Association of Immunofluorescence pattern of Antinuclear Antibody with Specific Autoantibodies in the Bangladeshi Population

Antinuclear antibody (ANA) is useful in the diagnosis of connective tissue disorder (CTD). Association of specific autoantibodies with the immunofluorescence pattern of ANA in CTD, noted in western literature has been considered as reference in all over the world. However, in Bangladesh no such research work or data correlating the autoantibodies and their ANA patterns is found. Objective of the study was to identify an association between immunofluorescence patterns of antinuclear antibody on HEp-2 cell and more specific antinuclear reactivities (e.g. anti-dsDNA and anti-extractable nuclear antigen) in the serum samples of CTD patients. Serum samples of 152 CTD patients (Systemic lupus erythematosus, Rhumatoid arthritis, Sjogren's syndrome, Systemic sclerosis, Polymyositis, Mixed connective tissue disease) were diagnosed clinically, attending at Bangabandhu Sheikh Mujib Medical University (BSMMU) during the study period of January, 2010 to December, 2010. Samples were subjected for ANA testing by Indirect Immunofluorescence (IIF) on HEp-2 cell (ALPHADIA) in dilution of 1:40, anti-dsDNA by ELISA and anti- extractable nuclear antigen (anti-ENA) by Dot Immunoblot. Dot blot strips were tested for anti-Sm, anti-RNP, anti-SSA/Ro, anti-SSB/La, anti-Scl-70 and anti-Jo-1. Out of 152 patients 110 (72.3%) cases were ANA positive by IIF on HEp-2 cell. ANA positive sera exhibited four fluorescence patterns such as speckled (50.8%), peripheral (21.6%) , homogenous (18.1%) and nucleolar pattern (9%). Peripheral pattern and homogenous pattern was predominantly associated with anti-dsDNA (p < 0.05). Speckled pattern was significantly associated with anti-ENA (p < 0.05).The most commonly identified antinuclear autoreactivity was directed towards anti-RNP (25.7%) then anti-Scl-70 (20%), anti-SSA (14.2%) and anti-SSB (5.7%). Multiple anti-ENA reactivities were identified in 34.28% cases. Peripheral and homogenous pattern is strongly associated with anti-dsDNA and speckled pattern may predict anti-ENA (specially ribonucleoprotiens). As a definite correlation between the ANA patterns and the group of antibodies was detected by dot immunoblot, one could predict presence of certain specific auto antibodies for a particular ANA pattern identified. This may restrict on the cost of laboratory investigations in a developing country like Bangladesh. Thus, ANA-IIF method may reduce the expense of detailed immunological work-up with minimal loss in diagnostic accuracy.