Random Platelets Research Articles

The Therapeutic Value of HPA-1a-Negative Platelet Transfusion in Post-Transfusion Purpura Complicated by Life-Threatening Haemorrhage

Post-transfusion purpura (PTP) was diagnosed in a female patient 1 week after transfusion for hysterectomy. Despite treatment with oral steroids and intravenous immunoglobulin, platelet counts remained low, and the patient developed profuse rectal bleeding. Random platelet transfusion is reported to be ineffective in PTP. We report a case in which the transfusion of HPA-1a negative platelets provided good increment and clinical haemostasis before intravenous immunoglobulin could have had an effect.

Neonatal Thrombocytopenia in HLA-DR, -DQ, -DP-Typed Mother due to Rare Anti-HPA-1b (PLA2) (Zwb) Fetomaternal Immunization

A new case of rare neonatal alloimmune thrombocytopenia, due to an IgG anti- HPA-1b in a mother HPA-1 (a+, b-), was diagnosed using monoclonal antibody- specific immobilization of platelet antigens. Clinically, it was similar to the 2 previously reported observations and confirmed that, in this particular case of anti-HPA-1b, the treatment with random platelet pools may be as effective as selected single-donor platelet units when maternal platelets are unusable. The HLA-DR, -DQ, -DP genotypes of the family were obtained by PCR-SSO. The mother’s typing, compared to the HLA-DR of the 6 similar cases reported in Europe, suggests that a combined effect of two rare HLA haplotypes might enhance this immunization.

Mechanical Properties and Fracture Toughness of α‐Al2O3‐Platelet‐Reinforced Y‐PSZ Composites at Room and High Temperatures

YPSZ/Al2O3‐platelet composites were fabricated by conventional and tape‐casting techniques followed by sintering and HIPing. The room‐temperature fracture toughness increased, from 4.9 MPa·m1/2 for YPSZ, to 7.9 MPa·m1/2 (by the ISB method) for 25 mol% Al2O3 platelets with aspect ratio = 12. The room‐temperature fiexural strength decreased 21% and 30% (from 935 MPa for YPSZ) for platelet contents of 25 vol% and 40 vol%, respectively. Al2O3 platelets improved the high‐temperature strength (by 110% over YPSZ with 25 vol% platelets at 800°C and by 40% with 40 vol% platelets at 1300°C) and fracture toughness (by 90% at 800°C and 61% at 1300°C with 40 vol% platelets). An amorphous phase at the Al2O3‐platelet/YPSZ interface limited mechanical property improvement at 1300°C. The influence of platelet alignment was examined by tape casting and laminating the composites. Platelet alignment improved the sintered density by >1%dth, high‐temperature strength by 11% at 800°C and 16% at 1300°C, and fracture toughness by 33% at 1300°C, over random platelet orientation.

Reactions to platelet transfusion: the effect of the storage time of the concentrate

Random platelet concentrates were pooled and depleted of leucocytes by centrifugation immediately prior to transfusion. The incidence and severity of reactions to 570 leucocyte-poor platelet transfusions in 74 patients were studied. An overall transfusion reaction rate of 13.7% was observed. The reaction rate to platelets stored for less than 3 days (8.7%) was significantly different from the reaction rate to platelets stored for 3 days or more (17.6%). Minor reactions as well as moderate and severe reactions were more frequent in the latter group. As most of the white blood cells were removed prior to transfusion, it is suggested that the reactions result from the transfusion of pyrogenic and/or vasoactive substances accumulated in the plasma of the concentrate during storage.

