Imunomodulation in acute pancreatitis- how can cytokines, B and T cells predict the outcome of the disease

• Autor(a) principal: Malheiro, Ana Filipa Loriente Alves
• Data de Publicação: 2024
• Idioma: eng
• Título da fonte: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Texto Completo: http://hdl.handle.net/10362/169758
• topic: Imunomodulation; Ciências Médicas

Abstract Acute pancreatitis is an acute inflammatory process of the pancreas with high prevalence and varying degrees of severity that can be life threatening. Patients with this disease require hospitalization and its incidence has been rising over the last few decades. It is known there is an activation of both innate and adaptive immune system, including T and B lymphocytes and release of inflammatory cytokines. The initial treatment of this condition consists of supportive treatment, requiring thorough monitoring in the first 48 hours, and it is unclear why some patients develop local or systemic complications being admitted that a systemic inflammatory response develops and determines prognosis in the beginning of the disease with yet non-completely defined mechanisms. This is the reason why the “therapeutic window” of 48h has been considered essential in these patients to decide the ones who need close surveillance and therefore try to reduce local and systemic complications and mortality. We first performed a systematic review on the role of peripheral blood lymphocytes and severity of acute pancreatitis. The primary objective of this review was to identify the potential association between circulating lymphocytes and the severity of acute pancreatitis. A systematic search was performed in Medline, Web of Science, Cochrane Central Register of Controlled Trials and ClinicalTrails.gov. The selection process as well as data extraction was recorded into a flow diagram following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P). The initial search identified 27 783 studies that were narrowed, by applying strict inclusion and exclusion algorithms, down to 13 studies of which five were case-control studies and eight were cohort studies. We could then conclude that lower peripheral blood lymphocytes during hospitalization are related to acute pancreatitis severity. Secondly, with the aim to characterize the immune profile of patients with acute pancreatitis at admission (T1), and 48 hours after admission (T2), 50 patients were prospectively recruited to this study. We also aimed to better define, early in the course of this inflammatory disease, patients who need close monitoring and subsequent vital support in differentiated care units. Recruited patients with acute pancreatitis were admitted to Hospital da Luz Lisboa. A control group of 15 ambulatory individuals observed at the Hospital da Luz Lisboa was also recruited. Quantification and phenotypic characterization of B cells and T cells according to the expression of specific cell surface markers has been performed by flow cytometry. As a first step to elucidate the features of immune responses during acute pancreatitis, we determined the blood levels of B and T cell subsets at hospital admission, compared with the healthy control group. Patients with acute pancreatitis presented, at admission, with higher leucocyte counts (p<0.0001), lower percentages of lymphocytes (p<0.0001), as well as higher neutrophil/lymphocyte ratio (p<0.0001), compared to the levels observed in healthy controls. As the first 48 hours of hospitalization are crucial for the evolution of acute pancreatitis and this is the time most severity scores are applied, the dynamics of the immune profile during this period was evaluated. Acute pancreatitis patients had higher leucocytes counts at admission (p<0.001) but higher C-reactive protein (CRP) levels at T2 (p=0.001). The neutrophil/lymphocyte ratio was higher at T1 than at T2 (p<0.001) and the lymphocyte percentages, within leucocytes, were lower at T1 than at T2 (p<0.001). Within the circulating B cell compartment there seems to be a modification during the first 48 hours of disease in patients with acute pancreatitis. Thus, assessing the early dynamics of B cells in acute pancreatitis patients, we were able to identify that the total percentages of B cells (within lymphocytes) decreased from T1 to T2 (p=0.004). Differentiated subsets of B cells such as double negative CD27-IgD- B cells also decreased from admission to 48 hours after diagnosis (p=0.020). Considering the Bedside Severity Index of Acute Pancreatitis (BISAP) score we found that patients with higher BISAP, expected to have increased disease severity, had higher CRP levels in both T1 and T2 (p=0.024 and p=0.010, respectively), but also extended hospital stays compared with patients with lower BISAP scores (p=0.035). Lower lymphocyte percentages were also observed in patients with higher BISAP (p≤0.025). Likewise, the neutrophil/lymphocyte ratio was higher in patients with higher BISAP and was also higher than in healthy controls (p<0.001). Moreover, by dividing patients according