Evaluating the presence of Toxoplasma gondii in peripheral blood of patients with diverse forms of uveitis.

The purpose of this study was to evaluate the presence of Toxoplasmosis gondii in samples of peripheral blood from patients with varying etiologies of uveitis. Whole blood from patients with different forms of uveitis was tested for the presence of T. gondii using real-time PCR targeting the well-characterized 529 bp fragment. Extracted DNA was both frozen. Thirty-one patients were included in the current study and grouped as follows: acute toxoplasmosis (n = 10); toxoplasmic retinal scars (n = 9); non-infectious etiologies of uveitis (n = 6); and IgG negative for toxoplasmosis (n = 6). In total, only two patients were shown to have circulating T. gondii in peripheral blood; both of these patients were IgG positive for toxoplasmosis, were receiving immunosuppressive therapy for autoimmune uveitis, and had no clinical features of toxoplasmosis. T. gondii was identified in peripheral blood of some immunosuppressed patients. No other patients, including those with acute toxoplasmosis, had circulating parasites in peripheral blood.

Post-prophylaxis Toxoplasma chorioretinitis following donor-recipient mismatched liver transplantation.

Toxoplasmosis may be transferred by organ transplantation. The most common clinical presentation is with multisystem disease, although isolated ocular toxoplasmosis has been described. Many centers have suggested that universal use of co-trimoxazole prophylaxis obviates the need for specific Toxoplasma testing. We report a case of donor-acquired ocular toxoplasmosis after liver transplantation despite co-trimoxazole prophylaxis. The diagnosis was confirmed by Toxoplasma polymerase chain reaction assay in conjunction with seroconversion. The fact that the infection was donor acquired was confirmed by serological mismatch and the absence of sporozoite-specific antigen antibody in the recipient.

Single nucleotide polymorphisms in the interferon gamma gene are associated with distinct types of retinochoroidal scar lesions presumably caused by Toxoplasma gondii infection.

The association of single nucleotide polymorphisms (SNPs) in the interferon (IFN)-γ gene ( IFNG ) with different types of retinal scar lesions presumably caused by toxoplasmosis were investigated in a cross-sectional population-based genetic study. Ten SNPs were investigated and after Bonferroni correction, only the associations between SNPs rs2069718 and rs3181035 with retinal/retinochoroidal scar lesions type A (most severe scar lesions) and C (least severe scar lesions), respectively, remained significant. The associations of two different IFNG SNPs with two different types of retinal lesions attributable to toxoplasmosis support the hypothesis that different inflammatory mechanisms underlie the development of these lesions. The in vitro analysis of IFN-γ secretion by peripheral blood mononuclear cells stimulated with Toxoplasma gondii antigens was also investigated. The association between SNP rs2069718 and type A scar lesions revealed that differential IFN-γ levels are correlated with distinct genotypes. However, no correlation was observed with IFN-γ secretion levels and the SNP rs3181035 , which was significantly associated with type C scar lesions. Our findings strongly suggest that immunogenetic studies of individuals with congenital or postnatally acquired infection are needed to better understand the role of IFN-γ and its polymorphisms in the pathogenesis of ocular toxoplasmosis.

Toxoplasma serotype is associated with development of ocular toxoplasmosis.

BACKGROUND: Worldwide, ocular toxoplasmosis (OT) is the principal cause of posterior uveitis, a severe, life-altering disease. A Toxoplasma gondii enzyme-linked immunoassay that detects strain-specific antibodies present in serum was used to correlate serotype with disease. METHODS: Toxoplasma serotypes in consecutive serum samples from German uveitis patients with OT were compared with non-OT seropositive patients with noninfectious autoimmune posterior uveitis. OT patients were tested for association of parasite serotype with age, gender, location, clinical onset, size, visual acuity, or number of lesions (mean follow-up, 3.8 years) to determine association with recurrences. RESULTS: A novel, nonreactive (NR) serotype was detected more frequently in serum samples of OT patients (50/114, 44%) than in non-OT patients (4/56, 7%) (odds ratio, 10.0; 95% confidence interval 3.4-40.8; P < .0001). Non-OT patients were predominantly infected with Type II strains (39/56; 70%), consistent with expected frequencies in Central Europe. Among OT patients, those with NR serotypes experienced more frequent recurrences (P = .037). Polymerase chain reaction detected parasite DNA in 8/60 OT aqueous humor specimens but failed to identify Type II strain alleles. CONCLUSIONS: Toxoplasma NR and Type II serotypes predominate in German OT patients. The NR serotype is associated with OT recurrences, underscoring the value of screening for management of disease.

