Background/Objectives: ACR/EULAR has recently developed new classification criteria for antiphospholipid syndrome (APS). The present study aims to analyze the impact of these new 2023 ACR/EULAR classification criteria in a cohort of pregnant women with primary APS. Methods: Retrospective cohort study of 93 consecutive pregnant women attending the Autoimmune Diseases Pregnancy Clinic, a multidisciplinary unit of a tertiary care teaching hospital, between 2005 and 2023. All of them fulfilled the Sydney classification criteria for APS. Women diagnosed with rheumatic autoimmune diseases other than APS were excluded. Results: Twenty-four out of ninety-three patients (25.8%) met the 2023 ACR/EULAR criteria for APS. Patients who met the new classification criteria were very similar to those who did not, except for being younger (p < 0.001), and had a lower number of clinical pregnancies (p = 0.004). The obstetric domain was clearly underrepresented in women who fulfilled the 2023 ACR/EULAR criteria (p < 0.001). Patients meeting the new classification criteria were primarily characterized by preterm births before 34 weeks due to severe placentation disorders (p = 0.004). Women with early and late fetal loss were significantly underrepresented (p < 0.0001 and 0.03, respectively). Nearly half of these patients had thrombocytopenia (p < 0.001). Serologically, these patients showed a higher frequency of persistent lupus anticoagulant (p = 0.02) and a lower frequency of IgM isotype antiphospholipid antibodies (p = 0.05). Conclusions: Almost three-quarters of the patients included in the study did not meet the 2023 ACR/EULAR criteria. Most patients who could not be classified according to these new classification criteria were those with early and/or late fetal deaths, as well as patients carrying only IgM aCL/AB2GPI antibodies. The high specificity of the 2023 ACR/EULAR criteria, restricted to severe placentation disorders, may leave the majority of patients with obstetric APS out of the new classification criteria.

This study aims to compare the demographic characteristics, clinical features, serology, and fetal–maternal outcomes between women with obstetric antiphospholipid syndrome (APS) and those with non-criteria (NC)-APS and seronegative (SN)-APS. Two-hundred and sixty-three women with APS obstetric morbidity ever pregnant were included. Of those, 66 met the APS classification criteria, 140 were NC-APS, and 57 were SN-APS. Patients with other autoimmune diseases were excluded. Adverse pregnancy outcomes (APO) included early pregnancy loss, fetal death, preeclampsia, abruptio placentae, and preterm birth. The mean age of the study group was 33.6 ± 5.3 years, and patients were followed up for 129.5 ± 81.9 months. In the NC-APS group, 31 (22.1%) did not fulfill clinical and serological criteria (Subgroup A), 49 (35%) did meet clinical but not serologic criteria (Subgroup B), and 60 (42.9%) fulfilled the serologic criteria but not the clinical ones (Subgroup C). The cardiovascular risk burden was higher in the APS group, due to a higher proportion of smoking. Patients with criteria APS received more intensive treatment than patients in the other study groups. The addition of standard of care (SoC) treatment significantly improved live birth and decreased APO in all groups. Significant clinical differences were observed between the study groups. However, when treated with SoC, fetal–maternal outcomes were similar, with a significant improvement in live births and a decrease in APO. Risk stratification in patients with obstetric morbidity associated with APS can help individualize their treatment.

