Major ABO-incompatible BMT: isohemagglutinin reduction with plasma exchange is safe and avoids graft manipulation.

The impact of donor-recipient ABO incompatibility on long-term BMT outcomes remains controversial. A common strategy is to deplete the donor marrow of red cells, although this variably reduces the number of CD34+ cells. This 10-year retrospective study assessed the impact of recipient plasma exchange in major ABO-incompatible allogeneic BMT on outcomes and survival. Target Ab titres were ≤ 1:4 for anti-A and ≤ 1:8 for anti-B. Patients with higher titres underwent plasma exchange before marrow infusion. Of 133 patients who underwent allogeneic BMT, 34 had a major ABO-incompatible donor. The median number of exchanges was 2 (range 1-4). There were no acute haemolytic transfusion reactions. Engraftment times, transfusion requirements and acute and chronic GVHD were no different from those of patients with an ABO-identical donor. Treatment-related mortality at 100 days was 21% in the group with a major ABO-incompatible donor and 17% in the group with an identical donor (P=0.8). Plasma exchange of the recipient is a safe method of managing donor-recipient major ABO incompatibility before BMT without the risk of haematopoietic progenitor cell loss associated with red cell depletion of the graft.

Age of blood in inventory at a large tertiary care hospital.

BACKGROUND AND OBJECTIVES: This major tertiary care centre transfers over 1000 red cell units monthly. Units are rotated as part of inventory management to ensure minimum wastage. In 1998, the expiration date of AS3 red cells was extended from 35 to 42 days, potentially affecting inventory. MATERIALS AND METHODS: The average age of the red cell units in inventory on any given day was evaluated to determine whether the extended expiration date would affect blood availability and to determine the feasibility of using blood at different ages for various purposes. Over a 6-month duration, 20 days were selected for review: units were categorized according to ABO group and Rh type and then analysed for age within certain categories. RESULTS: The average age of the blood in inventory was 1 to 2 weeks. The probability of having units less than 1-week old was highest for Group O and zero for Group B Rh(+) and Group AB Rh(+). More than 60% of the O Rh(-) blood was older than 28 days. CONCLUSION: The age of units in inventory varies with respect to ABO group, Rh type and weekday. In practice, the stock rarely reaches 42 days of age. Future studies on the effects of age of blood on patient outcome must consider the logistics of supply and the availability of blood of each group. Transfusion of large numbers of units of the same age and of a specific blood group and type may not always be possible.

A novel, automated method of temperature cycling to produce cryoprecipitate.

BACKGROUND: Cryoprecipitate continues to find wide application in transfusion practice. Current AABB standards call for a minimum of 80 units (U) of factor VIII and 150 mg of fibrinogen per bag of cryoprecipitate. However, individual cryoprecipitates can vary greatly in content, with as many as 20 different factors known to affect the yield. STUDY DESIGN AND METHODS: Plasma was processed in a new, rapid, automated device (CryoSeal, Thermogenesis) with computer-controlled temperature cycling to produce cryoprecipitate. RESULTS: In repeat runs (n = 20), the automated procedure yielded a product containing 184 mg of fibrinogen and 158 U of factor VIII in 55 minutes. Additional studies using plasma pools to compare the quality of the machine-generated products to those of traditionally prepared cryoprecipitate showed comparative recoveries of 182 and 187 mg of fibrinogen and 172.1 and 129.7 U of factor VIII and no significant difference in the levels of plasminogen, protein C, or protein S. CONCLUSION: The new system offers an automated method of cryoprecipitate production in which the steps involved in temperature cycling are initiated sequentially, producing within 1 hour a preparation that is equivalent to standard cryoprecipitate.