A Cross-matching Procedure for the Selection of Platelet Donors for Alloimmunized Patients

S ummary. A platelet cross-matching procedure has been assessed for selecting compatible donors for alloimmunized patients. This confirms the clinical value of combining an indirect platelet immunofluorescence test (PIFT) with a lymphocyto toxicity test (LCT) in predicting the survival of single-donor platelets. There was good agreement between the PIFT cross-match and post-transfusion platelet recovery. Compatibility in the LCT alone was insufficient for platelet donor selection, as this test did not detect all antibodies affecting platelet survival.
Positive LCT and PIFT cross-matches indicated the presence of HLA antibodies. Inclusion of an indirect lymphocyte immunofluorescence test (LIFT) helped to classify the platelet antibody when the LCT cross-match was negative. In such cases, parallel positive findings with the LIFT and PIFT suggested a cytotoxic-negative antibody of probable HLA specificity active against platelets. Disparity between the LIFT and PIFT was also observed; a strongly positive PIFT along with a weak reaction in the LIFT suggested that a platelet-specific antibody was responsible for the poor platelet survival in these cases. This study has also shown the presence in multitransfused patients of LIFT-positive antibodies not reacting in the LCT and PIFT, which do not affect the survival of transfused platelets.
A positive granulocyte cross-match was demonstrated in patients with febrile rigors associated with compatible platelet transfusions. Splenectomy and steroids may improve the survival of incompatible platelets depending on the nature of the platelet antibody.     

Immunologic Response of Patients With Acute Leukemia to Platelet Transfusions

Nine leukemic patients in aplasia receivedplatelet concentrates from random donorsover a period of 5 to 32 wk (an average of31 transfusions per patient). All nine developed lymphocytotoxic activity (presumably HL-A antibodies) in their serumagainst cells from a panel of 40 selecteddonors within 20-50 days after transfusions were begun. Lymphocytotoxic activity markedly diminished in the sera ofseven surviving patients over a period of8-24 wk despite continued occasionalplatelet transfusions. When lymphocytotoxic activity was present in the serum ofthese patients, survival of transfusedplatelets was significantly reduced. Sera inwhich lymphocytotoxic activity was detected released endogenous serotonin(26 ± 5% SEM) from washed humanplatelets (but not from dog or rabbit platelets) when incubated at 37°C for 30 min.In contrast, sera from these patients, obtained when lymphocytotoxic activity wasnot detected, released minimal amounts ofserotonin (6 ± 2%) and sera from ninehealthy subjects released none (0 ± 1%).The ability of serum to release serotoninwas abolished, and lymphocytotoxic activity was markedly diminished, after preincubation with allogeneic platelets.

Submitted on August 21, 1972 Revised on February 9, 1973 Accepted on February 16, 1973     

Use of 'Split' Plateletpheresis Products for Alloimmunized Patients

Single donor platelets obtained using the COBE Spectra were split into two halves and administered to alloimmunized patients with leukemia at two different points in time. The mean platelet yield was 6.83 times 10¹¹(n = 63) with 56% of collections having yields of >6.0times10¹¹(i.e. twice the current AABB recommendation for an apheresis platelet transfusion). In 58 instances, the two halves were administered to the same patient 24–96 h apart. The differences in the correct increments of the split transfusions administered 24–48 h apart were not statistically significant, although there were decreased increments after 72 and 96 h of storage. In 5 instances when the CCI for first transfusion was unacceptably low, the second half was successfully transfused to another patient. This study proves it is feasible to split apheresis platelets into two transfusions, and discusses approaches to optimally use this strategy for the transfusion support of alloimmunized patients.     

Use of HLA- and HPA - Matched Platelets in Alloimmunized Patients

Refractoriness for platelet transfusion is mostly due to clinical factors but may also be caused by alloimmunization. Use of leukocyte-depleted blood cells for transfusions of patients with hematological diseases has reduced if not eliminated HLA-alloimmunization. HLA-antibodies reduce the survival time of incompatible platelets complicating seriously the platelet transfusion support in at least 5% of patients. If consecutive transfusions of HLA matched platelets also fail without identifiable clinical causes, HPA-alloimmunization may have occurred. Platelets from donors phenotyped for both HLA and HPA may produce good platelet count increments and allow optimal treatment of the basic disease despite broad spectrum alloimmunization. Additional crossmatching of phenotyped platelets with patient serum may be needed to circumvent platelet-specific antibodies of unknown specificity.     

