Indirect Immunofluorescence Test Research Articles

Seroprevalence of Trypanosoma cruzi among children from Veracruz, Mexico: Epidemiological baseline for a control model based on Chagas disease active transmission

Introduction. In 2021, the Secretaría de Salud de México and the Pan American Health Organization launched an initiative to interrupt intra-domiciliary vector transmission of Trypanosoma cruzi based on the prevalence of Chagas disease in children. The Mexican State of Veracruz was leading this initiative. Objective. To estimate the seroprevalence of T. cruzi infection among children under 15 years of age from rural areas of Veracruz, México. Materials and methods. We identified eight localities of high priority from the Municipality of Tempoal, Veracruz, for baseline serology. Blood samples were collected on filter paper from 817 individuals between June and August 2017, for screening with a third-generation enzyme immunoassay. Reactive cases were confirmed by indirect hemagglutination, enzyme-linked immunosorbent assay, and indirect immunofluorescence tests on peripheral blood serum samples. We calculated seroprevalence and 95% confidence intervals (CI). Results. We confirmed Chagas disease cases in children under 15 years of age with a seroprevalence of 1,9% (95 % CI = 1,12-3,16) in the localities of Citlaltepetl, Cornizuelo, Cruz de Palma and Rancho Nuevo. Conclusions. These results indicate recent transmission of T. cruzi in these communities and allow to establish an epidemiological baseline for the design and implementation of a model focused on geographical areas with active transmission to advance toward the elimination of intra-domiciliary vector transmission of this parasite in Mexico.

Detection of Anaplasma spp. and Ehrlichia spp. in dogs from a veterinary teaching hospital in Italy: a retrospective study 2012-2020.

Anaplasma phagocytophilum, Anaplasma platys and Ehrlichia canis, responsible of diseases in dogs, are tick-borne pathogens with a proven or potential zoonotic role that have shown increasing prevalence worldwide. The aims of this retrospective study were to assess the frequency of Anaplasma spp. and Ehrlichia spp. exposure in dogs tested in a veterinary teaching hospital in Italy over a 9-year period, to compare the performance of the diagnostic tests used, to evaluate correlations with clinical data, and to genetically analyse the identified bacteria. During the study period, 1322 dogs tested by at least one of the rapid immunoenzymatic test, indirect immunofluorescent antibody test or end-point PCR assay for Anaplasmataceae detection were included. Dogs were tested if they had clinical signs or clinicopathological alteration or risk factors related to infection, and if they were potential blood-donor animals. Ninety-four of 1322 (7.1%) dogs tested positive for at least one pathogen: 53 (4.3%) for A. phagocytophilum, one (0.1%) for A. platys and 63 (4.6%) for E. canis. The number of dogs tested increased and the positivity rate progressively declined over the years. Comparison of tests showed a near-perfect agreement between serological tests and a poor agreement between PCR and indirect assays. A breed predisposition has been highlighted for A. phagocytophilum infection in hunting breed dogs and for E. canis infection in mixed breed dogs. Phylogeny confirmed potential zoonotic implications for A. phagocytophilum and showed no correlation of the identified bacteria with the geographical origin. Our study provides new insights into possible risk factors in dogs and evidenced discordant results between different tests, suggesting that a combination of serological and molecular assays is preferable for a correct diagnosis.

Toxoplasmosis Behind Bars: One Health Approach on Serosurvey Dynamics and Associated Risk Factors for Women Inmates, Correctional Officers, and In-Prison Feral Cats

