De Novo Produced Anti-Human Leukocyte Antigen Antibodies Relation to Alloimmunity in Patients with Chronic Renal Failure

Human Leukocyte Antigen Sensitization in Solid Organ Transplantation: A Primer on Terminology, Testing, and Clinical Significance for the Apheresis Practitioner

The human leukocyte antigen (HLA) system is an important immunologic barrier that must be considered for successful solid organ transplantation. Formation of donor-specific HLA antibodies in solid organ transplantation is an important cause of allograft injury and may contribute to recipient morbidity and mortality. Therapeutic plasma exchange is often requested to lower HLA antibody levels prior to or after transplantation and for management of HLA antibodies in the context of organ rejection. In this review, we summarize the current terminology, laboratory testing, and clinical significance of HLA sensitization in the solid organ transplant population. Furthermore, to illustrate applications of HLA testing in clinical practice, we summarize our own lung and kidney institutional protocols for managing HLA antibodies in the peri-transplant setting.

Effect of Single Sensitization Event on Human Leukocyte Antigen Alloimmunization in Kidney Transplant Candidates: A Single-Center Experience

OBJECTIVES

Human leukocyte antigen alloimmunization is caused by exposure to HLA antigens through transfusion, pregnancy, or transplant. Our study objective was to present the rate of positivity of anti-HLA antibody considering the effects of a single sensitization event in kidney transplant candidates at our center.

MATERIALS AND METHODS

Our study reviewed 606 kidney transplant candidates. Patient sera were analyzed using Luminex xMAP technology. Panel reactive antibody positivity rates and antibody strengths in patients were analyzed according to a single sensitization event.

RESULTS

Our findings showed 246 patients (40.6%) with a panel reactive antibody > 0, of which 97 (39.4%) were sensitized from a single event, 119 (48.4%) were sensitized by multiple events, and 30 (12.2%) had no known sensitizing event. Considering patients sensitized by a single event with a panel reactive antibody > 0, we found that 25.8% had received transplant only, 49.5% had previous pregnancy only, and 24.7% had received transfusion only. The strength of antibodies was significantly higher in patients with previous transplant procedures than in those with transfusion for HLA-A (P < .01), HLA-B (P < .05), HLA-C (P < .05), HLA-DR (P < .001), HLA-DQ (P < .05), and HLA-DP (P < .05). Similarly, we observed significantly higher median fluorescence intensity values for HLA-A, -DR, -DQ, and -DP loci in patients with a previous transplant procedure versus pregnancy. The strength of antibodies against HLA-DR was significantly higher in patients with a previous pregnancy compared with those with transfusion (P < .01).

CONCLUSIONS

This study documents the profile of HLA alloimmunization in kidney transplant candidates. In particular, transplant procedures appear to have a greater immunologic impact, followed by pregnancy and transfusion. Our data confirm and are in accordance with those of several studies in which the sensitization events were associated with higher prevalence of anti-HLA antibodies.

Comparison of Anti-HLA Antibody Production According to Gestational Periods in Pregnant Women

BACKGROUND

To evaluate paternal anti-HLA antibody profiles, sera samples were collected from pregnant women in different trimesters and the panel-reactive antibody (PRA) specificities were identified.

METHODS

From 2013 to 2015, serum samples were obtained from 41 pregnant women who had registered at the Izmir Tepecik Education and Research Hospital Gynecology Clinic. Anti-HLA antibodies were screened by using the panel reactive antibody screening and identification tests. Sera samples were obtained at the first, second, and third trimesters. The primary outcome was to determine the anti-HLA antibody production term during pregnancy; the secondary outcome was identification of anti-HLA antibodies.

RESULTS

None of the women had a sensitization history except during pregnancy. We observed that 54% of the women produced paternal antibodies, either class I or II. Class I PRA positivity of the women who had a first or second pregnancy was the same in all 3 trimesters, whereas class II positivity was increased in the third trimester. Class II and both class I and II positivity increased in the third trimester; class I positivity was decreased in the third trimester. PRA positivity could be affected by the history of pregnancy and could be raised, but no impact was observed from the history of abortion and miscarriage (odds ratios, 1.9, 0.4, and 0.5 [95% confidence intervals, 0.5-7.8, 0.1-2.0, and 0.3-0.7], respectively; P > .05). The most frequently detected antibodies were A2, B7, DR7, DR4, DR11, DR13, DQ2, and DQ8.

CONCLUSIONS

Anti-HLA antibodies against paternal HLA antigens were detected more in multiparous women than in primiparous women. Anti-HLA antibody detection ratios did not change until the third trimester and were followed by a specific increase in class II anti-HLA antibody production.