Comparative study of antinuclear antibody detection by indirect immunofluorescence and enzyme immunoassay in lupus patients.

To evaluate the value of immunofluorescent and ELISA techniques in early diagnosis of systemic lupus erythematosus (SLE) and to find out whether there is a correlation between Antinuclear antibodies (ANA) pattern and prognosis by observing clinical score changes using British Isles Lupus Assessment Group score. The study included 75 SLE patients, 11 disease control group, and 18 healthy control group. ANA and ds-DNA antibodies detection were done by ELISA and Immunofluorescence for all groups. Immunofluorescence technique is more sensitive for ANA and ds-DNA detection than ELISA technique (100% versus 90.7%,and 93% versus 89.3% respectively); ELISA showed 89.7 % specificity for ANA detection compared to 86.2% for Immunofluorescence, and both have 100% specificity for ds-DNA detection ;homogenous ANA pattern, showed statistically significant higher BILAG score compared to speckled pattern either at the start of the study or after the follow up period (p = 0.000); and ds-DNA titer showed statistically significant decrease in titer after therapy (p = 0.01). ANA detection by Immunofluorescence is more sensitive and effective screening assay in patients with clinical features of SLE and both ds-DNA titer by ELISA and BILAG score for severity index are considered the best markers for follow-up.