High Concentration of Anti-SARS-CoV-2 Antibodies 2 Years after COVID-19 Vaccination Stems Not Only from Boosters but Also from Widespread, Often Unrecognized, Contact with the Virus.

This study follows 99 subjects vaccinated with Pfizer/BioNTech COVID-19 vaccines over two years, with particular focus on the last year of observation (between days 360 and 720). The response to the vaccination was assessed with Diasorin's SARS-CoV-2 TrimericSpike IgG. Screening for SARS-CoV-2 infection was performed with Abbott's SARS-CoV-2 Nucleocapsid IgG immunoassay. Data from questionnaires were also analyzed. Two years after the first vaccine dose administration, 100% of the subjects were positive for anti-spike SARS-CoV-2 IgG and the median antibody level was still high (3600 BAU/mL), dropping insignificantly over the last year. Simultaneously, a substantial increase in seropositivity in anti-nucleocapsid SARS-CoV-2 IgG was noted, reaching 33%. There was no statistically significant agreement between anti-N seropositivity and reported COVID-19. Higher anti-spike concentrations and lower COVID-19 incidence was seen in the older vaccinees. It was noted that only subjects boosted between days 360 and 720 showed an increase in anti-spike IgG concentrations. The higher antibody concentrations (median 7440 BAU/mL) on day 360 were noted in participants not infected over the following year. Vaccination, including booster administrations, and natural, even unrecognized, contact with SARS-CoV-2 entwined two years after the primary vaccination, leading to high anti-spike antibody concentrations.

DiagSet: a dataset for prostate cancer histopathological image classification.

Cancer diseases constitute one of the most significant societal challenges. In this paper, we introduce a novel histopathological dataset for prostate cancer detection. The proposed dataset, consisting of over 2.6 million tissue patches extracted from 430 fully annotated scans, 4675 scans with assigned binary diagnoses, and 46 scans with diagnoses independently provided by a group of histopathologists can be found at https://github.com/michalkoziarski/DiagSet . Furthermore, we propose a machine learning framework for detection of cancerous tissue regions and prediction of scan-level diagnosis, utilizing thresholding to abstain from the decision in uncertain cases. The proposed approach, composed of ensembles of deep neural networks operating on the histopathological scans at different scales, achieves 94.6% accuracy in patch-level recognition and is compared in a scan-level diagnosis with 9 human histopathologists showing high statistical agreement.

A comparison of 7 commercial anti-SARS-CoV-2 antibody immunoassays.

Introduction: Serological testing in SARS-CoV-2 infection is gaining both patients' and clinicians' attention. Antibody assessment has potential multidirectional utility, hampered by the scarcity of clinical validation studies of the tests available on the market. Therefore, this study aimed to provide some evidence on the clinical utility of anti-SARS-CoV-2 commercial assays, based on the comparison of the results obtained with different methods. Material and methods: The study included 52 samples from patients and healthy volunteers. The control samples (n = 20) were obtained during the SARS-CoV-2 pandemic. The case cohort consisted of 32 consecutive patients referred to the Diagnostyka medical laboratory for anti-SARS-CoV-2 antibody testing. For the purpose of this study, the MAGLUMI chemiluminescent immunoassay (CLIA) was chosen as a comparative method. All samples were tested with this method, as well as with the Euroimmun enzyme-linked immunosorbent assay (ELISA) and five different lateral flow immunoassays (LFIAs). Results: The results obtained in this study provide evidence for high overall concordance between the comparative CLIA method and both ELISA and different LFIAs. The agreement between CLIA and LFIAs was 92.3-98.0% for IgG and 90.0-96.1% for IgM, depending on the kit. The concordance between CLIA and ELISA was 92.3% for IgG and 75.0% for IgA (compared to the MAGLUMI CLIA IgM). Conclusions: The results obtained in this study provide evidence for high overall concordance between the comparative CLIA method and different LFIAs. This could justify the use of LFIAs in some settings, where automated assays are not available, provided that some limitations are considered.

Comparative Analysis of the Results of Stroke Treatment With Multiple Administrations of Wharton's Jelly Mesenchymal Stem Cells-Derived HE-ATMP and Standard Conservative Treatment: Case Series Study.