[Interleukin 8 and interferon gamma in ocular toxoplasmosis]. / Interleukina 8 oraz interferon gamma w ocznej postaci toksoplazmozy.

UNLABELLED: Toxoplasmosis is one of the most common parasitic infections in the world, it is caused by Toxoplasma gondii. The infection is typically asymptomatic or the symptoms are very mild. Approximately 10% patients have limphadenopathy, involvement of the others organs, like eyes, nervous system, liver, heart, are observed more rarely. PURPOSE: The aim of our study was to assess the level of selected cytokines in blood among patients with ocular toxoplasmosis. MATERIAL AND METHODS: We have enrolled in the study 30 patients, 19-42 years old, treated for ocular toxoplasmosis, and 20 healthy volunteers, 20-48 years old, to the control group. Tests for blood morphology, C-reactive protein, the level of IL-8 and IFN-gamma were performed in all patients. The blood parameters in toxoplasmosis group were performed before antiparasitic treatment was given. RESULTS: The level of IFN-gamma in blood was lower among patients with ocular toxoplasmosis comparing with control group (1.52 vs. 4.18 pg/ml; p = 0.002). The level of IL-8 in blood was lower among patients with ocular toxoplasmosis comparing with control group (22.96 vs. 94.3 pg/ml; p = 0,007). There were no correlations between analyzed cytokines and blood morphology or CRP. CONCLUSIONS: The low level of IFN-gamma and IL-8 in blood is important factor leading to reactivation of the ocular toxoplasmosis.

Postnatal ocular toxoplasmosis in immunocompetent patients.

INTRODUCTION: Ocular toxoplasmosis is the most common cause of infectious posterior uveitis worldwide. It can be prenatal or postnatal in origin. Despite estimations that postnatal ocular toxoplasmosis is more prevalent, only several cases of proven postnatal ocular toxoplasmosis have been reported in non-epidemic settings. Here, the clinical evolution of ocular toxoplasmosis of conclusively proven postnatal origin in immunocompetent patients is reported. METHODOLOGY: Postnatal ocular toxoplasmosis was diagnosed based on clinical diagnosis supported by the longitudinal detection of Toxoplasma gondii-specific IgG, IgM and IgA antibodies in the serum as well as by direct detection of the parasite (bioassay) and/or its DNA (real-time PCR) in aqueous humor. RESULTS: Three cases involved adults in whom ocular toxoplasmosis developed during primary T. gondii infection, as part of the clinical presentation in two and as the sole manifestation in one patient. The fourth patient was a case of inactive ocular toxoplasmosis in a 14-year-old boy, where postnatal infection was confirmed by exclusion of maternal infection. The causative parasite strain was genotyped in only one case and it belonged to genotype II, the dominant type in Europe. One patient acquired the infection in Africa, suggesting an atypical strain. CONCLUSIONS: The distinction between prenatal and postnatal ocular toxoplasmosis is only possible in particular clinical situations, and requires extensive laboratory investigation. Genotyping of the parasite strain involved may be important, particularly if atypical strains are suspected, requiring tailored treatment approaches.

Ocular toxoplasmosis: phenotype differences between toxoplasma IgM positive and IgM negative patients in a large cohort.

