Detection Of Specific IgG Antibodies Research Articles

Hypersensitivity pneumonitis due to metal working fluids: Detection of specific IgG antibodies to microbial antigens

Occupational exposure to microbially contaminated metal working fluids (MWF) can cause hypersensitivity pneumonitis (HP). An important step in the diagnosis of HP is to identify the triggering antigen by detection of corresponding specific IgG antibodies (sIgG). As commercial sIgG tests are currently not available, protein antigens were prepared from MWF-workplace samples and from MWF-typical bacterial isolates. In 57 % of suspected HP-cases (n = 30) elevated sIgG concentrations were measured to at least one MWF-relevant antigen, of which Mycobacterium immunogenum was most prominent (88 %), followed by Pseudomonas oleovorans and Pseudomonas spec (82 % each), MWF-antigen mix and Pseudomonas alcaliphila (65 % each). Elevated sIgG concentrations to other microorganisms were measured to Micropolyspora faeni (82 %) and Aureobasidium pullulans (77 %). Correlation of sIgG values of all tested microbial antigens showed a significant relationship of MWF-antigen mixture to Pseudomonas antigens, but a low correlation to moulds. These newly prepared MWF-antigens are useful tools for the diagnosis of patients with suspected MWF-HP and are available for further investigations.

Development of a method for detection of specific antibodies to E protein of yellow fever virus (Flaviviridae: Flavivirus) by enzyme immunoassay

Yellow fever (YF) remains one of the most common natural focal infectious diseases in the world. In connection with the increasing tourist flow to countries endemic for YF, the discovery of stable populations of Aedes aegypti and Ae. albopictus which are the main vectors of the yellow fever virus (YFV), in the southern regions of Russia, and the fact that in medical institutions in our country it is possible to obtain a live attenuated vaccine against YF, but there is no way to evaluate the effectiveness of vaccination, the question arises of the development and implementation of diagnostic kits for detecting antibodies (AB) to the pathogen by enzyme immunoassay (ELISA).The aim of this study was to develop a method for detecting specific IgG antibodies to the E protein of YFV by ELISA and assessing its diagnostic characteristics. A specific cDNA was synthesized by reverse transcription on an RNA template of YFV isolated on a cell culture of Aedes albopictus clone C6/36, and a fragment of the genome coding the YFV E protein was amplified and subsequently cloned into the plasmid pET160 (Thermo Fisher Scientific, USA). The resulting gene fragment was used as a DNA template to obtain a recombinant analog of the third domain of the YFV E protein in Escherichia coli cells (BL-21(DE3)). Next, the immunogenicity of the obtained antigen was evaluated and the analysis conditions were optimized. The optimal conditions for the production of the obtained recombinant E protein of YFV were determined, its specificity was confirmed by immunological methods (Western blot and ELISA), sorption buffers and blocking solutions were selected, and sensitivity and specificity of detection of antibodies to YFV using the recombinant antigen were assessed. A method for the detection of specific IgG antibodies to the YFV E protein by ELISA was developed. This diagnostic kit can be used both to study the protective properties of the YF vaccine and to detect imported cases of infection in non-endemic areas.

An Innovative Test for the Rapid Detection of Specific IgG Antibodies in Human Whole-Blood for the Diagnosis of Opisthorchis viverrini Infection.

Chronic human liver fluke infections caused by Opisthorchis viverrini and Clonorchis sinensis can last for decades and cause liver and biliary diseases, including life-threatening pathology prior to cholangiocarcinoma (CCA). CCA generally has a poor prognosis. Serological diagnosis can support parasitological examination in diagnosing disease and screening for the risk of CCA. Here, we present an improved and innovative lateral flow immunochromatographic test (ICT) kit that uses whole-blood samples (WBS) rather than serum to diagnose human opisthorchiasis, which also successfully diagnosed human clonorchiasis. This ICT includes a soluble worm extract of O. viverrini adults and colloidal-gold-labeled conjugates of the IgG antibody to evaluate the diagnostic values with simulated WBS (n = 347). Simulated WBS were obtained by the spiking infection sera with red blood cells. The diagnostic sensitivity, specificity, positive and negative predictive values, and accuracy for detecting opisthorchiasis were 95.5%, 87.0%, 80.5%, 97.2%, and 90.1%, respectively. For clonorchiasis, these findings were 85.7%, 87.0%, 53.6%, 97.2%, and 86.8%, respectively. Combined for both diseases, they were 93.2%, 87.0%, 84.0%, 94.6%, and 89.6%, respectively. The ICT kit can possibly replace the ICT platforms for antibody detection in serum samples in field surveys in remote areas where sophisticated equipment is not available.