Stroke remains still the leading cause of long-term disability worldwide. Although interventions such as early reperfusion, intravenous thrombolysis, and endovascular revascularization have shown neurological benefit in stroke patients, there is still lack of effective treatment enabling regeneration of nervous tissue after cerebral ischemic episodes. Cell therapy is an evolving opportunity for stroke survivors with residual neurological deficits. The purpose of this study was to evaluate safety and potential efficacy of multiple administration of Hospital Exemption-Advanced Therapy Medicinal Product (HE-ATMP) comprising 3 × 107 Wharton's jelly mesenchymal stem cells (WJMSCs). A study group was composed of six patients-three women and three men. The patients were qualified to the treatment with diagnosis of chronic stroke (2-24 months after cerebral ischemic episode), during 2 years. All the patients undergone repeated rounds of HE-ATMP administration to the CSF (cerebrospinal fluid) via lumbar puncture. The control group consisted of six patients (two women and four men) who experienced stroke, treated at the same time (follow-up period: 24 months) using standard treatment methods, without endovascular treatment. To evaluate the results of the therapy, we used both impairment scales [National Institutes of Health Stroke Score (NIHSS)] and functional outcomes scales [Modified Rankin Scale (MRS) and Barthel Index (BI)]. In four patients, who received at least three repeated rounds of HE-ATMP, we reported neurological improvement and reduction of functional neurodeficiency. The biggest improvement concerned the reduction of speech disorders in two cases; significant improvement in the field of motor skills in three patients and reduction of apraxia and improvement of logical communication skills in two patients were also reported. All the patients became more independent. Significant improvement of the neurological condition using the same scales was registered only in two patients from the control group. We did not report any adverse events in the treated group during follow-up. At 1-year follow-up, we demonstrate safety and beneficial effect of WJMSC transplantation including neurological improvement and reduction of functional neurodeficiency. We are aware that the samples size of this study is relatively small. The treatment regimen needs to be further tested in larger group of patients.

Clinical Characterization of Targetable Mutations (BRAF V600E and KRAS G12C) in Advanced Colorectal Cancer-A Nation-Wide Study.

BRAF V600E and KRAS mutations that occur in colorectal cancer (CRC) define a subpopulation of patients with an inferior prognosis. Recently, the first BRAF V600E-targeting therapy has been approved and novel agents targeting KRAS G12C are being evaluated in CRC. A better understanding of the clinical characteristics of the populations defined by those mutations is needed. We created a retrospective database that collects clinical characteristics of patients with metastatic CRC evaluated for RAS and BRAF mutations in a single laboratory. A total of 7604 patients tested between October 2017 and December 2019 were included in the analysis. The prevalence of BRAF V600E was 6.77%. Female sex, primary in the right colon, high-grade, mucinous, signet cell, partially neuroendocrine histology, perineural and vascular invasion, and surgical tissue sample were factors associated with increased mutation rates. The prevalence of KRAS G12C was 3.11%. Cancer of primary origin in the left colon and in samples from brain metastases were associated with increased mutation rates. The high prevalence of the BRAF V600E mutation in cancers with a neuroendocrine component identifies a potential candidate population for BRAF inhibition. The association of KRAS G12C with the left part of the intestine and brain metastases of CRC are new findings and require further investigation.

The Influence of Booster Shot and SARS-CoV-2 Infection on the Anti-Spike Antibody Concentration One Year after the First COVID-19 Vaccine Dose Administration.

This study pictures the humoral response of 100 vaccinees to Pfizer/BioNTech COVID-19 vaccine over a year, with particular focus on the influence of a booster shot administered around 10 months after the primary immunization. The response to the vaccination was assessed with Diasorin's SARS-CoV-2 TrimericSpike IgG. Abbott's SARS-CoV-2 Nucleocapsid IgG immunoassay was used to identify SARS-CoV-2 contact, even asymptomatic. In contrast to the gradual decline of the anti-spike IgG between 30 and 240 days after the first dose, an increase was noted between days 240 and 360 in the whole cohort. However, a statistically significant rise was seen only in boosted individuals, and this effect of the booster decreased over time. An increase was also observed in non-boosted but recently infected participants and a decrease was reported in non-boosted, non-infected subjects. These changes were not statistically significant. On day 360, a percentage of new SARS-CoV-2 infections was statistically lower in the boosted vs. non-boosted subgroups. The booster immunization is the most efficient way of stimulating production of anti-spike, potentially neutralizing antibodies. The response is additionally enhanced by the natural contact with the virus. Individuals with a low level of anti-spike antibodies may benefit the most from the booster dose administration.