Transfusion Results of Filtered and Subsequently Stored Random Platelet Suspensions Prepared from Buffy Coats

There is almost general agreement that removal of leukocytes from blood components reduces the incidence of HLA-antibody formation and refractoriness to random platelet transfusions. Recently filters have become available, which are able to reduce leukocyte contamination in platelet suspensions with acceptable platelet loss. We evaluated a cellulose acetate (CA) and a polyester (PE) filter, and stored buffy coat-derived platelet suspensions after filtration. Both filters are effective for the removal of leukocytes to levels below 5 x 10(6) per transfusate. For the CA filter, platelet recovery was 73 +/- 13% yielding 256 +/- 53 x 10(9) platelets per transfusate from 6 donors. For the PE filter, platelet recovery was 90 +/- 9% and 327 +/- 51 x 10(9) platelets per transfusate. When a loading dose of less than 5 x 10(8) leukocytes was applied, 98% of the CA-filtered suspensions and 100% of the PE-filtered suspensions contained less than 5 x 10(6) residual leucocytes. In 123 patients transfusion results of CA-filtered platelet suspensions stored for 72 h, were compared with those obtained by non-stored, non filtered, random platelet suspensions which had been leukocyte depleted by differential centrifugation. Platelet increments 1 and 20 h after transfusion showed no statistical difference between CA-filtered platelet transfusions stored for 72 h and non-stored, non-filtered platelet transfusions. In a new cohort of 117 patients, two filters and various postfiltration storage times were compared. Using both filters, the 1-hour posttransfusion increments decreased to approximately 60% after 96 h of storage compared to results of storage periods of 72 h or less.(ABSTRACT TRUNCATED AT 250 WORDS)

Transfusion Results of Filtered and Subsequently Stored Random Platelet Suspensions Prepared from Buffy Coats

Transfusion Results of Filtered and Subsequently Stored Random Platelet Suspensions Prepared from Buffy Coats

Effective prophylaxis against platelet refractoriness in multitransfused patients by use of leukocyte-free blood components

Development of permanent platelet refractoriness is a major problem in multitransfused patients with diseases such as leukemia, aplastic anemia, or pediatric solid tumors. We tried to prevent alloimmunization in these patients by systematic use of leukocyte-free blood components with less than one million of contaminating leukocytes per unit of platelets or red cells. Our study group comprised 26 patients with a minimum of 10 platelet transfusions per patient. These patients were compared with a historical reference group of 21 patients who had received standard blood products. In the leukocyte-free group none developed platelet refractoriness, in contrast to the reference group where 11 of the 21 patients became refractory to random platelets. The median corrected platelet increment for random pooled platelets was significantly higher in the leukocyte-free group compared with the reference group. The increasing number of transfusions did not correlate with the development of platelet refractoriness; instead we propose that the lower limit of antigenic exposure is important. We conclude that systematic use of leukocyte-free blood components effectively prevents development of platelet refractoriness and contributes to optimal supportive care of children with cancer.

Effective Prophylaxis Against Platelet Refractoriness in Multitransfused Patients by Use of Leukocyte-Free Blood Components

Development of permanent platelet refractoriness is a major problem in multitransfused patients with diseases such as leukemia, aplastic anemia, or pediatric solid tumors. We tried to prevent alloimmunization in these patients by systematic use of leukocyte-free blood components with less than one million of contaminating leukocytes per unit of platelets or red cells. Our study group comprised 26 patients with a minimum of 10 platelet transfusions per patient. These patients were compared with a historical reference group of 21 patients who had received standard blood products. In the leukocyte-free group none developed platelet refractoriness, in contrast to the reference group where 11 of the 21 patients became refractory to random platelets. The median corrected platelet increment for random pooled platelets was significantly higher in the leukocyte-free group compared with the reference group. The increasing number of transfusions did not correlate with the development of platelet refractoriness; instead we propose that the lower limit of antigenic exposure is important. We conclude that systematic use of leukocyte-free blood components effectively prevents development of platelet refractoriness and contributes to optimal supportive care of children with cancer.

Factors influencing the transfusion response to HLA-selected apheresis donor platelets in patients refractory to random platelet concentrates.

