Acute pericarditis with pleuropulmonary involvement, fever and elevated C-reactive protein: A systemic autoinflammatory disease? A cohort study.

OBJECTIVES: This cohort study describes a systemic phenotype of pericarditis, comparing this phenotype with other forms of pericarditis. PATIENTS AND METHODS: Patients in our center were enrolled in a prospectively maintained registry from 2019 to 2022. 412 patients with idiopathic recurrent pericarditis were analyzed. "Systemic inflammatory" subset was defined as the presence of all the following criteria: fever ≥38C°, CRP ≥2 times normal values, pleural effusion detected with any imaging techniques. The absence of any of the 3 criteria was defined as "isolated" subset. RESULTS: We found that 211 (51.2%) of 412 patients (188 female) presented the systemic subset and the variables significantly associated with this subset in univariate analysis (p<0.001) were: higher mean age: 45.5 (±SD 17.2) vs 39.9 (±SD 16.4) years, higher mean CRP values: 128.8 vs 49.9 mg/L, higher proportion of pericardiocentesis: 19% vs 1.5%, higher mean leukocyte count: 13,143.3 vs 9910.3/mm3, higher mean neutrophils number: 10,402.5 vs 6779.8 /mm3 and lower mean lymphocyte count: 1693.9 vs 2079.3 /mm3. As results the neutrophil-to-lymphocyte ratio was higher in systemic inflammatory phenotype: 6.6 vs 3.4 (p< 0.001). Anti-IL1 therapy was started more frequently in the systemic subgroup (26%) than in the isolated subset (7.5%) (p < 0.001). On multivariate analysis neutrophil count and lymphopenia were statistically associated with the systemic subset (p < 0.001). CONCLUSION: This results demonstrate the relevance of the systemic inflammatory phenotype, characterized by pleural effusions, confirming its analogy with autoinflammatory diseases, thus possibly requiring an eventual escalation of therapy to IL-1 inhibitors.

Relapsing pericarditis: Peripheral blood neutrophilia, lymphopenia and high neutrophil-to-lymphocyte ratio herald acute attacks, high-grade inflammation, multiserosal involvement, and predict multiple recurrences.

AIMS: To identify peripheral blood cellular correlates of active pericarditis and to verify whether peripheral blood neutrophils, lymphocytes and the neutrophil to-lymphocyte ratio (NLR) are associated with disease phenotype or prognosis. METHODS: Observational prospective study on a cohort of 63 patients with idiopathic pericarditis followed for 12 months after each pericarditis recurrence. Two distinct analyses were performed: the "index attack" analysis focused on the first pericarditis episode in each patient, while the "all attacks" analysis included all episodes occurring during the study. RESULTS: Absolute and relative neutrophilia and lymphopenia, together with high NLR, were observed during active pericarditis, as compared with disease remission, at both analyses. Neutrophils showed a positive correlation with plasma C-reactive protein levels, while lymphocyte count showed a negative correlation. Relative neutrophil count was higher, and lymphocyte count lower in patients with pleural effusion; a higher NLR and lower absolute lymphocyte count were observed in those with peritoneal involvement. No correlations were found between peripheral blood neutrophil or lymphocyte counts and size of pericardial effusion, or with the presence of myocardial involvement. Peripheral neutrophilia, lymphopenia and NLR during acute attacks predicted the number of recurrences in the following 12 months. CONCLUSIONS: Peripheral blood neutrophilia and lymphopenia are typical of acute idiopathic pericarditis. Acute attacks of pericarditis are associated with neutrophilia and lymphopenia, as compared with disease remission. During acute attacks, neutrophilia and lymphopenia reflect the extent of serosal inflammation and could help to customize therapeutic management after remission has been achieved.