Clinical factors for predicting clinical responses to methotrexate

Abstract

Psoriasis is a persistent disease that causes inflammation throughout the body and affects approximately 1% to 3% of the world population. It generally appears as red scaly patches and papules over several areas of the skin. Methotrexate is an effective medication for the treatment of psoriasis; however, it is not widely used because its efficacy is unpredictable. This study aimed to determine whether clinical factors of psoriasis and the genes that make people more susceptible to it may affect the effectiveness of methotrexate. The authors identified 221 Chinese patients with psoriasis who were treated with methotrexate for 12 weeks. The patients were divided into the responder and non-responder groups, based on whether their psoriasis improved (responded) after the 12-weeks treatment. The responder group comprised patients with more than 75% improvement while the non-responder group comprised those with less than 50% improvement in psoriasis. Associations between 18 common variations of 14 genes that make people susceptible to psoriasis (LCE3D, IL12B, NFKB1A, TNIP1, ERAP1, ZNF683, MTHFR, AIM2, PTTG1, GJB2, SYNE2, IKZF3, SERPINB8, ZNF816A) and the HLA-Cw6 status were analysed, based on their response to methotrexate. The differences between the clinical factors of methotrexate responders and non-responders were compared. Body mass index, arthritis, and rs10036748 genotype were significantly associated with the patients’ response to methotrexate. The authors concluded that patients with psoriasis and the TT genotype of rs10036748 on the TNIP1 gene, those with lower body mass indices, and those without arthritis will respond better to methotrexate.