Complement Fixation Reaction Research Articles

Immunological reactivity of animals with tuberculosis under the influence of ionising radiation

Effective control of animal tuberculosis is possible only with a comprehensive examination of the biology of the pathogen, epizootiology, pathogenesis, prevention methods, economic and environmental factors that affect the course of the disease. It is known that radiation exposure leads to autosensitisation of the body by the breakdown products of its tissues and the development of non-specific (false) immunological reactions. Therefore, the purpose of the study was to examine the immunological (serological) reactivity of tuberculosis patients exposed to gamma radiation in laboratory animals. Radiological, bacteriological, allergic, serological, and pathoanatomical research methods were used in the study. Guinea pigs were consistently irradiated with various doses of gamma rays, infected with Mycobacterium tuberculosis of various types, and, for 90 days, were examined by clinical, allergic, pathoanatomical, and serological methods in the complement fixation reaction (CFR) and passive hemagglutination reaction (PHGR) according to Boyden to detect antitubercular complementbinding antibodies and tissue autoantibodies. 45 and 90 days after infection with M. bovis and M. tuberculosis antitubercular complement-binding antibodies were recorded in serum samples of irradiated and non-irradiated animals in diagnostic titres (1:20-1:80), which indicates the active development of the infectious process. In irradiated and intact guinea pigs infected with M. avium, no anti-tuberculosis antibodies were detected in since guinea pigs are not susceptible to infection with the causative agent of avian tuberculosis. In serum samples from uninfected guinea pigs, both irradiated and intact, antitubercular complement-binding antibodies were not detected during the entire follow-up period (90 days). The high content of tissue autoantibodies in blood serum samples of animals irradiated with a dose of 200 R (0.0516 C/kg) is a manifestation of autosensitisation of the body by the breakdown products of its tissues due to radiation damage. The presence of tissue autoantibodies in blood serum samples of irradiated and Mycobacterium-infected animals did not affect serological indicators for the indication of anti-tuberculosis antibodies, which should be considered when conducting diagnostic studies by veterinary medicine laboratories

УСТАНОВЛЕНИЕ ФАКТОРОВ, СПОСОБСТВУЮЩИХ ПОЯВЛЕНИЮ И ПОВТОРНОМУ ВОЗНИКНОВЕНИЮ БРУЦЕЛЛЕЗА КРУПНОГО РОГАТОГО СКОТА НА ТЕРРИТОРИИ САРАТОВСКОЙ ОБЛАСТИ

The aim of the study was to identify factors that contribute to the emergence and re-emergence of brucellosis in cattle in the Saratov region. Conducted epizootological analysis for the period from 2018 to 2022. made it possible to identify the main factors contributing to the functioning of the infectious system of brucellosis in the population of cattle in newly emerging, active and fading epizootic foci in the Saratov region. In the Saratov region, there are a number of areas where brucellosis is recorded much more often and is of a stationary nature. First of all, in the south-eastern part of the region, which is associated with an uncontrolled veterinary service, the importation of patients with brucellosis and animals infected with brucella from the nearby West Kazakhstan region of the Republic of Kazakhstan (RK), as well as the Republic of Dagestan of the Russian Federation, where brucellosis is also quite common . Another problem is that in the border areas of the Republic of Kazakhstan, many farm animals are grazing, which, when grazing in the summer, cross the border into the Saratov region, contact with the animals of our region, which also contributes to the emergence and spread of the disease. Another factor is the concealment from accounting of newly imported livestock and nascent young animals that are not subjected to serological tests for brucellosis. The fourth factor is that the livestock detected by laboratory tests, positively reacting to brucellosis, or is not sent to a specialized meat processing plant for slaughter in a timely manner. The fifth factor is that the methods used for serological diagnostics: agglutination reaction (RA) and complement fixation reaction (CFR) due to low sensitivity do not allow timely detection of animals infected with Brucella. The sixth factor is that the vaccine from Brucella abortus strain No. 82 used in disadvantaged areas of the region does not meet modern requirements. The seventh factor is that brucellosis is mainly recorded in small and individual farms, where there are difficulties in carrying out veterinary and sanitary measures, in particular, in the construction of disinfection barriers and disinfection mats, and in general, disinfection.

