ADA and rheumatoid arthritis: Variations in ADA activity levels have been described in different types of cancer [9] and in inflammatory diseases such as rheumatoid arthritis [10], celiac disease [11], ulcerative colitis [12], systemic lupus erythematosus [13], visceral leishmaniasis [14] and inflammatory obesity [15] or infections such as tuberculosis [16] in human serum, saliva or sputum samples.