Antibodies to equine antithymocyte globulin in heart transplant recipients: evaluation of an enzyme immunoassay.

The research article presents the development and evaluation of a specific enzyme immunoassay to measure antibodies to equine antithymocyte globulin in heart transplant patients. The findings of the study suggest that despite immunosuppression, most patients develop significant antibody responses post-transplant.

Methodology and Evaluation

• The researchers introduced an isotype-specific microELISA, a type of enzyme immunoassay designed to detect antibodies to equine antithymocyte globulin specifically in patients who have undergone heart transplantation.
• The conditions of this assay were optimized for ideal performance and then evaluated in samples taken periodically from 40 patients, each of whom had received a heart transplant.

Findings

• Despite the use of immunosuppressants – in this case, corticosteroids – and the presence of T cell cytopenia (a reduction in the number of T cells), the majority of patients developed measurable immune responses in the form of antibodies to antithymocyte globulin.
• A subset of these patients developed especially high levels, or titres, of these antibodies.
• The most common isotypes (classifications of antibodies with specific functions in immune response) developed by these patients were IgM and IgG.
• The peak development of these antibodies was generally observed during the second and third weeks after the transplantation procedure.

Implications

• The findings could suggest that the presence of these antibodies might be viewed as an expected physiological response after the administration of equine antithymocyte globulin, even in cases where immunosuppression therapy is administered.
• The knowledge derived from the use and evaluation of this specific immunoassay could help in understanding immune responses in transplant recipients, assisting in better management and possibly prediction of post-transplant complications related to immune response.