Gangadharan H, Singh A, Majumder S, et al. - Findings showed that adenosine deaminase (ADA) single nucleotide polymorphism rs244076 as well as serum ADA level were not associated with responsiveness to methotrexate (MTX) therapy in rheumatoid arthritis (RA).

• This study including 207 disease-modifying antirheumatic drug–naïve active RA patients was conducted to investigate if ADA gene polymorphism and serum levels of total ADA are related to response to MTX.

• Responders and nonresponders were 83.1% and 16.9%, respectively, after 4 months of MTX monotherapy.

• Following did not show any association with MTX response: single nucleotide polymorphisms in ADA gene, baseline serum ADA levels (10.52 ± 5.37 ng/mL in responders vs 12.28 ± 5.14 ng/mL in nonresponders), or alteration in ADA levels post-2 months of MTX treatment.

• Blood ADA level remained unaffected by adenosine deaminase genotype.