to disease severity, it was shown that CD27-IgD- B cells (p=0.015) are elevated in patients with higher BISAP than in patients with lower BISAP. When applying the classification system for severity according to the revised Atlanta classification system, moderate/severe AP patients also showed increased serum CRP levels and leucocyte counts and total B cell percentages were also higher in patients with moderate/severe acute pancreatitis than in the healthy control group (p = 0.025). Using a multivariable statistical based on neutrophil/lymphocyte ratio, percentage of B cells, and BISAP score values for acute pancreatitis patients we found that, adjusting for the other variables, for a unit increase in the neutrophil/lymphocyte ratio there is an estimated 2.4% increase in the expected number of days in hospital (p<0.001; 95% CI 1.015-1.033), while for B cells there is an estimated 1.8% increase (p=0.047; 95% CI 1.000-1.034). Additionally, this model predicts that patients with BISAP score of 2 or 3 will spend on average 34.3% more days at hospital (p=0.031; 95% CI 1.024-1.755) when compared with patients with BISAP score of 0 or 1. In conclusion, the neutrophil/lymphocyte ratio along with the widely used BISAP score and circulating B cells, form a robust predictive model for hospital stay duration in acute pancreatitis. We then included the same cohort of 50 patients with acute pancreatitis and a healthy control group of 30 individuals in another study. In this study we aimed to provide a broad view of the variation of the different cytokines, not only in the acute phase of acute pancreatitis, but also during the healing process, and their association with acute pancreatitis severity in the serum of acute pancreatitis patients as well as healthy controls. Blood samples were collected from patients with acute pancreatitis in the first 24 hours of diagnosis (T1) and at 48 hours (T2) of hospitalization, one month after discharge (T3) and at least 6 months after discharge (T4). The cytokines analyzed were interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, vascular endothelial growth factor (VEGF), interferon (IFN)-gamma, tumor necrosis (TNF)-alpha, IL-1alpha, IL-1beta, monocyte chemoattractant protein (MCP-1), and epidermal growth factor (EGF). We found most cytokines levels decrease from T1 to T2 namely IL-6, IL-8, IL-10, VEGF, TNF-alpha, MCP-1 and EGF. There were also differences between acute pancreatitis patients at T1 and healthy controls namely IL-6, IL-8, IL-10, VEGF, TNF-alpha and MCP-1. We have also found the decrease of the studied cytokines at T3 and T4, as well, as the absence of difference between most cytokines at T3 and at T4 and healthy controls probably reflects the resolution of acute pancreatitis. The exceptions were VEGF and EGF which still showed differences at T4 between acute pancreatitis patients and healthy controls. At T1 IL-4, IL6, IL-10, and TNF-alpha were related to higher length of hospital stay and at T2 IL-6, CRP and MCP-1 were related to increased length of hospital stay. When considering the severity scores used in clinical practice like the BISAP score we found that at admission IL-4, IL-6 and IL-10 were increased in the higher scores and at T2 it was VEGF and IL-6 that were related with the highest scores of BISAP. We found no difference with disease severity considering the BISAP score at T3 and T4. In our study we also found, when considering the revised Atlanta classification of 2012 of acute pancreatitis severity, that at T2 IL-6, IL8, VEGF, TNF-alpha and MCP-1 were increased in the moderately severe and severe acute pancreatitis patients. When considering both severity scores, the BISAP score and the revised Atlanta classification of 2012, we can conclude that IL-6 and VEGF are the two commonly cytokines that are good markers of disease severity at T2. In conclusion, cytokines levels in serum of patients with acute pancreatitis are related to the severity of this disease and to the length of hospital stay. Additionally, new markers of acute pancreatitis severity such as VEGF, MCP-1 and EGF, are valuable references for future study replication and validation, as well as developing therapeutic trials in patients with acute pancreatitis. Our findings suggest that peripheral blood B and T cells, as well as serum cytokines, undergo changes during the evolution of acute pancreatitis and are related to disease severity and hospital length of stay. Furthermore, the CD27-IgD- B cells subset is elevated in patients with higher BISAP score than in patients with lower BISAP score. In addition, IL-6 and VEGF are the two common cytokines that are good markers of disease severity at 48 hours after admission. Additionally, VEGF and EGF unlike other cytokines remained elevated at 6 months after hospital discharge. Therefore, these findings contribute to knowledge improvement of immunomodulation in patients with acute pancreatitis and provide some evidence for the development of a new biomarker of severity and help to design new therapeutic clinical trials.