Identification of the Farm Animals Immune to Pathogens of Zoonotic Infectious Diseases in the Republic of Guinea

The most common anthropozoonoses on the African continent are coxiellosis and Rift Valley fever. It is known that detection of specific IgG antibodies in the blood sera of farm animals is one of the indicators of the pathogen circulation in a certain territory. The aim of the work was to identify specific IgG antibodies in the blood sera of farm animals collected on the territory of the Republic of Guinea to pathogens of zoonotic infectious diseases: coxiellosis, brucellosis, glanders, CCHF, West Nile and Rift Valley fevers, using enzyme immunoassay (ELISA). Materials and methods. A panel of 970 samples of blood sera from farm animals inhabiting all landscape-geographical zones of Guinea was compiled for the work. Identification of specific antibodies was carried out using enzyme immunoassay with preparations recommended for veterinary studies. Results and discussion. Specific antibodies to zoonoses were detected in 700 out of 1074 samples (65.2 % of the total), including: to Coxiella burnetii – in 172 (16.0 %); to Brucella spp. – in 212 (19.7 %); viruses of Rift Valley fever – 85 (7.9 %); CCHF – in 139 (12.9 %) and West Nile fever – in 92 (8.6 %). Antibodies to Burkholderia mallei were not found in the tested material. Positive samples were registered in all landscape-geographical zones. Thus, an urgent task is to continue studying the circulation of pathogens of zoonoses and anthropozoonoses in the territory of the Republic of Guinea and to organize regular monitoring over the spread of zoonotic infectious diseases in collaboration with veterinary services, which will allow timely forecasting and coordinating prophylactic (anti-epidemic) measures to prevent cases of diseases.

Seroprevalence and Risk Factors Associated with Toxoplasma gondii and Chlamydophila abortus Infection in Domestic Small Ruminants in Cameroon

Toxoplasmosis and chlamydiosis remain among the primary causes of abortion and fetal loss in small ruminants. Consequently, they are a source of considerable economic losses for farmers. The objectives of this study were to determine the seroprevalence and highlight the risk factors associated with Toxoplasma gondii and Chlamydophila abortus infection in small ruminants in Cameroon. A cross-sectional study was conducted in 200 small ruminant farms during a period from April to October 2021. A total of 1061 small ruminants were sampled, and the sera obtained were analyzed using the indirect ruminant multi-species ELISA test for specific IgG antibody detection for T. gondii and C. abortus at the National Veterinary Laboratory. A questionnaire was constructed to collect information about flock management and risk factors possibly associated with T. gondii and C. abortus infection in goats and sheep. Overall, 329 small ruminants tested positive for T. gondii-specific IgG antibodies and 45 for C. abortus-specific IgG antibodies with a seroprevalence of 31.1% (95% CI: 28.2–33.8) for T. gondii and 4.2% (95% CI: 3.0–5.5) for C. abortus, respectively. However, a significant co-infection of 1.8% (95% CI: 0.37–3.3) was obtained between T. gondii and C. abortus (p = 0.02). Linear regression model analysis revealed that, the seroprevalence of T. gondii at the flock level was significantly correlated with the region (0.22 CI: 0.17; 0.26) the breeding objectives (0.36 CI: 0.17; 0.56) the level of hygiene (0.11 CI: 0.01; 0.21) and presence abortions (0.55 CI: 0.46; 0.64) on the farms and that of C. abortus was significantly correlated with the regions (0.01 CI: 0.00–0.02) and degree of abortion on the farms (−0.26 CI: −039; −0.14). At the individual level, a significant correlation was observed between the seroprevalence of T. gondii and region (−0.09 CI: −0.14; −0.04), species (0.07 CI: 0.01–0.14), sex (−0.11 CI: −0.18; −0.03), age (0.08 CI: 0.04–0.12) and physiological status (0.21 CI: 0.18; 0.24). For C. abortus seroprevalence, a significant correlation was observed with the regions (0.02 CI: 0.00; 0.03) and breed (0.01 CI: 0.01; 0.02) of small ruminants reared in the northern regions of Cameroon. These results could be used to implement efficient management measures to prevent and control T. gondii and C. abortus infection in goats and sheep in Cameroon.