PURPOSE: To investigate the differences in demographics and clinical characteristics of patients diagnosed with ocular toxoplasmosis according to their IgM status. METHODS: Retrospective case note analysis was carried out on patients who tested positive for serum Toxoplasma gondii-specific IgM antibodies (IgM+) as well as a comparator group who tested negative for serum IgM (IgM-), but positive for serum IgG. Patient demographics and clinical features were compared between the two groups to evaluate for any significant differences. RESULTS: One hundred and six patients were included in the study between March 2011 and June 2018, consisting of 37 in the IgM +group and 69 in the IgM- group. Patients in the IgM +group were significantly older (51.1 vs 34.1 years, p<0.0001), more likely to present with central macular lesions (32% vs 12%, p=0.012), and more likely to develop rhegmatogenous retinal detachment (11% vs 1%, p=0.049). In contrast, patients in the IgM- group were more likely present with pain (20% vs 3%, 0.017) and exhibit more severe inflammation of the anterior chamber and vitreous (p<0.05). Overall, retinal lesions were more likely to be superotemporal (55%) and superonasal (31%). Furthermore, age was associated with larger (p=0.003) and more peripheral lesions (p=0.007). CONCLUSIONS: This study demonstrated significant differences in clinical characteristics of ocular toxoplasmosis according to serum IgM status. IgM+ patients were older, less likely to report pain, had lower levels of intraocular inflammation, but were more likely to have macular involvement. We also found age to be correlated with larger and more peripheral lesions.

Intraocular and serum levels of vascular endothelial growth factor in acute retinal necrosis and ocular toxoplasmosis.

PURPOSE: To determine the intraocular and serum vascular endothelial growth factor (VEGF) levels in patients with acute retinal necrosis (ARN) and compare those with VEGF levels found in patients with ocular toxoplasmosis (OT). METHODS: Paired intraocular fluid and serum samples of 17 patients with ARN and of 16 patients with OT were analyzed by ELISA for VEGF levels, and the clinical records were reviewed. RESULTS: The mean intraocular VEGF levels in patients with ARN were higher than in patients with OT (P = 0.005), whereas the serum levels did not differ. Intraocular VEGF levels exceeded the serum levels in 8 of 17 patients (47%) with ARN compared with 1 of 16 patients (6%) with OT (P = 0.009). The group with high intraocular VEGF was associated with a more extensive retinitis and lower visual acuity at 3-month follow-up (P < 0.001 and P = 0.031, respectively). CONCLUSION: Intraocular VEGF levels were elevated in patients with ARN compared with OT patients. Our results suggest strong intraocular VEGF production in ARN, which might be of importance for the treatment of these patients.

Detection of Toxoplasma gondii DNA by PCR following microwave treatment of serum and whole blood.

Detection of Toxoplasma gondii in blood by means of the polymerase chain reaction (PCR) may facilitate early diagnosis of toxoplasmosis in different groups of patients. We evaluated this approach in 42 patients presenting with ocular or psychotic diseases by comparing the sensitivity and specificity of PCR after heat treatment using a microwave oven with a standard genomic DNA extraction method for paired serum and whole blood samples. The presence of serum IgM and IgG antibodies against T. gondii was detected using a standard commercial enzyme-linked immunosorbent assay and enzyme immunoassay for IgG avidity test. Of 42 whole blood samples, PCR after microwave treatment was positive in 8 samples with a sensitivity of 73% and specificity of 100% compared to 11 samples positive by the extraction method. Although none of 42 sera samples was PCR positive by the extraction method, 7 specimens were positive after microwave treatment. This is the first study to use a microwave heat treatment, which is simple, rapid and a promising alternative method, in detecting small amounts of T. gondii DNA in human blood. Furthermore, irradiation of blood samples with microwaves allows incorporation of PCR into a practical tool for routine clinical assessment of patients with Toxoplasma infection.

[Toxoplasmic central chorioretinitis]. / Corioretinita centrala toxoplasmozica--1 prezentare de caz.

Toxoplasma gondii is the most frequent cause of chorioretinitis in immunocompetent patients. This paper highlights the case of a 15 years old girl, an immunocompetent patient, with an active chorioretinal focus in the LE and a chorioretinal scar in the RE. Serologically, the IgG antiToxoplasma titre is increased, but the IgM antibodies are negative. It is the bilateral character of the lesions and the serology found that make this case special.

Putative biomarkers for early diagnosis and prognosis of congenital ocular toxoplasmosis.

