Earlier vs. later time period of COVID-19 infection and emergent autoimmune signs, symptoms, and serologies.

Objective: Autoantibodies and autoimmune diseases after SARS-CoV-2 infection are widely reported. Given evolving variants, milder infections, and increasing population vaccination, we hypothesized that SARS-CoV-2 infection earlier in the pandemic would be associated with more autoimmune connective tissue disease (CTD) symptoms and immunologic abnormalities.

Methods: Patients ≥18 years old with COVID-19 3/1/2020-8/15/2022 completed the CTD Screening Questionnaire and were tested for 27 autoimmune serologies, SARS-CoV-2 serologies, cell-bound complement activation products (CB-CAPs), and T and B lymphocyte immunophenotypes by flow cytometry.

Role of Platelet-Bound C4d (PC4d) in Predicting Risk of Future Thrombotic Events in Systemic Lupus Erythematosus.

Objective: Platelet-bound complement activation product C4d (PC4d) levels correlate with history of thrombosis in patients with systemic lupus erythematosus (SLE). The present study evaluated whether PC4d levels could assess risk of future thrombosis events.

Methods: PC4d level was measured by flow cytometry.

Erythrocyte complement receptor 1 (ECR1) and erythrocyte-bound C4d (EC4d) in the prediction of poor pregnancy outcomes in systemic lupus erythematosus (SLE).

Background: Complement activation has been associated with adverse pregnancy outcomes (APO) in SLE. Pregnant women with SLE were studied to evaluate whether complement dysregulation within the first two pregnancy trimesters predicts APO.

Methods: Pregnant women fulfilled classification criteria for SLE.

Antiphospholipid antibodies are persistently positive at high titers. Additive value of platelet-bound C4d.

Background: Classification criteria for antiphospholipid syndrome (APS) require that antiphospholipid antibody (aPL) positivity is confirmed after at least 12 weeks. We tested the hypothesis that aPL at high titers remain positive while low titers fluctuate over time. As both platelet-bound C4d (PC4d) and aPL are associated with thrombosis in systemic lupus erythematosus (SLE), we also evaluated whether PC4d can aid in APS diagnosis.

A multianalyte assay panel with cell-bound complement activation products demonstrates clinical utility in systemic lupus erythematosus.

Objective: To evaluate the clinical utility of the multianalyte assay panel (MAP), commercially known as AVISE Lupus test (Exagen Inc.), in patients suspected of SLE.

Methods: A systematic review of medical records of ANA-positive patients with a positive (>0.

Capillary Blood Levels of Hydroxychloroquine and Methotrexate Are Stable for up to 5 Years When Collected on Volumetric Absorptive Microsamplers.

Background: Hydroxychloroquine (HCQ) and methotrexate (MTX) are common antirheumatic drugs used chronically by patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) (1, 2). Therapeutic drug monitoring (TDM) of HCQ and MTX provides critical compliance information, but typically requires venipuncture and shipment of refrigerated blood samples to the clinical laboratory. Capillary blood collection by finger prick offers a convenient alternative to venipuncture.

A Multianalyte Assay Panel With Cell-Bound Complement Activation Products Predicts Transition of Probable Lupus to American College of Rheumatology-Classified Lupus.

Objective: To evaluate the usefulness of biomarkers to predict the evolution of patients suspected of systemic lupus erythematosus (SLE), designated as probable SLE (pSLE), into classifiable SLE according to the American College of Rheumatology (ACR) classification criteria.

Methods: Patients suspected of SLE were enrolled by lupus experts if they fulfilled three ACR criteria for SLE and were followed for approximately 1-3 years to evaluate transition into ACR-classifiable SLE. Individual cell-bound complement activation products (CB-CAPs), serum complement proteins (C3 and C4), and autoantibodies were measured by flow cytometry, turbidimetry, and enzyme-linked immunosorbent assay, respectively.

Cell-bound complement activation products associate with lupus severity in SLE.

Objectives: To evaluate the association between lupus severity and cell-bound complement activation products (CB-CAPs) or low complement proteins C3 and C4.

Methods: All subjects (n=495) fulfilled the American College of Rheumatology (ACR) classification criteria for SLE. Abnormal CB-CAPs (erythrocyte-bound C4d or B-lymphocyte-bound C4d levels >99th percentile of healthy) and complement proteins C3 and C4 were determined using flow cytometry and turbidimetry, respectively.