Intravenous Anti-D Gammaglobulin for the Prevention of Rhesus Isoimmunization Caused by Platelet Transfusions in Patients with Malignant Diseases

Previous studies of sensitization to RhD by RhD-positive platelet transfusions in RhD-negative cancer patients have shown different frequencies of alloimmunization (max. 19%). We studied 37 RhD-negative patients who received RhD-incompatible platelet transfusions and simultaneously anti-D-immune globulin. We provide evidence that in this setting RhD-prophylaxis is highly effective in preventing alloimmunization due to RhD antigen, since none of the patients studied developed anti-D. Detection of other red blood cell antibodies than anti-D proves the possibility of immunization in these patients. Prevention of isoimmunization in patients with malignant diseases is recommended especially in young females, since an increasing number of patients are having successful pregnancies, despite prior or even during cytotoxic therapy.     

Management of Fetal Alloimmune Thrombocytopenia by Weekly in utero Platelet Transfusions

Alloimmune neonatal thrombocytopenia (ANT) may cause intracranial haemorrhage in utero as well as at delivery. Recent management has concentrated on attempts to minimise fetal thrombocytopenia and prevent its complications. This report describes further experience with the use of repeated intravascular transfusions of compatible platelets in utero. The patient studied had already had one infant with intracranial haemorrhage due to ANT. In her next pregnancy, weekly intra-uterine platelet transfusions were given from 26 weeks, but intra-uterine death occurred at 30 weeks after the mother had a heavy fall. In her most recent pregnancy, weekly intravascular transfusions of platelets were given by cordocentesis from 29 to 34 weeks. The fetal platelet count was maintained above 30 X 10(9)/l for almost all of the last 6 weeks of pregnancy before delivery of a normal infant by Caesarean section at 35 weeks' gestation. This approach is effective in preventing severe fetal thrombocytopenia in the last trimester of pregnancy and is contrasted with alternative treatments of ANT. Further data are required to determine the efficacy and risks of these treatments.     

Platelet Transfusions: Shortened Survival of HL-A-Identical Platelets aud Failure of in vitro Detection of Anti-Platelet Antibodies after Multiple Transfusions

Abstract. In a case of congenital thrombasthenia the survival of transfused platelets was found to be extremely shortened. Although no isoimmune-antibodies could be detected by available immunologic techniques, such antibodies must be postulated as being responsible for the elimination of the donor platelets, since survival of the patient's own platelets is normal. The antibodies do not seem to be directed against an antigen of the HL-A type since the survival time of the thrombocytes from an HL-A-identical sibling is equally shortened.     

Adverse Reactions to Platelet Transfusions Are Reduced by Use of Platelet Concentrates Derived from Buffy Coat

We closely observed 86 transfusions to multitransfused hematologic patients with leukocyte-depleted platelet concentrates (PCs) prepared from buffy coats (BC PCs), filtered either prior to storage (BC1) or after 3–4 days' storage (BC3). The patients were first given, randomly, either BC1 or BC3, and were thereafter used as their own controls by giving them the two BC types alternately. The results were compared with an earlier study on standard platelet-rich plasma (PRP) PCs (46 transfusions to 23 patients) and leukocyte-depleted PRP PCs (23 transfusions to 12 patients). There was no difference in adverse reactions between BC1 and BC3 PCs, but BC PCs caused significantly fewer and milder adverse reactions than PRP PCs. Febrile reactions (FTR) occurred in 4.6%, urticarial skin reactions in 21%, and pulmonary reactions in 0% of BC PC transfusions (17, 29 and 0% of patients). The mean corrected increments (CI) at 16–18 h were higher after BC1 PCs than BC3 PCs (10.3 vs. 8.0, p = 0.046). We conclude that adverse reactions are reduced by use of BC PCs. Prestorage leukocyte depletion may improve platelet increments.     

Haemolytic Transfusion Reaction Due to ABO Incompatible Plasma in a Platelet Concentrate

A patient of blood type A₁ developed brisk, but transient haemolysis after receiving a platelet transfusion derived from 4 group 0 donors. Anti-A was detected on his red cells and in his plasma. 2 of the platelet donors were found to have very high titers (1:10240) of anti-A and positive haemolysin tests. Thus, a haemolytic reaction can result from transfusion of incompatible plasma in a platelet concentrate.     

