Delores G. Cordle

Comparing alloimmunization in preterm infants after transfusion of fresh unmodified versus stored leukocyte-reduced red blood cells

PURPOSE To compare the occurrence of red blood cell (RBC), platelet (PLT), and white blood cell (WBC) antibodies in preterm infants after transfusions. METHODS A randomized, blinded trial was conducted in which preterm infants were transfused either with stored RBCs, prepared by prestorage leukocyte reduction and transfused throughout 42 days of storage to limit donor exposure (n = 18), or with fresh RBCs prepared without leukocyte reduction and transfused within 7 days after collection from as many donors as needed to guarantee freshness (n = 17). Nontransfused preterm infants of comparable birth weight were control subjects (n = 11). RESULTS No RBC antibodies were detected in serial blood samples taken during the first 6 months of life. Similarly, no definite WBC antibodies were found, although weak reactivity was detected transiently in sera from two infants. Accordingly, RBC and WBC antibody production did not differ among groups. In all, 11% of the transfused the infants exhibited platelet antibodies: 14% of the infants given stored leukocyte-reduced RBCs and 7% of the infants given fresh nonleukocyte-reduced RBCs (difference not statistically significant). CONCLUSIONS Preterm infants rarely produce antibodies to blood cell antigens after RBC transfusions, regardless of whether the exposure is to fresh unmodified RBCs from several donors or to stored leukocyte-reduced RBCs from a limited number of donors. Therefore, efforts to limit donor exposures or to remove WBCs from blood components cannot be justified simply for purposes of preventing alloimmunization in neonates.

Alloimmunization in preterm infants after repeated transfusions of WBC-reduced RBCs from the same donor

BACKGROUND: Preterm infants are among the most heavily transfused of patient groups, yet multiply transfused infants only rarely produce alloantibodies against RBC or WBC antigens. It is not known whether rates of alloimmunization might be increased by repeated exposure to RBCs and WBCs from the same donor, as in limited‐donor‐exposure programs, or whether infants might benefit from WBC‐reduced RBC components as a means of diminishing the risk of possible alloimmunization.

The Sterility of Platelet and Granulocyte Concentrates Collected by Discontinuous Flow Centrifugation

Platelet concentrates prepared by a discontinuous flow centrifugal technique (Haemonetics) were examined for evidence of bacterial contamination and subsequent growth from 3 to 11 days after collection. Of the 126 platelet concentrates examined, 4 revealed bacterial growth. However, the growth patterns indicated contamination during the microbiologic manipulations rather than contamination of the units during preparation. These studies indicate that platelet concentrates prepared using the Haemonetics Blood Processor can be safely transfused for up to three days after collection if stored at 4 to 6 C.

Biological Mothers May Be Dangerous Blood Donors for Their Neonates

Premature neonates require blood transfusions, and biological parents may wish to be directed donors. Biological mothers pose a potential danger because their plasma may contain antibodies that will react with blood cell antigens inherited by the infant from the father. We studied 25 healthy, pregnant women at the time of delivery for the presence of antibodies against red blood cell, leukocyte and platelet antigens. Mothers known to have red cell antibodies earlier in pregnancy were excluded, and no new red cell antibodies appeared at delivery. Antileukocyte and antiplatelet antibodies were found in 16 and 12% of mothers, respectively. Because these antibodies have the potential to cause adverse reactions when transfused passively, we suggest that either biological mothers not provide blood components containing plasma for their neonates or that maternal red cells and platelets be given as washed products.

Providing leukocyte-reduced platelets using the CS-3000 plus

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 × 1011 (N = 1,146), and the mean WBC contamination is 0.50 × 106 (N = 32).

A Hemolytic Reaction Implicating Sda Antibody Missed by Immediate Spin Crossmatch

Anti‐Sda, an antibody not usually considered to cause of hemolytic transfusion reactions, possibly was related to hemolysis following transfusion of red blood cells expressing strong Sda antigen. Prior to transfusion, the antiglobulin antibody screen performed in LISS and an immediate spin crossmatch were negative. Retrospectively, after hemolysis was detected, an antiglobulin crossmatch with red cells from the transfused unit revealed microscopic incompatibility. The transfused unit proved to have strong expression of Sda antigen —facilitating identification of a weak Sda antibody in our patient. In addition, this case represents an unusual instance in which an antibody screen plus an immediate spin crossmatch failed to detect an incompatibility that would have been apparent had an antiglobulin crossmatch been performed.

A Patient with Transient Autoanti – Jka

We report a patient with an erythrocyte autoantibody in whose serum a broadly reactive antibody was transiently replaced by a monospecific autoanti-Jka. On preoperation evaluation, a 49-year-old man, who had never been transfused, exhibited both a positive antibody screen and a positive direct antiglobulin test. Although a broadly reactive antibody had been present 2 years earlier, only anti-Jka was found in the serum on preoperative testing. In contrast, an acid eluate prepared from the patients red cells at the time was reactive with all cells from a 10-cell panel--a finding consistent with the broadly reactive autoantibody noted earlier. Repeat testing of a sample obtained 1 week later revealed only a broadly reactive autoantibody in both serum and eluate. This patient is notable in two respects. He exhibited a rare autoantibody, monospecific anti-Jka, and the specificity of the autoantibody changed from broadly reactive when first detected to anti-Jka and then back to broadly reactive. Thus, antibodies directed against specific antigens, in the setting of autoimmune hemolytic anemia, may be part of the autoimmune process and not always alloantibodies.