Brazil holds the third highest general and fifth female incarcerated population worldwide. Despite the incarceration ecosystem that may favor the spreading of zoonotic diseases, particularly when unattended animals are present, no comprehensive study has focused on toxoplasmosis dynamics in such environment. Accordingly, the present study has aimed to serologically assess anti-Toxoplasma gondii (IgG) antibodies by indirect immunofluorescent antibody test in inmates, correctional officers, and feral cats at the Women’s State Penitentiary of Parana, southern Brazil. In overall, 230/506 (45.5%; CI 95%: 41.2–49.8) incarcerated women, 31/91 (34.1%; 95% CI: 25.2–44.3) correctional officers, and 23/39 (59.0%; CI 95%: 43.2–72.9) cats were seropositive to anti-T. gondii antibodies. Logistic regression revealed that seropositivity likelihood increased with consumption of raw meat (p=0.040) and decreased with elementary educational level (p=0.001). No statistical difference was found comparing seropositivity between inmates and correctional officers (p=0.057). As women inmates have been considered among the most vulnerable groups in disease morbidity and mortality, seropositivity observed herein may be directly related to vulnerability and high T. gondii oocyst exposure dispersed in cat feces during incarceration.

Prevalence of a large panel of systemic autoantibodies in the Bavarian adult population.

Autoimmune diseases commonly feature the presence of specific humoral autoantibodies. However, the prevalence of a large panel of systemic autoantibodies has never been assessed in the general population. We, therefore, described the prevalence of about 50 humoral systemic autoantibodies in a sample of the general Bavarian adult population. Non-fasting venous serum samples from 331 participants were analyzed for 7 autoantibody screening tests (nuclear, cytoplasmic, and mitotic ANA, ANCA, cANCA and pANCA, anti-ENA autoantibodies) and 44 different monospecific humoral non-organ specific/systemic autoantibodies using indirect immunofluorescence tests, ELISAs, and line blots. In order to assess associations between sex, age, BMI, education level, smoking status and the presence of systemic autoantibodies, logistic regression analyses were conducted. At least one screening test was positive in 29.9% of the participants, and 42.3% of the participants were seropositive for at least one monospecific autoantibody. The most frequently found monospecific autoantibodies were rheumatoid factor (35.6%), ß2-glycoprotein 1 IgM (4.8%), and cardiolipin IgG (1.8%). Only few associations between sex, age, BMI, education, smoking status and autoantibody frequencies were observed. Systemic autoantibodies are common in the general Bavarian population, and largely independent of sex, age, BMI, education, or smoking status. The study results may give orientation to clinicians about the occurrence of autoantibodies in the population, not (yet) associated with clinical symptoms.

Automation in Indirect immunofluorescence testing

Automation in Indirect immunofluorescence testing

Spontaneous splenic rupture associated with scrub typhus: a case report

BackgroundScrub typhus, an acute febrile disease with mild to severe, life-threatening manifestations, potentially presents with a variety of complications, including pneumonia, acute respiratory distress syndrome, cardiac arrhythmias (such as atrial fibrillation), myocarditis, shock, peptic ulcer, gastrointestinal bleeding, meningitis, encephalitis, and renal failure. Of the various complications associated with scrub typhus, splenic rupture has rarely been reported, and its mechanisms are unknown. This study reports a case of scrub typhus-related spontaneous splenic rupture and identifies possible mechanisms through the gross and histopathologic findings.Case presentationA 78-year-old man presented to our emergency room with a 5-day history of fever and skin rash. On physical examination, eschar was observed on the left upper abdominal quadrant. The abdomen was not tender, and there was no history of trauma. The Orientia tsutsugamushi antibody titer using the indirect immunofluorescent antibody test was 1:640. On Day 6 of hospitalization, he complained of sudden-onset left upper abdominal quadrant pain and showed mental changes. His vital signs were a blood pressure of 70/40 mmHg, a heart rate pf 140 beats per min, and a respiratory rate of 20 breaths per min, with a temperature of 36.8 °C. There were no signs of gastrointestinal bleeding, such as hematemesis, melena, or hematochezia. Grey Turner's sign was suspected during an abdominal examination. Portable ultrasonography showed retroperitoneal bleeding, so an emergency exploratory laparotomy was performed, leading to a diagnosis of hemoperitoneum due to splenic rupture and a splenectomy. The patient had been taking oral doxycycline (100 mg twice daily) for 6 days; after surgery, this was discontinued, and intravenous azithromycin (500 mg daily) was administered. No arrhythmia associated with azithromycin was observed. However, renal failure with hemodialysis, persistent hyperbilirubinemia, and multiorgan failure occurred. The patient did not recover and died on the fifty-sixth day of hospitalization.ConclusionsClinicians should consider the possibility of splenic rupture in patients with scrub typhus who display sudden-onset abdominal pain and unstable vital signs. In addition, splenic capsular rupture and extra-capsular hemorrhage are thought to be caused by splenomegaly and capsular distention resulting from red blood cell congestion in the red pulp destroying the splenic sinus.Graphical abstract