THE RESULTS OF LABORATORY STUDIES TO DETERMINE THE CAUSE OF THE DEATH OF RABBITS

in the process of pathoanatomical autopsy of dead and sick rabbits from an unknown disease, biomaterials were selected in order to determine the cause of the disease and death of rabbits.Biomaterials were examined for the presence of pathogens of pasteurellosis, clastridium, viral hemorrhagic disease of rabbits.In the experiment, polymerase chain reaction and complement fixation reaction were used, it was experimentally established that the cause of the disease and death of rabbits is the virus Rabbit Hemorrhagic Disease.

Diagnostic value of autoantibodies and novel automated methods of their detection

Autoantibodies (aAb) are human immunoglobulins that can specifically bind to antigenic epitopes of molecules of their own body. Most of AATs have diagnostic value and are serological markers, as well as reflect the main mechanisms of loss of tolerance and inflammation in patients with autoimmune diseases. Indirect immunofluorescence (IIF) was the first method used to detect aAb. During the 1970s and 1980s, there was an evolution in qualitative methods with the introduction of immunoblotting or dot blotting, and second generation quantitative immunometric assays (radioimmunoassay,, enzyme-linked immunosorbent assay (ELISA), fluoroimmunoassay, immunochemiluminescence assay) were suggested. The growing number of aAbs, as well as the growing request for aAb research in general, has fueled the development of automated and multiplex testing. An example is the Chorus trio multi-parameter automatic station (Italy), which combines the ELISA method and the complement fixation reaction (CFR) on one platform. The advantages of this device include a large panel of tests, minimal labor costs, the ability to use the analyzer to perform analyzes in the “cito” mode, perform CFR tests in an automatic mode, high accuracy and reproducibility of results, and a compact design of the analyzer. The Chorus trio multi-parameter automatic station has been implemented into the routine practice of our laboratory for the diagnosis of autoimmune diseases as a confirmatory test. Thus, the effectiveness of new technologies, the possibility of automation and an increase in the speed and quality of testing, as well as the extensive information provided by innovative multi-parameter systems, will bring significant benefits for clinical laboratory diagnostics and clinicians.

Alternative ways to introduce resuscitation at the prehospital stage in emergency conditions

Annotation. Objective – carrying out a comparative assessment of the advantages and disadvantages of intravenous (IV) and intraosseous (IO) resuscitation, which are used by emergency and emergency teams in the Vinnytsia region. The work used statistical data of the Vinnytsia Regional Center for Emergency Medical Care and Disaster Medicine for the period 2019-2021, carry through content analysis of domestic and foreign scientific sources, applied biblio-semantic, analytical, and statistical methods for studying the use of intraosseous and intravenous methods in emergency cases. According to the Vinnytsia Regional Center for Emergency Medical Care and Disaster Medicine for the three years 2019-2021. we observe a low percentage of use of intraosseous access 0,2% - 0,1%, respectively. In the event of an accident in the patient's condition “without changes” a total of 786 injections were carried out both intravenously and intraosseously. In 2019, out of the total number, non-infusion therapy was performed in 71,0% of male patients and 11,1% of female patients, and 11,2% intraosseously only in male patients. Compared to 2020, only 0,3% intraosseously (2 female patients) and in 2021, no intraosseous resuscitation was performed at all. In a state of “deterioration” during an accident (road accident, etc.) for 2019, 87,5% of men and 12,5% of women were injected with drugs intravenously; for 2020, 50% for both males and 50% for females were infused intravenously; for 2021, 87,5% of men and 12,5% of women underwent intravenous resuscitation, intraosseous resuscitation was never performed, provided that the condition of patients worsened. And “death in the presence” occurred during resuscitation for 2019 88,8% (of which 77,7% for men and 11,1% for women) by intravenous access and 11.2 VC (males); for 2020 88,9% intravenously (of which 72,2% for men and 16,7% for women) and 11,1% intraosseously (of which 1 male and 1 female article); in 2021, 65,0% of intravenous access was performed for men and 25,0% for women, while no patient received intraosseous access. In case of a sudden illness, the percentage of intraosseous resuscitation in the state of “deterioration” was as follows: for the period 2019-2021. no intraosseous access was performed. In the state of “death in the presence” for 2019, intraosseous infusion was 3,4%; 2020 – 3,8%; 2021 – 1,9%. Thus, the intraosseous method has several undeniable advantages compared to the intravenous one, but in Ukraine, it is little used in the practice of mobile emergency medical teams with a syringe gun (connector – BLG), both considering the age characteristics: for adults (blue) and children (red color) and prescribed in the fundamental algorithms of clinical/modern protocols for the treatment of circulatory arrest due to insufficient practical and theoretical skills of medical personnel of emergency teams. The analysis of the use of intraosseous methods in emergency medical care gave impetus to conducting theoretical and practical classes for future doctors to master skills and reduce prehospital and early hospital mortality in patients with complement fixation reactions.