Immune and nonimmune causes of platelet refractoriness were evaluated in a group of patients receiving HLA-selected single-donor platelet transfusions. During a 1-year observation period, 1 h and 24 h platelet recoveries wre determined after 522 single-donor platelet transfusions given to 43 patients persistently refractory to pooled random-donor platelet transfusions. 72% of patients tested ultimately developed lymphocytotoxic antibodies suggesting they were alloimmunized. When significant lymphocytotoxic antibodies were demonstrable in these patients, HLA well-matched platelet transfusions consistently produced good transfusion responses. In contrast, patients without lymphocytotoxic antibodies had clinical factors that adversely affected transfusion outcome (P less than 0.0001). Fever and splenomegaly markedly reduced 1 h post-transfusion platelet recoveries, while sepsis compromised the 24 h platelet recovery. Overall, the presence of any clinical factor was most likely to reduce 1 h platelet recovery, while donor-recipient HLA incompatibilities correlated best with poor 24 h post-transfusion platelet recovery. A platelet crossmatch test predicted the transfusion response when non-immune clinical factors were absent.

Preparation of leukocyte-poor platelets by filtration.

There is evidence that leukocyte contaminating red blood cells and platelet concentrates are responsible for refractoriness to platelet transfusions. The efficacy of a cotton-wool filter to remove leukocytes from red blood cells has been documented previously. The present study was designed to evaluate whether the cotton-wool filters can effectively remove leukocytes from platelet concentrates. Sixty pools of random-donor platelets and single-donor plateletpheresis products were filtered through a cotton-wool filter. The efficacy of filtration was determined by measuring the absolute numbers of leukocytes and platelets and subpopulations of mononuclear cells. The average platelet loss was 8% per pool of random platelets and 10% per plateletpheresis product. The average leukocyte removal was 99% from a pool of random platelets and plateletpheresis concentrates collected by CS-3000 and 90% from plateletpheresis concentrates harvested by single-stage COBE/IBM-2997. The filtration removed 100% of granulocytes, 95% of monocytes, 90% of B-lymphocytes, and 85% of T-lymphocytes. We conclude that filtration through a cotton-wool filter is an efficient and cost-effective method for preparation of leukocyte-poor platelets.

ＨＬＡ適合血小板輸注による抗ＨＬＡ抗体陽性血小板輸血無効例の長期管理

HLA-matched platelet concentrates, harvested from 4 family donors by plateletpheresis using the CS-3000 blood cell separator, were used in the treatment of three thrombocytopenic patients (two with aplastic anemia and one with relapse of acute myelogenous leukemia) who had become unresponsive to the transfusion of random platelet concentrastes due to HLA antibodies. During more than 2 years, 89, 98 and 151 procedures of HLA-matched platelet transfusions were performed, respectively. Mean 20-hour posttransfusion platelet recovery of HLA-matched platelet transfusions were 44%, 51% and 57%, respectively. In all patients, hemorrhagic diathesis such as gastrointestinal hemorrhage, nasal bleeding and genital bleeding were improved and no serious hemorrhage was occurred. During 23 months, donations of platelet concentrates were performed weekly on 2 family donors and two weekly on the other 2 family donors. No significant change in any donors was noted in counts of blood cells, differential leukocyte counts, lymphocyte subpopulations, serum total protein, serum albumin levels, serum immunoglobulin levels and serum complement levels.

血小板同種抗体の検索と適合血小板輸血症例の臨床的検討

Three methods (lymphocyte cytotoxicity test: LCT, anti-human immunoglobulin lymphocyte cytotoxicity test: AHG-LCT, mixed passive haemagglutination test: MPHA) were used in detecting platelet alloantibodies in the sera of 89 patients received multiple platelet transfusions and employed the same three cross-match techniques to select compatible platelet donors for 13 patients (5 aplastic anemia, 6 acute leukemia, 2 chronic leukemia) who had become refractory to random platelet transfusion. In the sera of 89 patients, the frequency of positive sera by LCT, AHG-LCT and MPHA were each 42.7%, 55.1% and 36.0%. And 13 refractory patients received 116 platelet transfusions from HLA matched single donors. Of 116 transfusions, 9 incompatible by AHG-LCT cross-match alone had no increase of platelet count. The 24 hour-posttransfusion platelet increment more than 20000/mm3 was 76 (71.0%) in 107 compatible cross-match transfusions and 0 in 9 incompatible transfusions. The more HLA was matched, the more platelet count increased.