Performance Analysis of Serodiagnostic Tests to Characterize the Incline and Decline of the Individual Humoral Immune Response in COVID-19 Patients: Impact on Diagnostic Management.

Serodiagnostic tests for antibody detection to estimate the immunoprotective status regarding SARS-CoV-2 support diagnostic management. This study aimed to investigate the performance of serological assays for COVID-19 and elaborate on test-specific characteristics. Sequential samples (n = 636) of four panels (acute COVID-19, convalescent COVID-19 (partly vaccinated post-infection), pre-pandemic, and cross-reactive) were tested for IgG by indirect immunofluorescence test (IIFT) and EUROIMMUN EUROLINE Anti-SARS-CoV-2 Profile (IgG). Neutralizing antibodies were determined by a virus neutralization test (VNT) and two surrogate neutralization tests (sVNT, GenScript cPass, and EUROIMMUN SARS-CoV-2 NeutraLISA). Analysis of the acute and convalescent panels revealed high positive (78.3% and 91.6%) and negative (91.6%) agreement between IIFT and Profile IgG. The sVNTs revealed differences in their positive (cPass: 89.4% and 97.0%, NeutraLISA: 71.5% and 72.1%) and negative agreement with VNT (cPass: 92.3% and 50.0%, NeutraLISA: 95.1% and 92.5%) at a diagnostic specificity of 100% for all tests. The cPass showed higher inhibition rates than NeutraLISA at VNT titers below 1:640. Cross-reactivities were only found by cPass (57.1%). Serodiagnostic tests, which showed substantial agreement and fast runtime, could provide alternatives for cell-based assays. The findings of this study suggest that careful interpretation of serodiagnostic results obtained at different times after SARS-CoV-2 antigen exposure is crucial to support decision-making in diagnostic management.

[Primeiros relatos de leishmaniose canina no noroeste do Rio Grande do Sul]

ABSTRACT This research aimed to carry out an epidemiological investigation of dogs with canine leishmaniasis in an area of Rio Grande do Sul with no history of notification of the disease. Leishmaniasis is considered an endemic zoonosis in different countries. In Brazil, it occurs mainly in the Southeast and Midwest regions, having drastically increased the number of notifications in recent years. In the state of Rio Grande do Sul, there are reports of the disease in the metropolitan region of Porto Alegre and in the border region in the west of the state, as well as in the central region. The investigation was conducted in 100 dogs from the municipalities of Frederico Westphalen and region. Whole blood was collected for immunochromatographic testing (TR DPP® Canine Visceral Leishmaniasis) and lymph node aspiration. Positives were confirmed by ELISA test and indirect immunofluorescence test with total dilution or immunohistochemistry after skin biopsy. Two animals were diagnosed with visceral leishmaniasis, considered the first reported cases of the disease in the canine population in the region. Therefore, it becomes necessary to research and control the potential presence of sandflies in the area. There is a hypothesis that the animals were contaminated in other regions of the country, remaining as a reservoir until the moment of diagnosis.

An impedimetric immunosensor for diagnosis of Brazilian spotted fever in blood plasma.

