Background. Allergic Contact Dermatitis (ACD) is an inflammatory skin disease mediated by direct contact with allergens as nickel, the most common allergen, that may be related with epigenetic changes.

Objective. Evaluate the miR-126 expression and its target VCAM-1, in the skin of patients with ACD to nickel.

Methods. Fifteen patients with positive patch test to nickel were included, and the expression of miR-126 and VCAM-1 was evaluated by RT-qPCR.

Patients that went to the dermatology and outpatient department of the Central Hospital "Dr. Ignacio Morones Prieto ", with a suspected diagnosis of nickel allergic contact dermatitis, were invited to participate in this study. Later, the objective and methodology of the study were explained to them, as well as the advantages of participating and the possible undesirable effects. All patients signed the informed consent previous perfom the medical history. After, the epicutaneous patch test was performed, and patients were divided according to the result them. Finally, under local anesthesia, two 3-mm punch biopsies, from lesional (positive parch test site) and adjacent non lesional skin, 10 cm apart, were performed. Tissues for reverse transcriptase real-time polymerase chain reaction (RT-qPCR) analyses were stored frozen in sterile tubes at 80ºC until processing

Inclusion Criteria:

• 18 years of age and older
• Epicutaneous Patch Test positive to Nickel
• without previous treatment within the previous 4 weeks

Exclusion Criteria:

• Pregnancy
• nursing
• menopause
• consumption of any type of drugs (including anti-inflammatories and hormonal treatments) within the previous 2 months
• coexistence of other dermatoses conditions

Female and male patients with allergic contact dermatitis for more than one year