In the present study we have evaluated the performance of several immunological biomarkers for early diagnosis and prognosis of congenital toxoplasmosis. Our results showed that ex vivo serum levels of CXCL9, and the frequencies of circulating CD4+CD25+ T-cells and T. gondii-specific IFN-γ+CD4+ T-cells measured 30-45 days after birth presented high accuracy to distinguish T. gondii-infected infants from healthy age-matched controls (Global Accuracy/AUC = 0.9; 0.9 and 0.8, respectively). Of note was the enhanced performance (Accuracy = 96%) achieved by using a combined stepwise analysis of CD4+CD25+ T-cells and CXCL9. In addition, high global accuracy (AUC = 0.9) with elevated sensitivity (Se = 98%) was also reached by using the total frequency of in vitro IFN-γ-producing T. gondii-specific T-cells (∑ IFN-γ+ CD4+ & CD8+) as a biomarker of congenital toxoplasmosis. Furthermore, the analysis of in vitro T. gondii-specific IL5+CD4+ T-cells and IFN-γ+NK-cells displayed a high accuracy for early prognosis of ocular lesion in infant with congenital toxoplasmosis (Global Accuracy/AUC = 0.8 and 0.9, respectively). Together, these findings support the relevance of employing the elements of the cell-mediated immune response as biomarkers with potential to endorse early diagnosis and prognosis of congenital ocular toxoplasmosis to contribute for a precise clinical management and effective therapeutic intervention.

Duffy blood group system and ocular toxoplasmosis.

Duffy blood group phenotypes [Fy(a + b-), Fy(a-b+), Fy(a + b+), Fy(a-b-)], characterized by the expression of Fya, and Fyb antigens, are present in red blood cells. Therefore, we hypothesize that the non-hematopoietic expression of these antigens might influence cell invasion by T. gondii. 576 consecutive patients from both genders were enrolled. The presumed OT clinical diagnosis was performed. Duffy phenotyping was performed by hemagglutination in gel columns and for the correct molecular characterization Fy(a-b-) phenotype, using PCR-RFLP. Anti-T. gondii IgG antibodies were detected by ELISA. Chi-square, Fisher's exact tests were used to compare the proportions. OT was present in 22.9% (n = 132) and absent in 77.1% (n = 444) of patients. The frequencies of anti-T. gondii IgG antibodies were higher in OT (127/132, 96.2%) than those without this disease (321/444, 72.3%) (p < .0001). None of the Duffy antigens or phenotypes were associated with T. gondii infection (χ2: 2.222, GL: 3, p = .5276) as well as the risk of OT (χ2: 0.771, GL: 3, p = .8566). Duffy blood group system phenotypes and their antigens do not constitute risk factors for infection by T. gondii infection and the development of OT.

Evaluation of RE and B1 Genes as Targets for Detection of Toxoplasma gondii by Nested PCR in Blood Samples of Patients with Ocular Toxoplasmosis.

INTRODUCTION: To evaluate B1 and RE genes as targets to detect Toxoplasma gondii, nested PCR is used in blood samples of patients with ocular toxoplasmosis. MATERIALS AND METHODS: Following the measurement of IgG and IgM antibodies using indirect ELISA, IgG avidity and assessment of blood samples by nested PCR, the agreement between various test results was studied. RESULTS: From 117 patients, 77 (65.81%) were found to be positive for IgG anti-Toxoplasma antibody, 12 cases were positive for both IgG and IgM, and 1 patient was positive for IgM only. The detection limit for the RE-nested PCR assay was one T. gondii tachyzoite, whereas the limit for B1-nested PCR was five tachyzoites. Nested PCR results showed higher agreement with IgM test results than IgG test results. CONCLUSION: The results of this study showed that nested PCR of peripheral blood is a useful and non-invasive method for detection of T. gondii in patients with OT, especially in case of recently acquired infections, and RE targeted assay is more sensitive than B1 targeted assay for this purpose.

Diagnostic Value of Positive Findings of Toxoplasma gondii-Specific Immunoglobulin M Serum Antibody in Uveitis Patients to Confirm Ocular Toxoplasmosis.

