Alteration of Immune System after Bariatric Surgery: A Systematic Review


Saeed Shoar1*, Siamak Khavandi2, Elsa Tabibzadeh3, Soheila Khavandi4

Background: It is well established that there is a significant correlation between overweight/obesity and immune system function. However, it is not clear how weight loss after bariatric surgery would affect the function of the human immune system.

Objectives: We aimed to conduct this systematic review to assess the current knowledge on alteration of the immune system after bariatric surgery.

Methods: We reviewed all potentially related articles published between January 2006 and September 2020 to review the obesity surgery literature and immune system activity in Medline/PubMed.

Results: The results of a review of studies showed that obesity is associated with a low-grade systemic inflammatory condition in which innate and adaptive immune cells increase the secretion of proinflammatory cytokines. Weight loss due to bariatric surgery leads to significant changes in adaptive immune cells. The number of CD4 + and CD8 + T cells decreases. Decreased Th1/Th2 ratio also occurs after weight loss due to obesity surgery. Also, the ratio of inflammatory and anti-inflammatory cytokines changes following change in immune cells ratio.

Conclusion: Weight loss following obesity surgery results in anti-inflammatory status, which occurs with obesity.