Transition of Methotrexate Polyglutamate Drug Monitoring Assay from Venipuncture to Capillary Blood-Based Collection Method in Rheumatic Diseases.

Objective: Methotrexate (MTX) polyglutamate (MTXPG) levels from isolated red blood cells (RBCs) collected by venipuncture have clinical utility in guiding MTX dosing for patients with rheumatoid arthritis (RA). Our objective was to transition this RBC-based therapeutic drug monitoring (TDM) assay to dried capillary blood collected by fingerstick.

Methods: Patients with RA treated with MTX were enrolled.

Randomised prospective trial to assess the clinical utility of multianalyte assay panel with complement activation products for the diagnosis of SLE.

Objective: We compared the physician-assessed diagnostic likelihood of SLE resulting from standard diagnosis laboratory testing (SDLT) to that resulting from multianalyte assay panel (MAP) with cell-bound complement activation products (MAP/CB-CAPs), which reports a two-tiered index test result having 80% sensitivity and 86% specificity for SLE.

Methods: Patients (n=145) with a history of positive antinuclear antibody status were evaluated clinically by rheumatologists and randomised to SDLT arm (tests ordered at the discretion of the rheumatologists) or to MAP/CB-CAPs testing arm. The primary endpoint was based on the change in the physician likelihood of SLE on a five-point Likert scale collected before and after testing.

Complement Activation in Patients With Probable Systemic Lupus Erythematosus and Ability to Predict Progression to American College of Rheumatology-Classified Systemic Lupus Erythematosus.

Objective: To evaluate the frequency of cell-bound complement activation products (CB-CAPs) as a marker of complement activation in patients with suspected systemic lupus erythematosus (SLE) and the usefulness of this biomarker as a predictor of the evolution of probable SLE into SLE as classified by the American College of Rheumatology (ACR) criteria.

Methods: Patients in whom SLE was suspected by lupus experts and who fulfilled 3 ACR classification criteria for SLE (probable SLE) were enrolled, along with patients with established SLE as classified by both the ACR and the Systemic Lupus International Collaborating Clinics (SLICC) criteria, patients with primary Sjögren's syndrome (SS), and patients with other rheumatic diseases. Individual CB-CAPs were measured by flow cytometry, and positivity rates were compared to those of commonly assessed biomarkers, including serum complement proteins (C3 and C4) and autoantibodies.

Cell-bound complement activation products in SLE.

Diagnosis of SLE is based on clinical manifestations and laboratory findings. Timely diagnosis and treatment are important to control disease activity and prevent organ damage. However, diagnosis is challenging because of the heterogeneity in clinical signs and symptoms, and also because the disease presents with alternating periods of flare and quiescence.

Capillary blood collected on volumetric absorptive microsampling (VAMS) device for monitoring hydroxychloroquine in rheumatoid arthritis patients.

A novel technique for collection of capillary blood, termed volumetric absorptive microsampling (VAMS), has been recently cleared by the FDA for collection of human blood. VAMS absorbs a fixed volume of blood (10μl) and overcomes area bias and homogeneity issues associated with dried blood spot (DBS). This study is the application of VAMS for therapeutic drug monitoring (TDM) in human capillary blood.

Validation of a multi-analyte panel with cell-bound complement activation products for systemic lupus erythematosus.

Background: We describe the analytical validation of an assay panel intended to assist clinicians with the diagnosis of systemic lupus erythematosus (SLE). The multi-analyte panel includes quantitative assessment of complement activation and measurement of autoantibodies.

Methods: The levels of the complement split product C4d bound to erythrocytes (EC4d) and B-lymphocytes (BC4d) (expressed as mean fluorescence intensity [MFI]) are measured by quantitative flow cytometry, while autoantibodies (inclusive of antinuclear and anti-double stranded DNA antibodies) are determined by immunoassays.

The Avise Lupus Test and Cell-bound Complement Activation Products Aid the Diagnosis of Systemic Lupus Erythematosus.

Background: Systemic lupus erythematosus (SLE) is a multifaceted disease, and its diagnosis may be challenging. A blood test for the diagnosis of SLE, the Avise Lupus test, has been recently commercialized and validated in clinical studies.

Objectives: To evaluate the use of the Avise Lupus test by community rheumatologists.