On the question of the complement binding reaction in brucellosis

The complement fixation reaction has long been recommended by many researchers for the diagnosis of brucellosis diseases. So, Rorre Rettger, White, Zeller, Karsten, Lentz and others believe that the simultaneous use of the agglutination reaction and the complement fixation reaction is the most reliable way to detect the Kantian infection. The same authors point out that in some cases the complement fixation reaction is superior to the agglutination reaction.

Значение иммуноферментного анализа в серологической диагностике бруцеллеза крупного рогатого скота

For the serological diagnosis of brucellosis in cattle in veterinary laboratories of the Russian Federation, one or several tests are used simultaneously. The sensitivity and specificity of the determination of antibodies to the pathogens of this disease using various methods varies significantly, none of the serological tests is suitable for all stages of the infectious process in brucellosis. ELISA is a modern serological test that has not found wide application in the state veterinary laboratories of the Russian Federation, although the number of studies conducted by this method increases annually. The use of enzyme-linked immunosorbent assay makes it possible to confirm the diagnosis of brucellosis at all stages of the infectious process and to identify more seropositive animals than classical serological methods. Among serological methods, enzyme-linked immunosorbent assay (hereinafter referred to as ELISA) is the most sensitive, specific and easy-to-perform test. In accordance with the Order of the Ministry of Agriculture of the Russian Federation dated 08.09.2020 No. 533 «On approval of Veterinary rules for the implementation of preventive, diagnostic, restrictive and other measures, the establishment and cancellation of quarantine and other restrictions aimed at preventing the spread and elimination of foci of brucellosis (including infectious epididymitis of sheep)» the ELISA method is one of the confirmatory in the diagnosis of brucellosis. The data obtained as a result of the studies indicates that the results of ELISA coincide with the complex of classical serological methods (BRS – Bengal roses sample; AR – agglutination reaction; CFR – complement fixation reaction; RIH – reaction of indirect hemaggtination; IDR – immunodiffusion reaction) and a higher diagnostic sensitivity of the test.

Serological diagnosis of gonorrhea

Alf. Cohn (Derm. Ztschr. Bd. 55, H. 2) gives detailed instructions for the preparation of a specific antigen, patient serum, and also describes in detail the technique of the Bordet-Gengou reaction itself. The author received as a result of his observations with acute gonorrhea in men 40% pos. responses, for chronic 60% and for complicated 80-100%. The results are especially demonstrative in gonorrhoid arthritis (100%). It is important to use the reaction in doubtful cases, when microscopic and bacteriological examinations do not give the necessary answer for making a diagnosis. If people who do not have gonorrhea are vaccinated, the reaction may be positive. If a positive reaction persists for months or years, you need to look for a focus with gonococci. According to the author, the complement fixation reaction cannot replace the previously tested diagnostic methods, but it complements them. Together with bacteriological and clinical research methods, the reaction sometimes helps to understand the diagnosis of difficult cases.

ІСТОРІЯ ІДЕЙ ЖУЛЯ БОРДЕ (до 150-ї річниці від дня народження вченого)

The experimental period in the history of immunology as a science can be attributed to the years of scientific activity of the world-famous bacteriologist and immunologist Jules Bordeaux, who was the first to experimentally prove the physicochemical nature of such immune reactions as agglutination, hemolysis, precipitation. He was also involved in revealing the nature of phagocytosis reactions and established the relationship between the virulence of the microorganism and the presence of a capsule and phagocytosis. Owing to the discovery of Jules Bordeaux, mankind became aware of the cytotoxic properties of blood serum. Bordeaux’s scientific heritage was the elucidation of the role of complement in immunological processes, which was proved experimentally during the work of a young scientist at the Pasteur Institute in the laboratory of I. I Mechnikov, who considered J. Bordeaux one of his favorite students. In collaboration with Octave Zhangou, the complement fixation reaction underlying Wasserman’s reaction was first proposed. Bordeaux is well known around the world for the «driving force» of immunity — the connection of antigen to antibody. He can be regarded as one of the founders of the method of serodiagnosis. Bordeaux was the director of the Pasteur Institute in Brussels for 35 years, the world’s only autonomous Pasteur Institute unrelated to Paris. Jules Bordeaux’s scientific legacy continued and became the basis for many epoch-making discoveries in medicine, including the explanation of the mechanisms of anaphylaxis, the study of blood clotting, the discovery of blood groups, etc. The theoretical substantiation of immunological reactions became the beginning of a new diagnostic direction in laboratory practice — immunoassay, which includes thousands of modern laboratory methods

On the Origin of Sensitivity and Specificity.