Detection of Specific IgG-Antibodies Against Toxoplasma gondii in the Serum and Milk of Domestic Donkeys During Lactation in China: A Potential Public Health Concern

Toxoplasma gondii is a worldwide zoonotic protozoan. Donkeys are often susceptible to many pathological agents, acting as carriers of pathogens for other animal species and humans. However, data on the prevalence of T. gondii in donkeys during lactation and on the status of antibodies against T. gondii in donkey milk are lacking. A cross-sectional study evaluated the variation of the anti-T. gondii antibodies in the blood and milk of domestic donkeys during lactation. A total of 418 domestic donkeys were randomly selected from the Shandong province, eastern China from January 2019 to March 2020. The anti-T. gondii antibodies were found in 11.72% (49/418) serum and 9.81% (41/418) milk samples using a commercial ELISA kit, respectively. There was a very high consistency between the serum and milk (Spearman’s coefficient = 0.858, p-value < 0.0001 and Kendall’s tau = 0.688, p-value < 0.0001), particularly at the 45th to 60th day of lactation. The present results of the statistical analysis showed that the history of abortion (p = 0.026; adjusted OR = 2.20; 95% CI: 1.15–4.20) and cat in the house (p = 0.008; adjusted OR = 2.36; 95% CI: 1.26–4.44) were significantly associated with T. gondii infection in the domestic donkeys. This is the first report to detect antibodies against T. gondii in donkey milk in China. These results indicate a potential risk of humans contracting the infection through the consumption of raw milk from the naturally infected donkeys.

Bacteremia with ESBL-producing Enterobacterales is associated with IgG antibodies reacting with CTX-M-15 and/or CTX-M-27

ObjectivesThe adaptive humoral immune response following clinical infection with extended spectrum beta-lactamase (ESBL)-producing Enterobacterales (EPE) has not been thoroughly investigated. The aim of this study was to investigate the presence of anti-CTX-M-15 and/or anti-CTX-M-27 IgG antibodies in bacteremia patients diagnosed with EPE compared to a control group consisting of patients suffering from bacteremia with third generation cephalosporin-susceptible Escherichia coli (3GCSE). MethodsPatientswith EPE (n = 59) or 3GCSE (n = 42) bacteremia were recruited in this case control study in the Skåne County (South of Sweden). Sera were collected 1–26 months after bacteremia. Enzyme-linked immunosorbent assay (ELISA) was used for detection of specific IgG antibodies directed against recombinant beta-lactamases CTX-M-15 and CTX-M-27. The beta-lactamase resistance genes of the corresponding EPE blood isolates were determined by DNA sequencing. ResultsThe majority (n = 47; 80 %) of the 59 EPE blood isolates carried blaCTX-M-15 or blaCTX-M-27 genes. IgG antibodies reacting to the corresponding CTX-M enzyme was seen in 28 % (13/47) of patients suffering from EPE-bacteremia, while antibodies were detected in only 9.5 % (4/42) of patients with 3GCSE (p = 0.03). Patients with EPE had a statistically significantly higher median Charlson comorbidity index and prevalence of renal disease (p = 0.01), compared to the 3GCSE control group. ConclusionThis study implies that EPE bacteremia can trigger production of IgG antibodies targeting ESBL. Further investigations are required to determine the functional role of anti-ESBL antibodies against EPE bacteremia.