Brazilian spotted fever (BSF) is a serious disease of medical importance due to its rapid evolution and high lethality. The effectiveness of the treatment mainly depends on the rapid diagnosis, which is currently performed by indirect immunofluorescence and PCR tests, which require high costs and laboratory structure. In order to propose an alternative methodology, we sought to develop an impedimetric immunosensor (IM) based on the immobilization of specific IgY antibodies for IgG anti Rickettsia rickettsii, using blood plasma from capybara (Hydrochoerus hydrochaeris), for characterization, validation and applications of the ready IM. IM selectivity was observed when comparing capybara reagent IgG (IgGcr) readings with non-reagent IgG (IgGnr). A reagent IgG calibration curve was obtained, from which the limits of detection (LOD) and quantification (LOQ) of 1.3 ng mL-1 and 4.4 ng mL-1 were calculated, respectively. The accuracy tests showed that different concentrations of IgGcr showed a maximum deviation of 20.0%, with CI between 90.00% and 95.00%. Intermediate precision tests showed a relative standard deviation of 2.09% for researcher 1 and 2.61% for researcher 2, and the F test showed no significant difference between the recovery values found between the two analysts, since Fcal 1.56 < 5.05 and P-value 0.48 > 0, 05. Therefore, an impedimetric immunosensor was developed to detect anti BSF IgG in capybara blood plasma, which greatly contributes to the improvement of diagnostic tests, cost reduction and ease of execution.

Serological profile of IGG antibodies to viral capsid antigen of epstein-barr virus in oral pre-cancer and cancer patients

Cancer of the oral cavity is a major and increasing public health problem. Oral cancer is the sixth most common cancer reported globally with an annual incidence of over 300,000 cases, of which 62% arise in developing countries. In India, because of cultural, ethnic, and geographic factors and the popularity of addictive habits, the frequency of oral cancer is high. Despite the various etiological and predisposing factors associated with oral pre-cancer and cancer, the role of co-carcinogenic effects of viruses like HSV has been documented. With this background and considering the high prevalence of oral cancer in India an attempt has been made to study the association of EBV with oral cancer using serological methods.1. To study the IgG antibodies to Viral Capsid Antigen (VCA) of Epstein-Barr virus in oral pre-cancer and cancer by a laboratory standardized Indirect Immuno Fluorescent (IIF) test. 2. To compare and corelate the results of IIF test with a commercially available ELISA for VCA IgG antibodies to EBV. 3. To assess the severity of disease progression in oral pre-cancer and cancer using the serological profile.In the present study, 84 subjects were assessed for serum IgG antibodies to VCA of EBV using the IIF technique and later the results were compared with an ELISA kit. Group I were controls, Group II to Group V were oral squamous cell carcinoma subjects according to the clinical staging. Group VI comprised of oral pre-cancer subjects. Age range was between 40-70 years, and the mean age was 50.31 +/- 8.23 years. All the 42 control sera were positive for IgG antibodies to VCA of EBV but with a significantly low geometric mean titre(GMT) of 8.561.The GMTs of oral squamous carcinoma and pre-cancer sera was positive but progressively increased when compared to control sera and were highly significant (P&amp;#60;0.001).As there was a significant increase in the GMTs in oral squamous cell carcinoma subjects and pre-cancer subjects, serology of EBV may be interpreted to be useful in assessing the severity of the disease and the techniques of IIF and ELISA may be used as first line screeners when large number of subjects need to be assessed.

Comparison of laboratory methods for diagnosis of human visceral leishmaniasis in the Center-West Region of São Paulo State, Brazil

Visceral leishmaniasis (VL) is a neglected disease and represents an important public health problem. The present study aimed to compare the conventional laboratory methods with the molecular method for VL diagnosis in human blood samples. Direct parasitological test of bone marrow aspirate (direct parasitological test), rapid immunochromatographic test (RIT), indirect immunofluorescent antibody test (IFAT) and polymerase chain reaction (PCR) were used to evaluate 26 human samples with clinical suspicion of VL. The positivity rates obtained for direct parasitological test, RIT, IFAT and PCR were 80.8%, 80.8%, 73.1% and 84.6%, respectively. PCR had greater positivity and agreement with the other methodologies. Therefore, the use of PCR in the diagnostic routine should be encouraged to complement the serological results.

Longitudinal study of patients with discrepant results in CLIFT and a solid-phase dsDNA antibody assay: does a gold standard dsDNA assay exist?

