Efficacy of HPA-1a (PlA1)-negative platelets in a patient with post-transfusion purpura

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Posttransfusion purpura with antibodies against human platelet antigen-4a following checkpoint inhibitor therapy: a case report and review of the literature

BACKGROUND

Posttransfusion purpura (PTP) is a rare condition characterized by severe thrombocytopenia following receipt of blood products. Most reported PTP cases involve alloantibodies directed against human platelet antigen (HPA)-1a. We present a case of PTP-mediated severe thrombocytopenia associated with alloantibodies directed against HPA-4a in the setting of combination checkpoint inhibitor therapy.

CASE REPORT

A 62-year-old woman with rectal melanoma that progressed on combination checkpoint inhibitors (ipilimumab and nivolumab) was admitted for abdominoperineal resection. She received multiple blood products during surgery, and between the sixth and eighth days post-surgery her platelet (PLT) count decreased from 126 × 10⁹ /L to a nadir of 1 × 10⁹ /L. She received intravenous immunoglobulin (IVIG), steroids, and romiplostim with eventual recovery of her PLT count to 50 × 10⁹ /L 20 days after surgery. She tested positive for anti-HPA-4a and was shown not to express HPA-4a, confirming a diagnosis of PTP.

CONCLUSION

Alloantibodies strongly reactive to HPA-4a were detected in this patient who received multiple blood products during abdominoperineal resection surgery. Her thrombocytopenia improved with prompt administration of IVIG, steroids, and romiplostim. PTP must always be considered in patients with acute severe thrombocytopenia after receipt of blood products, and treatment should not be delayed while awaiting laboratory confirmation. To our knowledge, this is the second reported case of PTP with antibodies against HPA-4a.

Anti-αIIb β3 immunization in Glanzmann thrombasthenia: review of literature and treatment recommendations

Glanzmann thrombasthenia (GT) is caused by inherited defects of the α_IIb β₃ platelet glycoprotein. This bleeding disorder can be treated with platelet transfusion therapy, but some patients will be immunized and begin to form anti-human leucocyte antigen (HLA) and/or anti-α_IIb β₃ antibodies. These antibodies can bind and interfere with the function of the transfused platelets, rendering treatment ineffective. However, platelet transfusion refractoriness attributable to HLA antibodies may be managed by the selection of compatible donors, although they are not always readily available, particularly in an emergency. Thus, anti-α_IIb β₃ antibodies represent one of the most severe complications in GT. Both genetic and environmental factors may contribute to the risk of anti-α_IIb β₃ development, but the underlying pathogenic mechanisms are still unknown. This review will summarize the current knowledge of the risk factors for development of anti-α_IIb β₃ antibodies in patients with GT and discuss how these findings may influence the clinical management of patients.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Etiology and significance of thrombocytopenia in critically ill patients

Thrombocytopenia is common in critically ill patients and increases morbidity and mortality. A diagnosis of heparin-induced thrombocytopenia (HIT) is frequently considered in any ICU patient who develops thrombocytopenia in the context of ongoing heparin exposure. As the usual tests to diagnose HIT are often neither specific nor sensitive enough to be confirmatory, the intensivist must largely rely on clinical judgment in treatment decisions. Patients in the ICU may also develop thrombocytopenia resulting from non-HIT immune mechanisms, nonimmune platelet consumption, and from decreased platelet production due to preexisting disorders or as a result of their critical illness and/or drug therapy.

Guidelines on the use of therapeutic apheresis in clinical practice--evidence-based approach from the Apheresis Applications Committee of the American Society for Apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. Beginning with the 2007 ASFA Special Issue (fourth edition), the subcommittee has incorporated systematic review and evidence-based approach in the grading and categorization of indications. This Fifth ASFA Special Issue has further improved the process of using evidence-based medicine in the recommendations by refining the category definitions and by adding a grade of recommendation based on widely accepted GRADE system. The concept of a fact sheet was introduced in the Fourth edition and is only slightly modified in this current edition. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. The article consists of 59 fact sheets devoted to each disease entity currently categorized by the ASFA as category I through III. Category IV indications are also listed.

Guidelines on the use of therapeutic apheresis in clinical practice—Evidence-based approach from the apheresis applications committee of the American society for apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. This elaborate process had been undertaken every 7 years resulting in three prior publications in 1986, 1993, and 2000 of "The ASFA Special Issues." This article is the integral part of the Fourth ASFA Special Issue. The Fourth ASFA Special Issue is significantly modified in comparison to the previous editions. A new concept of a fact sheet has been introduced. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. A detailed description of the fact sheet is provided. The article consists of 53 fact sheets devoted to each disease entity currently categorized by the ASFA. Categories I, II, and III are defined as previously in the Third Special Issue. However, a few new therapeutic apheresis modalities, not yet approved in the United States or are currently in clinical trials, have been assigned category P (pending) by the ASFA Clinical Categories Subcommittee. The diseases assigned to category IV are discussed in a separate article in this issue.

A critical comparison of platelet preparation methods

PURPOSE OF REVIEW

Platelet concentrates may be prepared from whole blood or by plateletpheresis. Currently, the non-evidence-based preponderance of apheresis units in the United States and the 50: 50 ratio in Europe may not optimize the gifts of whole-blood donors or minimize healthcare costs. Post-storage pooled, whole-blood-derived platelets, on the other hand, do not provide the convenience of or an equivalent level of safety as apheresis platelets.

RECENT FINDINGS

Some data suggest that different methods of manufacture of whole-blood-derived platelets (platelet-rich plasma or buffy coat intermediate steps) result in differing degrees of platelet activation, which may impact on the quality of stored concentrates. Recent studies have observed superior radiolabel recovery and post-transfusion increments for platelets derived from apheresis compared with platelet-rich plasma whole-blood-derived platelets. A pre-storage pooling system for whole-blood-derived platelets has just been licensed in the USA, and may eventually combine the benefits of apheresis-derived and whole-blood-derived platelets. The advantages of the European method of manufacture of buffy coat whole-blood-derived platelet concentrate have convinced the Canadian Blood Services to abandon platelet-rich-plasma-derived concentrates.

SUMMARY

We present a literature-based review of the relative merits of apheresis-derived and whole-blood-derived platelets. Additional studies are needed in order to define the optimal proportion of the platelet supply from apheresis collections and the choice of whole-blood-derived production method for US blood providers.

Genotyping of human platelet antigens 1 to 6 and 15 by high-resolution amplicon melting and conventional hybridization probes

High-resolution melting techniques are a simple and cost-effective alternative to other closed-tube genotyping methods. Here, we genotyped human platelet antigens (HPAs) 1 to 6 and 15 by high-resolution melting methods that did not require labeled probes. Conventional melting analysis with hybridization probes (HybProbes) was also performed at each locus. HybProbe assays were performed individually, whereas amplicon melting (HPAs 1 to 5 and 16) and unlabeled probe (HPA 6) assays were duplexed when possible. At all loci for each method, both homozygous and heterozygous genotypes were easily identified. We analyzed 100 blinded clinical samples (33 amniotic fluid, 12 cultured amniocytes, and 55 blood samples) for all 7 single-nucleotide polymorphisms (SNPs) by each method. Genotype assignments could be made in 99.0% of the SNPs by high-resolution melting and in 98.7% of the SNPs with HybProbes with an overall genotype concordance of 98.8%. Errors included two sample misidentifications and six incorrect assignments that were all resolved by repeating the analysis. Advantages of high-resolution melting include rapid assay development and execution, no need for modified oligonucleotides, and similar accuracy in genotyping compared with other closed-tube melting methods.