Serodiagnosis of Toxocariasis by ELISA test using anti- T. canis IgG antibodies in stray dogs compared to PCR

Toxocara (T.) canis is a nematode parasite of canines; belong to the Ascarididae family, which accidentally infected humans. Puppies expel the eggs with the feces from the fourth week of the life cycle. This study is the first study in Iraq for detection seroprevalence in stray dogs and extended from January to September 2017. Our study was aimed to investigate the seroprevalence of T. canis infection in stray dogs from different areas in the Al-Diwaniya province, Iraqto detection of specific IgG antibodies to T. canis compared to Conventional PCR technique with the effect of the risk factor. One hundred of the blood sample and one hundred of a faecal sample of same dogs after shooting were studied usingindirect ELISA test and PCR. The result revealed that 71% of the dogs had a seropositive result for this parasite by ELISA test. Dog age is an important factor and affects seroprevalence, were shown that positive rate in adult dogs was more 83.05% than the young dogs 53.65%, while no significant between dogs according to sex. PCR technique showed 58% of dogs were positive forinternal transcribed spacer 1 (ITS1) ribosomal RNA. The sensitivity and specificity of ELISA test was 79 and 40% respectively.

Study on Toxoplasma Gondii, Leptospira Spp., Coxiella Burnetii, and Echinococcus Granulosus Infection in Veterinarians from Poland.

IntroductionExposure to zoonotic factors in veterinary practice is closely related to the nature of the work. The main aim of the study was to determine the risk of selected zoonotic infections among the occupational group of veterinarians in Poland.Material and MethodsBlood samples of 373 veterinarians (162 males and 211 females) from 12 provinces of Poland were collected by the venipuncture of a forearm for serological tests. Commercial immunoenzymatic tests (ELISA) were used for detection of specific IgG antibodies to Echinococcus granulosus, IgM and IgG to Leptospira spp., and IgM, IgA, and I and II phase IgG to Coxiella burnetii. Enzyme-linked fluorescence assays (ELFA) were used to detect IgM and IgG antibodies to Toxoplasma gondii.ResultsPositive results were found in 209 (56.0%) veterinarians for at least one of the examined diseases. The overall proportion of participants found to have specific Toxoplasma gondii antibodies in the IgM and/or IgG assays amounted to 44.5%. The presence of Coxiella burnetii antibodies was found in 16 (4.3%) subjects, while Leptospira spp. antibodies were detected in 63 (16.9%) veterinarians. Among the 373 veterinarians examined, no Echinococcus granulosus antibodies were found.ConclusionResults of the study seem to indicate a slightly elevated risk of Toxoplasma gondii infection and a moderate risk of infection with Leptospira spp. and Coxiella burnetii in veterinarians.

Seroprevalencia de &lt;i&gt;Toxocara canis&lt;/i&gt; en perros de las ciudades de Corrientes y Esperanza (Argentina)

&lt;i&gt;Toxocara canis&lt;/i&gt; es un nematode de los caninos, que accidentalmente afecta al hombre provocando una enfermedad parasitaria zoonótica denominada toxocariasis. Los cachorros son responsables de la contaminación del ambiente a través de la eliminación de huevos infectantes al medio, mientras que las perras adultas representan un potencial reservorio, por ser capaces de transmitir verticalmente el parásito a sus crías. La infección en seres humanos constituye un problema sanitario de gran interés, principalmente por su impacto en niños. Los estudios coproparasitológicos en perros adultos han demostrado ser poco eficientes para detectar la infección. El objetivo de este estudio fue determinar valores de seroprevalencia de anticuerpos anti- &lt;i&gt;T. canis&lt;/i&gt; en caninos de dos ciudades de Argentina. Se estudiaron perros de diferentes barrios de las ciudades de Corrientes y Esperanza. Se realizó el test de ELISA indirecto para detección de anticuerpos de tipo IgG específicos para &lt;i&gt;T. canis&lt;/i&gt;. En Corrientes se estudiaron 119 perros. El análisis reveló que el 84,9% (n=101) de los canes presentaba serología positiva. En Esperanza se estudiaron 82 perros; el ELISA indirecto reveló que el 51,2% (n=42) del total de los canes presentaban serología positiva para este parásito. Los valores hallados son consistentes con los encontrados por otros autores en estudios similares, y no así con aquellos en los que se emplearon métodos directos para detección de huevos en heces, los cuales en general informan valores menores de prevalencia. La alta seroprevalencia hallada sugiere la necesidad de implementar medidas de control de la infestación en perros y de esa manera reducir el riesgo de transmisión al hombre.