During the COVID-19 pandemic, many studies have been carried out to evaluate different immune system components to search for prognostic biomarkers of the disease. A broad multiparametric antibody panel of cellular and humoral components of the innate and the adaptative immune response in patients with active SARS-CoV-2 infection has been evaluated in this study. A total of 155 patients were studied at admission into our center and were categorized according to the requirement of oxygen therapy as mild or severe (the latter being those with the requirement). The patients with severe disease were older and had high ferritin, D-dimer, C-reactive protein, troponin, interleukin-6 (IL-6) levels, and neutrophilia with lymphopenia at admission. Moreover, the patients with mild symptoms had significantly increased circulating non-classical monocytes, innate lymphoid cells, and regulatory NK cells. In contrast, severe patients had a low frequency of Th1 and regulatory T cells with increased activated and exhausted CD8 phenotype (CD8⁺CD38⁺HLADR⁺ and CD8⁺CD27⁻CD28⁻, respectively). The predictive model included age, ferritin, D-dimer, lymph counts, C4, CD8⁺CD27⁻CD28⁻, and non-classical monocytes in the logistic regression analysis. The model predicted severity with an area under the curve of 78%. Both innate and adaptive immune parameters could be considered potential predictive biomarkers of the prognosis of COVID-19 disease.

Objectives: Autoantibodies and, specifically antinuclear antibodies (ANA), are the hallmark of systemic autoimmune diseases (AID). In the last decades, there has been great technical development to detect these autoantibodies along with an increased request for this test by clinicians, while the overall pre-test probability has decreased. In this study, we compare the diagnostic performance of three different methods for ANA screening (indirect immunofluorescence [IIF], addressable laser bead immunoassay [ALBIA], and fluorescence enzyme immunoassay [FEIA]). Methods: Serum samples at baseline visit from 2,997 participants from the Camargo Cohort, a population with an overall low pre-test probability for systemic AID, were analyzed with the three methods. Participants have a minimum follow-up of 10 years and the development of autoimmune diseases was collected from clinical records. Results: The highest frequency of positive ANA was observed by IIF assay. However, ALBIA showed high sensitivity for AID. Likewise, solid phase assays (SPA) presented higher specificity than IIF for AID. ANA prevalence with any method was significantly higher in females and overall increased with age. Triple positivity for ANA was significantly related to the presence of anti-dsDNA–SSA/Ro60, Ro52, SSB/La, RNP, Scl-70, and centromere–specificities. No association was found for anti-Sm – RNP68, or ribosomal P – specificities. Noteworthy, triple positivity for ANA screening was associated with diagnosis of systemic AID both at baseline visit and follow-up. Conclusions: ANA detection by IIF may be better when the pre-test probability is high, whereas SPA techniques are more useful in populations with an overall low pre-test probability for systemic AID.

Objectives: Flow cytometry analyses of lymphocyte subpopulations (T, B, NK) are crucial for enhancing clinical algorithms and research workflows. Estimating the total error (TE) values for the percentage and absolute number of lymphocyte subpopulations using the state-of-the-art (SOTA) approach with real data from an external proficiency testing (EPT) scheme was performed. A comparison with previously published Biological Variability (BV)-based specifications was carried out. Methods: A total of 44,998 results from 86 laboratories over 10 years were analysed and divided into two five-year periods (2012–2016) and (2017–2021). Data come from the IC-1 Lymphocytes scheme of the Spanish External Quality Assurance System (EQAS) GECLID Program. This quantitative scheme includes percentages and absolute numbers of CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, CD19⁺, and CD3⁻CD56⁺CD16⁺ NK cells. The percentage of TE was calculated as: |reported value − robust mean|*100/robust mean for each laboratory and parameter. The cut-off for TE is set at 80 % best results of the laboratories. Results: A significant reduction in the SOTA-based TE for all lymphocyte subpopulations in 2017–2021 was observed compared to 2012–2016. The SOTA-based TE fulfils the minimum BV-based TE for percentages of lymphocyte subpopulations. The parameter with the best analytical performance calculated with SOTA (2017–2021 period)-based TE was the percentage of CD3⁺ (TE=3.65 %). Conclusions: The values of SOTA-based specifications from external quality assurance program data are consistent and can be used to develop technical specifications. The technological improvement, quality commitment, standardization, and training, reduce TE. An update of TE every five years is therefore recommended. TE assessment in lymphocyte subsets is a helpful and reliable tool to improve laboratory performance and data-based decision-making trust.