Specific IgM, IgG and IgG1 directed against Toxoplasma gondii detected by flow cytometry and their potential as serologic tools to support clinical indirect fundoscopic presumed diagnosis of ocular disease

Comparative Detection of Immunoglobulin Isotypes and Subclasses against Toxoplasma gondii Soluble Antigen in Serum and Colostrum Samples from Puerperal Women

Background: Toxoplasma gondii is an obligate intracellular parasite that can infect several species, including humans, and can cause severe damage to the fetus when the infection occurs during pregnancy. The environment and/or food contamination are critical to spreading the infection. Human milk is rich in nutrients and bioactive elements that provide growth and development of the immune system of the newborn. All isotypes of immunoglobulins are present in human colostrum and they are produced from systemic or local sources. Breastfeeding protects the infant against various pathogens, but there is no conclusive study to detect IgG subclasses in colostrum against T. gondii. Therefore, the aim of this study was to detect and evaluate the presence of antibody isotypes against T. gondii in paired samples of serum and colostrum. Methods: The study included 283 puerperal patients. ELISA (Enzyme-Linked Immunosorbent Assay) for detection of anti-T. gondii-specific IgM, IgA, and IgG isotypes and IgG1, IgG3, and IgG4 subclasses were conducted on paired samples of serum and colostrum. Results: It was found that 45.9%, 6.0%, and 2.1% of serum samples and 45.2%, 7.1%, and 2.1% of colostrum samples were positive for IgG, IgM, and IgA, respectively. Specific IgG1, IgG3, and IgG4 were positive, respectively, in 98.5%, 54.6%, and 44.6% of serum samples, in contrast with 56.9%, 78.5%, and 34.6% of colostrum samples. Thus, the predominant reactivity of IgG subclasses against T. gondii was IgG1 in serum and IgG3 in colostrum. The higher percentage of positive samples and higher levels of anti-T. gondii IgG3 antibodies were observed in colostrum, when compared to serum samples, suggesting a local production of this subclass. IgG3 and IgG1 subclasses presented different percentages of positivity in serum and colostrum. Only the IgG1 subclass showed a significant correlation between the levels of anti-T. gondii in serum and colostrum, suggesting that IgG1 in breast milk comes from a systemic source. IgG4 showed a similar percentage of positivity in both sample types, but no significant correlation was observed between their levels. Conclusion: Colostrum presents representative levels of IgM, IgA, IgG1, IgG3, and IgG4 antibodies specific to T. gondii. The detection of these antibodies presents the potential for diagnostic application of colostrum samples to better identify the diagnostic status of T. gondii infection, especially during the acute phase. In addition, breastfeeding can also be a possible source of protective antibodies for the newborn against toxoplasmosis, an anthropozoonosis maintained by environmental infection, which interferes in the public health of many countries.

Circulating inflammatory mediators as biomarkers of ocular toxoplasmosis in acute and in chronic infection

Toxoplasmosis is highly endemic worldwide. In Brazil, depending on the geographical region and socioeconomic status, 40-70% of individuals become seropositive at some point in their lives. A significant proportion of Toxoplasma gondii-chronically infected individuals who are otherwise immunocompetent develop recurrent ocular lesions. The inflammatory/immune mechanisms involved in development of ocular lesion are still unknown and, despite previous investigation, there are no reliable immune biomarkers to predict/follow disease outcome. To better understand the impact of the immune response on parasite control and immunopathology of ocular toxoplasmosis, and to provide insights on putative biomarkers for disease monitoring, we assessed the production of a large panel of circulating immune mediators in a longitudinal study of patients with postnatally acquired toxoplasmosis stratified by the presence of ocular involvement, both at the early acute stage and 6 months later during chronic infection, correlating them with presence of ocular involvement. We found that T. gondii-infected patients, especially during the acute stage of the disease, display high levels of chemokines, cytokines, and growth factors involved in the activation, proliferation, and migration of inflammatory cells to injured tissues. In particular, major increases were found in the IFN-induced chemokines CXCL9 and CXCL10 in T. gondii-infected patients regardless of disease stage or clinical manifestations. Moreover, a specific subgroup of circulating cytokines and chemokines including GM-CSF, CCL25, CCL11, CXCL12, CXCL13, and CCL2 was identified as potential biomarkers that accurately distinguish different stages of infection and predict the occurrence of ocular toxoplasmosis. In addition to serving as predictors of disease development, these host inflammatory molecules may offer promise as candidate targets for therapeutic intervention.

