Positive direct antiglobulin tests with antilymphocyte globulin

Area of Science:

• Immunology
• Transplantation Medicine
• Hematology

Background:

• Antilymphocyte globulin (ALG) is used for immunosuppression in renal transplantation.
• Equine ALG can cause immune reactions in patients.
• A positive direct antiglobulin test (DAT) is a concern in transplant recipients.

Purpose of the Study:

• To investigate the cause of positive direct antiglobulin tests (DAT) in patients receiving equine antilymphocyte globulin (ALG).
• To understand the implications of these positive DAT results on blood compatibility testing.

Main Methods:

• Analysis of direct antiglobulin tests (DAT) in patients treated with equine ALG.
• Serological testing of patient serum and red blood cell eluates.
• Cross-matching procedures to assess blood compatibility.

Main Results:

• Patients receiving equine ALG consistently developed positive DAT, primarily of the IgG type.
• The positive DAT was attributed to antihorse globulin reacting with ALG on red blood cells.
• Some patients' serum and eluates showed incompatibility in cross-matches without specific blood group antigen reactions.

Conclusions:

• Equine ALG administration leads to a positive DAT in renal transplant patients.
• The presence of antihorse antibodies coating red blood cells is the cause.
• This phenomenon can interfere with pre-transfusion compatibility testing, potentially impacting patient management.