Evaluation of apheresis platelet concentrates stored for 5 days in PL 732 bags

To assess the functional viability of platelets collected by standard apheresis techniques using the Fenwal CS-3000 "closed system" and stored in Fenwal PL 732 plastic bags for 5 days at room temperature with agitation, a number of in vitro parameters (pH, morphology, platelet volume distribution, osmotic recovery, aggregation, and platelet-associated IgG) were examined as a function of storage time. During the first 24 hours of storage, minimal changes were observed in the test parameters with the exception of ADP-induced aggregation (75% decrease [10 uM], 84% decrease [5 microM]). Significant differences were observed between fresh (day 0) and 5-day-old platelet concentrates in all parameters except median platelet volume. These observed changes in in vitro test parameters with storage time are similar to those previously observed for comparably stored random single-donor platelet concentrates. Thus, the "closed-system" PL 732 apheresis platelet concentrates would be expected to be as effective in vivo as random single-donor platelet concentrates, while minimizing recipient exposure to transmissible agents of infectious disease.

β‐トロンボグロブリン放出テストによる抗血小板抗体の検出法について

β-thromboglobulin (β-TG) release test was developed to detect heterologous anti-human platelet antibody (hetero-antibody) derived from rabbits and alloantibody obtained from multi-transfused patients refractory to random platelets. The highest dilution of hetero-antibody that gave a positive result was found to be 1:512 in the PSIFT. At a 1:32 dilution, β-TG release and 14C-5-HT release from PRP were 1, 292ng/ml and 31%, respectively. At a 1:512 dilution, β-TG release and 14C-5-HT release were 172ng/ml and 4.8%. With higher concentration of antibody, LDH in plasma was 128IU/L. It seems likely that β-TG release induced by higher concentrations of hetero-antibody was mediated in part by platelet lysis, as judged by LDH loss. The plasma from patients with alloantibody detected using PSIFT caused more significantly β-TG release (308±63ng/ml, N:14) than control plasma (38±12ng/ml, N:6). The results have suggested that β-TG release test is a reliable and sensitive marker for detecting platelet antibody.

抗ＨＬＡ抗体陽性の血小板輸血無効例に対する免疫グロブリン大量療法

High-dose intravenous immunoglobulin was given to eight patients who were refractory to platelet transfusions from random donors because of anti-HLA antibodies. They received intravenous infusions of polyvalent immunoglobulin (0.4g/kg/day for 5 days) just before random platelet transfusions. Two patients had an improvement in 20 hours post-transfusion platelet count increments and one patient had an improvement only in one hour post-transfusion platelet count increments. Five patients, however, had no improvement in one hour post-transfusion platelet count increments. After this therapy, titers of HLA-antibodies increased in three, unchanged in three and diminished in one patient. There was no relationship between post-transfusion platelet count increments and changes of titers of HLA antibodies.Random donor platelet concentrates or LCT-positive single donor platelet concentrates were incubated in vitro with polyvalent immunoglobulin at a final concentration of 3g/dl for 60 minutes at room temperature. Then those platelets were transfused to 4 patients. Following transfusion, one patient who had failed to respond to intravenous immunoglobulin therapy described above, had an increment at 20 hours. Three patients had no increment at one hour following transfusion.Nevertheless, on account of its cost, the exact place of this procedure in the management of such patients should be further documented with a prospecitve study.

The effects of splenectomy on engraftment and platelet transfusion requirements in patients with chronic myelogenous leukemia undergoing marrow transplantation.