Purpose: To assess the value of positive immunoglobulin (Ig) M serum antibody (Ab) findings in uveitis patients. Methods: We reviewed medical records of patients who had a positive serological test for Toxoplasma gondii-specific IgM Ab. Their clinical data, including history, demographic characteristics, laboratory findings, clinical findings, treatment outcomes, and recurrences, were reviewed retrospectively. Results: Of 2919 uveitis patients who underwent a serological test for suspected ocular toxoplasmosis (OT), 18 presented with positive Ig M results. All 18 patients (100.0% specificity) were clinically diagnosed with OT. None had any retinochoroidal scar at the initial visit, indicating the OT was a recent and primary infection. However, 15 patients (83.3%) had no history suspected to account for the Toxoplasma transmission. Conclusions: The T. gondii IgM serum Ab is a specific biomarker for diagnosis of primary OT. Epidemiological studies are warranted to investigate the non-classic transmission routes of T. gondii in OT.

Epidemiological Investigation of Toxoplasma gondii Infections in Commercial Sheep Flock in an Endemic Area for Ocular Toxoplasmosis in Southern Brazil.

INTRODUCTION: Toxoplasma gondii is a widely distributed parasite and of great importance to human and animal health. METHODS: The objective of this study was to assess the prevalence of T. gondii antibodies and risk factors associated with the infection in sheep in the Northwest region of the State of Rio Grande do Sul, Brazil; this region has a very high rate of human ocular toxoplasmosis. Ovine sera were tested by the modified agglutination test (cut-off 1:25). RESULTS: T. gondii antibodies were detected in 70.2% (224 of 319). According to the logistic regression, the most significant factors associated were age and cat access to food stock facility. CONCLUSION: Preventive measures are discussed to reduce the risk of transmission of this zoonosis.

Macular Colobomata: Comparison of Clinical and Optical Coherence Tomography Features With Serologic Results.

PURPOSE: To assess the correlation between the morphologic features and serology in eyes with macular colobomata (MC). DESIGN: Retrospective comparative case series. METHODS: Setting: Institutional. STUDY POPULATION: Patients presenting with MC to the retina clinic over a period of 2 years (January 2016 to December 2017). Interventional/Observational Procedure: Color fundus and swept-source optical coherence tomography (SSOCT) features were reviewed and assessed in 3 groups based on the serum IgG results: positive for Toxoplasma, positive for cytomegalovirus (CMV), and serology negative. MAIN OUTCOME MEASURE: Morphologic features on clinical and OCT-based examination. RESULTS: A total of 49 eyes of 27 patients were recruited. The mean age was 24.8 ± 14.9 years (range 7-60 years). While the lesion size, the presence of satellite lesions, choroidal excavation, and choroidal lacunae (large choroidal vessels) on SSOCT differed significantly among the groups, pigmentation, retinal fibrosis, shape, retinal vessel pattern, and choroidal vessel visibility did not vary significantly. The lesions in CMV serology-positive cases were mostly solitary (n = 8/8), large (n = 5/8) and deeply excavated (n = 8/8). The lesions in Toxoplasma serology-positive cases were mostly flat to shallow (n = 18/26), medium-sized (n = 19/26), and either a solitary lesion (n = 17/26) or multiple satellite lesions (n = 9/26). The lesions in serology-negative cases were mostly small to medium (n = 13/15), solitary (n = 15/15), deeply excavated lesions (n = 11/15) with choroidal lacunae (n = 8/15). CONCLUSIONS: The clinical and SSOCT features such as the lesion size, the presence of satellite lesions, choroidal excavation, and choroidal lacunae can provide a clue toward the etiology of macular colobomata.

Comparison of immunoblotting (IgA and IgG) and the Goldmann-Witmer coefficient for diagnosis of ocular toxoplasmosis in immunocompetent patients.

