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Francis S. Morrison MD was among the early developers and promoters of the American Society for Apheresis (ASFA). His work was pivotal in creating a lasting institutional structure from which American apheresis medical practice would develop decades after his death. Francis Morrison is honored each year at the ASFA annual meeting as ASFA awards the Francis S. Morrison MD Memorial Award Lecture to an individual who stands out as among its most accomplished members. This tribute seeks to describe the person and the key accomplishments of Francis S. Morrison in the historical context of a time when the future of apheresis medicine was uncertain., (© 2023 Wiley Periodicals LLC.)

Modern blood separators rapidly process many liters of donor blood and efficiently collect vast quantities of blood components from donors, who may be stimulated with potent recombinant hematopoietic growth factors or cytokines. Accordingly, the potential risks of modern multiple product/unit apheresis donations and recombinant growth factors is analyzed in this report. As is true for all medical procedures, risks are associated with apheresis donations. Risks of a "standard" apheresis donation, in which one unit of PLTs or plasma is collected, are comparable to the risks of whole blood donation. Risks of multiple unit apheresis donations, in which either vast quantities of a single blood component or multiple units of various components are collected, are incompletely understood, particularly, when donors are stimulated with recombinant hematopoietic growth factors to increase component yields. To minimize donor risks and to increase knowledge of multiple component apheresis donations, both short-term problems (e.g., donor reactions accompanying apheresis procedures and pre- vs. post-procedure changes in results of donor laboratory studies) and long-term problems (e.g., medical diagnoses/problems and abnormalities of donor blood counts and laboratory test results) should be monitored, ideally, by a repeat donor registry. When recombinant hematopoietic growth factors are prescribed, donors should give informed consent, and blood center professionals must be aware of 1) the effects of these drugs given at pharmacologic, rather than physiologic, doses; 2) the differences between the molecular structure of recombinant vs. natural/endogenous growth factors; 3) the fact that recombinant growth factors have both narrow/focused and broad biological activities; and 4) the probability that results of studies in sick/immunosuppressed patients may not be applicable to healthy/immunocompetent donors., (Copyright 2003 Wiley-Liss, Inc.)

A survey was completed by 25 medical directors at different institutions performing plateletpheresis. The practices of these 25 physicians were analyzed regarding the acceptance/rejection of plateletpheresis donors with a history of cardiac disease/surgery, seizures/epilepsy, cancer, or autoimmune diseases. Although available medical literature documents little risk of these disorders either to donors (i.e., donation reactions) or to transfusion recipients (i.e., disease transmission), up to 24% of medical directors outright reject some of these potential donors while others accept patients/donors with these illnesses, providing they meet certain medical/health criteria. Acceptance/rejection of individuals with medical disorders has relevance for the availability of the blood supply and blood product shortages because several million Americans, diagnosed with these illnesses, represent a sizable pool of potential blood and platelet donors., (Copyright 2002 Wiley-Liss, Inc.)

At one blood center, each of 20 donors underwent plateletpheresis on four blood cell separators in random order. We compared the CS3000+, Amicus V 2.41, MCS Plus, and Spectra LRS V 7 Turbo regarding platelet (PLT) yield, pre- and post-procedure PLT counts, percent fall in donor PLT count, process time, efficiency, PLT product and donor PLT volume (MPV). Using >or= 150 x 10(9) PLTs/L pre-donation counts, a goal was set of 4.5 x 10(11) PLTs unit in up to 100 minutes processing time. Results were (mean values) PLT yields of Amicus, Spectra, CS3000+, and MCS Plus: 4.3, 4.6, 4.3, 4.0 x 10(11) PLTS, respectively; percent donor PLT fall: 24, 32, 30, 29%, respectively; processing times: 50, 74, 87, 101 minutes, respectively; relative efficiency (RE): 2.2, 1.6, 1.2,1.0, respectively (based on the MCS Plus performance with RE of 1 = 4 x 10(9) PLTS/min); PLT product MPV: 6.7, 7.4, 6.8,7.1 fL, respectively; pre-procedure donor MPV: 7.7, 7.3, 7.6 and 7.6 fL, respectively; and percent donor MPV change: -5.2, 0, -6.6, and -10%, respectively. Significant changes in the donor MPV were noted (P < 0.05) but could not be related to product MPV. Spectra seemed to collect larger PLTs (higher MPV); the significance remains unknown for both donors and recipients. Importantly, all four separators gave acceptable and comparable PLT yields (P < 0.05) with Spectra trending higher. The short process time and high RE together indicate highly efficient collections particularly by Amicus and Spectra., (Copyright 2002 Wiley-Liss, Inc.)