Granulocyte and platelet recovery as well as platelet transfusion requirements following allogeneic marrow transplantation were analyzed in 67 patients with chronic myelogenous leukemia in the chronic phase. Twenty patients had splenectomy prior to transplantation. Forty-seven patients were transplanted without splenectomy, 21 of whom had splenic enlargement by physical examination. There were no differences in the proportion of patients with granulocyte recovery, but the recovery of peripheral granulocytes to levels of 200, 500 and 1,000/mm3 occurred more rapidly in the splenectomy group than in the no-splenectomy group. Patients with splenectomy received platelet transfusions for a mean of 10 (2-36) days as compared to 20 (3-82) days for patients without splenectomy (p less than .001). Eighteen (90%) patients with splenectomy became platelet transfusion independent at a median of 16 (2-32) days after transplantation as compared to 40 (85%) patients without splenectomy who became transfusion independent at a median of 28 (15-86) days (p less than .001). The proportion of patients achieving platelet levels of 50 and 100 X 10(3)/mm3 did not differ between the two groups (p = .07), but patients in the splenectomy group achieved these levels more rapidly following transplant (p less than .001). One of 17 evaluable patients in the splenectomy group and 31 of 46 in the no-splenectomy group became refractory to random platelets (p less than .001) and required platelets from family members or unrelated completely or partially HLA matched donors. In the no-splenectomy group, splenic size did not affect the speed of granulocyte or platelet recovery or platelet transfusion requirements.(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed alloimmunization using random single donor platelet transfusions: a prospective study in thrombocytopenic patients with acute leukemia

A randomized study was performed in 54 thrombocytopenic patients with acute leukemia. Alloimmunization of recipients of random multiple-donor platelet concentrates (MD group) was compared to that of patients receiving random single-donor platelets (SD group). In the SD patients, formation of alloantibodies (mostly anti-HLA) occurred less frequently (p less than 0.002), after a longer time period (p less than 0.002), and after a higher number of transfusions (p less than 0.005) as compared to MD patients. SD patients also became refractory to random platelets less frequently (p less than 0.005), after a longer time period, and after a higher number of transfusions (p less than 0.02). In SD patients, the increments after the first and the last transfusion were in the same range, whereas in MD patients, the 1-hr (p less than 0.001) and the 24-hr (p less than 0.025) increments decreased from the first to the last transfusion. Thus, the use of random SD platelet transfusions postponed alloimmunization.

Delayed Alloimmunization Using Random Single Donor Platelet Transfusions: A Prospective Study in Thrombocytopenic Patients With Acute Leukemia

AbstractA randomized study was performed in 54 thrombocytopenic patients with acute leukemia. Alloimmunization of recipients of random multiple-donor platelet concentrates (MD group) was compared to that of patients receiving random single-donor platelets (SD group). In the SD patients, formation of alloantibodies (mostly anti-HLA) occurred less frequently (p < 0.002), after a longer time period (p < 0.002), and after a higher number of transfusions (p < 0.005) as compared to MD patients. SD patients also became refractory to random platelets less frequently (p < 0.005), after a longer time period, and after a higher number of transfusions (p < 0.02). In SD patients, the increments after the first and the last transfusion were in the same range, whereas in MD patients, the 1-hr (p < 0.001) and the 24-hr (p < 0.025) increments decreased from the first to the last transfusion. Thus, the use of random SD platelet transfusions postponed alloimmunization.

Preparation of leukocyte-free platelets for transfusion by filtration through cotton wool.

Filtration through Imugard filters of random platelet concentrates or platelets obtained by plateletpheresis allow the preparation of leukocyte-free platelets for transfusion. The procedure is simple and determines only a small platelet loss (less than 10%). Filtered platelets seem to function normally in vivo. The use of leukocyte-free red cell and platelet transfusions for the support of patients suffering from leukemia or aplastic anemia could prevent major complications, such as refractoriness to platelet transfusion and to bone marrow transplantation.

Preparation of Leukocyte-Free Platelets for Transfusion by Filtration through Cotton Wool

Filtration through Imugard filters of random platelet concentrates or platelets obtained by plateletpheresis allow the preparation of leukocyte-free platelets for transfusion. The procedure is simple and determines only a small platelet loss (less than 10%). Filtered platelets seem to function normally in vivo. The use of leukocyte-free red cell and platelet transfusions for the support of patients suffering from leukemia or aplastic anemia could prevent major complications, such as refractoriness to platelet transfusion and to bone marrow transplantation.