BACKGROUND: Ocular toxoplasmosis (OT) is a common cause of posterior uveitis worldwide. The diagnosis of OT is based on clinical findings, but in most cases, laboratory tests are required to confirm the aetiology, especially when other diseases are suspected. The aim of this study was to evaluate which methods, between the Goldmann-Witmer coefficient (GWC) and immunoblotting (IB) with both IgG and IgA, in aqueous humour (AH) samples, can be the most sensitive to diagnose OT, in current practice, especially in the first three weeks. METHODS: Retrospectively reviewed records of 87 consecutive patients who had underwent AH and serum sample, 42 patients with suspected OT and 45 patients with suspected other ocular inflammatory diseases. All samples were analysed by both GWC and IB. RESULTS: The GWC was significant in 47.6% of patients presenting with suspected OT. The intraocular production of specific antibody anti-Toxoplasma gondii IgG and IgA was revealed by IB in 71.4% of samples. The combination of these two methods increased the sensitivity to 76.2%. Based on the interval between symptom onset and paracentesis, IB had a greater sensitivity than GWC when sample of AH was taken in the first three weeks (64.7% vs 23.5%, P=0.039), while the difference between the sensitivity of IB and GWC was less important in cases with an interval >3 weeks (76% vs 64% P=0.625). CONCLUSION: IB seems to be more useful than the GWC if only one of these methods can be performed, especially during the first three weeks after symptom onset.

Use of polymerase chain reaction (PCR) in the diagnosis of congenital toxoplasmosis.

Congenital toxoplasmosis (CT) is a parasitic disease that causes serious fetal and neonatal harm or death. In countries that do not have antenatal screening programs, the initiation of CT treatment relies on a postnatal diagnosis. Until recently, diagnosis was based on clinical signs and immunoglobulin seropositivity, which is fraught with difficulty. In these cases, diagnosis was often delayed or treatment, which carries risk, started empirically. We highlight the use of polymerase chain reaction to diagnose a case of congenital toxoplasmosis, allowing early treatment and justifying the treatment burden.

Serum levels of neurotrophic factors in active toxoplasmic retinochoroiditis.

Toxoplasmic retinochoroiditis (TR) is the most common identifiable cause of posterior uveitis in Brazil. Response to treatment and clinical presentation may vary significantly. We assessed serum levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), neurotrophin (NT)-3, and NT-4/5 in patients with active TR, before and after TR treatment. METHODS: Twenty patients with active lesion and 15 healthy controls were enrolled in the study. Serum concentration of neurotrophic factors was determined by enzyme-linked immunosorbent assay. RESULTS: BDNF levels were significantly higher in patients before treatment when compared with controls (p=0.0015). There was no significant difference in pro-BDNF, NGF, GDNF, NT-3, and NT-4/5 levels between TR patients and controls. Treatment did not affect the levels of these factors. CONCLUSION: BDNF may be released in the context of the active TR inflammatory response.

Systemic T cell response to Toxoplasma gondii antigen in patients with ocular toxoplasmosis.

PURPOSE: Analysis of systemic cellular response to Toxoplasma antigen in patients with ocular toxoplasmosis. METHODS: Activated (CD25(+)) T cells were detected by flow cytometry after a 7-day culture of whole blood from patients with ocular (n = 16) or asymptomatic (n = 14) toxoplasmosis, and controls (n = 10), in the presence of soluble Toxoplasma antigen (ST-Ag). Interferon (IFN)-gamma, interleukin (IL) 4, and IL-10 were measured in culture supernatants by enzyme-linked immunosorbent assay. RESULTS: Higher percentages of CD25(+) T cells were detected in ST-Ag-activated cultures from Toxoplasma-infected patients, with or without ocular lesions (37.0 +/- 19.1% or 41.1 +/- 19.3%, respectively) than from controls (3.2 +/- 1.2%) (P < 0.0001). Differences were not statistically significant between asymptomatic and ocular toxoplasmosis (P > 0.4) or among congenital, acquired, and undetermined ocular toxoplasmosis (P > 0.2). Higher levels of IFN-gamma were detected in ST-Ag-stimulated blood cultures from infected patients than in those from controls (P < 0.0001), with no difference between patients with asymptomatic or ocular toxoplasmosis (P > 0.05). IL-10 was detected only in activated culture supernatants from three patients with ocular toxoplasmosis and two patients with asymptomatic toxoplasmosis. IL-4 was never produced in ST-Ag-activated cultures. CONCLUSIONS: Systemic cellular response to ST-Ag does not differ between the patients with ocular and asymptomatic toxoplasmosis with regard to activation markers and type 1 cytokine production.