Overview on anticardiolipin ELISA standardization

Mycoplasma pneumoniae pneumonia with pulmonary embolism: A study on pediatric cases in Jilin province of China

Mycoplasma is one of the most common pathogens causing community-acquired pneumonia in pediatric patients. In recent years, the number of refractory or severe cases with drug resistance has been gradually increasing and cases that developed embolism after Mycoplasma pneumoniae (M. pneumoniae) infection have been reported. The present study retrospectively analyzed the clinical features, diagnosis and treatment of M. pneumoniae pneumonia (MPP) combined with pulmonary embolism (PE) in a series of 7 cases encountered between January 1st, 2016 to August 1st, 2019 at the Department of Pediatric Intensive Care Unit of The First Hospital of Jilin University (Changchun, China). Combined with relevant Chinese and international studies published during the last two decades, a comprehensive analysis was performed. All of the pediatric patients of the present study had fever, cough and dyspnea respiratory symptoms at onset and the disease progressed rapidly. Thereafter, PE was confirmed by a series of examinations. Pulmonary CT indicated patchy inflammations and significantly elevated D-dimer levels, accompanied by positive anticardiolipin antibodies. Furthermore, a filling defect in the pulmonary artery branch was observed on CT pulmonary angiography (CTPA) examination. In 2 cases, the condition was improved with anti-infection and anticoagulation treatment with low-molecular-weight heparin and warfarin, respectively, and the pulmonary embolism disappeared after 3-4 months. A total of 5 cases, who were not responsive to the drug treatment, underwent surgical resection. During the operation, the local tissues were determined to be infarcted and the pathological diagnosis was consistent with pulmonary infarction. Among the 5 cases, 2 died of Acute Respiratory Distress Syndrome at 3-8 days after the operation. The remaining patients underwent 6-12 months of follow-up and respiratory rehabilitation and their quality of life is now good. In conclusion, compared with healthy individuals, pediatric patients with critical MPP have an elevated risk of embolism. It is necessary to be vigilant regarding whether MMP is combined with PE and perform timely CTPA examination. Early detection, early treatment and surgical intervention (if necessary) may significantly reduce the risk of mortality and disability.

Headache and systemic lupus erythematosus

Headache is a common feature in patients with systemic lupus erythematosus (SLE) and represents a significant source of patient discomfort. The exact prevalence of headache in SLE is unknown. The results of different studies widely vary, most likely due to the use of different classification for headache and the lack of controls in most studies. The relationshipbetween headache and SLE is also unclear since it is difficult to determine which degree and type of headaches can be explained on the basis of chronic illness, or as part of the disease spectrum of SLE. No pathogenic mechanism has so far been described that can fully explain headache induced by SLE. The role of circulating cytokines, vascular injury, neuronal damage or antiphospholipid antibodies (aPL) in the development of headache in SLE patients is also a matter of debate. Other concomitant causes such as infection or hypertension should be excluded before assuming that headache is a feature of SLE activity. Therapeutic approach of headache SLE-related remains empirical and based on clinical experience.

Efficacy and safety of nadroparin in the treatment of pregnant women with antiphospholipid syndrome: a prospective cohort study

The optimal therapeutic management of patients with antiphospholipid syndrome (APS) during pregnancy is debatable. In the present prospective cohort study the use of a low molecular weight heparin (LMWH) (nadroparin), administered alone twice daily in 30 pregnant women who were diagnosed with APS on the basis of the current classification criteria, is evaluated. Dosage was adjusted according to anti-Xa levels in the patients as the pregnancies progressed. Three women, in whom an important gradual fall in platelet count in the first trimester did not respond to increased nadroparin doses, were shifted to a second-line treatment protocol. Fetal loss occurred in two of the 27 remaining women (7.40%), while 25 (92.59%) delivered 25 live infants, between the 32nd and 40th weeks of gestation. No fetal problems were registered during pregnancies, while maternal complications occurred in two of the 25 patients (8%). Moreover, there were no thrombotic events in any of the women during the study. Patient compliance was good and only minor side-effects were reported. The results of this study indicate that nadroparin alone is useful and safe in the management of pregnant patients with APS. However, in consideration of the good pregnancy outcome obtained in patients with only pregnancy morbidity when heparin and aspirin were used together, other studies comparing nadroparin twice daily with once daily plus Aspirin would be useful to ascertain which is more effective in these patients.

