Gondii IgM Antibodies Research Articles

Anti-Toxoplasma gondii antibodies in haemodialysis patients with chronic renal failure.

This study aimed to determine the prevalence of anti- Toxoplasma gondii antibodies in haemodialysis patients with chronic renal failure (CRF). One hundred and seventy three haemodialysis patients, and 40 healthy controls, were studied for the prevalence of anti-Toxoplasma gondii antibodies by a micro enzyme-linked immunosorbent assay (ELISA). Anti-T. gondii IgG antibodies were detected in 97 (56.06%) haemodialysis patients and 8 (20%) controls with a statistical significance. In addition, anti-T. gondii IgM antibodies were detected in 1.73% of patients, but none of the controls. In conclusion, a high percentage of positivity for Toxoplasma antibodies in patients with CRF undergoing haemodialysis was noticed, thus parasitological surveys of CRF patients should be periodically performed to prevent the possible dissemination of toxoplasmosis through the dialysis procedure.

Ocular toxoplasmosis after the fifth decade

PURPOSE: To describe the clinical features in patients presenting with ocular toxoplasmosis after the fifth decade and to analyze laboratory findings in comparison to uveitis history and clinical data. DESIGN: Prospective consecutive observational case series. METHODS: A prospective clinical analysis of 27 consecutive patients older than 50 years of age with primary or recurrent ocular toxoplasmosis was performed during a period of 8 years. These cases account for 12% of all ocular toxoplasmosis cases irrespective of age indexed in our institution during the same period. Paired serum and aqueous humor samples were tested for anti- Toxoplasma gondii IgG, IgM, and IgA antibodies. The presence of T. gondii DNA in aqueous humor was determined by polymerase chain reaction followed by DNA hydridization method. RESULTS: Although similar in age, two groups were distinguished clinically: 12 patients (44%) presented with usual forms of retinochoroiditis (mean ± SD, 1.6 ± 0.5 disk areas [DA] in size); 15 patients (56%) presented with atypical lesions, greater than 3 DA in size (mean ± SD, 5.0 ± 2.0 DA). The second group showed a higher rate of complications ( P = .028) and a poorer visual outcome ( P = .015). Twenty-four patients (89%) had intraocular IgG production, 17 (63%) had intraocular IgA production, 3 (11%) had intraocular IgM production, and 12 (44%) had a positive T. gondii DNA detection. CONCLUSIONS: After the fifth decade, ocular toxoplasmosis remains an important cause of posterior uveitis. The combination of antibody detection by immunocapture tests with T. gondii DNA detection, both in aqueous humor, allowed the diagnosis of toxoplasmic infection in the atypical cases with large ocular lesions.

Epidemiological and serological aspects in canine toxoplasmosis in animals with nervous symptoms.

The presence of anti-Toxoplasma gondii IgM and IgG antibodies was studied in samples of blood serum taken from eighty dogs with nervous symptoms at the Serviço de Enfermidades Infecciosas dos Animais, Faculdade de Medicina Veterinária e Zootecnia, Unesp, Botucatu, São Paulo, Brazil. The frequency of IgG titers were 16 (13.7%), 64 (13.7%), and 256 (5%), and for IgM titers were 16 (7.5%), 64 (15%), and 256 (8.7%). Positive reactions were more frequent in the older animals, males, from a rural environment, in constant contact with small animals, principally birds and rodents. There was a higher frequency of a positive reaction in dogs fed with kitchen food, especially in those fed with raw ingredients. The most common neurological pictures were alterations in consciousness, in movement, and in the hand-cart test. The percentage of reagents with specific IgM antibodies was high, indicating active infections, but the possibility of co-infection with the distemper virus can not be discarded, and this may be a predisposing factor for toxoplasmosis infection, once the distemper virus has a potent immunosuppressive action.

Prevalence of Toxoplasmosis in Children in Northeastern Brazil.

We conducted a survey of the prevalence of Toxoplasma gondii infection in children living in Jaboatao dos Guararapes, Pernambuco, Brazil from 1998 to 1999. This city is situated adjacent to Recife, capital of the state of Pernambuco. We determined the prevalence of specific anti-T. gondii IgG antibodies in 196 individuals from 2 to 16 years of age. Individuals who were IgG antibody negative also underwent specific anti-T. gondii IgM testing to detect recent infection with the parasite. Seroprevalence was 79.1%, and high titers of IgG antibody were observed in 49% of positive subjects. The prevalens of antibodies to T. gondii increased with age, with a multiple correlation coefficient (R) of 0.709; however, there was no significant difference in antibody status by sex. Out of 47 children who did not have specific anti-T. gondii IgG antibody, 4 were determined by specific anti-T. gondii IgM antibody analysis to have been recently infected. Stool was examined for soil-transmitted helminth eggs to assess the frequency of soil contact in the entire study population. Stool examination in the population revealed that soil-transmitted helminthiases was highly endemic, with an infection rate of 85.2%in this area. These results suggest that the primary mode of T. gondii transmission to humans is through contact with soil.

