An In-vitro Standardization of B Cell Elispot Assays

Northwestern University

Status: Terminated

Conditions: Sensitization to HLA Antigens; Transplant Sensitization; Panel Reactive Antibody

Treatments: Procedure: Blood Draw

Study type: Observational

Funder types: Other

Identifiers

NCT01334281

0037-370-285V-AT (Other Identifier)

STU00027653 1682-05

Details and patient eligibility

About

This study is being done because the study doctor is trying to develop a new test which will help transplant doctors monitor patients with high panel reactive antibodies (PRA). The test would be used to monitor patients' PRA when doctors are trying to lower it through a process known as desensitization. Desensitization lowers high PRA levels and allows patients to receive transplants. This is a single center study to evaluate and optimize the use of a new laboratory test to detect and measure the immune system's functioning.

Full description

Sensitization to HLA antigens is the main barrier to solid organ transplantation. Currently, HLA sensitization is monitored by testing patients' serum against a panel of HLA antigens (whether those will be presented on cell surface or on solid phase matrixes) and calculating the % of positive responses. Such result give indication of the relative breadth of sensitization but not on it "depth" - the relative strength of specific antibodies, nor does it provide any information regarding the memory B cells / plasma cells that can manufacture a specific HLA directed antibody.

This is a single center study to evaluate and optimize the use of in-vitro assay to enumerate B cells producing human leukocyte antigens (HLA)-specific antibodies. The proposed assay is based on principles used for enumeration of specific cytokine producing memory T cells - an ELISPOT assay. The investigators are currently using the T cell ELISPOT assay in our laboratory.

The investigators believe that the proposed assay will provide biologically relevant immune measures that are crucial for the long term outcome of transplantation in highly sensitized patients.

Highly sensitized patients encompass a high risk patient group among transplant recipients. The proposed assay is designed to predict the fate of DSA producing (or capable of producing) memory and plasma cells. Thus, it should allow prediction and early detection of activation of the humoral arm of the immune system, specifically against the donor. This, in turn, may prompt early intervention and preservation of the allograft. Three tubes of blood will be drawn twice, 8-12 weeks apart, during clinic or standard of care dialysis visits following optimization. Subjects undergoing desensitization will have three tubes of blood drawn seven times over the course of two years for the analysis.

Enrollment: 19 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Subjects should be listed for solid organ transplant at NU/NMH
• Subjects should be > or = to 18 years of age, either gender
• Subjects should have history of prior sensitization of HLA antigens
• Subjects should have documented antibody specificity previously tested at the transplant immunology lab at NU
• Subjects should be capable of understanding the study, consents, HIPAA process and be able to give informed consent.

Exclusion criteria

• Subjects younger than 18 years of age
• Subjects with no sensitization history

Trial design

19 participants in 2 patient groups

Blood: Undergoing Desensitization

Description:

Transplant subjects give blood at specified time points. Sensitization to HLA antigens is a barrier to transplant. Several U.S. institutions have protocols for desensitization where patients are treated with IV immunoglobulins (IVIg) and plasmapheresis (PP) to reduce circulating HLA-directed antibody levels. Labs provide doctors information on circulating donor-specific antibody (DSA) levels. These results are the main indicator whether to proceed with transplant. However, no information is given on the fate of the B cells that produce the DSA.

Treatment:

Procedure: Blood Draw

Procedure: Blood Draw

Blood: NOT Undergoing Desensitization

Description:

Transplant subjects give blood at specified time points. Sensitization to HLA antigens is a barrier to transplant. Several U.S. institutions have protocols for desensitization where patients are treated with IV immunoglobulins (IVIg) and plasmapheresis (PP) to reduce circulating HLA-directed antibody levels. Labs provide doctors information on circulating donor-specific antibody (DSA) levels. These results are the main indicator whether to proceed with transplant. However, no information is given on the fate of the B cells that produce the DSA.

Treatment:

Procedure: Blood Draw

Procedure: Blood Draw