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Background: Transfusion reactions to platelet concentrates prepared from buffy coats (BC-PCs) were reviewed to determine the effect of some variables of BC-PC preparation and storage: time of BC storage before BC-PC preparation (1-2 days); time of BC-PC storage before transfusion (1-5 days); no white cell reduction versus laboratory and bedside BC-PC white cell reduction., Study Design and Methods: A multiple linear logistic regression model was used by which the relative effect of one variable is expressed as the relative risk of transfusion reaction against a baseline level (1-day storage, no white cell reduction)., Results: During the 14 months of study, a total of 2707 BC-PC transfusions were given to 192 patients; 37 reactions (1.4%) were reported in 25 patients (13%). The transfusion reactions were febrile, nonhemolytic in 23 cases; allergic in 5; febrile and allergic in 2; and other in 7. The relative risk of transfusion reaction to BC-PCs prepared from BCs stored for 2 days was 1.98 times that to BC-PCs prepared from BCs stored for 1 day (p = 0.07). The relative risk of transfusion reaction of 5-day-old BC-PCs was 10.7 times that of 1-day-old BC-PCs (p = 0.001). The relative risk of transfusion reactions of BC-PCs white cell-reduced in the laboratory and at the bedside were 0.65 (p = 0.3) and 1.87 (p = 0.1) times, respectively, that of non-white cell-reduced BC-PCs., Conclusion: Time of storage seems to be an important variable associated with BC-PC transfusion reaction.

White cell (WBC) reduction, red cell (RBC) recovery, and filtration time were determined in 1-day-old standard and buffy coat-depleted RBCs filtered in the laboratory through six commercial filters for WBC reduction. Residual WBCs were counted with a Bürker chamber (BC), with a Nageotte chamber (NC), and by flow cytometry (FC). Results show that BC counts were 0 in several cases in which WBCs were detected with NC and FC, which indicated that the traditional BC method is too insensitive in use with currently available filters. Calibration curves performed by FC and with NC with samples containing known concentrations of WBCs from 1000 to 1 per microL showed that both FC and NC detected, on average, 67 percent of WBCs present in the samples (efficiency). However, the efficiency of FC showed small variability (61-70%) at different WBC levels, whereas the variability with NC was large (39-91%). This greater variability prevented the correction of NC counts by using a single factor and indicated difficulty in NC standardization. Therefore, because our main aim was to compare different filters rather than to define absolute levels of WBC contamination, uncorrected FC and NC counts were chosen to be reported. True WBC counts per unit should not exceed values that can be obtained by dividing uncorrected counts by the lowest efficiencies (61% for FC and 39% for NC). Uncorrected NC and FC counts were below 2 x 10(6) per unit in all units processed through three of the filters and below 5 x 10(6) per unit in all units processed through the other three.(ABSTRACT TRUNCATED AT 250 WORDS)

Procedure is described for purifying low-molecular-weight factors with antigen-aspecific properties from a dialysate of human leukocyte extract. It includes gel chromatography on Sephadex G-25 and G-15, ion-exchange chromatography, reversed-phase high-performance liquid chromatography (HPLC) on a C18 hydrophobic column and gel permeation HPLC. The immunosuppressive factor (mol.wt. 800-1000) was purified to near homogeneity. It is probably of peptidic nature, although it is pronase resistant. The enhancer factor (mol.wt. 300-600) is eluted from chromatographic columns together with a hypoxanthine-like substance. Nevertheless, the biological activity cannot be attributed to the purine derivative. Identification of this amplifier activity is still lacking.

The effectiveness of a new filter (RC100) for the preparation of white cell-depleted red cells (RBCs) at the bedside was evaluated in vitro and in vivo using three RBC products: standard RBC concentrate (CPDA units), RBCs suspended in saline-adenine-glucose-mannitol additive solution after the removal of plasma (SAGM units), and RBCs suspended in SAGM after the removal of plasma and buffy coat (SAGM-BC units). Median RBC recovery was at least 92 percent when 2 units were administered through one filter; median values for residual white cells and platelets were less than or equal to 20 x 10(6) and less than or equal to 2.5 x 10(9) per 2 units, respectively. The in vivo study was carried out in 80 multiply transfused patients with thalassemia, 35 of whom had experienced frequent nonhemolytic transfusion reactions when given standard or buffy coat-free RBCs. During the 6-month study, each patient was given two transfusions of each type of RBC product One febrile nonhemolytic transfusion reaction occurred in each of two patients receiving SAGM-BC units, but in no other case. If the flow rate is not reduced, the median transfusion time is 35 minutes per CPDA unit and 15 minutes per SAGM and SAGM-BC unit. It is concluded that the transfusion of RBCs through the RC100 is a simple and effective procedure to administer white cell-depleted RBCs prepared at the bedside.

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.

Comparison was made between platelet concentrates prepared from pools of buffy coats removed from standard blood donations and stored in a glucose-free, commercially available crystalloid solution (BC-PCs) and standard platelet concentrates prepared from platelet-rich plasma (PRP-PCs). Platelet yield in BC-PCs and PRP-PCs was 59 and 75 percent of donated platelets, respectively. The number of total white cells in 1 BC-PC unit, prepared from a pool of 7 buffy coats, was 21 x 10(6), i.e., 50 times lower than that of 7 units of PRP-PCs. The in vitro values of adequate platelet quality were maintained for 10 days in BC-PCs stored in 1000-mL polyolefin bags. Prolonged bleeding times were reduced or corrected in three of three thrombocytopenic leukemic patients evaluated before and after transfusion of stored BC-PCs. Pretransfusion and 1- and 24-hour posttransfusion median platelet counts in 57 leukemic recipients during 4 months of routine transfusion of BC-PCs (n = 93) were 14, 35, and 27 x 10(9) per L, while those of PRP-PCs (n = 246) were 13, 37, and 31 x 10(9) per L, respectively. No reactions to BC-PCs were reported, but a 1.3 percent rate of reaction to PRP-PC transfusions was reported. This study indicates that BC-PCs are a good alternative to PRP-PCs for platelet support of thrombocytopenic patients.

The effectiveness of red blood cells made leukocyte-free by filtration through cotton wool to prevent the production of antileukocyte antibodies was evaluated in children suffering from Cooley's anemia. Two studies were performed: study I was carried out prospectively in two groups of non transfused patients, one group treated with leukocyte-free filtered red cells, the other with buffy-coat-free packed red cell units. Different types of antileukocyte antibodies were looked for in both groups and the results were compared. In study II the behavior of pre-existing lymphocytotoxic antibodies found in the serum of children previously transfused with standard or buffy-coat-free packed red cell units was followed after the patients had been passed to a program of transfusion with leukocyte-free filtered red cells. Study I showed that none of the patients transfused with leukocyte-free filtered red cell units have produced antileukocyte antibodies, while these could be found in 2/3 of the patients transfused with buffy-coat-free packed red cell units. Study II showed that the repeated transfusion of leukocyte-free filtered red cells to patients who possessed in their serum preformed lymphocytotoxic antibodies did not cause any increase in the potency or spectrum of these antibodies, but was in fact accompanied in some cases by their decrease or disappearance. It is concluded that filtration through cotton is an easy and inexpensive means of preparing leukocyte-free red blood cells for transfusion capable of preventing (or reducing) the production of antileukocyte antibodies in multitransfused patients.