causadas pelo vírus Oropouche (Oro) nos Estados dpo Maranhäo (MA) e Goiás (GO) em 1988. 36 amostras de vírus foram obtidas a partir da inoculaçäo do sangue de 120 pacientes em camundongos recém nascidos. A doença foi caracterizada por febre, cefaléia, dores musculares, articulares, fotofobia, dor retro ocular, náuseas e tontura. 128 das 197 pessoas examinadas em Porto Franco, MA, tinham anticorpos inibidores da hemaglutinaçäo (IH) para o agente e, em 106 foram detectados anticorpos IGM por MACELISA. Todos os grupos etários foram infectados, embora a incidência tenha sido mais elevada entre aqueles com 10 a 19 anos de idade. Quanto ao sexo, a infecçäo ocorreu igualmente em ambos os sexos. Recorrência dos sintomas foi observada em 56% dos casos positivos estudados. A inoculaçäo em camundongos Swiss recém nascidos de 3.624 Culicoides paraensis (Ceratopogonidae) e 1.970 Culex (Culex) quinquefasciatus (Culicidae), coletados em Porto Francos-MA, resultou em um único isolamento do vírus ORO a partir dos Culicoides. Essa é a primeira descriçäo de casos confirmados de infecçäo pelo vírus Oropouche nos Estados do Maranhäo e Goiás, Brasil