Evaluation of a di-O-methylated glycan as a potential antigenic target for the serodiagnosis of human toxocariasis.

Serodiagnosis of human toxocariasis is based on the detection of specific IgG antibodies by the enzyme-linked immunosorbent assay (ELISA) using Toxocara larvae excretory-secretory (TES) antigens, but its production is a laborious and time-consuming process being also limited by the availability of adult females of T.canis as source for ova to obtain larvae. Chemical synthesis of the di-O-methylated (DiM) glycan structure found in the TES antigens has provided material for studying the antibody reactivity in a range of mammalian hosts, showing reactivity with human IgM and IgG. In this study, we have evaluated the performance of the DiM glycan against a panel of sera including patients with toxocariasis (n=60), patients with other helminth infections (n=75) and healthy individuals (n=94), showing that DiM is able to detect IgG antibodies with a sensitivity and specificity of 91·7% and 94·7%, respectively, with a very good agreement with the TES antigens (kappa = 0·825). However, cross-reactivity was observed in some sera from patients with ascariasis, hymenolepiasis and fascioliasis. These results show that the DiM glycan could be a promising antigenic tool for the serodiagnosis of human toxocariasis.

Seroprevalence of Brucellosis, Leptospirosis, and Q Fever among Butchers and Slaughterhouse Workers in South-Eastern Iran.

Zoonotic diseases can be occupational hazards to people who work in close contact with animals or their carcasses. In this cross-sectional study, 190 sera were collected from butchers and slaughterhouse workers in different regions of the Sistan va Baluchestan province, in Iran in 2011. A questionnaire was filled for each participant to document personal and behavioural information. The sera were tested for detection of specific IgG antibodies against brucellosis, leptospirosis, and Q fever (phase I and II) using commercial enzyme-linked immunosorbent assays (ELISA). The seroprevalence of brucellosis was 7.9%, leptospirosis 23.4%, and phase I and II of Q fever were 18.1% and 14.4%, respectively. The seroprevalence of Q fever and leptospirosis, but not brucellosis, varied among regions within the province (p = 0.01). Additionally, a significant relationship was found between seropositivity of Q fever and camel slaughtering (p = 0.04). Reduced seropositivity rate of brucellosis was associated with use of personal protective equipment (PPE) (p = 0.004). This study shows that brucellosis, leptospirosis and Q fever occur among butchers and slaughterhouse workers in this area.

High levels of anti-Phlebotomus perniciosus saliva antibodies in different vertebrate hosts from the re-emerging leishmaniosis focus in Madrid, Spain

From July 2009 to date, a leishmaniosis outbreak has occurred in the south-west of the Madrid region (Spain) and has already accounted for more than 450 human cases in an area that comprises a population of approximately 500,000. The causative agent is Leishmania infantum and the main vector in the area is Phlebotomus perniciosus. Although canine leishmaniosis prevalence in the focus is not higher than the average in the Madrid region, a wild reservoir – the hare – has been implicated. In this study, we examined the exposure of Leishmania reservoirs in the area: dogs, hares, and wild rabbits to sand fly bites using the detection of specific IgG antibodies against P. perniciosus salivary gland homogenate or recombinant salivary proteins.Hares collected in a green park adjacent to the focus (n=59) showed positive exposure to P. perniciosus bites in comparison to hares from a non-endemic area (Czech Republic, n=18). A significant positive correlation was found between IgG response to yellow protein rSP03B and salivary gland homogenate (r=0.902) and between apyrase rSP01B and salivary gland homogenate (r=0.710). Wild rabbits captured in the study area (n=21) presented higher anti-saliva antibody levels than negative control sera and their IgG response against recombinant salivary proteins were positively correlated with salivary gland homogenate (rSP03B: r=0.710; rSP01B: r=0.666). All sera of dogs from the focus (n=34) showed higher anti-saliva IgG levels than that of non-exposed dogs. Moreover, dogs protected against sand fly bites through the use of topical insecticides and sleeping indoors showed significantly lower antibody levels than the non-protected ones. Antibody response to all three recombinant salivary proteins tested showed positive correlation with salivary gland extract (rSP03B: r=0.858; rSP01: r=0.864; and rSP01B: r=0.861). Data confirmed the exposure of hares, rabbits and dogs to P. perniciosus bites in the context of an outbreak of human leishmaniosis in Spain, highlighting their involvement in Leishmania transmission by supporting their role as potential reservoirs.This novel methodology represents a promising tool for further epidemiological studies that would help to design better strategies for the control of leishmaniosis in this area and other foci.

