Antinuclear antibody positive autoimmune disorders in North India: an appraisal

The autoimmune disorders (AID) have since long been considered to be commoner in Western world as compared to Asian countries. This, however, may not be true as in developing countries, there are incomplete epidemiological data and lack of advanced diagnostic facilities leading to under diagnosis in many cases. In this study, we performed an 11-year retrospective analysis of medical records of all clinically suspected and immunofluorescence antinuclear antibody test (IF-ANA)-positive cases. The IF-ANA-positive cases in the year 2006-2007 were further analyzed to find out the morbidity contribution by IF-ANA-positive AID. A total of 36,310 serum samples were screened for antinuclear antibody (ANA) between the years 1996 and 2006. The mean positivity was 12.3%. A constant and statistically significant increase in AID was noticed over the last 11 years. In the year 2006-2007, out of 3,435 suspected AID cases, 18.9% were ANA positive. Of these, 86.0% were adult patients with age ranging from 2¼ to 88 years. A female preponderance was also noted with a female-to-male ratio of 3:1. Among the ANA-positive connective tissue disorders (CTD), systemic lupus erythematosus was the most common clinical diagnosis (4.6/10,000 cases) followed by scleroderma (1.2/10,000) and overlap syndrome (0.7/10,000). Rheumatic, renal and hematopoietic systems were commonly involved. The overall frequency of CTD was 21%. The report is the first and largest hospital-based study from India, highlighting the rising incidence and clinical profile of ANA-positive AID.