TNF and psoriasis: However, interventions (e.g., nonsteroidal anti-inflammatory drugs, TNFα-inhibitors, including adalimumab, etanercept or infliximab) designed to block these cytokine pathways effectively in psoriasis, are lesssuccessful in treating PsA manifestations, perhaps because the precise mechanisms underlying the pathogenesis of PsA are multi-factorial, involving genetics, environmental factors, and immune-mediated inflammation, whose interactions and inter-relationshipremain poorly understood [24,25,26,27,28].