Alloimmunization to RhD by Platelet Transfusions in Autologous Bone Marrow Transplant Recipients

Platelet transfusions from RhD-positive (D-positive) donors are often given to RhD-negative (D-negative) cancer patients. The low observed rate of alloimmunization has been attributed to disease and therapy-related immunosuppression. We have studied the occurrence of alloimmunization in 16 D-negative patients who did not have detectable anti-D prior to autologous bone marrow transplantation for malignant disease. All received D-positive platelets, but no other D-positive blood product. Three patients (19%) developed anti-D at 13, 24 and 83 days, respectively, after first receiving D-positive platelets, and after a total dose of 53, 65 and 119 D-positive platelet unit equivalents, respectively. Two of them also developed anti-C. The 13 patients in whom anti-D was not detected were also heavily transfused with D-positive platelets (mean +/- SD = 136 +/- 82 platelet unit equivalents). In 6 of them, the last recorded antibody screen was less than 3 months after the first D-positive platelets, and may not exclude a primary immune response. Thus, despite profound immunosuppression associated with autologous marrow transplantation, alloimmune responses to D-positive red cells in platelet concentrates can occur in some D-negative recipients.     

Beneficial Effect of Granulocyte Transfusions in Patients with Defects in Granulocyte Function and Severe Infections

A 3-year-old boy (patient A) with a congenital and a 24-year-old man (patient B) with an acquired granulocyte function defect received supportive granulocyte transfusions for the management of severe infections. The boy had suffered from recurrent infections since birth. His granulocytes showed in vitro almost no chemotactic responsiveness, an impaired phagocytosis and reduced intracellular killing of Candida albicans. Family studies suggested that it was an inherited autosomal recessive defect. The child developed a Pseudomonas pneumonia at the age of 3 years, which did not respond to antibiotic therapy. Granulocyte transfusions were then started and soon after the fever and pneumonia disappeared. Patient B showed the haematological signs of a preleukaemic state. He had 3 recurrent episodes of furunculosis which led each time to cellulitis and septic temperatures accompanied by symptoms of an enterocolitis. Tests of granulocyte function in vitro showed reduced intracellular killing of Staphylococcus aureus. Granulocyte transfusions were started, since no clinical improvement could be attained by antibiotics. With transfusion therapy, fever, cellulitis and enterocolitis disappeared each time.     

A Study of the Effect of AB0 Incompatible Plasma in Platelet Concentrates Transfused to Bone Marrow Transplant Recipients

Bone marrow transplant recipients at Huddinge Hospital have routinely received single-donor platelet concentrates (PC) from blood group O donors. These PC contain approximately 350 ml plasma, which is incompatible with patients of group A, B and AB. In 27 patients transplanted with an ABO-identical bone marrow, serological investigations have been performed every week after transplantation (median 6 weeks, range 3-14). Nine of 11 recipients with blood group A developed a positive direct antiglobulin test (DAT) after PC transfusions, while none of 15 patients of blood group O developed a positive DAT. Anti-A could be eluted in DAT-positive cases. In no case was there any clinical sign of hemolysis. Nor did recipients of groups A, B or AB (n = 34) require more red blood cells or PC transfusions compared to recipients of group O (n = 47).     

