Living Donor Liver transplantation in an alloimmunised patient: Immunological challenges and Management in Indian Settings

Liver transplantation (LT) is often associated with hematological abnormalities with immune or non-immune etiologies and require timely diagnosis and interventions. We report a case of a patient suffering from non-alcoholic steato-hepatitis (NASH) related end stage liver disease (ESLD) with multiple red cell antibodies who underwent LT surgery. In postoperative phase, she developed immune hemolysis as well as acute antibody mediated rejection (AMR) which was managed with therapeutic plasma exchange and IVIG. The case highlights the need to develop an algorithm for red cell and HLA antibody screening in high-risk patients for timely detection and management.

Alloimmunization Against RBC Antigens Is Not Associated With Decreased Survival in Liver Transplant Recipients

BACKGROUND

Improvement of liver transplantation (LT) outcomes requires better understanding of factors affecting survival. The presence of RBC alloantibodies (RBCAs) on survival in LT recipients was evaluated.

METHODS

This study was a single-center, retrospective cohort study reviewing transfusion records and all-cause mortality between 2002 and 2021.

RESULTS

Between 2002 and 2021, 2079 LTs were completed, 1,396 of which met inclusion criteria (1,305 RBCA negative; 91 RBCA positive [6.5%]). The cohorts were similar in age (mean [range], 55.8 [17-79] years vs 56.8 [25-73] years; P = .41, respectively) or sex (RBCA negative, 859 [65%] men and 446 [35%] women vs RBCA positive, 51 [56%] men and 40 [44%] women; P = .0684). Of 132 RBCAs detected, 10 were most common were to E (27.27%), Jka (15.91%), K (9.09%), C (8.33%), M (6.06%), D (5.3%), Fya (4.55%), e (2.27%), c (2.27%), and Jkb (2.27%). Twenty-seven patients (29.7%) had more than 1 RBCA; the most common combinations were C with Jka (7.4%) and E with Dia (7.4%). All-cause mortality was increased in men (men, 14.45 years vs women, 17.27 years; P = .0266) and patients 65 years of age and older (≥65 years of age, 10.21 years vs <64 years of age, 17.22 years; P < .0001). The presence of RBCA (≥1) did not affect all-cause mortality (RBCA negative, 14.17 years vs RBCA positive, 15.29 years; P = .4367). The top 5 causes of death were infection (11.9%), primary malignancy (solid) (10.8%), recurrent malignancy (10.5%), cardiovascular arrest (7.1%), and pulmonary insufficiency/respiratory failure (5.7%).

CONCLUSIONS

Survival in RBCA-positive LT recipients is no different from that in RBCA-negative LT recipients.

Cell Salvage During Liver Transplantation for Hepatocellular Carcinoma: A Retrospective Analysis of Tumor Recurrence Following Irradiation of the Salvaged Blood

BACKGROUND

Orthotopic liver transplantation (OLT) is the treatment option for early-stage hepatocellular carcinoma (HCC). OLT is often associated with high blood loss, requiring blood transfusion. Retransfusion of autologous blood is a key part of blood conservation. There are, however, concerns that the retransfusion of salvaged blood might cause the spread of cancer cells and induce metastasis. Irradiation of salvaged blood before retransfusion eliminates viable cancer cells. Here, we analyzed the incidence of tumor recurrence in patients with HCC undergoing OLT who received irradiated cell-salvaged blood during transplant surgery.

METHODS

We retrospectively analyzed patients undergoing OLT for HCC between 2002 and 2018 at our center. We compared the tumour recurrence in patients who received no retransfusion of autologous blood with patients who received autologous blood with or without preceding irradiation of the blood.

RESULTS

Fifty-one (40 male, 11 female) patients were included in the analysis; 10 patients developed tumor recurrence within a time period of 2.45 ± 2.0 years. Statistical analysis revealed that there was no significant difference in tumor recurrence between patients who received autologous blood with or without irradiation.

CONCLUSION

Intraoperative transfusion of cell-salvaged blood did not increase tumor recurrence rates. Cell salvage should be used in liver transplantation of HCC patients as part of a blood conservation strategy. The effect of blood irradiation on tumor recurrence could not be definitively evaluated.

Human Leukocyte Antigen Class I Antibodies and Response to Platelet Transfusion in Patients Undergoing Liver Transplantation

BACKGROUND

Patients undergoing liver transplantation (LT) frequently receive platelet transfusion (PLT) to minimize their risk of hemorrhage. Alloimmunization to platelets may lead to refractoriness to PLT. Data on the implications of platelet alloimmunization in patients undergoing LT remain limited. We examined the effect of human leukocyte antigen class I (HLA-I) antibodies on PLT refractoriness and short-term outcomes after LT.

METHODS

Peritransplant clinical and PLT factors were reviewed for all adult liver or simultaneous liver-kidney transplantations from 2012 to 2017. Sensitized patients (SE) with pretransplant HLA-I calculated panel-reactive antibody ≥20% were compared with unsensitized patients (US) with calculated panel-reactive antibody <20%. The mean follow-up was 21.4 mo.

RESULTS

Alloimmunization was observed in 39% of the study cohort. SE (n = 28) received 272 PLTs, and US (n = 44) received 246 PLTs. History of pregnancy was higher among SE than US (P < 0.01); otherwise, both groups had similar clinical characteristics. SE had higher rates of PLT refractoriness (66% versus 47%; P < 0.01) than US. The mean platelet corrected count increment was lower among SE compared with US up to 100 min after PLT (P < 0.05). Alloimmunization and simultaneous liver-kidney transplantation independently predicted refractoriness on multivariate logistic regression (P < 0.05). Early allograft rejection and patient survival rates were comparable for both groups.