FUT3 and FUT2 genotyping and glycoconjugate profile Lewisb as a protective factor to Toxoplasma gondii infection

The interaction between the ABO, FUT2 and FUT3 genes results in the synthesis of different glycoconjugates profiles expressed in gastrointestinal tract. Moreover, the protozoan Toxoplasma gondii, which causes toxoplasmosis, utilizes this organ as an infection route. We analyzed the frequencies of the different glycoconjugate profiles which were determined by phenotyping ABO and genotyping the status secretor (FUT2; substitution G428A) and Lewis (FUT3; substitution T202C and C314T) histo-blood systems, assessed by PCR-RFLP and PCR-SSP, respectively. A total of 244 pregnant women (G1: Seropositive; G2: Seronegative) for IgG T. gondii antibodies were enrolled. IgG anti-T. gondii antibodies were determined by ELISA. G1 was composed of 158 (64.8%) sample and G2 by 86 (36.2%). The glycoconjugate profile was accessed in 151 seropositive and 85 seronegative samples by the combination of ABO and Lewis phenotyping as well as FUT2 and FUT3 genotyping. In G1, 36 (22.8%) presented the glycoconjugate profile ALeb, 5 (3.3%) A, 13 (8.6) BLeb, 1 (0.6%) B, 41 (27.1%) Leb, 13(8.6%) H, 38(25.2%) Lea and 4 (2.6%) Lec. G2 was composed of 13 (15.3%) of ALeb, 15 (17.6%) BLeb, 1 (1.2%) B, 42 (49,4%) Leb and 14 (16.5) Lea. H and Lec glycoconjugate profiles were not found in G2. The frequencies of the glycoconjugates profiles Leb (p = 0.001) and H (p = 0.005) were significantly different compared between G1 and G2. The glycoconjugate profile H inferred from the ABO phenotyping and FUT3 and FUT2 genotyping is associated with infection by T. gondii in pregnant women and the Leb profile appears to protect the infection by this parasite.

CCR5 chemokine receptor gene polymorphisms in ocular toxoplasmosis

CC chemokine receptor type 5 (CCR5) is a chemokine receptor that influences the immune response to infectious and parasitic diseases. This study aimed to determine whether the CCR5Δ32 and CCR5 59029 A/G polymorphisms are associated with the development of ocular toxoplasmosis in humans. Patients with positive serology for Toxoplasma gondii were analyzed and grouped as 'with ocular toxoplasmosis' (G1: n=160) or 'without ocular toxoplasmosis' (G2: n=160). A control group (G3) consisted of 160 individuals with negative serology. The characterization of the CCR5Δ32 and CCR5 59029 A/G polymorphisms was by PCR and by PCR-RFLP, respectively. The difference between the groups with respect to the mean age (G1: mean age: 47.3, SD±19.3, median: 46 [range: 18-95]; G2: mean age: 61.3, SD±13.7, median: 61 [range: 21-87]; G3: mean age: 38.8, SD±17.9, median: 34 [range: 18-80]) was statistically significant (G1 vs.G2: p-value <0.0001; t=7.21; DF=318; G1 vs.G3: p-value <0.0001; t=4.32; DF=318; G2 vs. G3: p-value <0.0001; t=9.62; DF=318). The Nagelkerke r² value was 0.040. There were statistically significant differences for the CCR5/CCR5 (p-value=0.008; OR=0.261), AA (p-value=0.007; OR=2.974) and AG genotypes (p-value=0.018; OR=2.447) between G1 and G2. Individuals with the CCR5/CCR5 genotype and simultaneously the CCR5-59029 AA or AG genotypes have a greater risk of developing ocular toxoplasmosis (4% greater), which may be associated with a strong and persistent inflammatory response in ocular tissue.

