scholarly journals P1604SIGNIFICANT DETECTION OF UNEXPLAINED HLA ANTIBODIES WITH SINGLE-ANTIGEN BEADS IN PATIENTS ON THE WAITING-LIST WITHOUT PREVIOUS SENSITIZING EVENTS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Sara Núñez Delgado ◽  
Carla Burballa Tarrega ◽  
José Luis Caro ◽  
Carlos Arias Cabrales ◽  
Marisa Mir Fontana ◽  
...  
Keyword(s):  
Solid Phase ◽  
Class Ii ◽  
Automated Detection ◽  
Waiting List ◽  
Hla Antigen ◽  
Hla Antibodies ◽  
Single Antigen ◽  
Screening Assays ◽  
As Solid Phase ◽  
Limit Access

Abstract Background and Aims The introduction of more sensitive and specific tools as solid phase immunoasssays has improved the ability to detect HLA antibodies. The techniques based on solid phase immunoassays in Luminex system can be performed either as screening assays (with pooled antigen panels that use bead populations coated in affinity-purified class I or class II HLA molecules) or to assess the specificity with single-antigen bead (SAB) assays (single cloned allelic HLA antigen).The sensitivity of each assay Is different, and their results may be discordant. Our objective was to evaluate the potential discrepancies between tests in a cohort of patients on our waiting list with no previous sensitizing events, for their potential influence in the access to transplantation. Method Observational study of 184 patients included in the kidney-transplant waiting list on March 31st, 2019. All possible sensitizing events (pregnancy, transfusion and previous transplants) were registered. HLA antibodies where analyzed both by screening and SAB tests. Results We limited the observations to males (64.7% of the cohort), as most women (95.4%) had a known sensitizing event, not being possible to discard possible pregnancies in the remaining. Of men, 46.2% had a sensitizing event and 63.8% did not. All 63 unsensitized patients showed a negative screening test, and 49 (77,78%) had at least one SAB done being positive in 73.4% (36/49). The positive SAB yielded a cPRA >10% in 30 cases (between 21-85%), mostly (27/30) due to HLA class II antibodies (88.8% with at least one DQ antibody) with a median MFI of 1571 (range:752-17650). A thorough review of specificities showed that 81% DQB1* and 89.6% DQA1* antibodies did not show consistency in all beads included for the same allele. Conclusion Screening and SAB assays show a significant discordancy in unsensitized men included in the waiting list for kidney transplantation. Automated detection of antibodies by SAB without a proper specialized interpretation may wrongly limit access to transplantation.

Comparison Between Phenotypic Bead Assay and Single Antigen Bead Assay for Determining Specificity of HLA Antibodies in Kidney Transplant Waiting List

2020 ◽  
Vol 52 (6) ◽  
pp. 1675-1679
Author(s):  
Duangtawan Thammanichanond ◽  
Sireewan Sukhumvat ◽  
Chutima Tammakorn ◽  
Sukanya Siriyotha ◽  
Surasak Kantachuvesiri
Keyword(s):  
Kidney Transplant ◽  
Waiting List ◽  
Hla Antibodies ◽  
Single Antigen

Monitoring for HLA Antibodies in Cord Blood Transplantation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2031-2031
Author(s):  
Jonathan A. Gutman ◽  
Susan K. McKinney ◽  
Sandra L. Warnock ◽  
Anajane Smith ◽  
Ann E. Woolfrey ◽  
...  
Keyword(s):  
Cord Blood ◽  
Graft Rejection ◽  
Cord Blood Transplantation ◽  
Hla Antigens ◽  
Class Ii ◽  
Class I ◽  
Antibody Specificity ◽  
Hla Antigen ◽  
Hla Antibodies ◽  
Blood Transplantation

