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Chagas disease (CD) is a neglected disease caused by Trypanosoma cruzi Chagas, 1909. Causative treatment can be achieved with two drugs: benznidazole or Nifurtimox. There are some gaps that hinder progress in eradicating the disease. There is no test that can efficiently assess cure control after treatment. Currently, the decline in anti-T. cruzi antibody titres is assessed with conventional serological tests, which can take years. However, the search for new markers of cure must continue to fill this gap. The present study aimed to evaluate the decline in serological titres using chimeric proteins after treatment with benznidazole in chronic patients diagnosed with CD. It was a prospective cross-sectional cohort study between 2000 and 2004 of T. cruzi-positive participants from the Añatuya region (Argentina) treated with benznidazole. Serum samples from ten patients were collected before treatment (day zero) and after the end of treatment (2, 3, 6, 12, 24 and 36 months). For the detection of anti-T. cruzi antibodies, an indirect ELISA was performed using two chimeric recombinant proteins (IBMP-8.1 and IBMP-8.4) as antigens. The changes in reactivity index within the groups before and after treatment were evaluated using the Friedman test. All participants experienced a decrease in serological titres after treatment with benznidazole, especially IBMP-8.1. However, due to the small number of samples and the short follow-up period, it is premature to conclude that this molecule serves as a criterion for sustained cure. Further studies are needed to validate tests based on these or other biomarkers to demonstrate parasitological cure.

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The clinical manifestation of foetal anaemia caused by maternal Kell alloantibodies differs from that caused by non-Kell alloantibodies. Severe anaemia develops in the foetus in the early weeks of gestation; therefore, proper management and early intervention are important. A systematic review and meta-analysis was performed to determine whether the anti-K1 titre can determine the sequelae of Kell alloimmunised pregnancies. Prospective and retrospective cohort studies were used to conduct a systematic review following a comprehensive literature search, in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Studies were screened based on a defined set of inclusion and exclusion criteria. A total of 5143 potential articles were identified. Ten studies were used in the meta-analysis of pregnancy outcomes for a specific anti-K1 titre cut-off. The meta-analysis identified statistical significance for intrauterine transfusion (ARD: 0.351; 95 % CI: 0.593-0.109; p-value = 0.004), hydrops (ARD: 0.808; 95 % CI: 1.145-0.472; p-value <0.001), intrauterine foetal death (ARD: 0.938; 95 % CI:1.344 to -0.533; p-value <0.001) and intrauterine transfusion for Doppler middle cerebral artery >1.5 MoM (ARD: 0.381; 95 % CI:1.079 to -0.317; p-value = 0.285). It was concluded that there is no correlation between anti-K1 titre and Kell sensitised pregnancy outcomes, but monitoring the anti-K1 titre is important to manage the pregnancy and it helps clinicians determine the need for intrauterine transfusions. Doppler middle cerebral artery peak systolic velocity is strongly correlated with foetal anaemia and is an efficient routine method for determining the need for intrauterine transfusions in pregnancies affected by anti-K1.

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The SARS-CoV-2 Omicron variant has increased infectivity and immune escape compared with previous variants, and caused the surge of massive COVID-19 waves globally. Despite a vast majority (~90%) of the population of Santa Fe city, Argentina had been vaccinated and/or had been infected by SARS-CoV-2 when Omicron emerged, the epidemic wave that followed its arrival was by far the largest one experienced in the city. A serosurvey conducted prior to the arrival of Omicron allowed to assess the acquired humoral defences preceding the wave and to conduct a longitudinal study to provide individual-level real-world data linking antibody levels and protection against COVID-19 during the wave. A very large proportion of 1455 sampled individuals had immunological memory against COVID-19 at the arrival of Omicron (almost 90%), and about half (48.9%) had high anti-spike immunoglobulin G levels (>200 UI/ml). However, the antibody titres varied greatly among the participants, and such variability depended mainly on the vaccine platform received, on having had COVID-19 previously and on the number of days elapsed since last antigen exposure (vaccine shot or natural infection). A follow-up of 514 participants provided real-world evidence of antibody-mediated protection against COVID-19 during a period of high risk of exposure to an immune-escaping highly transmissible variant. Pre-wave antibody titres were strongly negatively associated with COVID-19 incidence and severity of symptoms during the wave. Also, receiving a vaccine shot during the follow-up period reduced the COVID-19 risk drastically (15-fold). These results highlight the importance of maintaining high defences through vaccination at times of high risk of exposure to immune-escaping variants.

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ABSTRACT Background Transfusion of platelets (PLTs) with high ABO antibody titres can pose a risk of hemolysis if the unit crosses the ABO type. The PLTs stored in the platelet additive solution (PAS) remove asubstantial fraction of plasma and replace it with an isotonicbuffered solution.We aimed to assess the difference in anti-A/B antibody levels in Groups O, A and B apheresis platelets (APs) suspended in plasma and PAS. Methodology Apheresis donors are categorized into two groups, Plasma (Group I) and PAS (Group II), each blood group (A, B and O) had 20 samples. The anti-A/B(IgM)antibody levels were recorded from the AP donor (Group II) and from the AP units for both groups. The reduction in the anti-A/B(IgM) antibody levels in the APs suspended in the PAS for each blood group was determined. Results The median anti-A titres in blood Groups B (p = 0.009) and O (p = 0.005) was significantly lower in Group II. However, the difference in anti-B levels was not significant in the blood groups A (p = 0.057) and O (p = 0.205). The median level of reduction in IgM antibody titres across donor samples and the PAS-stored platelets was two-fold. The regression showed a level of reduction in antibody titres which can be explained by baseline donor antibody titres in blood groups A and B compared to blood group O. Conclusion The medianABO antibody titres were lower in APs suspended in PAS than in plasma. Addition of the PAS significantly lowered the IgM antibody titres by twofold, compared to plasma.

