Known external factors that can lead to elevated anti-dsDNA titers include drugs, such as selected antiarrhythmics (e.g. procainamide), antihypertensives (e.g. hydralazine), TNF-α inhibitors and sulfasalazine, inter alia (48), but also viral infections (e.g. Epstein–Barr virus infection) (49) and concomitant diseases like autoimmune hepatitis (50). This evidence concerns the gene TNF and viral infectious disease.