Different Aspects of Psoriasis : Comorbidity, Comedication and Disease Biomarkers

Sammanfattning: Psoriasis is a common heterogeneous inflammatory disease with its predominant manifestation occurring in the skin. The impact of this disease, however, extends far beyond the skin surface. During the last decades, mounting scientific evidence of psoriasis disease impact on quality of life, stigmatization and comorbidity has led to the predominant view that psoriasis care needs a holistic approach. Epidemiological research is needed to visualize the greater picture whereas research on disease pathomechanisms can provide answers to disease evaluation challenges, facilitate development of new treatments, and provide insights into mechanistical bridges explaining comorbidity occurrence. In study I of this thesis, serum S100A8/A9 was evaluated as a possible biomarker of psoriasis skin disease activity. Dramatic reductions in S100A8 and S100A9 and S100A8/A9 heterocomplex levels were found in lesional psoriasis skin after NB-UVB treatment without any significant reduction occurring in serum. Study II was designed as a retrospective, cross-sectional population study including the adult population of the county of Jönköping. The odds of having pharmacologically treated depression among individuals with psoriasis was compared to the odds of the background population. Psoriasis was associated with an elevated depression risk. Depression was more prevalent among women (both in the background population and among individuals with psoriasis). Young age was associated with higher odds for depression among individuals with psoriasis. Study III was based on the same study population as study II. In this study the comedication burden of individuals with psoriasis was compared to the background population. Comedication assessed were prescription drugs used to treat comorbidity associated with psoriasis in previous scientific publications. Patients with psoriasis were found to have a high comedication burden. Patients receiving systemic treatment for psoriasis had a higher number of different dispensed drugs suggesting that severe disease implies a higher risk of comorbid disease. Study IV was an exploratory study assessing numerous potential biomarkers for psoriasis disease activity. Extensive Luminex analysis of skin and serum samples collected during study I was performed. No serum mediator (potential biomarker of disease activity) showed a significant change after NB-UVB (following correction for multiple testing). In skin, NB-UVB had effects on mediators of the Th17 pathway and multiple chemokines but also previously undescribed or less explored disease mediators. Study II and III suggest that comorbidity and its comedication is common among Swedish psoriasis patients in contact with the health care system. This research reinforces the perception that a holistic approach is needed when treating patients with psoriasis. Behind the failure to identify a biomarker for skin disease activity in study I and IV lurks the questions to how, if or when inflammation in the skin affects systemic inflammation and in extension comorbid disease.