Detection of specific IgG antibodies in blood donors and tick-borne encephalitis virus in ticks within a non-endemic area in southeast Norway

Tick-borne encephalitis (TBE) is an emerging tick-borne disease in Europe. In Norway, the first TBE case occurred in 1997, and since then 1-14 cases have been detected annually along the southern coast. No TBE cases have yet been notified from the eastern coastal area. This study was conducted to assess the need for diagnostic tests and vaccine recommendation for this part of Norway. Four hundred and sixty-one blood donors living in the county of Østfold were enrolled. After informed consent was obtained, the participants submitted a blood sample and filled out a questionnaire regarding tick bites, outdoor activities, and Flavivirus vaccines and diseases. Ixodes ricinus ticks were collected from the immediate vicinity and were examined in pools of 10 for TBE virus. Eight human samples were TBE virus IgG-positive by ELISA and 5 of these samples were confirmed positive by neutralization test. Excluding the 2 samples from participants who had reported previous TBE vaccination, this shows a seroprevalence among blood donors of 0.65%. The existence of TBEV in the region was verified in nymphs of Ixodes ricinus by a prevalence of 0.14%. The seroprevalence of TBE virus IgG and the TBE virus detected in ticks, indicate that TBE cases could occasionally occur in the area. The results should be made available to health care personnel to raise awareness for preventative measures.

Comparative study of amplification systems in immunoenzyme assays for the diagnosis of American tegumentary leishmaniasis

We compared the accuracy and reliability of three amplification systems for enzyme immunoassays in the detection of specific IgG antibodies for the diagnosis of cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis in patients from an endemic area in Rio de Janeiro, Brazil. Partially soluble antigens obtained from the promastigote forms of L. (V.) braziliensis were used. For development of the reaction, two chromogens, 1,2-orthophenylenediamine (OPD) and 3,3',5,5'-tetramethylbenzidine (TMB), and a fluorogen, 4-methylumbelliferylphosphate (MUP), were tested. The performance of each system was compared using the following parameters: accuracy, intraclass correlation coefficient (ICC), and area under the receiver operating characteristic (ROC) curve. Sensitivity was the same (97.4%) for all systems. The reliability was excellent (ICC = 98.6, 98.7, and 99.1%) and specificity was 93.7, 95.8, and 97.4% for OPD, MUP, and TMB, respectively, showing no statistical significance. Despite the absence of differences in the performance of the three systems, the use of TMB is suggested because of its operational advantages, such as low cost compared with fluorogens, easy manipulation, greater stability, and lower toxicity.