Use of Multiple Wharton Jelly Mesenchymal Stem Cell Transplants in Treatment of Incomplete Spinal Cord Injury: A Case Report.

Interruption of spinal cord continuity remains an incurable condition that leads to functional loss below the lesion level. Effective treatment to enable spinal cord regeneration is lacking, although cell therapy is an evolving opportunity. Therefore, the purpose of this study was to evaluate the safety and potential efficacy of multiple Wharton jelly mesenchymal stem cell transplants in a patient with a spinal cord injury. A patient with incomplete spinal cord interruption at the T11 to T12 vertebrae was enrolled in experimental therapy. The patient scored A/B on the ASIA scale (developed by the American Spinal Injury Association) with deep paraparesis and sphincter palsy. However, full ability to fix the patient's trunk upon admission was confirmed. Bilateral axonal damage of motor and sensory neural fibers of lower extremities was confirmed with electromyography and electroneurography. One year of standard therapy did not bring any positive results. The patient underwent 5 rounds of Wharton jelly mesenchymal stem cell transplants every 3 months (total treatment time of 18 months). There were no complications connected with therapy during the 18- month follow-up. Continuous neurological and quality of life improvements were seen after every transplant. The patient's ASIA score changed from A/B to C/D and from 112 to 231 points. The sensation level decreased from the T12 to L3 to L4 level. The patient regained bladder control and anal sensation. Muscle strength at the left lower extremity improved. The patient gained the ability to stand in a standing frame and walk with an orthosis. Neurophysiological examinations objectively confirmed the improvement. Magnetic resonance imaging demonstrated no changes in the spinal cord signal. The treatment demonstrated an objective improvement that could be used for patients with chronic thoracic incomplete spinal cord injury.

Head-to-Head Comparison of 5 Anti-SARS-CoV-2 Assays Performance in One Hundred COVID-19 Vaccinees, over an 8-Month Course.

The immunoassays used to measure anti-spike SARS-CoV-2 antibodies are widely available on the market. However, their performance in COVID-19 vaccinees is not yet adequately assessed. Our study provides a head-to-head comparison of five methods: Abbott's S1-RBD IgG, Roche's S1-RBD total antibody, Euroimmun's S1 IgG, and DiaSorin's TrimericS IgG and S1/S2 IgG assays. Testing was performed in one hundred vaccinated subjects, at eight timepoints over eight months after vaccination. The results differed substantially between methods; however, they correlated strongly and demonstrated the individuals' responses to both doses of vaccination and the waning of humoral immunity after eight months. Importantly, we encountered a high percentage of results above the assay-specific upper quantitation limit (UQL) for undiluted samples. This was the most pronounced for the Roche's and Euroimmun's assays. The Abbott's assay showed the lowest percentage of results above the UQL. We also attempted to find a common way to establish antibody concentrations that might be classified as high. However, this resulted in between 10% and 100% of such results for different methods on day 240'. This highlights the need for an assay-specific approach for adjusting the cut-offs that may indicate COVID-19 immunity.

Anti-Spike SARS-CoV-2 IgG Assessment with a Commercial Assay during a 4-Month Course after COVID-19 Vaccination.

We intended to assess the humoral response induced by the Pfizer/BioNTech Comirnaty COVID-19 vaccine with commercially available immunoassays: anti-spike (S) IgG and IgM, and anti-nucleocapsid (N) IgG antibodies, over a 4-month course. One hundred subjects, including 15 COVID-19 convalescents, comprised the study cohort. The SARS-CoV-2 antibodies concentrations were measured on day 0' and 10', 20', 30', 60', 90', and 120' after the first dose administration. Over the course of the study, 100% of the participants developed and sustained anti-SARS-CoV-2 S IgG antibodies. The highest concentration, exceeding the quantification range of the test (2080 BAU/mL), was reached by 67% of the subjects on day 30'. The concentration of the antibodies remained stable between days 30' and 90' but was followed by a significant decrease between days 90' and 120'. The stronger and more persistent humoral response was noted for women. The COVID-19 convalescents developed higher antibody levels, particularly 10 days after the first Comirnaty dose. Twenty-three out of the eighty-five naïve vaccinees failed to develop a detectable IgM response. LIAISON® SARS-CoV-2 TrimericS IgG (DiaSorin S.p.A, Saluggia, Italy) may be useful in the assessment of the humoral response to the Comirnaty vaccine. In contrast, Abbott's anti-S SARS-CoV-2 IgM has a limited utility in this context.

