Nature and Clonality of the Fluoresceinated Secondary Antibody in Luminex Multiplex Bead Assays Are Critical Factors for Reliable Monitoring of Serum HLA Antibody Levels in Patients for Donor Organ Selection, Desensitization Therapy, and Assessment of the Risk for Graft Loss.

Luminex multiplex immunoassays enable simultaneous monitoring of Abs against multiple Ags in autoimmune, inflammatory, and infectious diseases. The assays are used extensively to monitor anti-HLA Abs in transplant patients for donor organ selection, desensitization, and assessing the risk for graft rejection. To monitor IgG Abs, fluoresceinated IgG constant H chain-binding polyclonal F(ab') () is used as the fluoresceinated secondary Ab (2nd-Ab), whereas IgG subclasses are monitored with Fc-specific monoclonal whole IgG ().

Conformational Variants of the Individual HLA-I Antigens on Luminex Single Antigen Beads Used in Monitoring HLA Antibodies: Problems and Solutions.

Background: Single antigen beads (SAB) are used for monitoring HLA antibodies in pretransplant and posttransplant patients despite the discrepancy between virtual and actual crossmatch results and transplant outcomes. This discrepancy can be attributed to the presence of conformational variants of HLA-I on SAB, assessment of which would increase the concordance between SAB and flow cytometry crossmatch (FCXM) results, thus enabling improved organ accessibility for the waiting list patients and a better prediction of antibody-mediated rejection.

Methods: The conformational variants were examined on HLA-I beads, iBeads, acid-/alkali-treated beads, and T cells using HLA-I monoclonal antibodies (W6/32, TFL-006, and heavy chain (HC)-10).

Prevalence and Clinical Impact of Donor-Specific Alloantibody Among Intestinal Transplant Recipients.

Background: Rejection remains the leading cause of allograft loss, and a major barrier to improving long-term outcomes after intestinal transplantation. Our aim is to define the prevalence and investigate the role of donor-specific antibody (DSA) on intestinal graft outcomes.

Methods: The study includes 109 transplants performed in 95 recipients at a single center.

Dynamics and epitope specificity of anti-human leukocyte antibodies following renal allograft nephrectomy.

Background: A considerable proportion of patients awaiting kidney transplantation is immunized by previous transplantation(s). We investigated how allograft nephrectomy (Nx) and withdrawal of maintenance immunosuppression (WD-MIS) in patients with a failed renal allograft contribute to allosensitization.

Methods: HLA antibodies (HLAabs) were analyzed before and after Nx and/or WD-MIS using a single antigen bead assay.

Significance of the differences in the prevalence of anti-HLA antibodies in matched pairs of mother's and cord blood.

The presence of IgG against pathogens in the cord blood (CB) of vaccinated mothers is attributed to transplacental transfer. However, previous studies using lymphocytotoxicity assay showed anti-HLA IgG in mother's blood (MB) but not in CB, perhaps due to non-transfer of anti-HLA IgG or assay limitations in detecting anti-HLA IgG. Anti-HLA IgG of native and purified sera of 16 MB and CB pairs were measured using an array of microbeads coated with HLA-I/-II molecules on a Luminex platform.