Although widely used, the reliability of fingerstick platelet counts for determining donor eligibility and for use with plateletpheresis predict yield programs has not been established. We compared platelet counts obtained from fingerstick vs. venous samples in several aspects of apheresis platelet collection. Analysis of 25 paired fingerstick and venous predonation samples demonstrated a poor correlation between platelet counts (r2 = .43), with fingerstick counts having a 20% lower mean value (P < .05). The effect of using fingerstick vs. venous predonation platelet counts with apheresis instrument predict yield calculations to obtain target yields was determined. Mean yields collected using fingerstick/predict yield were 12% (Fenwal CS3000 PLUS) and 15% (Haemonetics MCS+) higher than venous/predict yield units (P < .05). The coefficients of variation (CV) of fingerstick/predict yield and venous/predict yield collections were comparable (15% vs. 14% [CS3000] and 23% vs. 21% [MCS+], respectively), indicating that possible differences in accuracy between fingerstick and venous platelet counts had little effect on the variability of predict yield collections. A retrospective analysis of the CV of 100 fingerstick/predict yield units vs. 100 units collected by processing standard volumes showed no difference: 22% vs. 20% (F = 0.99, CS3000), and 22% vs. 24% (F = 0.89, MCS+), respectively. We conclude that fingerstick platelet counts are systematically lower and correlate poorly with venous counts, though their use seldom results in false disqualification of donors. We also conclude that fingerstick count/predict yield collections do not produce more consistent yields of platelets than standard volume collections.

For over 20 years blood components have been collected from normal donors by automated hemapheresis. Cell separators have become increasingly sophisticated, and relatively pure component "concentrates" can be obtained quite safely. Cytapheresis donors are monitored carefully, and serious reactions are very rare. In contrast, therapeutic apheresis procedures may be technically demanding and frequently are performed on very sick patients. Large volumes of blood are rapidly removed from the patient, anticoagulated, and separated into components by the automated cell separator. The blood component containing the pathogenetic factor (e.g., plasma containing an antibody) is retained outside of the body, and the remaining components (e.g., red cells, white cells, and platelets) plus the replacement fluid are reinfused. Complications can occur in normal cytapheresis donors because of the technical challenges of the procedure (e.g., extracorporeal circuit to be filled, use of citrate anticoagulant, need for large bore intravascular access, and rapid blood flow rates). All of these factors apply also to therapeutic patients plus the additional requirement for replacement fluids, and the clinical features of the underlying illness for which each patient is being treated. Fortunately, even with therapeutic patients, most complications are of modest severity and are easily managed with only temporary slowing or interruption of the hemapheresis procedure.

Reducing leukocyte (WBC) contamination of platelet (PLT) concentrates diminishes some adverse effects associated with transfusions. To provide WBC-reduced PLTs, we initiated a program using bedside filtration. However, the inability to easily quantitate WBC removal and PLT loss at the bedside prompted us to perform filtration in the blood bank. To establish optimal methods, production of WBC-reduced PLTs using the CS-3000 PLUS was studied in three phases, during which technical modifications were made. During phase 1, prestorage WBC reduction was performed using the PALL LRF-10H filter, sterilely connected. WBC reduction was satisfactory, but PLT loss was excessive. During phase 2, the PLT-30 collection chamber and Fenwal Closed System Apheresis Kit with Integral Sepacell Leukocyte Reduction Filter were used. PLT yields were improved, but now WBC contamination was excessive. During phase 3, the interface offset was reduced from 10 to 6, and both PLT yields and WBC reduction were satisfactory. Using this final method (CS-3000 PLUS, PLT-30 collection chamber, integral filter and offset setting of 6), the mean PLT yield per unit is 4.29 x 10(11) (N = 1,146), and the mean WBC contamination is 0.50 x 10(6) (N = 32).