Platelet Antibodies in Thrombocytopenic Patients

Platelet antibodies either bound to the surface of platelets or free in the serum were sought in patients who had low platelet counts for a variety of reasons. They were detected by finding excess IgG on the surface of washed platelets either directly or after incubation of the serum with normal platelets. The technique used was a modification of that described recently (Dixon et al , 1975) in which the greater the amount of anti-IgG consumed by the reaction with platelets the less the subsequent lysis of sheep red cells coated with IgG. This test could be calibrated by adding known quantities of IgG to the antisera and thus the amount of bound IgG could be measured. Platelets from normal donors and those with thrombocytopenia due to non-immunological causes such as aplastic anaemia or acute leukaemia were found to have 15–70 ng IgG/10⁷ platelets (mean 53 ng). 37 out of 38 thrombocytopenic patients in whom immune destruction of platelets was suspected were found to have excess IgG on their platelets ranging from 70 to 720 ng/10⁷ (mean 297 ng, P < 0.001) and there was a significant inverse correlation between this amount and the platelet count ( r = 0.85, P < 0.001). Antibody in the serum was found in 14 of 22 patients with 'idiopathic'thrombocytopenic purpura (ITP), three of four patients with underlying lymphoma and in all five cases of systemic lupus erythematosus (SLE). Four non-thrombocytopenic patients with autoimmune haemolytic anaemia (AIHA) due to IgG on the red cells were also studied and were shown to have no increase in platelet-bound IgG. Our results confirm the work of Dixon et al (1975) that platelet antibody as excess IgG can be readily detected on the surface of platelets in patients with immune thrombocytopenia. The clinical implications of these findings are discussed.     

降压治疗对高血压患者血小板参数的影响

目的 探讨降压治疗对高血压患者血小板4项参数的影响.方法 采用全血细胞自动分析仪检测32位正常对照者与37名原发性1级高血压患者治疗3周前后血小板4项参数指标:血小板计数(PLT)、平均血小板体积(MPV)、血小板分布宽度(PDW)、血小板压积(PCT),统计分析其数据变化.结果 高血压时,血小板4项参数均有不同程度增高,而降压治疗能使上述4项指标降低[PLT:(治疗前201.8±72.9 vs治疗后187.1±68.6)109L-1(P＜0.05);MPV:(治疗前10.3±1.9 vs治疗后10.0±1.9)fL,PDW:(治疗前15.5±1.1 vs治疗后15.2±1.0)fL;PCT:(治疗前0.20±0.05 vs治疗后0.19±0.04)%](P＜0.05).结论 降压治疗能降低PLT、PCT,改善血压升高所致的前血栓状态.     

降压治疗对高血压患者血小板参数的影响

目的探讨降压治疗对高血压患者血小板4项参数的影响。方法采用全血细胞自动分析仪检测32位正常对照者与37名原发性1级高血压患者治疗3周前后血小板4项参数指标:血小板计数(PLT)、平均血小板体积(MPV)、血小板分布宽度(PDW)、血小板压积(PCT),统计分析其数据变化。结果高血压时,血小板4项参数均有不同程度增高,而降压治疗能使上述4项指标降低[PLT:(治疗前201·8±72·9vs治疗后187·1±68·6)109L-1(P<0·05);MPV:(治疗前10·3±1·9vs治疗后10·0±1·9)fL,PDW:(治疗前15·5±1·1vs治疗后15·2±1·0)fL;PCT:(治疗前0·20±0·05vs治疗后0·19±0·04)%](P<0·05)。结论降压治疗能降低PLT、PCT,改善血压升高所致的前血栓状态。     

Platelet Dysfunction in Vincristine Treated Patients

Recent revival of interest in the use of vincristine (VCR) for the treatment of idiopathic thrombocytopenic purpura prompted us to evaluate the platelet function of our patients on VCR. Eighteen patients with acute lymphoblastic leukaemia (ALL) in remission, and nine children with solid tumours were studied on 80 occasions at different time intervals after their last VCR dose. A mildly elevated threshold for epinephrine-induced second phase aggregation and a delay in the onset of collagen-induced aggregation was found in patients with ALL not on VCR. Vincristine induced unobtainable second phase aggregation to epinephrine in 67%, 38%, 30% and to ADP in 53%, 13%, 33% of the patients 1 week, 2-3 weeks and 4 weeks respectively after administration. The thrombocytopathy was relative, not absolute, since collagen induced aggregation at all times. Platelet counts, uptake and release of serotonin, bleeding times, clot retractions and release of platelet factor 3 were normal. Platelet adhesion was abnormal in five of 12 patients tested. In vitro platelets are a hundred-fold less sensitive to VCR than in vivo. Cyclic adenosine monophosphate, cyclic guanosine monophosphate and dimethylsulfoxide do not protect platelets from VCR. The exact mechanism by which VCR abolishes second phase aggregation in patients is uncertain. Because of VCR's narrow therapeutic index between thrombocytopenia and thrombocythaemia, the use of VCR should be reserved for life-threatening haematologic disorders when treating non-malignant conditions.