Acute Viral Infections in Patients With Systemic Lupus Erythematosus

Few studies have evaluated the impact of viral infections on the daily management of patients with systemic lupus erythematosus (SLE). We analyzed the etiology and clinical features of acute viral infections arising in patients with SLE and their influence on the diagnosis, prognosis, and treatment of SLE. Cases occurring within the last 5 years were selected from the databases of 3 large teaching hospitals. Acute viral infections were confirmed by the identification of specific antiviral IgM antibodies and subsequent seroconversion with detection of specific IgG antibodies. In autopsy studies, macroscopic findings suggestive of viral infection were confirmed by direct identification of the virus or viruses in tissue samples. We performed a MEDLINE search for additional cases reported between January 1985 and March 2008. We included 88 cases (23 from our clinics and 65 from the literature review) of acute viral infections in patients with SLE. Twenty-five patients were diagnosed with new-onset SLE (fulfillment of the 1997 SLE criteria) associated with infection by human parvovirus B19 (n = 15), cytomegalovirus (CMV; n = 6), Epstein-Barr virus (EBV; n = 3), and hepatitis A virus (n = 1). The remaining 63 cases of acute viral infections arose in patients already diagnosed with SLE: in 18 patients, symptoms related to infection mimicked a lupus flare, 36 patients, including 1 patient from the former group who presented with both conditions, presented organ-specific viral infections (mainly pneumonitis, colitis, retinitis, and hepatitis), and 10 patients presented a severe, multiorgan process similar to that described in catastrophic antiphospholipid syndrome-the final diagnosis was hemophagocytic syndrome in 5 cases and disseminated viral infection in 5. Twelve patients died due to infection caused by CMV (n = 5), herpes simplex virus (n = 4), EBV (n = 2), and varicella zoster virus (n = 1). Autopsies were performed in 9 patients and disclosed disseminated herpetic infection in 6 patients (caused by herpes simplex in 4 cases, varicella in 1, and CMV in 1) and hemophagocytic syndrome in 3. A higher frequency of renal failure (54% vs. 19%, p = 0.024), antiphospholipid syndrome (33% vs. 6%, p = 0.023), treatment with cyclophosphamide (82% vs. 37%, p = 0.008), and multisystemic involvement at presentation (58% vs. 8%, p < 0.001); and a lower frequency of antiviral therapy (18% vs. 76%, p < 0.001) were found in patients who died, compared with survivors. The most common viral infections in patients with SLE are parvovirus B19 (predominantly mimicking SLE presentation) and CMV (predominantly presenting in severely immunosuppressed patients). CMV infection may mimic a lupus flare or present with specific organ involvement such as gastrointestinal bleeding or pulmonary infiltrates. Other herpesviruses are common in immunosuppressed SLE patients and may produce a wide range of manifestations. Physicians should examine the pharynx, eyes, skin, and genitalia and should conduct serologic and molecular studies to improve early detection of viral infection in patients with SLE.

Recombinant nucleocapsid-based ELISA for detection of IgG antibody to Rift Valley fever virus in African buffalo

Wild ruminants are thought to serve as natural hosts for Rift Valley fever virus (RVFV) but the role of these animals as reservoirs for RVFV during inter-epidemic periods and as amplifiers during epidemics is not well understood. An indirect enzyme-linked immunoassay (I-ELISA) based on the recombinant nucleocapsid protein (rNp) of RVFV was validated for the detection of specific IgG antibodies in African buffalo. Data sets derived from testing buffalo sera from Kenya ( n = 405) and South Africa ( n = 618) were dichotomised according to the results of a virus neutralisation test. The assay characteristic performance was analysed using threshold values optimised by the two-graph receiver operating characteristics (TG-ROC) analysis, and by mean plus two, as well as by mean plus three standard deviations derived from I-ELISA PP values in uninfected animals. Among 1023 buffalo sera tested, 77 (7.5%) had detectable virus neutralising antibodies. The assay had high intra- and inter-plate repeatability in routine runs. At a cut-off optimised by the TG-ROC at 95% accuracy level, the diagnostic sensitivity of the I-ELISA was 98.7% and diagnostic specificity 99.36% while estimates for the Youden's index ( J) and efficiency (Ef) were 0.98 and 99.31%. When cut-off values determined by traditional statistical approaches were used, the diagnostic sensitivity was 100% but estimates of J, Ef and other combined measures of diagnostic accuracy were lower compared to those based on cut-off value derived from the TG-ROC. Results of the study indicate that the I-ELISA based on the rNp would be useful for seroepidemiological studies of RVFV infections in African buffalo.

