Turk J Immunol. 2020; 8(2): 37-43 | DOI: 10.25002/tji.2020.1157

Comparison of Different Laboratory Methods in the Detection of Anti-dsDNA Antibodies and Their Diagnostic Utility

Ceyda Tunakan Dalgýç¹, Emine Nihal Mete Gökmen¹, Aytül Zerrin Sin¹
Ege University Medical Faculty, Department of Internal Medicine, Division of Allergy and Clinical Immunology, Ýzmir, Turkey

Introduction: We aimed to analyze the positivity of Crithidia luciliae immunofluorescence tests (CLIFT), to compare CLIFT with ANA-IFA (antinuclear antibody–immunofluorescence assay), ANA-IB (immunoblot), and ELISA (enzyme-linked immunoassays), and to determine the relevant method to test anti-dsDNA in systemic lupus erythematosus (SLE). Materials and Methods: We conducted a retrospective, cross-sectional study between January 1st, 2015 and January 1st, 2016. We focused on the positive CLIFT results firstly, then, we compared the ANA-IFA, ELISA, and ANA-IB results to diagnose SLE. Demographic features were obtained from the hospital records. Results: To analyse CLIFT, 3242 seras were tested, and 72 (2.2%) were positive. Among CLIFT positivity [n=64; 57 female, 7 male (mean, range; 41.96, 11–82)]; 73% (n=47) had SLE. Out of 61 patients were analyzed by ANAIFA, 36 had peripheral (n=1) and homogenous (n=35) patterns; 83% (n=30) had SLE. Out of 46 patients were analyzed by ANA-IB, 30 had dsDNA; 73% (n=22) had SLE. Out of 25 patients who were analyzed by ELISA, 18 had dsDNA; 83% (n=15) had SLE. In the two-sided correlations, CLIFT positivity (?grade 2) was found to be statistically significantly associated with having SLE (p=0.005, r [64]=0.92); CLIFT positivity was also statistically significantly associated with ANA-IFA (p=0.003, r=0.85). In order to exclude SLE diagnosis, CLIFT positivity was statistically significantly correlated with ANA-IB (p=0.002, r=0.90). Conclusion: CLIFT can not be used instead of ELISA and ANA-IB, but it can reduce their usage. We recommend to use CLIFT and ANA-IFA for first-line screening; and ANA-IB and ELISA for confirmation and identification of dsDNA.

Keywords: Anti-dsDNA, laboratory methods, systemic lupus erythematosus

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Anti-dsDNA Antikorlarýnýn Varlýðýnýn ve Tanýsal Deðerinin Belirlenmesinde Farklý Laboratuvar Taný Metotlarýnýn Karþýlaþtýrýlmasý

Ceyda Tunakan Dalgýç¹, Emine Nihal Mete Gökmen¹, Aytül Zerrin Sin¹
Ege University Medical Faculty, Department of Internal Medicine, Division of Allergy and Clinical Immunology, Ýzmir, Turkey

Giriþ: CLIFT (Crithidia luciliae immünofloresan test) pozitifliðinin sýklýðýný belirlemeyi, CLIFT’i ANA-IFA (anti-nükleer antikor-immünfloresan analizi), ANA-IB (immünblot) ve ELISA (enzim-baðlantýlý immün analiz) ile kýyaslamayý ve SLE’de (sistemik lupus eritematozus) anti-dsDNA’yi saptamak için uygun yöntemi belirlemeyi amaçladýk. Gereç ve Yöntemler: 1 Ocak 2015 ile 1 Ocak 2016 arasýnda geriye dönük kesitsel bir çalýþma gerçekleþtirilmiþtir. Öncelikle, CLIFT pozitif sonuçlara odaklandýk, sonrasýnda CLIFT pozitif hastalarýn ANA-IFA, ELISA ve ANA-IB sonuçlarý incelendi ve laboratuvar yöntemleri SLE tanýsý ile karþýlaþtýrýldý. Hastalarýn demografik özellikleri hastane kayýtlarýndan elde edilmiþtir. Bulgular: CLIFT analizi için, toplam 3242 serum çalýþýldý ve bunlarýn 72’si (%2,2) pozitifti. CLIFT pozitiflikleri (n=64; 57 kadýn / 7 erkek) arasýnda ortalama yaþ 41,96 (aralýk, 11–82) ve %73’ü (n=47) SLE tanýlýydý. ANA-IFA 61 olguda çalýþýldý; periferik (n=1) ve homojen (n=35) örüntü 36’sýnda mevcuttu ve bu olgularýn %83’ü (n=30) SLE tanýlýydý. Kýrkaltý hastada ANA-IB çalýþýldý; ve 30’unda dsDNA saptandý. Bunlarýn %73’ü (n=22) SLE tanýlý idi. Hastalarýn 25’inde ELISA metodu kullanýldý ve bunlarýn 18’inde pozitiflik saptandý. %83’ü (n=15) SLE tanýlýydý. Ýki yönlü korelasyonlarda, CLIFT pozitifliði (?2. derece), SLE tanýsý ile güçlü korelasyon gösterdi (p=0.005, r [64]=0,92); SLE tanýsýný doðrulamada; CLIFT testi ANA-IFA ile ileri derecede iliþkili bulundu (p=0.003, r=0,85). Ayrýca SLE tanýsýný dýþlamada; CLIFT ile ANA-IB güçlü korelasyon gösterdi (p=0.002, r=0,90). Sonuç: CLIFT, ELISA ve immünoblot tetkiklerinin yerini alamaz, fakat onlarýn kullanýmýný azaltabilir. Sonuçta, CLIFT ve ANA-IFA’nýn ilk basamak görüntülemede; ANA-IB ve ELISA’nýn ise doðrulama ve tanýmlamada kullanýmýný önermekteyiz.

Anahtar Kelimeler: Anti-dsDNA, laboratuvar metotlarý, sistemik lupus eritematozus

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