ObjectiveAntidouble-stranded DNA (dsDNA) antibodies are essential for diagnosis and follow-up of systemic lupus erythematous (SLE). To ensure the best diagnostic approach, most healthcare laboratories opt for a combination of highly...

A-309 Challeging Diagnostic of Neurosyphilis: Use of CXCL13 Concentration in Cerebrospinal Fluid

Abstract Background Previous retrospective has been demonstrated the concentration of chemokine ligand CXCL13 in cerebrospinal fluid (CSF-CXCL13) is a promising biomarker in the diagnosis of neurosyphilis (NS) and monitoring of therapeutic efficacy. The goal of this study was to measure CXCL13 concentrations in CSF of NS suspected patients and compare with patients with syphilis non-NS and patients with treated syphilis. Methods One hundred and eleven NS-suspected participants from Rio de Janeiro (Brazil) were investigated for the detection of IgG antibodies against Treponema pallidum, using ELISA and Indirect Immunofluorescence tests (EUROIMMUN, Lübeck, Germany). CSF-CXCL13 concentration was prospectively performed by ELISA (EUROIMMUN, Lübeck, Germany) assay in all participants at baseline and in participants diagnosed with NS in follow-up visits at 3, 6, and 12 months after therapy. Results CSF-CXCL13 concentrations were significantly higher in patients with established NS presenting a median concentration of 207.4 pg/mL (IQR 69.3–1515.5 pg/mL) than in patients with syphilis non-NS with a median of 1.0 pg/mL (IQR 0.1–11.0 pg/mL, P &amp;lt; 0.001) or patients with treated syphilis with a median of 0.1 pg/mL (IQR 0.1–7.1 pg/mL, P &amp;lt; 0.001). The CSF-CXCL13 concentrations decreased after 3, 6 and 12 months of therapy compared to baseline in all cases of NS. The added concentration of CSF-CXCL13 above 62.8 pg/mL plus CSF-FTA-ABS reactivity agreed with diagnosis of NS in 88.9% of People Living with HIV (PLWHs) and plus CSF-TPHA reactivity agreed with the diagnosis of NS in 100% of HIV-uninfected patients. Conclusion The study suggests that the clinical use of CSF-CXCL13 is useful for supplementary biomarker for NS and as monitoring the effectiveness of NS therapy, especially in PLWHs with nonreactive CSF-VDRL, excluded other neurologic diseases.

Molecular characterization of a novel serine proteinase from Trichinella spiralis and its participation in larval invasion of gut epithelium.

A novel serine proteinase of Trichinells spiralis (TsSPc) has been identified in the excretion/secretion (ES) antigens, but its role in larval invasion is unclear. The aim of this study was to clone and express TsSPc, identify its biological and biochemical characteristics, and investigate its role on larval invasion of gut epithelium during T. spiralis infection. TsSPc has a functional domain of serine proteinase, and its tertiary structure consists of three amino acid residues (His88, Asp139 and Ser229) forming a pocket like functional domain. Recombinant TsSPc (rTsSPc) was expressed and purified. The rTsSPc has good immunogenicity. On Western blot analysis, rTsSPc was recognized by infection serum and anti-rTsSPc serum, natural TsSPc in crude and ES antigens was identified by anti-rTsSPc serum. The results of qPCR, Western blot and indirect immunofluorescence test (IIFT) showed that TsSPc was expressed at diverse stage worms, and mainly localized at cuticle, stichosome and intrauterine embryos of this nematode. The rTsSPc had enzymatic activity of native serine protease, which hydrolyzed the substrate BAEE, casein and collagen I. After site directed mutation of enzymatic active sites of TsSPc, its antigenicity did not change but the enzyme activity was fully lost. rTsSPc specifically bound to intestinal epithelium cells (IECs) and the binding sites were mainly localized in cell membrane and cytoplasm. rTsSPc accelerated larval invasion of IECs, whereas anti-rTsSPc antibodies and TsSPc-specific dsRNA obviously hindered larval invasion. TsSPc was a surface and secretory proteinase of the parasite, participated in larval invasion of gut epithelium, and may be considered as a candidate vaccine target molecule against Trichinella intrusion and infection.

