ABSTRACT

Connective tissue diseases (CTD) are characterized by the presence of autoantibodies against several tissues. These autoantibodies occur against cell membrane, cell receptors, plasma proteins, and cytoplasmic and nuclear components. In laboratories, anti-nuclear antibodies (ANA) and anti-double stranded DNA (anti-dsDNA) antibodies are widely used in diagnosis of CTD. The aim of this study was to investigate the presence and accompaniment of ANA and anti-dsDNA antibodies in diagnosis of several CTD and also to study the prevalence of ANA and anti-dsDNA in a group of 88 patients with various types of CTD. ANA were detected by immunofluorescence (IFA) using HEp-2 cells (Zeus Scientific, Inc. USA) and anti-dsDNA antibodies using Crithidia luciliae (BioSystems, Spain) as substrates in immunofluorescence. ANA Western Blot (WB) Immunoassay (ImmuBlot, International Immuno–Diagnostics, USA) was also used along with the tests referred to previously. ANA was found in the sera of 84 (96.5%) patients while anti-dsDNA was detected in 7 (7.95%). Moreover different fluorescence patterns were also evaluated with ANA IFA in accordance with anti-dsDNA results. Mixed patterns in three and a homogeneous pattern in four anti-dsDNA positive patients’ sera were determined on HEp-2 cell line by IFA. Seven sera which were ANA and anti-dsDNA positive with IFA were also found to be positive with WB and their ANA patterns with the specific ANA WB bands were also evaluated. It was observed that IFA results were in concordance with WB results. Our data indicated that the above findings should be controlled and evaluated with a more advanced method such as western blotting technique in order to confirm the presence of specific antibodies along with clinical outcome of the patients. As a result we think that ANA WB method is an appropriate technique in diagnosis of CTD as anti-dsDNA and ANA bands can be evaluated together with this method.

Keywords: Antinuclear antibodies, anti-dsDNA, connective tissue diseases, HEp-2 cell line, Crithidia luciliae, IFA, Western blotting