Variability in Anticardiolipin Antibody Detection: Role of Nonspecific IgG Binding and Different Microtiter Plates

There are many studies that are available on the Internet that attempt to standardize the assay for anticardiolipin antibody evaluation because of the variability of results. The aim of this study was to evaluate simultaneously the role of different microplates and the importance of sample nonspecific binding in determining different results in anticardiolipin antibody detection. Sera from 8 patients with raised levels of IgG anticardiolipin antibodies and 10 control sera were assayed by enzyme-linked immunosorbent assay in the presence (specific binding) or in the absence of cardiolipin (sample blank) with four different microplates, that is, NUNC PolySorp, FALCON ProBIND, Greiner 655061 (high binding), and Greiner 655001 (medium binding). Results were expressed as optical densities or net-optical densities (following sample blank subtraction) as well as international IgG anticardiolipin units (GPL) or net-GPL. A wide interplate variability of optical densities was found. When results were expressed as GPL, significant differences were only found between Greiner 655061, FALCON ProBIND, and NUNC PolySorp ( P < .05 and P < .001, respectively) whereas differences were not statistically significant if interplate variability was analyzed as net-GPL. Results expressed as categorical variables (ie, positive/negative, according to a GPL cut-off and net-GPL cut-off, obtained with sera from 100 apparently healthy blood donors) showed a good or excellent Cohen's κ coefficient of concordance among plates when positivity was evaluated on net-GPL. Our data strongly suggest that quantification and subtraction of sample blank may improve both interlaboratory agreement and reliability of anticardiolipin assay and minimize false-positive results.

Use of a new silica clotting time for diagnosing lupus anticoagulant in patients who meet the clinical criteria for antiphospholipid syndrome

The silica clotting time (SCT) is a phospholipid-dependent coagulation assay used for the laboratory diagnosis of lupus anticoagulant (LA) antibodies. The sensitivity and specificity of a new commercial SCT for identifying LA in patients who meet the clinical criteria for antiphospholipid syndrome (APS), and its association with thrombotic events were evaluated here. Forty-five patients who met the clinical criteria for APS according to the Sapporo International Consensus Statement were examined. Sixty-nine patients who did not meet the clinical criteria for APS, and 20 blood donors were used as controls. Plasma samples from the patients and controls were tested for LA using a new commercial SCT with low and high synthetic phospholipid concentrations. The results were compared with those obtained by diluted Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT). SCT's sensitivity for identifying LA in patients who met the clinical criteria of APS was higher compared to APTT and dRVVT (53.3% vs. 31.1% and 31.1%), and the specificities of these assays were 96.6%, 100%, and 98.9%, respectively. When dRVVT was combined with SCT, and dRVVT was combined with APTT their sensitivities were 57.7% and 48.8%, and their specificities were 96.6% and 98.9%, respectively. A stepwise logistic regression analysis indicated that the combination of dRVVT with SCT was associated with total thrombotic events (odds ratio (OR)=11.5, 95% confidence interval (CI)=1.25-106.3, P=0.031) as well as with venous thrombosis (OR=4.09, 95% CI=1.16-14.43, P=0.028). According to our results, SCT is the most sensitive assay for identifying LA in patients who meet the clinical criteria for APS. Moreover, the highest sensitivity was reached with a combination of SCT and dRVVT. The method's association with total thrombotic events and venous thrombosis was in fact significant.

Recent advances in the diagnosis of antiphospholipid syndrome

Antiphospholipid antibodies are autoantibodies directed against anionic phospholipids or protein-phospholipid complexes measured in solid-phase immunoassays such as anticardiolipin (aCL) antibody or detected in phospholipid-dependent clotting tests as lupus anticoagulant (LA). The term "antiphospholipid syndrome (APS)" was first coined to denote the clinical association between antiphospholipid antibodies and a syndrome of episodes of thrombosis in arteries and/or veins, pregnancy loss, and thrombocytopenia. The diagnosis of APS is based on the finding of "moderate-to-high" aCL antibody titer and/or an LA test with any one of the characteristic clinical features presented. Recently, the diagnostic criteria of APS was revised and several newer assays that use phosphatidylserine, a mixture of negatively charged phospholipids or beta2-glycoprotein 1 (beta2-GP1) have been proposed for more specific measurements of antibodies present in APS. In this section, recent progress in the laboratory diagnosis of antiphopholipid syndrome will be discussed.