Validation of an indirect ELISA based on a recombinant nucleocapsid protein of Rift Valley fever virus for the detection of IgG antibody in humans

An indirect enzyme-linked immunoassay (I-ELISA) based on the recombinant nucleocapsid protein (rNp) of Rift Valley fever virus was validated for the detection of specific IgG antibody in human sera. Validation data sets derived from testing sera collected in Africa ( n = 2967) were categorized according to the results of a virus neutralisation test. The assay had high intra- and inter-plate repeatability in routine runs. No detectable cross-reactions between IgG antibodies generated from mice experimentally infected with viruses representing genus Phlebovirus, Nairovirus, Orthobunyavirus and Bhanja virus of the family Bunyaviridae were observed. At a cut-off optimised by the two-graph receiver operating characteristics analysis at 95% accuracy level, the diagnostic sensitivity of the I-ELISA was 99.72% and diagnostic specificity 99.62% while estimates for the Youden's index ( J) and efficiency (Ef) were 0.993 and 99.62%. When cut-off values determined by mean plus two and by mean plus three standard deviations derived from I-ELISA readings in an uninfected reference population were used, the diagnostic sensitivity was 100% but estimates of Y, Ef and other combined measures of diagnostic accuracy were lower. The I-ELISA based on rNp is highly sensitive, specific and robust and can be applied for diagnosis of infection of Rift Valley fever and disease-surveillance studies in humans.

Specific immune responses in workers exposed to benzene

The aim of this study was to elaborate a method for detection of specific IgG antibodies (Abs) to the haptenes p-benzoquinone (p-BQ) and hydroquinone (HQ) for assessment of specific humoral immune responses. Plasma and urine, collected from petrochemical plant workers have been analyzed. The workers were divided into three professional groups in ascending order of benzene exposure. The concentration of benzene in the air was determined by gas chromatography with mass-spectrometry and trans, trans-muconic acid (biomarker of benzene exposure) in urine—by liquid chromatography with UV-detection. Specific IgG Abs to haptenes p-BQ and HQ in plasma were determined with newly developed ELISA. The relationships “exposure–effect,” revealed increased levels of specific IgG to haptens correlating with the benzene exposure. The “exposure–response” relationships demonstrated that workers with value of OD over X + 2SD were 62% low exposure group, 68% in group with level of exposure on Threshold Limit Value (TLV) and 91% in the highest exposure group. The data obtained show that there is a good correlation between antibody production and the biomarker of exposure t, t-muconic acid. Conclusion The newly developed method is applicable for assessment of specific humoral immune responses in workers exposed to benzene. There was a good correlation between benzene exposure and formation of antibodies against benzene metabolites.

Toxoplasmose: soroprevalência em puérperas atendidas pelo Sistema Único de Saúde

OBJECTIVE: to establish the rate of toxoplasmosis soroprevalence in postpartum women, attended in two hospitals of the Public Health System (SUS) in Cuiaba, and its correlation with age, previous abortion and women's knowledge of the disease. METHODS: a cross-sectional study including 205 women with ages from 14 to 43 (mean 22.4) years old, attended in these hospitals for two months, in the first or second days postpartum. Each woman answered a short questionnaire and had peripheral blood sample collected. Blood samples were stored at 20°C until assay. The seroprevalence was determined by quantitative detection of specific IgG antibody against Toxoplasma gondii, using a microparticle enzyme immunoassay. All samples were assayed at the same time. RESULTS: The average number of pregnancies in the women included in this study was 2.2, and the majority of them was pregnant for the first time. The seroprevalence found was 70.7% (165 of 205 women). No statistical correlation was found between seroprevalence and age (p = 0.967) or previous abortion (p = 0.82). Most of the women in this study (78%) did not know about toxoplasmosis and no statistical correlation was found between this condition and seroprevalence (p = 0.49). CONCLUSION: the high seroprevalence found in the present study is in accordance with surveys previously reported in our country and other developing countries. Among the women included in this study, an expressive number (29.3%) is still under risk of contamination. The lack of statistical correlation between seroprevalence and women's age, lack of knowledge about the disease and report of previous abortion is in accordance with some previous studies and in disagreement with others.