Expansion of a SARS-CoV-2 Delta variant with an 872 nt deletion encompassing ORF7a, ORF7b and ORF8, Poland, July to August 2021.

Routine genomic surveillance on samples from COVID-19 patients collected in Poland during summer 2021 revealed the emergence of a SARS-CoV-2 Delta variant with a large 872 nt deletion. This change, confirmed by Sanger and deep sequencing, causes complete loss of ORF7a, ORF7b, and ORF8 genes. The index case carrying the deletion is unknown. The standard pipeline for sequencing may mask this deletion with a long stretch of N's. Effects of this deletion on phenotype or immune evasion needs further study.

The real life performance of 7 automated anti-SARS-CoV-2 IgG and IgM/IgA immunoassays.

OBJECTIVES: This study was aimed at providing some insights into the real-life performance of the commercial, clinically validated anti-SARS-CoV-2 antibody assays. METHODS: The residual, anonymized samples from 97 patients referred for anti-SARS-CoV-2 antibodies testing were included in the study. The initial assessment was performed with the Euroimmun ELISAs, followed by the assays provided by: NovaTec, Snibe, Vircell, Roche, Abbott and DiaSorin. The analyses of the results were performed separately for the antibodies of the early (IgM/IgA) and late (IgG) immune response. RESULTS: We observed a high variability of the results obtained with the investigated immunoassays. The fully concordant results were reported for only 57 out of 97 samples tested for IgG antibodies and for 34 out of 97 samples for IgM/IgA. The highest percentage of positive results was noted for the Euroimmun and Vircell ELISAs and the lowest for Novatec ELISAs.We proposed to distinguish true and false positive results based on the sum of positive results obtained with different methods. We arbitrarily considered reference positive samples reactive in at least half of the assays. The assay that proved to correlate the best with those reference results was the Roche electrochemiluminescence immunoassay. CONCLUSIONS: The differences observed between immunoassays targeting the early phase antibodies were much more pronounced than between IgG assays, suggesting their lower value for clinical use. Our study also showed a high percentage of plausibly false (positive or negative) results obtained with ELISAs, which suggests their inferiority to the automated immunoassays.

DNA extraction from FFPE tissue samples - a comparison of three procedures.

AIM OF THE STUDY: One of the critical steps in molecular oncology diagnostics is obtaining high quality genomic DNA. Therefore, it is important to evaluate and compare the techniques used to extract DNA from tissue samples. Since formalin-fixed, paraffin-embedded (FFPE) tissues are routinely used for both retrospective and prospective studies, we compared three commercially available methods of nucleic acid extraction in terms of quantity and quality of isolated DNA. MATERIAL AND METHODS: Slides prepared from 42 FFPE blocks were macro-dissected. Resulting material was divided and processed simultaneously using three extraction kits: QIAamp DNA FFPE Tissue Kit (QIAGEN), Cobas DNA Sample Preparation Kit (Roche Molecular Systems) and Maxwell 16 FFPE Plus LEV DNA Purification Kit (Promega). Subsequently, quantity and quality of obtained DNA samples were analysed spectrophotometrically (NanoDrop 2000, Thermo Scientific). Results of quantitative analysis were confirmed by a fluorometric procedure (Qubit 3.0 Fluorometer, Life Technologies). RESULTS: The results demonstrated that the yields of total DNA extracted using either Maxwell or Cobas methods were significantly higher compared to the QIAamp method (p < 0.001). The Maxwell Extraction Kit delivered DNA samples of the highest quality (p < 0.01). However, the highest total yield of extracted DNA was achieved with the Cobas technique, which may be due to a higher volume of eluate compared to the Maxwell method. CONCLUSIONS: To our knowledge, this is the first paper which directly compares three extraction methods: Cobas, Maxwell and QIAamp. The data herein provide information required for the selection of a protocol that best suits the needs of the overall study design in terms of the quantity and quality of the extracted DNA.

Risk factors for arterial thrombosis in antiphospholipid syndrome.