Although it is commonly said that the notions of sensitivity and specificity were first defined by Jacob Yerushalmy in 1947, the sensitivity and specificity of diagnostic tests have been assessed as far back as the early 1900s. These notions share a common origin with the development of serology. They were originally immunologic concepts, closely associated with the development of complement fixation reactions for syphilis. Here, the authors trace how immunologic sensitivity and specificity were transformed into diagnostic sensitivity and specificity. By relocating the origins of these concepts to the early 20th century, they highlight how these origins were bound to then-commonplace assumptions about specific infectious disease entities.

Coxiella burnetii in ticks and wild birds

The study objective was to get more information on C. burnetii prevalence in wild birds and ticks feeding on them, and the potentialities of the pathogen dissemination over Europe by both. MaterialsBlood, blood sera, feces of wild birds and ticks removed from those birds or from vegetation were studied at two sites in Russia: the Curonian Spit (site KK), and the vicinity of St. Petersburg (site SPb), and at two sites in Bulgaria: the Atanasovsko Lake (site AL), and the vicinity of Sofia (site SR). MethodsC. burnetii DNA was detected in blood, feces, and ticks by PCR (polymerase chain reaction). All positive results were confirmed by Sanger's sequencing of 16SrRNA gene target fragments. The antibodies to C. burnetii in sera were detected by CFR (complement fixation reaction). ResultsEleven of 55 bird species captured at KK site hosted Ixodes ricinus.C. burnetii DNA was detected in three I. ricinus nymphs removed from one bird (Erithacus rubecula), and in adult ticks flagged from vegetation: 0.7% I. persulcatus (site SPb), 0.9% I. ricinus (site KK), 1.0% D. reticulatus (AL site). C. burnetii DNA was also detected in 1.4% of bird blood samples at SPb site, and in 0.5% of those at AL site. Antibodies to C. burnetii were found in 8.1% of bird sera (site SPb). C. burnetii DNA was revealed in feces of birds: 0.6% at AL site, and 13.7% at SR site. ConclusionsBoth molecular-genetic and immunological methods were applied to confirm the role of birds as a natural reservoir of C. burnetii. The places of wild bird stopover in Russia (Baltic region) and in Bulgaria (Atanasovsko Lake and Sofia region) proved to be natural foci of C. burnetii infection. Migratory birds are likely to act as efficient “vehicles” in dispersal of C. burnetii -infested ixodid ticks.

Experimental application of a split-conjugated vaccine against animal brucellosis in small cattle

A study was made of the blood samples of small cattle for brucellosis with various serological reactions when testing a split-conjugated vaccine against animal brucellosis three and a half, four and a half months and nine months after immunization. Positive reaction of small cattle to brucellosis in the complement fixation reaction and the agglutination reaction of 40.7% of sheep and goats, and 44.4% of animals in Ros-Bengal after 3.5 months of vaccination. The vaccine has a high immunogenicity against goats, a high enough antibody titer in blood three and a half months after vaccination, when tested with agglutination and Rose-Bengal, breakdown was detected in 83.3% of animals, and in the complement fixation reaction it was 66.7%, which will, in our opinion, effectively use this vaccine in the fight against goat brucellosis. Immunized sheep in the complement-fixation reaction and Rose-Bengal assay reacted positively only in 33.3% of cases. When the agglutination reaction was established three and a half months after the introduction of the vaccine - in 28.6% of the animals, in connection with the data obtained, we recommend looking for new immunoprotectors capable of enhancing the humoral immune response of sheep to the antigen of the tested anti-brucellosis vaccine. Nine months after the vaccination of the split-conjugated vaccine in all blood samples of small cattle (sheep and goats) with all of the above reactions, there was no positive test, which indicates the disappearance and complement-binding and agglutinating antibodies from the bloodstream of animals, and thus the opportunity is given differentiate postvaccinal antibodies in the blood serum of animals, from post-infection, in the case of their detection within the time specified above.

