Pheresis with the IBM 2997

Reemphasis on leukocyte transfusions: induction of myeloid marrow recovery in critically ill neutropenic children with cancer

Neutropenia is the major factor predisposing to sepsis in cancer patients, and its duration is important for survival. We administered leukocyte transfusions (LT) to 10 children suffering from documented life-threatening infections during profound, prolonged neutropenia. Nine had acute leukemia, and one had aplastic anemia; three were bone marrow transplant recipients. These 10 were the only patients in our unit who received LT during the past 7 years. The median leukocyte dose was 0.6 x 10(9)/kg in total. Instead of leukapheresis products, we used pooled buffy coats from random donors, with a high relative content of lymphocytes and especially T lymphocytes. The leukocyte concentrates were irradiated with 15 Gy. In all 10 patients, we observed prompt and sustained myeloid marrow recovery following LT. Such an effect of LT has never been described before. We hypothesize that in the internal milieu of these aplastic patients the transfused leukocytes were stimulated to secrete cytokines, the result being a cascade-like phenomenon and stimulation and proliferation of the patient's own bone marrow cells. The bone marrow-stimulating effect of LT merits further study.

Velocities and stress levels of axisymmetric, azimuthal flow within the toroidal rotary seal of the IBM 2997 continuous flow cell separator and the implications

Continuous flow blood fraction separators are used to facilitate the removal of specific blood components for donation or for certain medical procedures. Problems with one such device, the IBM 2997 Blood Processor, have been noted in a number of independent investigations. A key feature of this particular unit is a ceramic rotary seal that allows the continuous separation by centrifugation to take place. The equation of motion for flow inside a split toroid cavity within the rotary seal has been solved numerically; velocities and shear stresses found numerically compare favorably with limiting case, analytical solutions. Predicted torque values as a function of rotation rate and fluid viscosity also served as an experimental check on the validity of the mathematical findings. Comparison of calculated shear stress levels and exposure times with known thresholds for cell damage shows that platelet and leukocyte losses may indeed be caused by the seal. Suggestions are made to improve performance of the IBM Blood Processor.

Platelet collection using the IBM 2997 cell separator

Platelets were collected using the dual-channel module on the IBM 2997 Blood Fraction Separator. We carried out 320 procedures to harvest platelets for therapeutic purposes and yielded 5.1 +/- 1.5 X 10(11) platelets (mean +/- SD). Infusion into previously unsensitized recipients with hypomegakaryocytic thrombocytopenia achieved increments at 1 hr of 19 +/- 7.3 X 10(9)/liter/m2 (mean +/- SD) and at 24 hr of 15 +/- 6.3 X 10(9)/liter/m2. The only consistent donor reaction was mild hypocalcaemia, easily corrected by calcium gluconate infusion. Changes in donor packed-cell volume and white cell count were not statistically altered (p greater than 0.05) but donor platelet counts fell from 216 +/- 43.1 X 10(9)/liter to 162.5 +2- 41.7 X 10(9)/liter (mean +/- SD) (p less than 0.01). Additional plateletphereses were carried out in seven normal volunteers, using the same technique, in order that the function of the harvested platelets could be studied. Following radiochromium labelling and reinfusion into the same donors, normal in vivo recoveries were obtained at 10 min (59.4 +/- 3.4%; mean +/- SD) and platelet mean life span was also normal (218 +/- 12 hr; mean +/- SD). Furthermore, in vitro platelet factor III availability and aggregation patterns of the harvested platelets did not differ from control values and their ultrastructural appearance was normal.

Preliminary Study on Plateletpheresis with the CS-3000 Blood Cell Separator Using a Single Phlebotomy Technique

A coaxial dual flow catheter has been tested for thrombapheresis with a continuous flow blood cell separator in order to render the procedure as comfortable as possible for our donors.

Therefore, two groups of five donors underwent a standard plateletpheresis: 3500 ml of blood were withdrawn at a speed of 35-45 ml per minute and were anticoagulated with ACD-A in a 1/9 ratio to whole blood.

In the first group one vein puncture was effectuated with the coaxial catheter after local anesthesia. Two 14G catheters were used in the second group. In both groups the platelet yield was studied as well as the half life of 111-Indium-oxinate labeled platelets after autologous transfusion.

Although the comfort of the donors was greatly improved, the one needle procedure resulted in a mean platelet yield of 1,28.1011 while the two needle procedure yielded 3,46.1011 platelets.

In contrast, the survival of the platelets after autologous transfusion did not differ significantly in the two groups: t 1/2 in group I was 3,94 d, in group II 3,66 d.

It is advocated that the poor efficacy of the single needle procedure might be due to recirculation.

Sustained post-transfusion granulocyte count increments following transfusion of leukocytes obtained from donors with chronic myelogenous leukemia

Leukocyte transfusions from patients with chronic myelogenous leukemia (CML) and elevated WBC counts were given to 14 patients with acute leukemia for the treatment of 16 infectious episodes. The WBCs were not irradiated to determine if engraftment with production of granulocytes would occur following infusion of immature myeloid elements. No recipient was alloimmunized by clinical and serologic criteria. High leukocyte yields were obtained using a variety of differential centrifugation techniques with a mean WBC yield/transfusion of 95 X 10(9) (range 19-275). A mean of 2.5 transfusions (range 1-11) were administered/recipient with a mean total dose of 235 X 10(9) WBC/transfusion episode (range 50-590). Seven patients had granulocyte counts greater than 500/microliters for four or more days (range 4-11 days) following the last transfusion. Ph1 chromosomes were documented in 2 of 4 patients tested 2-8 days following transfusion. Leukocyte alkaline phosphatase scores were increased (greater than 150) in 5/5 recipients tested post-transfusion demonstrating that production of this enzyme can be induced in CML granulocytes. Except for one severe transfusion reaction, there were no significant side effects and no recipient developed signs of graft versus host disease. All patients with sustained increments demonstrated rapid clinical improvement including 3 severely infected, poor risk patients undergoing initial induction therapy. These 3 patients all achieved complete remission with no evidence of the Ph1 chromosome. Because of the high dose of WBC which can be collected and the salutary effect of continued leukocyte production, CML WBC may be the preparation of choice for selected, non-alloimmunized, severely infected patients.

Adverse reactions to whole blood donation and plasmapheresis

Whole blood donation is recognized to be extremely safe, yet there have been reports of serious problems stemming from whole blood donation, and so-called "donor reactions" are regularly seen. While the physiologic causes of the common donor reactions are not completely understood, some effects of whole blood donation (such as transient iron deficiency) are understood but probably not significant. In order to avoid accepting any volunteer donor who might be at risk of a serious reaction, we may have been overly cautious in exclusion of potential donors. The pheresis donor is subjected to potential depletion of the protein or cellular elements being removed, problems caused by the device used for automated pheresis, or problems related to the infusion of potentially toxic substances. Documented benefit to the patient must balance these additional risks.