CONCLUSIONS

LT patients experienced high rates of HLA-I alloimmunization and PLT refractoriness. SE had higher rates of refractoriness and lower mean corrected count increment after transfusion compared with US. Our study suggests that further research to evaluate the utility of HLA-matched PLTs in HLA-I alloimmunized LT patients is warranted.

Red blood cell alloimmunization in transfused patients with bone marrow failure syndromes

BACKGROUND

Red blood cell (RBC) alloimmunization is a concern for patients who receive multiple or chronic transfusions. Alloimmunization prevalence in transfused patients with bone marrow failure syndrome (BMFS) is unknown. This study aimed to determine physician practice for RBC antigen matching, immunization rates, and antibody specificities in patients with BMFS.

STUDY DESIGN AND METHODS

The clinical records of all patients with BMFS seen at the Children's Hospital of Philadelphia between 2001 and 2015 were reviewed. Immunization rate was determined per 100 units transfused.

RESULTS

ABO/D, C, E, and K (CEK) RBC matching was requested for 21.8% of patients. A total of 3782 RBC units were transfused to 87 patients, of which 2551 (67.5%) were CEK matched and 1231 (32.5%) were ABO/D only matched. The majority of units transfused to patients on a chronic transfusion regimen were CEK matched (89.6% of 2728 units). No anti-C, -E, or -K antibodies formed in any patient during the 14-year study period. Two alloantibodies and two autoantibodies formed, resulting in a rate of 0.05 alloantibodies and 0.05 autoantibodies per 100 units transfused. The prevalence of alloimmunization was 2.3%.

CONCLUSION

The rate and prevalence of RBC alloimmunization were low in patients with BMFS. CEK matching avoided alloimmunization to these antigens in chronically transfused patients.

The Influence of Clinical and Biological Factors on Transfusion-Associated Non-ABO Antigen Alloimmunization: Responders, Hyper-Responders, and Non-Responders

In the context of transfusion medicine, alloimmunization most often refers to the development of antibodies to non-ABO red blood cell (RBC) antigens following pregnancy, transfusion, or transplantation. The development of RBC alloantibodies can have important clinical consequences, particularly in patients who require chronic transfusions. It has been suggested that alloimmunization is more common in some clinical circumstances and patient populations than in others. As such, individuals that develop alloantibodies are frequently referred to as 'responders' in the medical literature. In contrast, individuals that do not develop alloantibodies despite repeated exposures to non-self blood group antigens have been referred to as 'non-responders'. The purpose of this article is to review the phenomenon of RBC alloimmunization in the context of responders and non-responders to: i) establish a basic framework for alloimmunization as reported across several diverse patient populations; ii) more fully explore literature reports which support the concept of responders/non-responders regarding blood group antigen alloimmunization; iii) summarize the mechanisms that have been shown to predispose an individual to alloimmunization to determine how these factors may differentiate 'responders' from 'non-responders'; and iv) briefly discuss some practical approaches to prevent alloimmunization in patients who may be prone to alloantibody development.

Rituximab, plasma exchange and intravenous immunoglobulins as a new treatment strategy for severe HLA alloimmune platelet refractoriness

Platelet refractoriness (PR) due to HLA alloimmunization is a common and serious complication of patients receiving long-term packed red blood cell and platelet transfusions. Although most alloimmunized patients will respond to HLA-matched platelets, 20-50% of patients will remain refractory even to matched platelets. Several measures have been reported to overcome this complication, such as intravenous immunoglobulins (IVIG), plasma exchange (PE), protein A column therapy, or rituximab. We report a woman with acute myeloid leukemia secondary to myelodysplastic syndrome who was diagnosed with PR because of HLA alloimmunization. Due to difficulties in finding HLA-compatible platelet donors by cross-reactive groups in our panel of HLA-typed platelet donors, the patient received treatment with rituximab, PEs and IVIG. With this treatment strategy, the presence of HLA antibodies decreased from a panel-reactive antibody (PRA) of 89-0%. This allowed the performance of hematopoietic progenitor cell transplantation with random donor platelets. Rituximab, PE, and IVIG may be an option to overcome severe PR due to poly-specific HLA alloimmunization.

Intravenous hemostats: challenges in translation to patients

Excessive bleeding and the resulting complications are a leading killer of young people globally. There are many successful methods to halt bleeding in the extremities, including compression, tourniquets, and dressings. However, current treatments for internal hemorrhage (including from head or truncal injuries), termed non-compressible bleeding, are inadequate. For these non-compressible injuries, blood transfusions are the current treatment standard. However, they must be refrigerated, may potentially transfer disease, and are of limited supply. In addition, time is of the essence for halting hemorrhage, since more than a third of civilian deaths due to hemorrhage from trauma occur before the patient even reaches the hospital. As a result, particles that can cross-link activated platelets through the glycoprotein IIb/IIIa receptor expressed on activated platelets are being investigated as an alternative treatment for non-compressible bleeding. Ideally, these particles would interact specifically with platelets to stabilize the platelet plug. Initial designs used biologically derived microparticles with red blood cell fragment or albumin cores decorated with RGD or fibrinogen, which bind to GPIIb/IIIa. More recently there has been research into the use of fully synthetic nanoparticles with liposomal or polymer cores that crosslink platelets through a targeting peptide bound to the surface. Some of the challenges for the development of these particles include appropriate sizing to prevent blocking the capillaries of the lungs, immune system evasion to prevent strong reactions and increase circulation time, and storage and resuspension so that first responders can easily use the particles. In addition, the effectiveness of the variety of animal bleeding models in predicting outcomes must be examined before test results can be fully understood. Progress has been made in the development of particles to combat hemorrhage, but issues of immune sensitivity and storage must be resolved before these types of particles can be translated for human use.