Occurrence of anti-Brucella antibodies in intensive pig farming and in non-technified pig herds

ABSTRACT: The aim of this study was to determine the occurrence of antibodies anti-Brucella in 1,940 swine blood samples. Out of the 1,940 sera samples, 1,594 were from 30 intensive pig farming from seven different states, collected during the slaughtering of animals, and 346 samples from 56 non-technified (subsistence) pig herds from Jaboticabal region, São Paulo State, Brazil. All samples were tested by Buffered Plate Acidified Antigen (BPAA) and considered positive in case of agglutination. If positive, the samples were tested by Complement Fixation Reaction (CFR) as a confirmatory test. Out of the 1,594, two were positive for BPAA but negative for CFR, so the occurrence was 0%. Among the 346 samples, two were positive for BPAA but only one was positive in the confirmatory test, whith a titer of 1:8. Thus, the occurrence was 0.29%, an important result to demonstrate the improvement of the sanitary status of Brazilian non-technified pig herds, despite the low conditions of production.

Transmisión congénita de la enfermedad de chagas en el Hospital Regional Honorio Delgado de Arequipa, Centro de Salud de La Joya y Hospital Regional de Aplao

Se estudió a 220 parturientas y sus respectivos recién nacidos del Hospital Regional Honorio Delgado de Arequipa, del Hospital de Aplao y del Centro de Salud de la Joya. De estas muestras, solamente en 212 ( ... 96.36%) se realizó las pruebas serológicas, reacción de fijación de complemento (RFC) y hemoaglutinación indirecta (Hal) para enfermedad de Chagas. A los 220 recién nacidos se les aplicó xenodiagnóstico. Se empleó una ficha clínico-epidemiológica. Pensamos que esta muestra es significativa de acuerdo a los partos tomados durante el periodo en estudio (Arequipa 19.61%, La Joya 53.33% y Aplao 43.48%) y porque observamos altos porcentajes de antecedentes epidemiológicos (61.9% parturientas nacieron en zona endémica, 69.57% presentaron antecedentes de picadura del vector). Obtuvimos 6 casos de parturientas v 4 recién nacidos serológicos positivos; se encontró correlación de la serorreactividad parturienta/recién nacido en 4 casos, sea a la RFC o a la Hal. No se comprobó los casos de los recién nacidos mediante el xenodiagnóstico, ya que la lectura de este fue negativa; creemos que la seropositividad es por pasaje de anticuerpos.

STUDY OF THE RELIABILITY OF TECHNOLOGY DIAGNOSIS OF BRUCELLOSIS

INTRODUCTION Clear evidence of Brucella infection is provided by the isolation and identification of the organism using certain methods. As it is not always possible to isolate the causative agents from infected patients, at the Regional Veterinary Laboratory Draa Ben Khedda, we use four serological tests have a key role in the routine diagnosis of brucellosis. The buffered antigen test, or test antigen Rose Bengal plate, or “test card” (EAT). The European technical agglutination tubes or slow Wright (SAW). The reaction of complement fixation (F.C). Abstract Our job was through an epidemiological survey of brucellosis in some regions Algeria on the Bovine species (34 161 sera), sheep (18 329 sera) and goat (7858serums) and the comparative study of the different serological techniques performed in the laboratory of the Department of Veterinary Tizi-Ouzou showed that the SAW has a specificity and less sensitive than other tests (EAT, FC, ELISA). ETA showed a sensitivity of 100%.

Toxoplasmosis en pacientes del Hospital Obrero de Lima

Se ha realizado una investigación para detectar anticuerpos específicos para Toxoplasma en 32 pacientes del hospital Obrero de Lima, de los que 13 fueron tomados al azar entre los hospitalizados en Servicios de Medicina General; 15 procedían del Servicio de Oftalmología y presentaban síntomas y/o signos de toxoplasmosis y 4 del Servicio de Obstetricia. Están incluídos 25 hombres y 7 mujeres. Se usó la reacción de fijación del complemento (RFC), según la técnica del 50% de hemólisis de Bozicevich y la reacción de hemaglutinación (RHA), por la técnica del micrométodo en placa. El antígeno de toxoplasma empleado fue proporcionado por el National Communicable Disease Center de Atlanta, Georgia. En 15 (46,87%), la serología fue positiva; de éstos, 8 estaban entre 21 y 30 años de edad y 5 entre 31 y 50, vale decir en la etapa de mayor capacidad de trabajo. De 4 con sintomatología obstétrica, 3 tuvieron serología positiva y de ellas, una refirió 7 embarazos con síntomas de amenaza de aborto, de los que 4 terminaron en aborto y, la otra, 6 embarazos de los que 3 terminaron en aborto; la tercera presentó coriorretinitis y desprendimiento de retina. La serología fue positiva en 5 de los 12 varones con síntomas y/o signos de toxoplasmosis. En 2, se encontró uveítis severa unilateral, hemorragias retinales, nódulos de Koeppe y de Busaca y, en 3 coriorretinitis, desprendimiento retinal y en una estrabismo divergente. En 13 hombres y 3 mujeres que no presentaron síntomas y signo, hubo 7 positivos. Se ha tratado de demostrar no sólo la difusión e importancia clínica y epidemiológica de ésta parasitosis, sino también la gravedad de la patología obstétrica y lesiones oculares que causa entre los asegurados obreros de Lima.

