Feasibility of Indirect immunofluorescence (IIF) alone as a screening method for antinuclear antibody in connective diseases in India's sub-Himalayan region

Background: For the management of connective tissue disorders (CTDs), antinuclear antibody (ANA) testing is essential, both from diagnostic and prognostic points of view. Usually, patterns obtained by ANA-IIF testing correlates to specific autoantibodies as obtained from the test for ENA (by LIA/ELISA, etc.). But to apply these data from western studies, we may need validation in the local population like our subjects in sub-Himalayan (Garhwal region) area where CTDs are common. Also, suppose ANA-IFA pattern's correlation is reliably known in our population, it can minimize the cost of managing CTDs by limiting ENA testing, which is 10 times costlier than ANA-IIF. Hence, this study was undertaken to know the specific autoantibody targets (ENA by LIA) against ANA-IIF patterns in our local population. Materials and Methods: In this retrospective cross-sectional work, serum samples of CTDs were tested for ANA by IIF (Euroimmune AG) and ENA by LIA (Euroline ANA-3G) continuously for 36 months. The manufacturer's kit insert was followed, and results were analyzed applying appropriate statistical methods. Results: Major ANA-IIF patterns were found to be associated with specific autoantibodies, for example, Nuclear homogenous with dsDNA, nucleosomes, histones; speckled pattern with nRNP/Sm, Sm, SSA/Ro-52, SSB; nucleolar pattern with Scl-70, Pm-Scl 100 and centromere pattern with CENP-B. Anticytoplasmic (ACA) are found to be linked with some ANA negative (by IIF) samples, emphasizing the need for careful observation for ACA especially where ANA is not found. Conclusions: In most subjects, specific ENA targets correlated well with ANA-IIF patterns, implying effective cost minimization in CTD management. Similar future prospective studies (with clinical data) can provide a database and reference for our population.

The clinical value of ANA,anti-dsDNA antibody and anti-ENA antibody repertoire in systemic lupus erythematosus diagnosis / 国际检验医学杂志

Objective To investigate clinical value of the anti-nuclear antibody (ANA ) ,anti-double strand DNA (dsDNA ) anti-body and anti-extractable nuclear antigen(ENA) antibody repertoire in systemic lupus erythematosus (SLE) diagnosis .Methods 158 SLE patients were served as SLE group and another 50 healthy people as the control group .Indirect immunofluorescence(IIF) and immunoblotting test(IBT ) were employed to detect ANA ,anti-dsDNA antibody and anti-ENA antibody repertoire .Results Positive rates of ANA ,anti-dsDNA antibody and anti-ENA antibody repertoire in SLE diagnosis were 81 .65% ,68 .35% and 87 .34% ,respectively ,which were all lower than that of their combined detection (93 .04% ) ,with statistically significant difference (P<0 .05 ) .Among anti-ENA antibody repertoire ,the positive rate of anti-U1-nuclear ribonucleoprotein (U1-Nrnp ) antibody (52 .53% ) was the highest .Conclusion Combined detection of ANA ,anti-dsDNA antibody and anti-ENA antibodies repertoire has some clinical value of early diagnosis of SLE .

Degree of Agreement between Phadia EliA ENA and Euroimmun line Immunoassay; Comparison of Two Methods to Evaluate the Ability to Detect ENA Antibodies / 고신대학교의과대학학술지

OBJECTIVES: The purpose of this study is to compare newly developed assay for identification of ENA antibody, Phadia EliA ENA with Euroimmun line immunoassay by analyzing the degree of agreement and the individual antibodies between two methods. METHODS: A total of 82 patient samples were used. Indirect immunofluorescence assay using Hep-2 cell was performed to screen the antinuclear antibody (ANA). Euroimmun line immunoassay (LIA) and Phadia EliA ENA assay were tested to identify the antibodies against extractable nuclear antigens (ENAs). Kappa statistics was used to evaluate the degree of agreement. RESULTS: Mean age of patients was 41.0 (8-79), and the M:F ratio was 21:61. ANA was positive in 74 samples, and negative were 8 samples. Kappa analysis of the 82 tested samples showed a moderate strength of agreement (kappa = 0.521, P = 0.000). There were differences in the order of identified individual antibodies between two methods (Ro > La = RNP > Centromere > Sm > Scl-70 in Phadia EliA ENA, Ro > RNP > Sm>La > Scl-70 > Centromere=Jo-1 in Euroimmun LIA). Ro antibody was most frequently identified in Phadia EliA ENA negative-Euroimmun LIA positive specimens (Ro > RNP = Jo-1 > La = Sm = Centromere > Scl-70). CONCLUSIONS: A moderate strength of agreement was observed between the Phadia EliA ENA and the Euroimmun LIA. There seemed to be a significant difference in the ratio of individual antibodies, especially in the anti-Ro and Sm antibodies.

Effect of Autoantibody Tests in Diagnosis of Autoimmune Diseases in Children / 实用儿科临床杂志

Objective To study the effect of autoantibody test which includes antinuclear antibodies(ANA),antinuclear antibody fluorescence patterns,anti-extractable nuclear antigen(ENA) antibodies and anti-double strands DNA(ds-DNA) antibodies in the diagnosis of pediactic autoimmune diseases.Methods Of all the inpatients which had positive results of autoantibody tests,135 cases were reviewed.The autoantibody assay,positive value(PV) analysis were performed respectively.Results PV of ANA test to autoimmune diseases was 0.36 which was proportional to the intensity of fluorescence;Of all the fluorescence patterns,speckled(fine) had a relatively high PV;Anti-ENA and anti-dsDNA antibody tests had higher PV than ANA test.Conclusion Fluorescence intensity,(anti-ENA) antibody test and anti-dsDNA antibody test may be useful in identifying autoimmune diseases in clinic.