Identification of specific antigens between Toxoplasma gondii and Neospora caninum and application of potential diagnostic antigen TgGRA54.

Toxoplasma gondii is a zoonotic parasite that is very common in livestock. Meat products from livestock infected with T. gondii are one of the important transmission routes of toxoplasmosis. Rapid and reliable diagnosis is a prerequisite for the prevention and control of toxoplasmosis. Neospora caninum and T. gondii are similar in morphology and life history, and there are a large number of cross antigens between them, making clinical diagnosis of toxoplasmosis more difficult. In this study, immunoprecipitation-mass spectrometry (IP-MS) was used to screen for T. gondii-specific antigens, and the specific antigen was cloned and expressed in Escherichia coli. The specific antigen was then used to establish an indirect ELISA diagnostic method. A total of 241 specific antigens of T. gondii and 662 cross antigens between T. gondii and N. caninum were screened by IP-MS. Through bioinformatics analysis and homology comparison, seven proteins were selected for gene cloning and prokaryotic expression, and the most suitable antigen, TgGRA54, was selected to establish an indirect ELISA for T. gondii. Compared with the indirect immunofluorescent antibody test (IFAT), the positive coincidence rate of the ELISA based on rTgGRA54 was 100% (72/72) and the negative coincidence rate was 80.95% (17/21). The indirect ELISA method based on TgGRA54 recombinant protein was established to detect T. gondii antibodies in bovine sera, and the recombinant protein reacted well with T. gondii positive sera from sheep, mouse, and swine, indicating that the recombinant protein is a good diagnostic antigen for T. gondii.

Seroprevalence and risk factors associated with caprine toxoplasmosis in the State of Goiás, Brazilian Savanna

Toxoplasmosis is a zoonosis of cosmopolitan distribution responsible for the infection of different mammals including humans. In small ruminants, this parasitosis is responsible for the emergence of reproductive alterations that lead to considerable economic losses. Despite the importance of the subject in goats, until now there is a lack of data on goat toxoplasmosis in herds in Goiás. The present study aimed to evaluate the spatial distribution and risk factors for infection by Toxoplasma gondii in goats in the State of Goiás, located in the Brazilian Cerrado, an unprecedented fact in the consulted literature. For this purpose, 894 blood serum samples obtained from goats from all regions of the State of Goiás were analyzed for the presence of anti-T. gondii by means of the indirect immunofluorescence test (IFAT). Data referring to the sex, age of the animals, size of the property, breeding system, water source, purpose of breeding, replacement of the herd, type of slaughter, veterinary assistance, presence of domestic felines, and presence of wild felines were obtained at the time of sampling. Differences between the seroprevalences obtained in relation to the analyzed variables were estimated using Pearson's chi-square test (χ2). The odds ratio (OR) values for each assessed risk factor were statistically analyzed. A positivity was observed for the IgG anti-T. gondii (title ≥ 64) in 60.4% (540/894) of the samples. We found a wide distribution of seropositive animals within the State of Goiás, with the presence of at least one seropositive goat in all mesoregions and microregions analyzed. Furthermore, in 91.40% (85/93) of the municipalities in the State and 93.80% (121/129) of the evaluated farms, the presence of at least one serum reactive goat was detected. The animals’ age, property size, water source, rearing system, and purpose of rearing were the risk factors statistically associated with the occurrence of T. gondii in goats. Through the results obtained, it was possible to identify a high prevalence of serum reactivity in the animals for T. gondii in the state of Goiás, with a wide distribution of this parasitosis in the state. Such inference leads to the need to establish several control measures that can be related with the statistically identified risk factors such as age, property size, water source, rearing system, and purpose of rearing. This action will be taken aiming avoid the spread and evolution of caprine toxoplasmosis in the Savanna region of Brazil.