To halt bleeding in patients with severe thrombocytopenia due to bone marrow failure, it is desirable to achieve a post-transfusion blood platelet count of 40 x 10(9)/L by platelet transfusions. Based on calculations of corrected count increments, each 1 x 10(11) platelets transfused will increase the blood platelet count approximately 10 x 10(9)/L per each square meter of patient body surface area. Thus, the post-transfusion blood platelet count will be approximately 20 x 10(9)/L following transfusion of 3 x 10(11) platelets to a 5 foot, 8 inch patient weighing 170 pounds (2.0 m2), who is bleeding because of a pre-transfusion platelet count of 5 x 10(9)/L. The post-transfusion platelet count likely will be even lower in sick patients (sepsis, amphotericin B plus antibiotic therapy, splenomegaly, graft-vs.-host disease, etc.) or if platelets are lost from the unit by leukofiltration before transfusion. Although a dose of 3 x 10(11) platelets is acceptable, in a regulatory sense for product quality, it is inadequate to control bleeding in most thrombocytopenic adult patients. Adjusting dose for body size, bleeding patients with pre-transfusion blood platelet of < 10 x 10(9)/L and weighing > 120 pounds should receive approximately 6 x 10(11) platelets, those weighing 30 to 120 pounds should receive 3 x 10(11) platelets, and infants weighing < 30 pounds (15 kg) should receive 5-10 ml/kg of platelet concentrate.

Our practice is to defer donors with blood platelet (PLT) counts of < 180 x 10(9)/L because PLT yields are low, when compared to PLT units collected from donors with higher counts. In an attempt to minimize deferral, we determined whether 33 donors, who repeatedly demonstrated low-normal PLT counts (150-180 x 10(9)/L) on multiple occasions during the prestudy period. might safely donate satisfactory apheresis PLT units simply by extending the apheresis collection time by 20 min (men) and 40 min (women). Repeat plateletpheresis procedures were scheduled at > or = 28-day intervals. The mean PLT yield (N = 92) was 5.8 x 10(11) with 97% of units containing > or = 4.0 x 10(11) PLTs. Although donors entered the study only after they had repeatedly exhibited predonation PLT counts of < 180 x 10(9)/L, PLT counts were not always below this level at the time of study collections. However, analyzing only donations with true predonation PLT counts of < 180 x 10(9)/L (N = 35), the mean PLT yield was excellent-5.4 x 10(11) with 97% of units containing > or = 4.0 x 10(11) PLTs. The average fall in donor blood PLT counts (pre-vs. postdonation) was 36%, with only ten of 99 postdonation counts being < 100 x 10(9)/L; the lowest was 69 x 10(9)/L. Thus, extending the apheresis collection time permitted donors who in the past were routinely deferred because of low PLT counts to safely donate satisfactory PLT units.

The literature pertaining to the use of granulocyte transfusions as treatment for progressive bacterial, yeast, and fungal infections in severely neutropenic patients is reviewed. Efficacy in treating bacterial infections that are unresponsive to antimicrobial therapy is well established--especially if bone marrow failure does not recover rapidly and neutropenia is persistent. The role of therapeutic granulocyte transfusions for yeast and fungal infections has potential merit, but current data are incomplete and findings are inconsistent. The possibility of greater success has been raised by use of recombinant granulocyte colony stimulating factor to greatly increase the yield of neutrophils collected from normal donors.

All blood components collected by automated cytapheresis contain donor leukocytes. The possibility that repeated cytapheresis donation might lead to clinically important leukocyte losses and immunodeficiency has been a long-standing concern. Although convincing data do not exist to substantiate this concern, it is common practice to limit the number of annual cytapheresis donations per donor and to monitor donors for developing lymphocytopenia. Clinically significant immunodeficiency is unlikely to occur unless donors lose > 1 x 10(11) lymphocytes within a few weeks period of time or unless donor lymphocyte counts fall persistently to < 0.5 x 10(9)/L. Each plateletpheresis procedure, when performed using modern cell separators that are designed to produce a relatively "pure" platelet concentrate, leads to the loss of 1.0 x 10(6) to 5.0 x 10(7) leukocytes. Thus, automated plateletpheresis as performed in 1994 is extremely unlikely to cause clinically significant lymphocyte depletion and consequent immunodeficiency.