Abstract Though graft rejection in hematopoietic cell transplantation (HCT) is presumed to be mediated primarily by host anti-donor T cells and natural killer cells, host antibodies which generate antibody dependent cellular cytotoxic reactions to donor antigens may also contribute. For patients undergoing HCT with a cord blood graft which is usually markedly mismatched to the recipient, alloimmunization is a potential significant issue. Cross-matching is not able to be performed secondary to limited cell numbers available from a cord blood graft. Delayed hematopoietic recovery and graft failure are known complications of cord blood transplantation (CBT), and though likely related primarily to small graft size and presence of primarily naïve immune cells in a cord blood graft, HLA antibodies may also contribute. At our center, we investigate recipient alloimmunity in all patients undergoing CBT to guide donor selection. Patients are first screened for the presence of antibodies against HLA antigens using an ELISA-based assay in which patient serum is tested against pools of purified class I and class II HLA antigens bound in wells of a plastic microtiter plate. Serum from patients noted to have evidence of HLA antibodies prompts further testing to identify the specific HLA antibodies using panels of color coded plastic microspheres each coated with a single purified class I or class II HLA antigen. To date, 4 of 29 patients screened have had evidence of HLA alloimmunization. Further investigation of antibody specificity in one patient undergoing double unit CBT demonstrated antibodies to HLA-Bw6, an epitope known to be present on one of the donor units. Because no other donors were available, the unit was used. Following a reduced intensity preparative regimen (RIT), the patient engrafted neutrophils on day 24 and platelets on day 42. However, the HLA-Bw6 positive unit was absent on all chimerism studies (beginning day 21 post transplantation). Three other patients with HLA alloimmunization did not have identifiable antibody specificity directed against mismatched HLA antigens, and engrafted neutrophils on days 25, 29, 25 and platelets on days 29, 41, and 102 respectively. To our knowledge, we are the first to report monitoring for alloimmunization in CBT and the first to describe the outcome of grafting a cord blood unit known to be HLA antibody incompatible with the patient. When patients undergo double unit CBT, cells from both units can generally be detected in the blood of the recipient during the first month, especially following RIT conditioning, but one unit eventually and consistently prevails (though predictive factors for the winning unit have not yet been satisfactorily described). In this case the compatible unit prevailed and there was no evidence at day 21 of cells from the antibody incompatible unit. Although we cannot attribute cause and effect to the anti-Bw6 alloantibody, it is interesting to note that all seven other patients transplanted on the same RIT protocol have demonstrated at least minimal bone marrow contributions to chimerism from both units at day 28. Hence, alloimmunization may be an important factor influencing graft rejection in CBT. CBT patients should likely be screened for HLA antibodies, and positive screenings warrant further investigation to avoid whenever possible donor/recipient mismatches against which the patient is sensitized. Ongoing monitoring will help clarify the clinical significance of this issue.

Preconcentration of atrazine and simazine with multiwalled carbon nanotubes as solid-phase extraction disk

2010 ◽  
Vol 96 (2) ◽  
pp. 348-351 ◽  
Author(s):  
Hideyuki Katsumata ◽  
Hiroshi Kojima ◽  
Satoshi Kaneco ◽  
Tohru Suzuki ◽  
Kiyohisa Ohta
Keyword(s):  
Carbon Nanotubes ◽  
Solid Phase Extraction ◽  
Multiwalled Carbon Nanotubes ◽  
Solid Phase ◽  
Phase Extraction ◽  
Multiwalled Carbon ◽  
As Solid Phase

The impact of anti-HLA antibodies on unrelated cord blood transplantations

Blood ◽  
2010 ◽  
Vol 116 (15) ◽  
pp. 2839-2846 ◽  
Author(s):  
Minoko Takanashi ◽  
Yoshiko Atsuta ◽  
Koki Fujiwara ◽  
Hideki Kodo ◽  
Shunro Kai ◽  
...  
Keyword(s):  
Cord Blood ◽  
Solid Phase ◽  
Human Leukocyte ◽  
Antibody Detection ◽  
Red Cross ◽  
Hla Antibodies ◽  
Platelet Recovery ◽  
Neutrophil Recovery ◽  
Unrelated Cord Blood ◽  
The Impact

Abstract The majority of cord blood transplantations (CBTs) have human leukocyte antigen (HLA) disparities. We investigated the impact that patients' pretransplantation anti-HLA antibodies have on the outcome of CBTs. Testing for anti-HLA antibody and its specificity was performed retrospectively at the Japanese Red Cross Tokyo Blood Center with sensitive solid-phase antibody detection assays. Among 386 CBTs, which were first myeloablative stem cell transplantations for malignancies and used a single unit of cord blood, 89 tested positive. Among the antibody-positive group, the cord blood did not have the corresponding HLA type for the antibody in 69 cases (ab-positive), while 20 cases had specificity against the cord blood HLA (positive-vs-CB). Cumulative incidence of neutrophil recovery 60 days after transplantation was 83% (95% confidence interval [CI], 79%-87%) for the antibody-negative group (ab-negative), 73% (95% CI, 61%-82%) for ab-positive, but only 32% (95% CI, 13%-53%) for the positive-vs-CB (P < .0001, Gray test). With multivariate analysis, the ab-positive showed significantly lower neutrophil recovery than the ab-negative (relative risk [RR] = 0.69, 95% CI, 0.49-0.96, p = .027). The positive-vs-CB had significantly lower neutrophil recovery (RR = 0.23, 95% CI, 0.09-0.56, P = .001) and platelet recovery (RR = 0.31, 95% CI, 0.12-0.81, P = .017) than the ab-negative. Patients' pretransplantation anti-HLA antibodies should be tested and considered in the selection of cord blood.

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