ABSTRACT
Background@#The PLASMIC score is a convenient tool for predicting ADAMTS13 activity of ＜10%.Lactate dehydrogenase (LDH) is widely used as a marker of haemolysis in thrombotic thrombocytopenic purpura (TTP) monitoring, and could be used as a replacement marker for lysis. We aimed to validate the PLASMIC score in a multi-centre Asia Pacific region, and to explore whether LDH could be used as a replacement marker for lysis. @*Methods@#Records of patients with thrombotic microangiopathy (TMA) were reviewed. Patients’ ADAMTS13 activity levels were obtained, along with clinical/laboratory findings relevant to the PLASMIC score. Both PLASMIC scores and PLASMIC-LDH scores, in which LDH replaced traditional lysis markers, were calculated. We generated a receiver operator characteristics (ROC) curve and compared the area under the curve values (AUC) to determine the predictive ability of each score. @*Results@#46 patients fulfilled the inclusion criteria, of which 34 had ADAMTS13 activity levels of ＜10%. When the patients were divided into intermediate-to-high risk (scores 5‒7) and low risk (scores 0‒4), the PLASMIC score showed a sensitivity of 97.1% and specificity of 58.3%, with a positive predictive value (PPV) of 86.8% and negative predictive value (NPV) of 87.5%. The PLASMIC-LDH score had a sensitivity of 97.1% and specificity of 33.3%, with a PPV of 80.5% and NPV of 80.0%. @*Conclusion@#Our study validated the utility of the PLASMIC score, and demonstrated PLASMIC-LDH as a reasonable alternative in the absence of traditional lysis markers, to help identify high-risk patients for treatment via plasma exchange.
ABSTRACT
BackgroundImmunization stress-related responses presenting as stroke-like symptoms may develop following COVID-19 vaccination. This study aimed to describe the clinical characteristics of immunization stress-related responses causing stroke-like events following COVID-19 vaccination. MethodsWe conducted a retrospective study of the secondary data of reported adverse events following COVID-19 immunization that presented with neurologic manifestations. Between March 1 and July 31, 2021, we collected and analyzed the medical records of 221 patients diagnosed with stroke-like symptoms following immunization. Demographic and medical data included sex, age, vaccine type, sequence dose, time to event, laboratory data, and recovery status as defined by the modified Rankin score (i.e., defining the degree of severity/dependence, with higher scores indicating greater disability). The affected side was evaluated for associations with the injection site. ResultsIn total, 221 patients were diagnosed with immunization stress-related responses (stroke-like symptoms) following CoronaVac (Sinovac) or ChAdOx1 (AstraZeneca) vaccinations. Most patients (83.7%) were women. The median (interquartile range) age of onset was 34 (28-42) years in patients receiving CoronaVac and 46 (33.5-60) years in those receiving ChAdOx1. The median interval between vaccination and symptom onset for each vaccine type was 60 (16-960) min and 30 (8.8-750) min, respectively. Sensory symptoms were the most common symptomology. Most patients (53.8%) developed symptoms on the left side of the body; 99.5% of the patients receiving CoronaVac and 90% of those receiving ChAdOx1 recovered well (modified Rankin scores [≤]2, indicating slight or no disability). ConclusionsImmunization stress-related responses presenting as stroke-like symptoms can develop following COVID-19 vaccination. Symptoms that are more likely to occur on the injection side are transient (i.e., without permanent pathological deficits). Public education and preparedness are important for administering successful COVID-19 vaccination programs.
ABSTRACT
IntroductionVaccine-induced thrombotic thrombocytopenia (VITT) has been reported after vaccination with the adenoviral vector COVID-19 vaccine ChAdOx1 nCoV-19 in European countries. To date, no case of VITT has been reported in Thais after COVID-19 vaccination. We determined the frequency of anti-PF4/polyanionic antibodies in the Thai population receiving the COVID-19 vaccines. MethodsWe conducted a cross-sectional study to evaluate the prevalence of anti-PF4/polyanionic antibodies in health care workers who received COVID-19 vaccination with ChAdOx1 nCoV-19 or CoronaVac within 7-35 days. A control population who had not been vaccinated was also included. Anti-PF4/polyanionic antibodies were detected using enzyme-link immunosorbent assay (ELISA). Functional assay with platelet aggregation was performed for all positive anti-PF4/polyanionic antibody ELISA tests. ResultsA total of 646 participants were included in the study. 221 received ChAdOx1 nCoV-19, 232 received CoronaVac, and 193 participants were in the control group. The prevalence of anti-PF4 antibodies was 2.3% (95% confidence interval [CI] 0.7 to 5.2), 1.7% (95% CI, 0.5 to 4.4) in the ChAdOx1 nCoV-19 and CoronaVac groups, respectively. There was no positive test in the control group. None of the PF4/polyanionic positive sera induced platelet aggregation. ConclusionWe found a low prevalence of anti-PF4 antibodies in Thais after vaccination with ChAdOx1 nCoV-19 and CoronaVac. Low titer positive PF4/polyanionic ELISA results should be interpreted with caution when screening asymptomatic individuals after vaccination against COVID-19. HighlightsO_LIHigh titer PF4/polyanion antibodies are associated with vaccine-induced immune thrombotic thrombocytopenia (VITT). C_LIO_LILow titer PF4/polyanion antibodies occur after vaccination with ChAdOx1 nCoV-19 and CoronaVac in some vaccinees. C_LIO_LIThese PF4/polyanion antibodies do not activate platelets and lack of association with VITT. C_LIO_LILow-titer positive PF4/polyanionic ELISA results should be interpreted with caution when screening asymptomatic individuals after vaccination against COVID-19. C_LI
