Anti-dsDNA antibodies in systemic lupus erythematosus: A combination of two quantitative methods and the ANA pattern is the most efficient strategy of detection

Anti-dsDNA Testing Specificity for Systemic Lupus Erythematosus: A Systematic Review

BACKGROUND

Autoantibody specificity in autoimmune diseases is variable due to each patient's individual spectrum of autoantibodies and the inherent differences between detection methods and tests. Since false-positive results have downstream consequences, we conducted a comprehensive assessment of anti-double stranded DNA (anti-dsDNA) specificity from published studies of systemic lupus erythematosus (SLE).

METHODS

A systematic review (MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and Database of Abstracts of Reviews of Effects) identified cross-sectional or case-control studies published January 2004 to August 2019, reporting anti-dsDNA test accuracy data in SLE. Study quality was assessed using Quality Assessment Tool for Diagnostic Accuracy Studies, version 2. A meta-analysis was conducted to estimate specificity by test method or named test where feasible.

RESULTS

Thirty studies were included covering 43 different tests. The Crithidia luciliae indirect immunofluorescence test (CLIFT) and fluorescence enzyme immunoassay methods are likely to be ≥ 90% specific (Euroimmun 97.8% (95% CI 96.2%-98.7%) 4 studies; EliA 94.7% (95% CI 91.7%-96.7%), 6 studies; CLIFT 98.7% (95% CI 96.7%-99.5%), 8 studies/7 tests]. For other test methods, specificity was not fully demonstrated to be ≥ 90% and/or the control group included healthy patients possibly overestimating specificity. More studies are required for NOVA Lite [96.0% (95% CI 87.2%-98.9%), 5 studies], chemiluminescence immunoassays [92.3% (95% CI 83.6%-96.6%), 6 studies/4 tests], multiplex immunoassays [89.3% (95% CI 86.1%-91.8%), 4 studies/2 tests], and Farr fluorescent immunoassays (no estimate, 2 studies). Specificity data reported for Farr radioimmunoassays [93.8% (95% CI 85.4-97.5%), 11 studies, 9 tests] and enzyme-linked immunosorbent assays [93.4% (95% CI 89.9%-95.7%), 15 studies/16 tests] lacked consistency.

CONCLUSION

Anti-dsDNA testing shows considerable variation in test specificity, with potential impact on the management of SLE patients. This review may help laboratory specialists and clinicians choose and interpret the appropriate anti-dsDNA test for their setting.

Anti - Dense Fıne Speckled (DFS) Antibody: its staınıng pattern in indirect immunofluorescence and its clinical relevance

BACKGROUND

Dense fine speckled (DFS) pattern defined by very intense, heterogeneous speckled staining of nucleoplasms of interphase HEp-2 cells and chromosomal areas of metaphase cells. The association of Anti-DFS70 and rheumatologic signs, symptoms, and diagnosis were evaluated.

METHODS

One-hundred-eight anti-DFS70 positives who consecutively admitted Rheumatology clinic between January-June 2020 were analyzed. The clinical and laboratory findings of positives for anti-DFS70 antibody were compared with those with DFS pattern ANA IFA staining rates. Also, anti-DFS70 positivity rates and their correlation with the DFS staining pattern were analyzed retrospectively in 1016 CTD patients.

RESULTS

The most common complaint was joint pain seen in 77(71.3%) and the most common laboratory abnormality was RF-positivity observed in 10/108(9.3%) who had anti-DFS70 positivity. The most common ANA staining pattern was DFS (72/108;66,7%); one-third had other than DFS. No statistical significance was found for the association of any of the rheumatological complaints and laboratory findings with the DFS70 staining pattern. ANA analysis was performed in a total of 964/1016(94.88%) CTD patients and 44 (4.56%) of these positive for anti-DFS70. The correlation coefficient showed good correlations between the DFS pattern staining and anti-DFS70 antibody positivity (r=+0.773, p<0.001).

CONCLUSIONS

Anti-DFS70-positives have a low rate of CTD. A low anti-DFS70 positivity rate was observed in patients with CTD. As such, it can be considered that anti-DFS70 does not predict CTD or even excludes it.

Analytical variability in the determination of anti-double-stranded DNA antibodies: the strong need of a better definition of the old and new tests

Anti-dsDNA antibodies are a heterogeneous group of antibodies, quite specific for SLE. Their variability is related to the assay used, the immunoglobulin class secondary antibody, and the dsDNA source. The standardization of measuring anti-dsDNA antibodies is still poor and different methods yield different results. Several novel technologies were developed during the last decades that represent viable alternatives to the traditional methods such as the chemiluminescent immunoassay (CIA) and multiplex flow immunoassay (MFI). Additionally, positive results for anti-dsDNA antibodies can be detected in patients with inflammatory arthritis (IA) treated with different biologics reducing its clinical specificity for SLE. Anti-dsDNA antibody levels were evaluated in 246 patient samples: 70 SLE and 176 disease control (including 96 IA during treatment with different biologics), using three enzyme immunoassays (indirect enzyme immunoassay, Bio-Rad Laboratories; chemiluminescent immunoassay, Inova Diagnostics; multiplex flow immunoassay, Bio-Rad Laboratories) and three Crithidia luciliae immunofluorescence tests (CLIFT) (Euroimmun AG, Bio-Rad Laboratories, INOVA Diagnostics). Diagnostic performances were assessed both including and excluding the IA patients. Agreements, measured by the Cohen's Kappa between all methods, ranged from moderate to substantial (0.47-0.68). The clinical sensitivities for the anti-dsDNA antibody tests varied from 5.7% by CLIFT A up to 33.3% provided by EIA while the clinical specificities varied from 89.8% by MFI to 98.9% provided by CLIFT B and C. Newer technologies, such as MFI and CIA, showed great potential as a diagnostic application. Significant variations among anti-dsDNA antibody assays were observed confirming the lack of standardization.