Preoperative autologous blood donation (PABD) is both under- and overused. Although the decision to order PABD lies with the surgeon, it is quite likely that other surgery clinic personnel influence patient acceptance and enrollment into PABD programs. Accordingly, we measured knowledge, attitudes, and the referral practice of clinic personnel pertaining to PABD. We administered a questionnaire to 102 nurses and 33 clerks working in surgery clinics at three university medical centers--one center in an area with a high incidence of AIDS and two centers in areas of low incidence of AIDS. Knowledge of PABD was poor when assessed by six questions. Only 6% each of nurses and clerks answered all questions correctly; 55% of nurses and 54% clerks missed three or more of the six questions. Surprisingly, no differences (P > .05) in knowledge deficits were noted when personnel from high and low AIDS areas were compared--indicating an overall need for education about PABD. In general, attitudes about PABD were positive, as most respondents (63%) gave favorable answers. Clinic personnel from the high AIDS area had even more favorable attitudes (P = .02). Because of these favorable attitudes, it seems likely that educational programs dealing with PABD would be readily accepted by clinic personnel. Greater knowledge should enhance the effectiveness of clinic staff in identifying, counseling, and referring eligible patients for this service.

Two patients were treated with photopheresis for marked cardiac allograft rejection with hemodynamic compromise that had become unresponsive to standard therapy. Multiple episodes of rejection had occurred, and initial response to standard therapy was favorable. However, progressive deterioration was documented by serial endomyocardial biopsies, fever, congestive heart failure, and abnormal cardiac catheterization findings. In the absence of retransplantation, death seemed imminent. Photopheresis was begun. Both patients received oral 8-methoxypsoralen and > or = 5 x 10(9) mononuclear cells were collected, treated with ultraviolet light A for 1.5 hours, and were reinfused. One procedure was performed weekly x4 and then monthly x5. Responses were striking with rapid loss of fever, improvement in exercise tolerance, normalization of cardiac hemodynamics, and improvement in endomyocardial biopsies. Although our experience with these two patients is anecdotal, photopheresis merits further study as treatment for severe cardiac allograft rejection.

We retrospectively analyzed our 2-year experience with venous access for 363 therapeutic plasma exchanges in 46 patients with neurological disease, including acute Guillain-Barré syndrome (N = 20), myasthenia gravis (N = 17), and chronic inflammatory demyelinating polyneuropathy (N = 9). Twenty-three patients (50%) completed the planned course of therapy using only peripheral venous access, and 28 central venous catheters were placed in the remaining 23 patients. Patients utilizing central venous access did not undergo a greater number of procedures, but they were more likely to have acute Guillain-Barré syndrome (P < 0.02) or to be hospitalized in a medical intensive care unit (P < 0.01). Three types of central catheters were used, and although our experience was predominantly with 1 type, differences were noted. Only 3% of procedures (3 of 96) done with a Quinton-Mahurkar catheter were associated with a catheter failure, compared to 27% (4 of 15, P < 0.01) with a Hickman catheter and 67% (2 of 3) with a triple-lumen catheter. Life-threatening complications occurred with 3 of 28 (11%) central catheters. To optimize the success of therapeutic plasma exchange using central access, it is critical that hemapheresis personnel advise each patient's primary physician regarding the type of central venous catheter required. Currently, we recommend use of a Quinton-Mahurkar or other dual-lumen hemodialysis catheter.

Donor exposure can be strikingly reduced for patients with classical hemophilia A and von Willebrand's disease when large volumes of potent cryoprecipitated AHF are prepared from donors following DDAVP (1-deamino-8-D-arginine vasopressin) stimulation and automated plasmapheresis--a procedure called "plasma exchange donation." Although this procedure has been reported to be relatively safe for donors, data are limited. Accordingly, we studied 20 donors during 48 procedures using DDAVP (0.3 micrograms/kg IV) followed by 2-3 L plasma collection. Replacement fluid for each initial plasma exchange donation was plasma protein fraction; autologous cryoprecipitate-poor plasma was used for subsequent procedures. Mild reactions, particularly facial flushing, were noted in all 48 procedures. No procedure was discontinued, but four were modified due to either an increased pulse rate (> or = 20/min from baseline) or a fall in systolic or diastolic blood pressure (> or = 20 mm Hg from baseline). No donor was deferred or withdrew from the program. Based on our modest experience, DDAVP stimulated plasma exchange donation appears to be a safe and effective method for collecting large quantities of plasma from which potent cryoprecipitated AHF can be prepared.

