Altered lymphocyte subsets during cardiopulmonary bypass

Area of Science:

• Immunology
• Cardiovascular Surgery

Background:

• Open heart surgery involves cardiopulmonary bypass (CPB).
• CPB can impact immune function.
• Lymphocyte subsets play a crucial role in immune response.

Purpose of the Study:

• To quantify peripheral blood lymphocyte subsets in patients undergoing open heart surgery.
• To investigate the impact of CPB on T4 (helper) and T8 (cytotoxic) lymphocyte subsets.
• To assess the temporal changes in lymphocyte subsets and the T4/T8 ratio post-surgery.

Main Methods:

• Immunofluorescence was used to quantify lymphocyte subsets in peripheral blood.
• Nine patients with coronary artery, valvular, and congenital heart disease were studied.
• Measurements were taken preoperatively, 2 hours post-CPB, and 24 hours post-surgery.

Main Results:

• All patients exhibited absolute lymphopenia and reduced T4 lymphocytes 2 hours post-CPB.
• A significant reversal of the T4/T8 ratio was observed 2 hours post-CPB.
• Lymphocyte subsets and the T4/T8 ratio returned to normal 24 hours post-surgery.

Conclusions:

• CPB induces transient immune dysfunction, characterized by lymphopenia and altered T4/T8 ratio.
• This temporary immune suppression may increase susceptibility to postoperative infections.
• Potential implications include concerns about viral transmission and acquired immune deficiency syndrome post-CPB.