INTRODUCTION: Antiphospholipid syndrome (APS) is associated with the risk of both arterial and venous thrombosis. However, it is not known which factors might determine the location of thrombosis. MATERIALS AND METHODS: To retrospectively characterize factors associated with the risk of arterial thrombosis in a cohort of APS patients. Analysis included laboratory and clinical criteria of APS, together with classical cardiovascular risk factors and the possible role of platelet integrin α2ß1 (807 C/T) and α(IIb)ß3 (PI A1/2) genetic polymorphisms. We enrolled 163 APS patients (123 women and 40 men aged 21-75; mean age 43 years); 78 suffered from arterial thrombosis. RESULTS: There were no significant differences in the frequency or titers of different antiphospholipid antibodies with the exception of slightly increased frequency of IgG anticardiolipin antibodies (ACL) in the arterial thrombosis group. Livedo reticularis was observed significantly more often in the arterial thrombosis group, particularly in stroke patients. In univariate analysis arterial thrombosis was associated with male gender (OR-2,201; p=0,033), arterial hypertension (OR-2,81; p=0,002) and hypercholesterolemia (OR-3,69; p=0,001). On multivariate analysis arterial hypertension (OR=1,78; p=0,008) and hypercholesterolemia (OR=2,001; p=0,002) remained as independent risk factors for arterial thrombosis. Platelet glycoprotein polymorphisms studied did not show any significant associations with arterial thrombosis in APS patients. CONCLUSIONS: Among APS patients those with ACL IgG antibodies, having livedo reticularis, and suffering from hypertension an hypercholesterolemia are at the increased risk of arterial thrombosis.

Increased level of tumor necrosis factor-α in patients with antiphospholipid syndrome: marker not only of inflammation but also of the prothrombotic state.

Connections between inflammation and thrombosis are intriguing, especially in a condition such as an antiphospholipid syndrome (APS), a disease characterized by immune-mediated thrombosis. Tumor necrosis factor alpha (TNF-α) is a cytokine which shares proinflammatory and prothrombotic actions, while a soluble form of interlukin-2 receptor (sIL-2R) is considered a typical marker of (auto)immune inflammation with not known direct links to thrombosis. The differences in the pathogenesis of APS as compared to other autoimmune diseases might be connected with different serum levels of both mediators. To answer this question, we studied 147 patients with systemic lupus erythematosus (SLE), 21 with SLE-like syndrome (SLE-LS), 20 with isolated APS (primary antiphospholipid syndrome, PAPS), and 32 healthy controls. Thirty-six patients from the SLE group fulfilled the updated APS criteria (secondary APS, SAPS). In comparison to healthy subjects, TNF-α concentration was increased in all patients, while sIL-2R rose significantly in the SLE group only. APS (both SAPS and PAPS) was characterized by the highest levels of TNF-α. Moreover, patients with lupus anticoagulant or elevated levels of IgG anticardiolipin or IgG anti-ß(2)-glycoprotein I antibodies had higher TNF-α levels than patients without the presence of any type of antiphospholipid antibodies (aPL). In conclusion, the presence of aPL is associated with higher TNF-α level, whereas increased level of sIL-2R is rather connected with definite SLE where inflammatory processes prevail. It might be hypothesized that TNF-α plays a major role in pathogenesis of APS thrombotic phenomena.

[Antibodies to N-homocysteinylated albumin in patients with systemic lupus erythematosus]. / Przeciwciala przeciwko N-homocysteinylowanej albuminie u chorych na toczen rumieniowaty ukladowy.

INTRODUCTION: Hyperhomocysteinemia is known to predispose to atherosclerosis and occurs more commonly in patients with systemic lupus erythematosus (SLE) than in the general population. It has been shown that elevated plasma total homocysteine (tHcy) results in protein N-homocysteinylation and production o autoantibodies against N-homocysteinylated (N-Hcy) proteins. OBJECTIVES: The aim of the study was to investigate whether anti-N-Hcy-albumin antibodies occur in patients with SLE and identify factors that determine these antibodies in such population. Patients and methods. In 50 subjects with SLE and 50 age- and sex-matched healthy controls, we determined serum IgG antibodies to N-Hcy-albumin using an in-house enzyme linked immunosorbent assay. RESULTS: Patients had higher plasma tHcy and C-reactive protein (CRP) than controls, while serum folate and witamin B12 were lower in patients. Levels of anti-N-Hcy-albumin were higher in patients with SLE than in controls (medians: 0.31; vs. 0.19; p < 0.0001). In SLE patients, levels of anti- N-Hcy-albumin antibodies correlated with tHcy (r = 0.83; p <0.0001), CRP (r = 0.33; p = 0.02) and the duration of the disease (r = 0.3; p = 0.04). Seropositivity to anti-N-Hcy-albumin antibodies was more frequent in SLE patients than in controls (50% vs. 10%; p < 0.001). In SLE patients tHcy and CRP concentrations, along with the duration of the disease were independent predictors of anti-N-Hcy-albumin antibodies level. There were no associations between a type or levels of antinuclear antibodies patent's, or age with anti-N-Hcy-albumin antibodies. CONCLUSIONS: Compared with healthy controls, in SLE patients levels of anti-N-Hcy-albumin antibodies are significantly higher and are largely determined by tHcy, CRP and the disease duration. This novel autoimmune response might contribute to increased risk of vascular events in SLE patients.

