Drinking brick tea containing high fluoride increases the prevalence of osteoarthritis in Tibetan, China

The prevalence of osteoarthritis (OA) in Tibetans is higher than that in Han, while Tibetans have a habit of drinking brick tea with high fluoride. A cross-sectional study was conducted to explore the association between fluoride exposure in drinking brick tea and OA. All subjects were divided into four groups by the quartiles (Q) of tea fluoride (TF) and urine fluoride (UF). ROC was plotted and OR were obtained using logistic regression model. The prevalence of OA in the Q3 and Q4 group of TF were 2.2 and 2.7 times higher than in the Q1 group, and the prevalence of OA in the Q2, Q3 and Q4 group of UF were 3.2, 3.5, and 4.1 times higher than in the Q1 group. ROC analysis showed the cutoff values were 4.523 mg/day (TF) and 1.666 mg/L (UF). In conclusion, excessive fluoride in drinking brick tea could be a risk factor for developing OA.

Autoantibodies to double-stranded DNA-Intermethod comparison between four commercial immunoassays and a research biosensor-based device

Patients with systemic lupus erythematosus (SLE) often develop a wide variety of serological manifestations including the presence of antibodies to double-stranded DNA (anti-dsDNA). Positivity for anti-dsDNA constitutes one of the laboratory criteria for the diagnosis of SLE and is therefore clinically relevant. We analyzed the diagnostic accuracies of four commercial anti-dsDNA immunoassays and compared the results with a recently established surface plasmon resonance (SPR) biosensor chip with covalently chip-immobilized dsDNA. The anti-dsDNA measurements were performed retrospectively in 50 patients with clinically proven SLE, 39 patients with other autoimmunopathies and 20 healthy controls. Data were evaluated by Receiver-Operator Characteristic (ROC) analysis, with special regard to SLE patients suffering from lupus nephritis. The ROC analyses for the four immunoassays and the SPR biosensor resulted in the following area-under-the-curve (AUC) and diagnostic efficiency (DE) values in descending order: Bindazyme AUC, 0.89; DE, 0.88; ELiA AUC, 0.89; DE, 0.86; SPR biosensor AUC, 0.82; DE, 0.80; Farrzyme AUC, 0.77; DE, 0.77; Farr AUC, 0.77; DE, 0.70. When considering the 22 nephritis SLE patients the following AUC were observed: Bindazyme 0.98; EliA 0.95; SPR biosensor 0.93; Farr 0.89; Farrzyme 0.88. Although various methodologies for the determination of anti-dsDNA were compared, the overall diagnostic accuracy was found satisfactory in all immunoassays. Best data were found for the Bindazyme assay. We referenced the measurements to our in-house SPR biosensor device which showed good AUC and DE values. When optimized, this technique, allowing to monitor antigen/ antibody interactions in real-time, may add a new analytical quality to the existing methods, potentially beneficial in diagnosis and clinical monitoring of SLE.

Controversies and unresolved issues in antiphospholipid syndrome pathogenesis and management

While much is understood concerning the clinical features of patients with antiphospholipid syndrome (APS), many issues remain. The proper designation of patients with "definite" APS and the correct categorization of patients by both laboratory and clinical features are matters of ongoing debate. Recent proposals have identified new subsets of patients who have many typical features of APS but either do not fit the criteria for a "definite" diagnosis or have initially negative laboratory tests for antiphospholipid antibodies. Meanwhile, decisions about laboratory tests are based on expert opinion, rather than the results of controlled trials. As for treatment, many guidelines are offered, but few are backed by data from strong clinical trials. This article summarizes the clinical questions remaining to be answered and debates concerning pathogenesis, diagnosis, and management.

Anti-cyclic citrullinated peptide autoantibodies in IgM rheumatoid factor-positive patients

BACKGROUND

Antibodies to citrullinated proteins have been described in patients with RA and these appear to be the most specific markers of the disease. The objective of this study was to analyse the improvement in diagnostic accuracy of anti-cyclic citrullinated peptide autoantibodies and IgA rheumatoid factor in patients with clinical suspicion of RA and who were IgM rheumatoid factor-positive. Anti-CCP antibodies were measured with three different second-generation enzyme immunoassays.

METHODS

We chose 133 serum samples with IgM RF levels greater than 20 IU/mL sent to our Laboratory from Specialized Care Units. Subsequently, patients were classified according to their clinical records. Eighty-seven had rheumatoid arthritis and 46 had other diseases. In all samples anti-CCP and IgA RF were measured by the corresponding ELISAs.

RESULTS

Comparison of the three anti-CCP second-generation ELISAs revealed differences between them. Likewise, clinical performances in terms of sensitivity, specificity, and positive and negative likelihood ratios were different. In patients with IgM RF higher than 20 IU/mL, anti-CCP antibodies increased the clinical efficiency of IgM RF and offered better performance as compared with IgA RF.

CONCLUSIONS

The use of anti-CCP antibodies affords good clinical efficiency and modifies the pre-test probability of the occurrence of RA in patients with IgM rheumatoid factor higher than 20 IU/mL.