The face of automated hemapheresis in the United States is changing. No longer is it appropriate to view hemapheresis primarily in terms of therapeutic plasma exchange. For many centers, the bulk of day-to-day activities revolves around donor cytapheresis to satisfy the ever-increasing need for units of platelet concentrates. Indications of therapeutic plasma exchange are becoming better focused, with neurological patients being among those most frequently managed. New and innovative applications of automated hemapheresis technology will continue to be developed. Current examples include the production of lymphocyte-activated leukocytes for cancer therapy, use of extracorporeal photoactivation of leukocytes for immune modulation, and the collection of hematopoietic progenitors from peripheral blood for autologous transplantation. As we enter the 1990s, it is important to be aware of new technology and applications and to have the vision to apply them in innovative ways. However, it is also critical to demand rigorous scientific review before broadly adopting any new idea as a standard of practice.

Results of 3,214 plateletpheresis procedures, using the Fenwal CS-3000 cell separator, were reviewed to determine the effects on performance when the donor blood flow rate was increased by 30% (i.e., to 65 ml/min instead of 50 ml/min). Ninety-two percent (2,962 of 3,214) of procedures completed the rapid flow protocol, and results were compared with those reported by others using the more conventional blood flow rates of 32-55 ml/min. When the rapid flow procedure was used, mean platelet yields (4.07 x 10(11)) and leukocyte contamination (2.65 x 10(8)) were satisfactory, and major donor reactions were infrequent (0.6% of procedures). Thus, CS-3000 plateletpheresis can be performed at a relatively rapid, donor blood flow rate of 65 ml/min to shorten the procedure and make it more appealing to donors.

Hematopoietic stem cells, collected by leukapheresis from peripheral blood, can be used as an alternative to autologous bone marrow transplantation following high-dose chemotherapy as treatment of several malignancies. We compared the ability of the Cobe Spectra and the Fenwal CS3000 to collect peripheral blood mononuclear cells (MNC) for autologous peripheral blood stem cell transplantation. Ten patients experienced repeated leukapheresis (10 L blood processed per procedure) using both instruments. Procedures were alternated between the two until a total of 7 x 10(8) MNC/kg was collected. Data from 61 Spectra and 50 CS3000 collections were analyzed. The yield (mean per procedure) of nucleated cells (NC) and MNC was higher (P less than .005) with the Spectra (0.77 x 10(10) NC and 0.54 x 10(10) MNC) than with the CS3000 (0.59 x 10(10) NC and 0.40 x 10(10) MNC). However, colony forming units (CFU-GM) were not different (P greater than .05) for Spectra (0.92 x 10(4)) and Fenwal (0.65 x 10(4) collections. Platelet contamination was lower (P less than .001) with the Spectra (2.2 x 10(11)) than the CS3000 (5.0 x 10(11)). This correlated with a higher patient blood platelet count immediately following Spectra collections (117 x 10(9)/L) versus the CS3000 (86 x 10(9)/L). Using the methods described, the Spectra product contained greater yields of NC and MNC with less platelet contamination than did the CS3000.

Abstracts afford an opportunity to report data at professional meetings and, when published, in the literature. Accordingly, they should be prepared with great care. When writing an abstract, anticipate questions the reviewer will ask when judging it and provide complete answers. The presentation of an abstract should follow similar thought processes. State why a problem or question is important, how you addressed it, what you found, and how your findings can be applied to the issue at hand. Slides and text should provide coordinated visual and auditory input, respectively, to ensure complete comprehension.

Techniques for collecting granulocytes for transfusion either to neutropenic patients or to neonates are described. Currently, the best granulocyte concentrates are prepared using continuous-flow centrifugation leukapheresis of steroid-stimulated donors in the presence of pentastarch. Donor reactions are mild and are similar to those expected with automated plateletpheresis.

A blood sampling pack is available on closed system apheresis kits for the Fenwal CS3000 blood cell separator to facilitate same day donor testing while maintaining the closed system. Conceivably, the accuracy of complete blood counts (CBC) performed using pack samples might be compromised by clotting in the pack, by adherence of blood cells to the inner surface of the pack, or by dilution of the sample with priming fluid--should it inadvertently contaminate the pack. We studied paired blood samples collected simultaneously via the pack and a separate venipuncture in 17 donors. When collected properly, CBC values from pack and vein were nearly identical. Even when purposely contaminated with saline, pack values were lowered only slightly. Thus, the inline pack permits accurate sampling of donor blood for CBC while maintaining a closed system.

