Automated indirect immunofluorescence antinuclear antibody analysis is a standardized alternative for visual microscope interpretation.

BACKGROUND: Screening for antinuclear antibodies (ANA) is a basic tool in the serological work-up of systemic rheumatic disorders. Despite the emergence of alternative screening methods and the difficulties in standardization, indirect immunofluorescence (IIF) remains the recommended method for ANA detection. This study aimed to assess the reliability of automated ANA IIF analysis as a standardized alternative for the conventional manual approach. METHODS: ANA testing on HEp-2000 cells was performed on 304 consecutive routine sera, 28 serumbank samples displaying rare staining patterns, 219 samples of well-defined disease cohorts [141 systemic sclerosis (SSc), 13 polymyalgia rheumatica, 22 osteoarthritis, 5 ANCA-associated vasculitis and 38 spondyloarthritis] and 100 healthy donors. All samples were analyzed by automated IIF (Zenit G-sight), by conventional visual IIF microscopy and two ANA screening enzyme immunoassays (EIA). RESULTS: Automated and conventional ANA IIF analysis were comparable for negative/positive interpretation as well as intensity assessment (>90% agreement). In contrast, the accuracy of pattern recognition (26%) was limited. Likelihood ratios (LR) for SSc on results intervals of both Zenit G-sight and EIA increased with increasing level of positivity. Sensitivity within the SSc-associated antibody subsets was higher for Zenit G-sight (97%-100%) than EIA (10%-96%). A significant correlation between the quantitative result obtained by Zenit G-sight and the conventional end-point titer was found. CONCLUSIONS: The use of Zenit G-sight for automated ANA IIF analysis offers opportunities to improve standardization. However, a complementary role of the expert technicians remains, especially for pattern recognition and classification of uncertain/negative samples.

Acquired factor X deficiency in a multiple myeloma without amyloidosis: a case report.

BACKGROUND: Multiple myeloma is one of the most common hematologic malignancies. Acquired factor X deficiencies are often observed in primary (AL) amyloidosis and rarely in multiple myeloma. OBJECTIVE: We report a case of an acquired factor X deficiency in a patient with a newly diagnosed IgA lambda multiple myeloma, without any evidence of concomitant amyloidosis. METHODS: We present the patient's medical history, clinical and physical examinations, laboratory analysis, and outcome. RESULTS: A 76-year-old male presented at the emergency department with ongoing gingival bleeding. Several analytical problems with blood sample analysis arose, which eventually led to the diagnosis of a multiple myeloma. Further exploration revealed an acquired factor X deficiency, explaining the ongoing bleeding. There was no evidence of concomitant amyloidosis. The multiple myeloma was treated, leading to complete remission of the malignancy and bleeding tendency. CONCLUSION: While coagulopathy is rarely observed in patients diagnosed with multiple myeloma, considering an acquired factor X deficiency becomes relevant when such patient present with bleeding diathesis.

Evaluation of a new set of automated chemiluminescense assays for anticardiolipin and anti-beta2-glycoprotein I antibodies in the laboratory diagnosis of the antiphospholipid syndrome.

INTRODUCTION: The laboratory diagnosis of antiphospholipid syndrome (APS) requires the demonstration of antiphospholipid antibodies (aPL): lupus anticoagulant (LAC) measured through coagulation assays, anticardiolipin IgG or IgM antibodies (aCL) and/or anti-ß2glycoprotein I IgG or IgM antibodies (aß2GPI), usually detected by ELISA. MATERIALS AND METHODS: We evaluated the diagnostic value of aCL and aß2GPI measured by a new automated system using the chemiluminescence principle, the immunoanalyzer Zenit RA (Menarini). RESULTS: Results of aCL and aß2GPI were correlated with the clinical background of the patients and with results of ELISA (n=314). Correlated to the clinical background sensitivity/specificity ranged for aCL IgG between 7.5-45.2% / 54.2-98.8%, for aCL IgM 3.4-5.5% / 89.9-94%, for aß2GPI IgG 5.5-25.3% / 75.6-100% and aß2GPI IgM 3.4-4.8% / 89.9-92.3%, depending on the cut-off used. Sensitivity with manufacturer's cut-offs was comparable to ELISA, except for aß2GPI IgG with a significantly lower sensitivity compared to ELISA (5.5% vs 11.6%). In the APS patient population (n=30) sensitivity of aCL IgG and aß2GPI IgG was higher measured by ELISA compared to Zenit RA (46.7% vs 30.0%, and 46.7% vs 26.7%, respectively). Agreement between Zenit RA results and ELISA results for the four parameters was moderate (Kappa-values ranging 0.509-0.565). Sensitivity was 38.5%, 53.3%, 40% and 69.2% for aCL IgG, aCL IgM, aß2GPI IgG and aß2GPI IgM, respectively, applying the highest cut-off value for Zenit RA, raising towards 64.3%, 100%, 57.1%, for aCL IgG, aCL IgM, aß2GPI IgG, respectively, in a APS patient population. CONCLUSIONS: The new technology of chemiluminescense for measuring aPL showed good performance characteristics. Interpretation of results with a cut-off value associated with a good discrimination for disease, resulted in a lower sensitivity for the diagnosis of APS for aß2GPI IgG measured by Zenit RA assays compared to ELISA; sensitivity for aCL IgG was comparable to ELISA. Specificity for all parameters was high and comparable for aCL and aß2GPI.