Saghiri et al. [31] showed that total ADA activity and ADA2 activity (one of ADA isoenzymes) were increased in serum of SLE patients and suggested that ADA and its isoenzymes analysis in serum could be used as a useful and noninvasive marker in evaluation of SLE active phase and disease severity. The gene discussed is ADA2; the disease is systemic lupus erythematosus.