Strategies to improve the efficiency of celiac disease diagnosis in the laboratory

The demand for testing to detect celiac disease (CD) autoantibodies has increased, together with the cost per case diagnosed, resulting in the adoption of measures to restrict laboratory testing. We designed this study to determine whether opportunistic screening to detect CD-associated autoantibodies had advantages compared to efforts to restrict testing, and to identify the most cost-effective diagnostic strategy. We compared a group of 1678 patients in which autoantibody testing was restricted to cases in which the test referral was considered appropriate (G1) to a group of 2140 patients in which test referrals were not reviewed or restricted (G2). Two algorithms A (quantifying IgA and Tissue transglutaminase IgA [TG-IgA] in all patients), and B (quantifying only TG-IgA in all patients) were used in each group, and the cost-effectiveness of each strategy was calculated. TG-IgA autoantibodies were positive in 62 G1 patients and 69 G2 patients. Among those positive for tissue transglutaminase IgA and endomysial IgA autoantibodies, the proportion of patients with de novo autoantibodies was lower (p=0.028) in G1 (11/62) than in G2 (24/69). Algorithm B required fewer determinations than algorithm A in both G1 (2310 vs 3493; p<0.001) and G2 (2196 vs 4435; p<0.001). With algorithm B the proportion of patients in whom IgA was tested was lower (p<0.001) in G2 (29/2140) than in G1 (617/1678). The lowest cost per case diagnosed (4.63 euros/patient) was found with algorithm B in G2. We conclude that opportunistic screening has advantages compared to efforts in the laboratory to restrict CD diagnostic testing. The most cost-effective strategy was based on the use of an appropriate algorithm.

Pattern of initial clinical manifestations of systemic lupus erythematosus in a tertiary care hospital

Objective:

To determine the pattern of initial clinical manifestations of Systemic Lupus Erythematosus (SLE) and to compare these features with those recorded elsewhere in Pakistan

Methods:

This cross-sectional, descriptive study was performed in the Department of Rheumatology, Fatima Memorial Hospital, Lahore, Pakistan, from November 2015 to January 2016. Sixty one patients of SLE diagnosed as per ACR (American College of Rheumatology) 1982 revised criteria, were enrolled. The patients were evaluated for the initial clinical manifestations of SLE. The information was collected on a specially designed proforma and analyzed by using SPSS version 17.

Results:

Out of 61 patients, 49 (80.3%) were females and 12 (19.7%) males, showing a female to male ratio of 4:1. The mean age of patients was 26.2 ± 7.9 years. Fatigue was the most common presenting feature in 56 (91.8%) patients, followed by joint pains in 55 (90.2%) and fever in 54 (88.5%). Renal involvement was found in 46 (75.4%). Comparison of these presenting features was made with other studies carried out in Northern Pakistan (Islamabad) and in central Punjab (Pakistan). There were statistically significant differences in fever, fatigue and arthritis between our patients and the other two above mentioned study groups. However, comparison of renal manifestations showed significant difference only with Islamabad study, and not with previous study from central Punjab.

Conclusion:

In this study, majority of patients presented with combination of fatigue, fever, rash and arthritis. Almost three-fourth of patients had renal manifestations at initial presentation. Therefore, it is important for clinicians to have high index of suspicion for SLE, when patients present with above symptoms.

Comparison of antibody assays for detection of autoantibodies to Ro 52, Ro 60 and La associated with primary Sjögren's syndrome

Anti-Ro(52/60) and anti-La constitute the hallmark autoantibodies in primary Sjögren's syndrome, being present in 40-70% of sera. Several anti-Ro/La assays exist, but antibody detection appears to be assay-specific, thus the aim of this study was to compare several anti-Ro/La assays. In total, 96 sera from individuals with primary Sjögren's syndrome and 114 healthy controls were tested for anti-Ro 52/60 and anti-La in 17 immunoassays. Especially the immunoassays used for detection of anti-Ro 52 differed in their sensitivity (48-79%), while only small differences in sensitivities were observed for the anti-Ro 60 (69-77%) anti-La (39-44%) assays. Concordances of 65%, 79% and 73% for the anti-Ro 52, anti-Ro 60 and anti-La assays were found, respectively. The majority of the assays yielded high specificities, primarily ranging from 97 to 100%, except from a single anti-Ro 60 assay, which yielded a specificity of 79%. Occasionally, reactivity levels were increased in a few assays, indicating that false-positive results can be obtained when applying assays of reduced specificity. In general, the commercial assays appeared to perform better than the in-house analyses. When correcting the in-house assays for background reactivity, sensitivities were reduced by approximately 7%, 17%, and 19% for anti-Ro 52, anti-Ro 60 and anti-La assays, respectively, illustrating the pitfalls when applying immunoassays for detection of autoantibodies, which in theory may apply to commercial assays as well. Finally, increased total sensitivities were obtained when combining assays. These studies contribute to clarify the clinical utility of immunoassays for detection of autoantibodies of Ro 52, Ro 60 and La and illustrate that the most efficient strategy to maximize antibody sensitivity is to combine several assays.