The value of PLA2R antigen and IgG subclass staining relative to anti-PLA2R seropositivity in the differential diagnosis of membranous nephropathy

BackgroundThe diagnostic performance of PLA2R and IgG subclass staining of kidney biopsies relative to anti-PLA2R seropositivity in the differentiation of primary and secondary membranous nephropathy (pMN, sMN) was examined. Besides PLA2R staining – which has a lower specificity than anti-PLA2R antibody serology – there is insufficient knowledge to decide which IgG1-4 subtype immunohistological patterns (IgG4-dominance, IgG4-dominance/IgG1-IgG4-codominance or IgG4-dominance/IgG4-codominance with any IgG subtype) could be used to distinguish between pMN and sMN.Methods87 consecutive Hungarian patients (84 Caucasians, 3 Romas) with the biopsy diagnosis of MN were classified clinically as pMN (n = 63) or sMN (n = 24). The PLA2R and IgG subclass staining was part of the diagnostic protocol. Anti-PLA2R antibodies were determined by an indirect immunofluorescence test in 74 patients with disease activity.ResultsFor pMN, the sensitivity of anti-PLA2R seropositivity was 61.1%, and the specificity was 90.0%; and similar values for PLA2R staining were 81.0%, and 66.7%, respectively. In all stages of pMN, IgG4-dominance was the dominant subclass pattern, while the second most frequent was IgG3/IgG4-codominance. The sensitivity and specificity scores were: IgG4-dominance 52.2% and 91.7%, IgG4-dominance/IgG3-IgG4-codominance 76.2% and 87.5%, IgG4-dominance/IgG1-IgG4-codominance 64.2% and 75%, and IgG4-dominance/codominance with any IgG subclass 92.1% and 70.8%, respectively. Anti-PLA2R seropositivity, glomerular PLA2R, and IgG4-dominance/codominance significantly correlated with each other. The IgG4 subclass was rarely encountered in sMN.ConclusionIn our series, IgG4-dominance had the highest specificity in the differentiation of MN, just as high as that for anti-PLA2R seropositivity. The specificity values of PLA2R staining and IgG4-dominance/codominance with any IgG subclass or IgG4-dominance/IgG1-IgG4 codominance were ≤ 75%. Apart from IgG4 dominance, IgG4-dominance/IgG3-IgG4-codominance also had good statistical value in differentiating pMN from sMN. As IgG subclass switching during the progression of pMN was not the feature of our cohort, pMN in Hungarian patients is presumed to be an IgG4-related disorder right from the start. Although anti-PLA2R seropositivity has become the cornerstone for diagnosing pMN, if a kidney biopsy evaluation is conducted, besides the staining of PLA2R antigen, the evaluation of IgG subclasses provides relevant information for a differential diagnosis. Even in cases with IgG4-dominance, however, malignancy should be thoroughly checked.

One Health Approach in Serosurvey of Toxoplasma gondii in Former Black Slave (Quilombola) Communities in Southern Brazil and Among Their Dogs.

Brazilian quilombos are rural semi-isolated remnant communities of former black slaves and their descendants who traditionally maintained themselves through archaic subsistence livestock and agriculture practices and historically lacked specific public health policies. Although such individuals and their dogs may be exposed to zoonotic pathogens such as Toxoplasma gondii, no study to date has assessed these human-animal populations together. Populations in four different Brazilian quilombos in southern Brazil were evaluated. Overall, 93/208 people (44.7%) and 63/100 dogs (63.0%) were seropositive for IgG anti-T. gondii antibodies by indirect immunofluorescent antibody test (IFAT), 4/208 (1.9%) human samples seropositive for IgM anti-T. gondii antibodies, with a human-dog seropositivity ratio for IgG of 0.71. Quilombola individuals ingesting game meat were 2.43-fold more likely (95% CI: 1.05-5.9) to be seropositive. No risk factors were associated with seropositivity among dogs, thus suggesting that their exposure to T. gondii was random. Surprisingly, our research group had previously found an inverted human-dog ratio for T. gondii seropositivity of 2.54 in the urban area of a nearby major city. Because consumption of raw/undercooked game meat by quilombola individuals may have contributed to higher exposure, higher overall seroprevalence among dogs may have also indicated interaction with wildlife. Although these dogs may hunt wildlife without their owners' awareness, the higher dog seropositivity may also be related to feeding from discarded food in the community or backyard livestock animals and drinking surface water contaminated with oocysts. Thus, wildlife cannot be singled out as the reason, and future studies should consider sampling water, soil, wildlife, and livestock tissues, to fully establish the source of infection in dogs herein.