A Brazilian report using serological and molecular diagnosis to monitoring acute ocular toxoplasmosis

Background

Toxoplasmosis was recently included as a neglected disease by the Center for Disease Control. Ocular toxoplasmosis is one clinical presentation of congenital or acquired infection. The laboratory diagnosis is being used worldwide to support the clinical diagnosis and imaging. The aim of this study was to evaluate the use of serology and molecular methods to monitor acute OT in immunocompetent patients during treatment.

Methods

Five immunocompetent patients were clinically diagnosed with acute OT. The clinical evaluation was performed by ophthalmologic examination using the Early Treatment Diabetic Retinopathy Study, best-corrected visual acuity, slit lamp biomicroscopy, fundoscopic examination with indirect binocular ophthalmoscopy color fundus photography, fluorescein angiography and spectral optical coherence tomography (OCT). Serology were performed by ELISA (IgA, IgM, IgG) and confirmed by ELFA (IgG, IgM). Molecular diagnoses were performed in peripheral blood by cPCR using the Toxoplasma gondiiB1 gene as the marker. Follow-up exams were performed on day +15 and day +45.

Results

Only five non-immunocompromised male patients completed the follow up and their data were used for analysis. The mean age was 41.2 ± 11.3 years (median: 35; range 31–54 years). All of them were positive for IgG antibodies but with different profiles for IgM and IgA, as well as PCR. For all patients the OCT exam showed active lesions with the inner retinal layers being abnormally hyper-reflective with full-thickness disorganization of the retinal reflective layers, which assumed a blurred reflective appearance and the retina was thickened.

Conclusions

The presence of IgA and IgM confirmed the acute infection and thus was in agreement with the clinical evaluation. Our results show the adopted treatment modified the serological profile of IgM antibodies and the PCR results, but not the IgG and IgA antibodies and that imaging is a good tool to follow-up patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1650-6) contains supplementary material, which is available to authorized users.

Prematurity and Low Birth Weight did not Correlate with Anti-Toxoplasma gondii Maternal Serum Profiles--a Brazilian Report

Gestational Toxoplasma gondii infection is considered a major risk factor for miscarriage, prematurity and low birth weight in animals. However, studies focusing on this topic in humans are scarce. The objective of this study is to determine whether anti-Toxoplasma gondii maternal serum profiles correlate prematurity and low birth weight in humans. The study examined 213 pregnant women seen at the High-Risk Pregnancy Hospital de Base, São José do Rio Preto, São Paulo, Brazil. All serological profiles (IgM-/IgG+; IgM-/IgG-; IgM+/IgG+) were determined by ELISA commercial kits. Maternal age, gestational age and weight of the newborn at birth were collected and recorded in the Statement of Live Birth. Prematurity was defined as gestational age <37 weeks and low birth weight ≤ 2499 grams. The t-test was used to compare values (p < 0.05). The mean maternal age was 27.6±6.6 years. Overall, 56.3% (120/213) of the women studied were IgM-/IgG+, 36.2% (77/213) were IgM-/IgG- and 7.5% (16/213) were IgM+/IgG+. The average age of the women with serological profile IgM+/IgG+ (22.3±3.9 years) was different from women with the profile IgM-/IgG+ (27.9±6.7 years, p = 0.0011) and IgM-/IgG- (27.9±6.4 years, p = 0.0012). There was no statistically significant difference between the different serological profiles in relation to prematurity (p = 0.6742) and low birth weight (p = 0.7186). The results showed that prematurity and low birth weight did not correlate with anti-Toxoplasma gondii maternal serum profiles.