Evaluation of intestinal inflammation with fecal calprotectin in psoriasis patients

Introduction and Aim: Psoriasis is a common chronic inflammatory disease. It is known that psoriasis is not only a disease limited to the skin, but can occur with comorbidities such as psoriatic arthritis, metabolic syndrome, cardiovascular events, inflammatory bowel disease, and mood disorders. Inflammatory bowel disease, one of these comorbidities, is a recurrent, chronic inflammatory disease of the gastrointestinal system. It has genetic bases and pathogenesis mechanisms that overlap with psoriasis. Fecal calprotectin is a protein produced from neutrophils, which shows mucosal inflammation in the intestine, directly. Recently, it has been used quite frequently in the diagnosis of inflammatory bowel disease, monitoring the course of the disease and evaluating the treatment response. In this study, we aimed to evaluate the intestinal inflammation with fecal calprotectin level in psoriasis patients without a diagnosis of inflammatory bowel disease, to identify psoriasis patients who may be at risk of inflammatory bowel disease, and to determine whether there is a relationship between fecal calprotectin and disease characteristics of psoriasis. Patients and Methods: Eighty psoriasis patients over the age of 18 who admitted to our clinic between June 2022 and February 2023; eighty age/sex-matched healthy volunteers were included as the control group. All of the included people were older than 18 years old, younger than 65 years old, not using any immunosuppressive therapy in the last 6 months, without pregnancy, active infection or malignancy. Demographic data, smoking habits, medical histories and family histories of all participants were recorded in the data form. The gastrointestinal symptoms of all participants were evaluated using the Turkish version of the Gastrointestinal Symptoms Rating Scale. This scale consists of questions evaluating 5 main symptoms: abdominal pain, diarrhea, constipation, indigestion, and reflux. Height and weight of all participants were measured, and body mass indexes were calculated. Erythrocyte sedimentation rate and C-reactive protein values were measured. Fecal calprotectin was studied using Euroimmun Calprotectine ELISA (Lübeck, Germany). In addition, psoriasis disease characteristics of the patient group were examined. All obtained results were recorded. Statistical analysis was performed using the IBM SPSS V23 statistical package program. Results: The groups was similar in terms of age and gender. The median fecal calprotectin level of the patient group was 235.0 (11.2-2100.0) µg/g, while the median of the control group was 44.6 (6.7-711.6) µg/g. When the median fecal calprotectin levels of both groups were compared, it was found to be statistically significantly higher in the patient group. When the cut-off value was determined as 50 µg/g recommended by the kit company, fecal calprotectin values were found to be high in 95% of the patient group and 48.8% of the control group. When 250 µg/g was determined as the cut-off value, fecal calprotectin values were found to be high in 47.5% of the patient group and 5% of the control group. When the distribution of both groups according to these threshold values was compared, more people who exceeded the threshold values were found in the patient group, significantly. It was determined that the fecal calprotectin level was correlated with the maximum and current PASI, maximum and current BSA values. The mean of Gastrointestinal Symptoms Rating Scale scores was significantly higher in patient group. No correlation was found between fecal calprotectin level and Gastrointestinal Symptoms Rating Scale score in the patient group. Discussion and Conclusion: According to fecal calprotectin measurement, there is significant intestinal inflammation in psoriasis patients compared to the control group. It is not known that the elevation of fecal calprotectin that we detected in psoriasis patients clearly indicates the risk of inflammatory bowel disease. However, since high fecal calprotectin levels were found to be a risk factor for the development of inflammatory bowel disease in the studies conducted in first-degree relatives of individuals with inflammatory bowel disease, it was thought that a similar risk may be present in psoriasis patients who have common pathogenetic mechanisms with inflammatory bowel disease. Fecal calprotectin level was found to be associated with psoriasis severity. For this reason, fecal calprotectin level measurement comes into prominence especially in patients with severe psoriasis. In patients with psoriasis, fecal calprotectin may be elevated independently of gastrointestinal complaints. It may be beneficial to initiate systemic agents used in both psoriasis and inflammatory bowel disease in patients with elevations detected by fecal calprotectin.