Modern techniques of mechanical hemapheresis have made it possible to selectively remove vast quantities of lymphocytes and plasma immunoglobulins, and the concentration of these substances in donor blood can fall below the normal range. It is feared that this may lead to immunosuppression; a condition associated in some clinical settings with infections, malignancy and autoimmune diseases. Using primary immunodeficiency diseases and induced immunodeficiency states (for example, therapeutic lymphocytapheresis, chronic thoracic duct drainage and intestinal lymphangiectasia) as models to judge competency of the immune system, it can be predicted that body defense mechanisms can become defective when serum IgG levels are less than 200 mg/dl or the blood lymphocyte count is less than 1000/microliter. However, impaired immunologic function can occur in the presence of normal quantities of these substances in the blood stream; conditions that may be related either to imbalances of immune regulatory factors or to qualitative (rather than quantitative) abnormalities of the immune system. A number of investigators have documented the losses of lymphocytes and plasma immunoglobulins incurred by donors experiencing mechanical hemapheresis. In addition, both the immediate and long-term decreases in the concentration of these substances in donor blood have been reported. In summary, the immediate decreases in blood lymphocyte counts and serum immunoglobulin concentrations are of slight to moderate degree and are without known adverse effects. Less information is available regarding long-term alterations of the immune system, and little data have been collected from prospective studies in which large numbers of donors have been thoroughly evaluated by modern techniques. In general, results of many laboratory studies have been altered. However, these abnormalities have been transient for the most part, and it has been difficult to document clinically significant adverse effects. Thus, the quantities of blood lymphocytes and plasma immunoglobulins that can be removed from healthy donors without causing significant immediate or long-term harm is unknown. Bearing these limitations in mind, the following recommendations are suggested regarding the frequency of repeated mechanical plasma-and-cytapheresis. 1) The usual requirements for whole blood donation must be met if the frequency of mechanical hemapheresis does not exceed once every eight weeks.(ABSTRACT TRUNCATED AT 400 WORDS)

Neonates are unusually susceptible to severe bacterial infections. Antibiotic therapy has been supplemented with granulocyte transfusions (GTX) to treat neonatal infections. The precise role of GTX to treat neonatal sepsis is controversial, and 11 reports (including six controlled studies) were critically analyzed. When all data are combined, 79% of 78 neonates receiving antibiotics plus GTX survived vs. 62% of 90 infants treated only with antibiotics. Among the six controlled trials, four found significantly better survival for neonates given GTX plus antibiotics. However, each of these trials can be criticized (few subjects, heterogeneous patients, defective design, inadequate granulocyte product, etc.). Although firm recommendations for GTX cannot be made currently, it seems reasonable to combine them with antibiotics to treat septic neonates that exhibit neutropenia for age and evidence of a diminished neutrophil marrow storage pool. Once the decision to transfuse is made, neonates should receive a minimum dose of 1 x 10(9) fresh neutrophils per kg per transfusion.

With the advent of sophisticated automated blood processors, the collection of large numbers of granulocytes for transfusion has been made more practical in the past ten years. Harvesting granulocytes by filtration leukapheresis has been abandoned in most centers because of adverse reactions in both donors and recipients. Currently, both continuous and discontinuous flow centrifugation leukapheresis techniques are available. However, both corticosteroids and hydroxyethyl starch are required for optimal granulocyte collection. In this paper, we critically compare the three major cell separators used for the collection of granulocytes by centrifugation leukapheresis. All three instruments separate blood cells by centrifugation; the IBM-2997 and the Fenwal CS-3000 function by continuous-flow centrifugation, and the Haemonetics Model 30 by discontinuous-flow centrifugation. Factors such as the donor preapheresis white blood cell count, the blood flow rate through the machine and the centrifuge speed effect granulocyte collection. Comparisons will be made of the cost of the software for each machine, the time required for granulocyte collection, the convenience of set-up and tear-down, the amount of skill and experience demanded of the operator. Donor factors will be discussed. Since the blood processor may be used for other procedures including plateletpheresis, therapeutic plasma exchange, lymphocytapheresis and erthrocytapheresis, the pros and cons of each machine as used for some of these procedures will be included in the discussion. In our experience, total leukocytes and granulocytes (neutrophils) collected with the three different instruments varied only slightly when unstimulated donors were studied.(ABSTRACT TRUNCATED AT 250 WORDS)