Current debates in antiphospholipid syndrome: the acquired antibody-mediated thrombophilia

Antiphospholipid (APL) syndrome is the most common form of acquired thrombophilia. It can cause significant morbidity and even mortality. The term "APL antibodies" represents a heterogeneous group of antibodies associated with this disorder. Currently no single assay can identify every APL antibody. Clinically relevant APL antibodies are mainly anticardiolipin antibodies (ACA) detected by solid phase enzyme-linked immunosorbent assay (ELISA) and lupus anticoagulants (LA) demonstrated by in vitro coagulation assay. However, there are some other antibodies associated with the APL syndrome (i.e., subgroup APL antibodies). ACAs, LAs, and subgroup APL antibodies represent intersecting, but non-identical, subsets of autoantibodies. Thus, those autoantibodies may coexist or may occur independently. Any organ system and any size of vessel can be affected during the clinical course of the disease. Therefore, the APL syndrome can manifest itself in a wide variety of clinical thrombotic features. Fetal loss and pregnancy morbidity represent a specific challenge. Despite tremendous advances in the understanding of the pathogenesis of APL syndrome during the past decade, the mainstay of management is still anticoagulation. However, there is no general agreement regarding the duration and intensity of anti-coagulant therapy. In this review, we focused on the current dilemmas and their present clarifications in the wide clinicopathologic spectrum of APL syndrome and APL antibody-related distinct pathologic conditions.

Methodology in Diagnostic Laboratory Test Research in Clinical Chemistry and Clinical Chemistry and Laboratory Medicine

Background: The application of epidemiologic principles to clinical diagnosis has been less developed than in other clinical areas. Knowledge of the main flaws affecting diagnostic laboratory test research is the first step for improving its quality. We assessed the methodologic aspects of articles on laboratory tests.

Methods: We included articles that estimated indexes of diagnostic accuracy (sensitivity and specificity) and were published in Clinical Chemistry or Clinical Chemistry and Laboratory Medicine in 1996, 2001, and 2002. Clinical Chemistry has paid special attention to this field of research since 1996 by publishing recommendations, checklists, and reviews. Articles were identified through electronic searches in Medline. The strategy combined the Mesh term “sensitivity and specificity” (exploded) with the text words “specificity”, “false negative”, and “accuracy”. We examined adherence to seven methodologic criteria used in the study by Reid et al. (JAMA1995;274:645–51) of papers published in general medical journals. Three observers evaluated each article independently.

Results: Seventy-nine articles fulfilled the inclusion criteria. The percentage of studies that satisfied each criterion improved from 1996 to 2002. Substantial improvement was observed in reporting of the statistical uncertainty of indices of diagnostic accuracy, in criteria based on clinical information from the study population (spectrum composition), and in avoidance of workup bias. Analytical reproducibility was reported frequently (68%), whereas information about indeterminate results was rarely provided. The mean number of methodologic criteria satisfied showed a statistically significant increase over the 3 years in Clinical Chemistry but not in Clinical Chemistry and Laboratory Medicine.

Conclusions: The methodologic quality of the articles on diagnostic test research published in Clinical Chemistry and Clinical Chemistry and Laboratory Medicine is comparable to the quality observed in the best general medical journals. The methodologic aspects that most need improvement are those linked to the clinical information of the populations studied. Editorial actions aimed to increase the quality of reporting of diagnostic studies could have a relevant positive effect, as shown by the improvement observed in Clinical Chemistry.

Anti-nucleosome, anti-chromatin, anti-dsDNA and anti-histone antibody reactivity in systemic lupus erythematosus

Anti-nucleosome (anti-chromatin) antibodies play a key role in the pathogenesis of systemic lupus erythematosus (SLE). The objective of the present study was to determine the clinical significance of anti-nucleosome (anti-chromatin) antibodies, anti-dsDNA antibodies and anti-histone antibodies in patients with SLE in relation to patients with positive nuclear antibodies and healthy controls. We measured anti-nucleosome (anti-chromatin) antibodies, anti-dsDNA antibodies and anti-histone antibodies in 70 patients with SLE, 35 antinuclear antibody (ANA)-positive subjects without autoimmune disease and 35 blood donors. All antibodies were determined by enzyme-linked immunosorbent assay (ELISA). We obtained the receiver operating caracteristic (ROC) curve and the area under the curve (AUC) for each autoantibody. Likewise, we obtained the sensitivity, specificity and positive and negative likelihood ratios for each autoantibody. The highest AUC was obtained for anti-nucleosome (0.898) and the lowest AUC for a kit for anti-dsDNA (0.725). Stratification of the control group (ANA-positive subjects without autoimmune disease and blood donors) produced significant changes in the AUCs; all AUCs decreased when ANA-positive patients without autoimmune disease were considered as controls and all AUCs increased when blood donors were considered as controls. These effects were less marked in anti-dsDNA antibodies. We observed discrepancies between kits (anti-nucleosome and anti-chromatin and two for anti-dsDNA). The highest sensitivity for SLE was obtained for anti-nucleosome antibodies (86%) and the highest specificity was obtained for anti-dsDNA antibodies (90%). In conclusion, anti-nucleosome and anti-chromatin kits show different degrees of clinical accuracy due to the cut-off selected by the manufacturer. Once the kits with the best performance and the optimal cut-offs have been selected, anti-nucleosome antibodies and anti-dsDNA antibodies provide similar information in established SLE.