[Antiphospholipid syndrome in autoimmune diseases]. / Zespól antyfosfolipidowy w przebiegu chorób autoimmunologicznych.

Classification criteria for antiphospholipid syndrome were first proposed in 1987, revised in 1999 (Sapporo criteria) and up-dated in 2006. The aim of the study was to analyze associations between clinical and laboratory symptoms of antiphospholipid syndrome in the group of patients with autoimmune diseases, based on recently up-dated classification criteria. 336 patients were enrolled into the study, with the majority (n=235) suffering from SLE. Laboratory determinations included: lupus anticoagulant (LA), anticardiolipin (aCL) and anti-beta2-glycoprotein I (abeta2GPI) (both of IgG and IgM class). Clinical and laboratory symptoms of antiphospholipid syndrome were quite common among patients studied. There was a significant association between laboratory and clinical features of antiphospholipid syndrome, according to recently modified classification criteria.

[Necrotic central retinitis due to the lupus erythematosus]. / Martwicze zapalenie centralnej siatkówki w przebiegu tocznia trzewnego.

We present a case of a twenty six years old patient who had been treated for systemic lupus erythematosus (SLE) for five years. The patient developed a sudden significant disturbance of vision quality of both eyes. A lot of additional examinations were done and central necrotic retinitis was diagnosed. After treatment insignificant improvement of vision quality of both eyes was achieved.

Clinical significance of antiphospholipid protein antibodies. Receiver operating characteristics plot analysis.

OBJECTIVE: To investigate the utility of receiver operating characteristic (ROC) analysis in determining the strength of association between various antiphospholipid and anti-protein cofactor antibodies (aPA) and thrombosis, pregnancy morbidity, and thrombocytopenia. METHODS: Clinical and laboratory variables were retrospectively studied in 204 patients: 160 with systemic lupus erythematosus (SLE), 22 with lupus-like syndrome (SLE-LS), and 22 with primary antiphospholipid syndrome (APS). Laboratory evaluation included detection of lupus anticoagulant (LAC) and measurement of IgG and IgM anticardiolipin (aCL), antiphosphatidylserine (aPS), antiphosphatidylinositol (aPI), anti-beta 2 glycoprotein I (a beta 2GPI), and antiprothrombin (aPT) antibodies. ROC plot analysis was used to determine the clinical accuracy of aPA tests, and calculate cut-off values which best associate with clinical symptoms typical for APS. RESULTS: The LAC was associated with a history of thrombosis [odds ratio (OR): 3.04; 95% confidence interval (CI): 1.5-6.2] and even more strongly with recurrent fetal loss (OR: 8.7; 95%CI: 2.8-26.7). ROC plot analysis revealed that the most accurate test for thrombosis was aCL IgG (ROC-derived cutoff value > 17.2 GPL; OR: 3.69; 95% CI: 1.8-7.4), for recurrent fetal loss, aPI IgG [> 22.1 theoretical units (TU); OR: 6.21; 95%CI: 2.1-18.5], closely followed by aCL IgG and a beta 2GPI IgG, and for thrombocytopenia aPS IgM (> 6.7 TU; OR: 1.9; 95%CI: 1.04-3.4). Among 182 autoimmune patients (SLE + SLE-LS), 6.6% presented clinical symptoms of APS without classic aPA (LAC and/or aCL), but with elevated levels of antibodies against other phospholipids, mainly aPI IgM. CONCLUSION: A laboratory that evaluates APS patients should establish its own threshold values for aPA tests. We suggest that ROC plot analysis is a valuable tool in establishing cutoff values. LAC and aCL determinations seem sufficient for the majority of laboratories. However, in specialized centers other tests should be available to detect those patients with clinical symptoms for APS but who are positive for antiphospholipid antibodies other than aCL and the LAC.