Serologic evaluation of patients with primary and recurrent ocular toxoplasmosis for evidence of recent infection

PURPOSE: To identify the frequency of recently acquired vs chronic systemic Toxoplasma gondii infections in patients with ocular toxoplasmosis. METHODS: Serum samples from 22 patients with primary ocular toxoplasmosis (not from scars) and 42 patients with recurrent ocular toxoplasmosis were tested for the presence of anti– T. gondii IgM, IgG, and IgA antibodies and compared with samples from 24 patients with other causes of uveitis. Intraocular production of anti– T. gondii IgG and IgA, and the presence of T. gondii DNA was determined in patients and control subjects from whom ocular fluid was available. RESULTS: Serologic evidence of recently acquired infection was found for 11 (50%) of 22 patients with primary ocular toxoplasmosis and for one (2%) of 42 with recurrent ocular toxoplasmosis. In the uveitis control group, anti– T. gondii IgM antibodies could be detected in two (8%) of 24 patients, but anti– T. gondii IgA antibodies were not detectable. Patients with primary ocular toxoplasmosis and serologic markers of recently acquired systemic infection were significantly older than those with chronic infection ( P = .008). Intraocular production of anti– T. gondii IgG was more frequently noted in patients with recurrent than primary ocular toxoplasmosis (81% vs 41%; P < .001), but intraocular T. gondii DNA was more frequently found in patients with primary ocular toxoplasmosis than in those with recurrent ocular toxoplasmosis (37% vs 4%; P < .01). CONCLUSIONS: Primary ocular toxoplasmosis can be seen in either recently acquired or chronic T. gondii infection. Patients with ocular disease and recently acquired infection were older and more likely to have T. gondii DNA in intraocular fluids.

Intraocular anti– Toxoplasma gondii IgA antibody production in patients with ocular toxoplasmosis

PURPOSE: To investigate the immunoglobulin classes associated with the intraocular anti– Toxoplasma gondii antibody response during clinical ocular toxoplasmosis and to determine which immunoglobulin class is most helpful in the diagnosis of this disease. METHODS: Paired serum and intraocular fluid samples from 155 patients who had uveitis were tested for intraocular anti– T. gondii IgG, IgA, and IgM antibody production. The presence of T. gondii DNA was determined by polymerase chain reaction. Patients were divided into two groups, based on the initial clinical diagnosis; group 1 included 78 patients with presumed ocular toxoplasmosis, and group 2 included 77 patients with uveitis that was not clinically suspected to be ocular toxoplasmosis. Samples from 27 nonuveitis patients who underwent intraocular surgery were used as control subjects. The final diagnosis was based on the clinical course and interpretation of laboratory tests. RESULTS: A final diagnosis of ocular toxoplasmosis was made in 88 of 155 patients (group 1, 68; group 2, 20). Among these patients, 65% had intraocular IgG production, 52% had intraocular IgA production, 37.5% had both IgG and IgA production, 27% had IgG production only, and 15% had IgA production only. Of the 13 patients tested, only one had intraocular IgM production. Intraocular IgA could not be detected in patients who had final diagnoses other than ocular toxoplasmosis or in control subjects. A positive polymerase chain reaction combined with a test that was positive for intraocular IgG production had a sensitivity of 77%, which increased to 91% after the detection of intraocular IgA production was added. CONCLUSIONS: Immunoglobulin G is the major class involved in the humoral immune response against the T. gondii parasite, followed by IgA. The determination of IgA production is useful as an additional test in the diagnosis of ocular toxoplasmosis.

