A meta-analysis of risk factors associated with platelet transfusion refractoriness

Virtual platelet cross-matching as transfusion management for patients with immune platelet refractoriness

BACKGROUND AND OBJECTIVES

This study describes the use of the Epvix platform for virtual cross-matching (VC) of human leucocyte antigen (HLA)-compatible platelets for patients with immune platelet refractoriness, and demonstrates effectiveness of the selected platelets.

MATERIALS AND METHODS

A prospective cohort of haematological patients was evaluated from 2018 to 2022. HLA-typed donor bank profile was previously uploaded to the Epvix platform. Each patient's antibody reactivity panel (PRA) was included in the platform. Then, search, selection and VC were performed, and 24-h-corrected count increment (CCI) platelet transfusion was calculated (reference ≥2500).

RESULTS

Six patients were included (four female, two male), with mean age of 61 years. HLA antibodies were detected as the cause of immunity for all patients, whereas four patients also had non-immune causes. High percentage of alloimmunization was detected in all studied patients (mean PRA: 85.7%). Thirty different donors were able to schedule and perform platelet donations. The mean 24-h CCI count was 9882. All platelet transfusions achieved a satisfactory CCI count except for two transfusion events. Presence of non-immune causes identified in these two cases could account for the unsatisfactory CCI.

CONCLUSION

Epvix is a free application hosted on the Web and uses the HLAMatchmaker algorithm to generate histocompatibility reports. This study demonstrates the efficiency of VC performed by Epvix. However, physical cross-matching will still be necessary in some instances, as the platform does not support human platelet antigen polymorphism.

Differentiating patient characteristics between platelet refractory patients with and without antibodies to human leukocyte antigens

BACKGROUND

Predicting whether a patient's platelet refractoriness (PR) is due to immune or nonimmune causes can be challenging. This study compared the demographics and clinical history of PR patients with human leukocyte antigen (HLA) antibodies (HLA-PR) versus PR patients without HLA antibodies.

MATERIALS AND METHODS

A retrospective review of all patients with PR consults at a single institution over a 3-year period was performed. Patient charts were reviewed for all patients with confirmed PR, and demographic information (e.g., sex, race and ethnicity, preferred language) and clinical history (e.g., pregnancy, transfusion, primary diagnosis) were collected. Patient characteristics were compared among the HLA and non-HLA cohorts.

RESULTS

A total of 295 patients with confirmed PR were identified, of whom approximately 70% did not have HLA antibodies and 30% did. Approximately 84% of the HLA-PR cohort was female. A history of transfusions was not associated with HLA-PR (p = .1). A history of pregnancy was strongly associated with the occurrence of HLA-PR (p < .001). Splenomegaly was associated with PR in the absence of HLA alloimmunization whereas infection, fever, bleeding, and disseminated intravascular coagulation were not.

CONCLUSION

In this single-institution retrospective review, a history of pregnancy was strongly associated with HLA-PR, whereas a history of transfusion was not.

Platelet transfusion refractoriness due to HLA alloimmunization: Evolving paradigms in mechanisms and management

Platelet transfusion refractoriness due to HLA alloimmunization presents a significant medical problem, particularly among multiply transfused patients with hematologic malignancies and those undergoing hematopoietic stem cell transplants. HLA compatible platelet transfusions also impose significant financial burden on these patients. Recently, several novel mechanisms have been described in the development of HLA alloimmunization and platelet transfusion refractoriness. We review the history of platelet transfusions and mechanisms of HLA-sensitization and transfusion refractoriness. We also summarize advances in the diagnosis and treatment of platelet transfusion refractoriness due to HLA alloimmunization.