The prevalence and clinical phenotype of dual seropositive neuromyelitis optica spectrum disorders at a national reference center in South Asia.

Neuromyelitis Optica Spectrum Disorders (NMOSD) is an autoimmune syndrome that is frequently positive for Aquaporin 4 (AQP4) IgG or Myelin Oligodendrocyte Glycoproteins (MOG) IgG. However, dual positivity to both is rare. To assess the prevalence of dual-positive NMOSD and outline its clinical phenotype. This is a retrospective cross-sectional study conducted at a tertiary healthcare center in South Asia between August 2018 and November 2021. The serum and/or CSF samples of suspected cases of NMOSD were tested for both AQP4-IgG and MOG-IgG using an Indirect immunofluorescence test on transfected cells. During the study period, 1935 cases of NMOSD were tested for both antibodies- 65 patients (3.35%; 57 females and 8 males) tested positive for AQP4-IgG, 217 patients (11.21%; 122 females and 95 males) tested positive for MOG-IgG and 3 patients (0.15%; 2 females and 1 male) showed dual positivity. There was a strong female preponderance in all three groups (87.69%, 56.22%, and 66.66% respectively). This study identified 3 patients with dual positivity. The first patient (42 years, Male) presented with area postrema syndrome initially and subsequently relapsed by developing right-sided numbness of the temporal area and limbs during which he tested dual positive. The second patient (27 years, Female) presented with bilateral optic neuritis (left>right) initially and subsequently relapsed following an episode of a seizure with left-sided hemiplegia. The third patient (25 years, Female) initially presented with acute bilateral optic neuritis and later developed left-sided hemiplegia post-recovery at which point she tested dual positive. Management using methylprednisolone was ineffective for all three patients, however, plasmapheresis and/or periodic rituximab injections produced an excellent response. Our study reports that the prevalence of dual-positive NMOSD is 0.15% and its clinical phenotype is more similar to NMO rather than MOG- associated disease.

The diagnostic and prognostic value of a line immunoblot assay in Taiwanese patients with systemic sclerosis

Background and aimsWe aimed to evaluate the diagnostic performance and prognostic value of disease-specific antibodies and anti-Ro52 using a commercial line immunoblot assay (LIA) in Taiwanese patients with systemic sclerosis (SSc). Materials and methodsWe retrospectively enrolledall individuals at the Taichung Veterans General Hospital. We evaluated the diagnostic performance of LIA, anti-nuclear antibody (ANA) by indirect immunofluorescence (IIF) and also the association between the autoantibodies and the clinical phenotype using multivariable logistic regression. ResultsThe LIA exhibited a sensitivity of 65.4% and a specificity of 65.4%, at the optimal cutoff values of 2 + signal intensity. By taking the result of ANA into consideration, the optimal cutoff point was redefined as 1+. We observed a higher risk of diffuse cutaneous SSc (dcSSc) in those with negative autoantibodies, positive anti-Scl-70, anti-RNA polymerase III, and anti-Ro-52. Interstitial lung disease (ILD) was associated with negative autoantibodies, as well as positive anti-Scl-70 and anti-Ro52. Anti-Ro52 positivity was also associated with pulmonary arterial hypertension (PAH) and gastrointestinal tract involvement. ConclusionThe presence of anti-Ro52 or the absence of SSc-specific autoantibodies may potentially indicate advanced diseases in patients with SSc. The incorporation of both IIF and LIA testing may improve the diagnostic specificity of SSc.