Total fecal IgA levels increase and natural IgM antibodies decrease after gastric bypass surgery

Area of Science:

• Immunology
• Gastroenterology
• Metabolic Surgery

Background:

• Obesity is linked to chronic low-grade inflammation and oxidative stress.
• Roux-en-Y gastric bypass (RYGB) surgery improves metabolic dysfunction in obese individuals.
• Gut immune responses, including natural antibodies, may be altered by obesity and RYGB.

Purpose of the Study:

• To investigate changes in fecal natural antibody levels before and after RYGB surgery.
• To compare these changes in obese individuals with and without type 2 diabetes (T2D).
• To assess the impact of RYGB on specific antibodies targeting oxidized LDL, MAA adducts, Rgp44, and PCho.

Main Methods:

• Chemiluminescence immunoassay was used to measure total and specific antibody levels (IgA, IgG, IgM).
• Fecal samples were collected from 16 T2D and 14 non-diabetic (ND) obese individuals pre-surgery and 6 months post-RYGB.
• Analysis focused on total IgA, IgG, IgM, and antibodies against oxLDL, MAA adducts, Rgp44, and PCho.

Main Results:

• Total fecal IgA significantly increased post-RYGB in both T2D and ND groups.
• Fecal IgM specific to oxLDL decreased significantly in both groups after RYGB.
• Specific IgG and IgM antibodies to Rgp44 and PCho showed significant decreases, particularly in the T2D group.

Conclusions:

• RYGB surgery significantly modulates the gut immune system, increasing total fecal IgA.
• The surgery leads to a reduction in specific natural IgG and IgM antibodies, including those targeting oxLDL.
• These alterations in natural antibodies suggest a significant impact of RYGB on gut homeostasis and immune defense mechanisms.