Special conditions associated with laboratory autoimmune testing are not well compatible with recent developments in regulatory frameworks such as EN/ISO 15189 accreditation or in vitro diagnostic medical device regulation (IVD-R). In addition, international recommendations, guidelines and disease criteria are poorly defined with respect to requirements on autoantibody testing. Laboratory specialists from Austria, Belgium, Croatia, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Norway, Poland, Portugal, South Africa, Spain, Sweden, Switzerland, and The Netherlands collected information, reported national experience, and identified quality issues in relation to autoantibody testing that require consensus on interpretation of the regulatory frameworks and guidelines. This process has been organized by the European Autoimmunity Standardisation Initiative (EASI). By identifying the critical items and looking for a consensus, our objective was to define a framework for, in particular, EN/ISO accreditation purposes. Here, we present a review of current publications and guidelines in this field to unify national guidelines and deliver in this way a European handout on quality control and accreditation for laboratories involved in autoantibody testing. We focus on quality items that can be checked during accreditation visits. Despite various local varieties, we encountered an overwhelming dedication to quality assurance in all contributing countries.

Tigecycline attenuates polymorphonuclear leukocyte (PMN) receptors but not functions: Tigecycline achieves high intracellular concentrations in polymorphonuclear leukocytes (PMNs). To evaluate the effects of tigecycline on human PMNs, PMNs were incubated with tigecycline dilutions (0.1 to 100 mg L^-1). Phagocytosis-associated PMN Fcγ- and complement receptors as well as phagocytosis and oxidative burst induced byStaphylococcus aureuswere measured by flow cytometry. Incubation with tigecycline caused small but significant decreases in the density of complement receptors CD11b and CD35 (all concentrations) and Fcγ receptors CD16 and CD32 (high concentrations), but not in the percentages of receptor-bearing cells, except for small reductions in the proportions of CD16 positive cells at high concentrations. Tigecycline had no effect on phagocytosis or oxidative burst induced byS. aureus. Tigecycline was thus associated with decreased density of PMN complement and (at high concentrations) Fcγ receptors. Although statistically significant, the differences were small and did not influence the PMN function as measured by phagocytosis and oxidative burst.

IgA anti-β2glycoprotein I antibodies (IgA-anti-β2GPI) seems to be the most prevalent isotype in patients with Systemic Lupus Erythematosus (SLE) with a significant association to thrombotic events. Both SLE and antiphospholipid syndrome (APS) can be associated with implantation failure, fetal loss and obstetric complications. Recent reports highlight the clinical value of IgA-anti-β2GPI determination in supporting in vitro fertilization (IVF) treatment and IVF pregnancy outcomes. We report a 36-year-old female diagnosed with SLE, endometriosis and unexplained infertility. Conventional APS markers were consistently negative: anti-cardiolipin (aCL) and anti-β2GPI: IgG/IgM. She was then tested with reports of repeatedly high IgA-anti-β2GPI and tested positive from 2014 after IgA (aCL; anti-β2GPI) were established in our APS diagnostic panel. She underwent successful first IVF procedure with a 30 week live birth pregnancy outcome. During the follow up no lupus flare, thrombosis or ovarian hyperstimulation syndrome were registered. Serum IgA anti-β2GPI and anti-dsDNA levels declined statistically significant during the second and third trimester. Titres of IgA-anti-β2GPI remained lower postpartum as well. This case highlights the clinical importance of IgA-anti-β2GPI testing for family planning, assisted reproduction and pregnancy in women with SLE and/or APS.

Measurable Residual Disease (MRD) assessment in pediatric acute lymphoblastic leukemia (ALL) is crucial for relapse prediction and treatment guidance. Multiparameter flow cytometry (MFC) enhances detection but faces limitations due to insufficient leukemia-associated immunophenotypes (LAIPs) and antigen modulation. This study explores new markers to improve MFC-based MRD detection in B-cell precursor ALL (BCP-ALL). Expression-patterns of seven aberrancy markers, i.e., CD44, CD304, CD73, CD86, CD123, CD99, CD58, and one B-cell maturation marker, CD22, were studied in 143 samples with leukemic-blasts from sixty-one childhood BCP-ALL patients and in hematogones of 20 non-leukemic bone marrow (BM) samples using fourteen-color MFC. The highest relative frequences of LAIPs amounted to 82.50%, reported for CD99 and CD58, followed by CD44 (81.10%), CD73 (76.20%), CD22 (73.40%), CD304 and CD86 (68.50%), while the lowest relative frequence was CD123 (44.40%). Differential expression of CD58, CD304, and CD73 in diagnostic samples was highly significant (p < 0.01) between pre-B-I, pre-B-II, immature B cells, and BCP-ALL blasts. In MRD-positive samples CD73 showed significantly high (p < 0.01) differential expression between all stages of hematogones and residual blasts, followed by CD304, CD58, and CD22. CD73 and CD304 were identified as the most reliable among the tested markers for distinguishing both diagnostic and MRD blasts from normal B cell precursors.