Assuntos

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BACKGROUND: Transfusion of platelets (PLTs) with high ABO antibody titres can pose a risk of hemolysis if the unit crosses the ABO type. The PLTs stored in the platelet additive solution (PAS) remove asubstantial fraction of plasma and replace it with an isotonicbuffered solution.We aimed to assess the difference in anti-A/B antibody levels in Groups O, A and B apheresis platelets (APs) suspended in plasma and PAS. METHODOLOGY: Apheresis donors are categorized into two groups, Plasma (Group I) and PAS (Group II), each blood group (A, B and O) had 20 samples. The anti-A/B(IgM)antibody levels were recorded from the AP donor (Group II) and from the AP units for both groups. The reduction in the anti-A/B(IgM) antibody levels in the APs suspended in the PAS for each blood group was determined. RESULTS: The median anti-A titres in blood Groups B (p = 0.009) and O (p = 0.005) was significantly lower in Group II. However, the difference in anti-B levels was not significant in the blood groups A (p = 0.057) and O (p = 0.205). The median level of reduction in IgM antibody titres across donor samples and the PAS-stored platelets was two-fold. The regression showed a level of reduction in antibody titres which can be explained by baseline donor antibody titres in blood groups A and B compared to blood group O. CONCLUSION: The medianABO antibody titres were lower in APs suspended in PAS than in plasma. Addition of the PAS significantly lowered the IgM antibody titres by twofold, compared to plasma.

RESUMO

Abstract Seroprevalence of the antibodies of Brucella canis and Brucella abortus in dogs was assessed using a cross-sectional survey in Anambra and Enugu States, Nigeria. A total of 123 Companion dogs made up of 65 clinic dogs, 34 slaughter dogs and 24 household dogs were screened. For B. abortus antibody assay, the collected serum was used for Rose Bengal plate test (RBPT), Serum agglutination test (SAT) and Solid Phase Immunoassay technique with Immunocomb® Canine Brucellosis Antibody Test Kit was used. Out of the 123 dogs screened, none was positive for Brucella abortus antibodies while 34 (27.7%) of the dogs screened were positive for B. canis antibodies. There was a significant association (P<0.05) between infection and sex, the infection was significantly higher (P<0.05) in female than male dogs. Prevalence was significantly higher (P<0.05) in Exotic breeds than in mixed and local dog breeds. There was no association (P>0.05) between infection and antibody titre levels in the different categories of dogs. However, there was significant association (P<0.05) between the presence of Brucella canis antibodies and free roaming of dogs. This study provides the first serological evidence of B. canis infection in dogs in Enugu and Anambra States. This shows that B. canis is endemic in both states, underscoring the need for further studies. Female dogs, exotic breeds and freely roaming dogs are at a higher risk of Brucella infection in the study area; therefore, preventive and control measures are strongly recommended.

Resumen Se evaluó la seroprevalencia de los anticuerpos de Brucella canis y Brucella abortus en perros usando un sondeo transversal en los Estados Anambra and Enugu, Nigeria. Se examinó un total de 123 perros de compañía, de los cuales 65 eran perros de clínica, 34 perros de matadero y 24 perros caseros. Para el ensayo de anticuerpos de B. abortus, el suero muestreado se usó para la prueba de Rosa de Bengala (RBPT), prueba de aglutinación del suero (SAT) y se usó la técnica de inmunoensayo en fase sólida con el kit de prueba de anticuerpos para brucelosis canina Immunocomb®. De los 123 perros analizados, ninguno dio positivo para los anticuerpos de Brucella abortus mientras que 34 (27.7%) de los perros analizados dieron positivo para los anticuerpos de B. canis. Hubo una asociación significativa (P<0.05) entre infección y género; la infección fue significativamente más alta (P<0.05) en las hembras que en los machos. La prevalencia fue significativamente más alta (P<0.05) en las razas exóticas que en las razas cruzadas y las razas locales. No hubo ninguna relación (P>0.05) entre la infección y los niveles de titulación de anticuerpos en las diferentes categorías de perros. Sin embargo, hubo una relación significativa (P<0.05) entre la presencia de anticuerpos Brucella canis y los perros que andan libremente por doquier. Este estudio provee la primera evidencia serológica de infección con B. canis en perros de los Estados Enugu y Anambra. Esto muestra que la B. canis es endémica en ambos estados, enfatizando la necesidad de hacer más estudios. Las hembras, las razas exóticas y los animales que deambulan libremente se encuentran en el riesgo más alto de infección con Brucella en el área de estudio; por consiguiente, se recomienda enormemente tomar medidas preventivas y de control.

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