Tendon pathologies (enthesitis) are a characteristic component of psoriatic arthritis (PsA), and are observed in 35% to 50% of PsA patients. The Achilles tendon is one of the most commonly affected sites. This condition often causes great morbidity and loss of quality of life, and response only suboptimal to current intervention strategies. One of the main obstacles for the development of effective treatment methods is that the disease mechanisms remain poorly understood. To our knowledge, no one has yet ascertained the presence and function of immune-competent cells and inflammatory markers in tendons tissue from PsA patients suffering from Achilles enthesitis.