Vitritis as the primary manifestation of ocular syphilis in patients with HIV infection

To describe dense vitritis as the primary manifestation of ocular syphilis in three human immunodeficiency virus (HIV)-positive patients and to determine the response of these patients to the established regimen for neurosyphilis. Anti-Toxoplasma gondii IgM and IgG antibody titers, tuberculin skin test, chest radiograph, and serum angiotensin-converting enzyme level were obtained because tuberculosis, sarcoidosis, and toxoplasmosis were in the differential diagnosis. Two of the three patients were not known to have HIV infection at the time of initial examination and consented to HIV testing. Treponemal and nontreponemal tests were performed on serum and cerebrospinal fluid to establish a definitive diagnosis. Treatment for neurosyphilis was initiated, and daily ophthalmic examinations were performed, with careful attention to signs commonly associated with syphilitic eye disease. All three patients exhibited improvement in visual acuity and resolution of vitreous haze. There was no evidence of other signs of posterior uveitis. The one patient for whom there has been a 6-month follow-up showed no sequelae of his eye disease. Human immunodeficiency virus-positive patients with syphilis may present atypically dense vitritis. In these patients, vitritis may be the first manifestation of syphilis. The regimen for neurosyphilis provides effective therapy. Moreover, in some patients, syphilitic vitritis may be the initial manifestation of HIV disease.

Prenatal diagnosis of congenital toxoplasmosis in 261 pregnancies.

Two hundred and sixty-one pregnant women underwent prenatal screening by cordocentesis and/or amniocentesis between 1987 and 1994. The following tests were used: (i) detection of anti-Toxoplasma gondii IgM, IgA, and IgE antibodies by immunocapture and the comparative immunological profile method based on enzyme-linked immunofiltration assay of fetal blood and (ii) direct detection of the parasite in cell culture and by mouse inoculation with fetal blood (FB) and/or amniotic fluid (AF). Of the 31 cases of congenital toxoplasmosis, 24 (77 per cent) were detected prenatally. Overall, the FB and AF inoculation methods were the most effective (50 per cent sensitivity with FB inoculation to mice and/or cell culture and 74 per cent with AF). However, antibody detection in FB was the only positive test in three cases. Of 18 surviving children diagnosed prenatally, only one developed chorioretinitis (9 months of age). Seven newborns (23 per cent) with negative prenatal tests were diagnosed by postnatal laboratory monitoring, but none of these children developed clinical toxoplasmosis. There may have been more false negatives, as only 48 per cent of unaffected children were followed up for at least 12 months. All the tests had a specificity of 100 per cent. Fetal blood sampling has considerable value but also carries some risks and is currently being abandoned in favour of amniocentesis alone with gene amplification and mouse inoculation.

A maternal screening program for congenital toxoplasmosis in Quindio, Colombia and application of mathematical models to estimate incidences using age-stratified data.

We studied 937 pregnant women from Quindio, Colombia for the presence of specific anti-Toxoplasma gondii IgG antibodies using the indirect immunofluorescence antibody technique (IFAT-IgG). Specific anti-T. gondii IgM antibodies detected using the immunosorbent agglutination assay (ISAgA-IgM) were investigated in patients with high titers in the IFAT-IgG (dilutions > or = 1:1,024). We used mathematical models based on the age prevalence results of the IFAT-IgG to estimate the number of seroconversions and these were compared with the results predicted by the IgM based-incidence results. We found 15 positive cases by ISAgA-IgM and we were able to follow the children of six mothers from this group in which we found one case of congenital toxoplasmosis with the development of a retinal scar despite prenatal and postnatal treatment. The estimation of new cases for the annual total of pregnancies (approximately 8,000) in the Quindio region was 30-120 according to the ISAgA-IgM results and 57-85 using mathematical models. Thus, mathematical models based on age prevalence can give useful estimations of the magnitude of the problem.

Lack of detection of enteroviral rna or bacterial dna in magnetic resonance imaging–directed muscle biopsies from twenty children with active untreated juvenile dermatomyositis

To investigate for the presence of increased titers of circulating antibody to putative infectious agents and for detectable viral RNA or bacterial DNA in children with active recent-onset juvenile dermatomyositis (DM). Magnetic resonance imaging-directed muscle biopsies were performed in 20 children with active, untreated, recent-onset juvenile DM and in age-matched children with neurologic disease. Sera were tested for complement-fixing antibody to Coxsackievirus B (CVB), influenza A and B, parainfluenza 1 and 3, Mycoplasma pneumoniae, mumps, respiratory syncytial virus, and Reovirus; and by immunofluorescence for IgG antibody to Toxoplasma gondii cytomegalovirus and IgM antibody to Epstein-Barr virus. Muscle from juvenile DM patients and control children, CD-1 Swiss mice with and without CVB1 infection, and viral stock positive for CVB1-6 were tested using reverse-transcriptase polymerase chain reaction with 5 primer sets, 4 probes (1 Coxsackievirus, 3 Enterovirus), and universal primers for DNA. No increased antibody, viral RNA, or bacterial DNA was present in the juvenile DM patients or the control children. Juvenile DM may be triggered by unidentified agent(s) in the genetically susceptible host.