Sero-epidemiologic survey of the equine rhinopneumonitis in the region of Khenchela (Algeria)

The aim of this study is to evaluate the prevalence of respiratory infections of viral origin in equines. In this perspective we have researched antiviruses antibodies in equine’s rhinopnemonitis in 210 horses of different breeds, Arabian purebred,Thoroughbred, arab barb and barb, all stationed in the region of Khenchela, located in the north east of Constantine. These animals are prealably recognised, upon a clinical exam, in a good health. They have received a diet containing barley and hay. They are of different sexe and their age is varying between 2 and 7 years old. The equines play an important socioeconomic role. In several rural areas, equines are regularly used as a tensile force for the animal traction cultivation and transport of persons and goods. They thus contribute widely to the increase of agricultural production and the improvement of socio economic conditions of rural populations. These results demonstrate that among the 210 serums tested, 5 were positive to the reaction of complement fixation. These results are discussed in relation with those observed by other authors.

Study of equinine influenza in the region of Khenchela (Algeria)

The objective of this study was to evaluate the prevalence of respiratory viral infections in horses.In this perspective we looked for antibodies to influenza in 132 horses with chronic respiratory diseases, all stationed in the area Khenchela, situated north-east of Constantine (Algeria). Horses played an important socio-economic role. In many rural areas, horses were regularly used as a pulling force for animal traction and transport people and goods. They contributed greatly to the increase in agricultural production and improve socio-economic conditions of the rural populations. The results showed that on the132 sera tested, of which 32 were positive (ie 24.24 percent): 30 to test for the inhibition of the hemagglutination and 2 to the reaction of complement fixation. These results were discussed in relation to those observed by other authors.

Programa de Controle da Doença de Chagas no Estado de São Paulo: aspectos sorológicos e entomológicos de inquéritos entre escolares de ensino fundamental

Two serological surveys were carried out to evaluate the effectiveness of measures put into effect in the State of São Paulo (Brazil) to control Chagas disease vectors. The first one, during the period from 1968 to 1970; the complement fixation reaction was performed on serum samples from school-children resident in all municipalities of the State of São Paulo, with the exception of the Greater São Paulo. The second one, annually, from 1973 to 1983, involving school-children resident in municipalities with high trypanosomiasis prevalence values; the indirect immuno-fluorescence test was performed on filter paper total blood eluates. Data on the occurrence of triatomines and their infection with Trypanosoma cruzi in each municipality formed the basis of insight into the epidemiological situation associated with the school-children's dates of birth. Most positive serological results, as well as the highest proportion of autochthonous cases associated with Triatoma infestans were observed in the region of Sorocaba until the early 1970s, while the proportions of both autochthonous and imported cases were kept in equilibrium elsewhere. It has been inferred that as recently as 1974, vectorial transmission of Chagas disease could still be observed in the State of São Paulo. We emphasize that, even rather lacking in coverage, no seropositive cases have been observed in people inhabiting the regions included in the Control Program for the State of São Paulo and now aged less than 15 years.

Multiple sclerosis: search for a serologic inhibitor.

Complement-fixing (CF) antibrain antibodies are frequently found in serum and CSF in multiple sclerosis (MS). A negative result in the test for these antibodies might depend not only on a lack of antibodies, but also on serologic inhibiting factors. To test this possibility, serum and concentrated CSF samples without demonstrable CF antibrain antibodies were allowed to interact with two standardized positive complement fixation reactions; one for antibrain antibodies and the other a Wasserman reaction. No evidence of inhibiting activity was found in 11 CSF and 15 serum samples from 20 MS patients. On the other hand, inhibiting activity was seen in serum from four of 12 patients with neoplasms and from three of 11 patients with rheumatoid arthritis.