Serologic Response of the Opossum Didelphis virginiana to a Temperature-Sensitive Mutant (ts-4) of Toxoplasma gondii

A study was designed to measure the Toxoplasma gondii-specific IgM and IgG antibody responses of opossums inoculated with tachyzoites of the temperature-sensitive mutant of T. gondii, ts-4, and to examine its persistence in the tissues. Four young opossums seronegative for anti-Toxoplasma gondii IgM and IgG antibodies immediately after capture and 4 wk later were injected subcutaneously with 1.8 x 10(6) ts-4 tachyzoites; a fifth opossum (also seronegative) received an injection of saline only. Serum was collected weekly and titered by modified direct agglutination for anti-Toxoplasma gondii IgM and IgG. IgM titers were detectable from week 1 to week 6 postinoculation (PI). IgG was measurable by week 3 and remained high for 30 wk PI when the opossums were killed and examined. The control opossum did not develop a specific antibody response. At necropsy major lesions were not found. No anti-Toxoplasma gondii IgG was detected in serum collected from mice injected with tissues prepared from the opossums at necropsy, and no T. gondii was found on impression smears made at necropsy from these mice. Modified direct agglutination performed with or without 0.2 M 2-mercaptoethanol worked well for measuring specific IgM and IgG antibodies in experimentally infected opossums.

IgA antibody response during acquired and congenital toxoplasmosis.

Toxoplasma gondii specific IgA and IgM antibodies were quantitated by an antibody capture agglutination assay in 260 patients with acquired toxoplasmosis and from 94 fetuses suspected of congenital toxoplasmosis and 30 infected children. In acquired toxoplasmosis, IgA antibodies to T gondii were found in 95% of the cases. In congenital toxoplasmosis IgA antibodies were more frequently detected (75%) in cord blood than IgM antibodies (61%). They persisted after birth, in some cases for up to 24 months. IgA antibodies were also detected in fetuses whose mothers had toxoplasmosis during their pregnancy. In infected fetuses IgM and IgA antibodies were detected in fetal blood as early as week 24 of pregnancy. Detection of IgA T gondii antibodies may be useful for the diagnosis of some recently acquired infection and for the diagnosis and follow up of the infection in the fetus and neonate.

Amplification of the secretory IgA response to Toxoplasma gondii using cholera toxin

Our study demonstrates that cholera toxin (CT) markedly enhances the intestinal anti-T. gondii antibody response following oral immunisation of mice with a T. gondii sonicate (TSo) and CT. The antibodies induced were mostly IgA and secretory IgA but a small quantity of IgG was also produced. In contrast, no intestinal anti-T. gondii IgM antibodies were detected. Anti-CT IgA antibodies were also present in intestinal secretions but in much lower quantities than the T. gondii-specific IgA. No anti-CT IgG nor IgM antibodies were detected. Western blot analysis showed that CT induced not only an increase of the intensity of the intestinal IgA antibody response to the 30-kDa band but also induced intestinal IgA antibodies against other major T. gondii proteins (p22, and the 28-kDa antigen) as recognised by specific monoclonal antibodies. The amplification of the anti-T. gondii secretory IgA response by means of an appropriate adjuvant may be one major step leading towards an orally induced immune protection against toxoplasmosis.

Amplification of the secretory IgA response toToxoplasma gondiiusing cholera toxin

Our study demonstrates that cholera toxin (CT) markedly enhances the intestinal anti-T. gondii antibody response following oral immunisation of mice with a T. gondii sonicate (TSo) and CT. The antibodies induced were mostly IgA and secretory IgA but a small quantity of IgG was also produced. In contrast, no intestinal anti-T. gondii IgM antibodies were detected. Anti-CT IgA antibodies were also present in intestinal secretions but in much lower quantities than the T. gondii-specific IgA. No anti-CT IgG nor IgM antibodies were detected. Western blot analysis showed that CT induced not only an increase of the intensity of the intestinal IgA antibody response to the 30-kDa band but also induced intestinal IgA antibodies against other major T. gondii proteins (p22, and the 28-kDa antigen) as recognised by specific monoclonal antibodies. The amplification of the anti-T. gondii secretory IgA response by means of an appropriate adjuvant may be one major step leading towards an orally induced immune protection against toxoplasmosis.