Clinical significance of the anti-complement component of antiglobulin antisera

The need for anti-complement (anti-C') activity in antiglobulin antisera (AHG) for the detection of clinically significant antibodies was evaluated during a three-year period. While performing routine compatibility testing using standard blood banking procedures, eight patients were found whose antibodies were detectable primarily or only by AHG containing anti-C' activity; monospecific anti-igG AHG gave weak or negative reactions. Seven of the antibodies were anti-jka or jkb. Two of the anti-jka antibodies were responsible for clinically unsuspected delayed hemolytic transfusion reactions. The anti-jkb antibody resulted in a shortened survival of incompatible 51Cr-labelled red blood cells. The incidence of such "complement-only" Kidd antibodies was 23 percent of all Kidd antibodies found. These data suggest that the omission of anti-C' in AHG in routine compatability testing could result in substantial risk of failure to detect clinically significant antibodies.

"Pseudo-hemolytic" transfusion reaction caused by intravenous iron-dextran therapy

Intravenous iron-dextran therapy can cause a red-brown discoloration of the plasma, simulating a hemolytic transfusion reaction. A rapid and simple test to differentiate between true hemolysis and plasma discoloration due to circulating iron-dextran complexes is described.

Automation of cross-matching and red cell antibody screening

This automatic system combines the major cross-match with screening for allo- and autoantibodies. Moreover, the detected antibodies can be identified on a panel of frozen and thawed red blood cells (RBC). The system is made up of two connected samplers, three channels working, respectively, with bromelin PVP, LISP and saline PVP at 4 degrees C, three colorimeters or three red cell autocounters and their recorders. The optimal speed is 50 samples/h and one whole test requires 19 min. Our experience indicates that this automatic system is appreciably more sensitive and much more rapid and efficient than manual techniques. In spite of increased sensitivity, the ratio of rejected bags does not exceed 2.7%.

Incompatible crossmatch following nonreactive antibody detection test. Frequency and cause

In order to determine the frequency and cause of an incompatible crossmatch found in specimens for which the antibody detection test was nonreactive, 261, 136 crossmatches performed on 116,278 patient samples from approximately 46,000 different patients were reviewed. One-hundred and one patients were identified whose sera were incompatible in at least one crossmatch following a nonreactive antibody detection test. The cause of the incompatibility was determined in 69 of these. Incompatibility was detected only after 37 degrees C incubation and/or after the antiglobulin phase in 36 (52%). Incompatibility was detected after an immediate-spin and/or incubation at room temperature in 33 (48%). Serologic evaluation did not identify the cause of the incompatibility in 16 of the 101 patients. In eight of these 16 the incompatibility was noted only after 37 degrees C incubation and/or after the antiglobulin phase. Detailed serologic evaluation was not performed on 16 of the 101 patients (all of whose sera were incompatible with only 1 donor unit). In 12 of these 16, the incompatibility was detected only after the antiglobulin phase.

Role of the crossmatch in testing for serologic incompatibility

Nine unexpected antibodies of unquestioned clinical significance were detected when the major crossmatch was performed on 31,320 pretransfusion blood samples from 8969 patients whose screening test for unexpected antibodies was nonreactive. Three of the antibodies retrospectively were found to manifest a positive screening test. Another antibody was not detected by the antibody screening test due to an error in preparation of the screening red blood cells. The overriding importance of the major crossmatch is the assurance of ABO compatibility between donor blood and recipient. Therefore, while this study does not resolve whether the antiglobulin phase of the procedure might be considered optional, the major crossmatch should not be eliminated.

51Chromium survival of Yt(a+) red cells as a determinant of the in vivo significance of anti-Yta

A case is presented in which anti-Yta produced a moderately accelerated removal of chromium-labeled Yt(a+) red blood cells (T1/2, 96 hours). Other reported examples of anti-Yta either have rapidly removed transfused Yt(a+) red blood cells or have permitted apparently normal survival of these cells. In light of this wide variation in in vivo potency of anti-Yta, it is recommended that chromium red blood cell survival studies be done before transfusion of Yt(a+) red blood cells in sensitized individuals.

Monocyte-mediated erythrocyte destruction. A comparative study of current methods

Three assay systems-EAIgG rosette formation, 51Cr release, and erythrophagocytosis-were used to quantitate interaction between antibody-coated human erythrocytes and normal blood monocytes. The three methods were compared in terms of time requirements and sensitivity. Erythrophagocytosis required more time to perform (2 hours) than did rosette tests (30 minutes) but less than minimum 51Cr release assays (5.5 hours). Erythrophagocytosis was 20-fold more sensitive than either of the other two procedures. Results obtained with purified IgG anti-D and with antibodies induced by transfusion or pregnancy were similar.

Hemolytic transfusion reaction due to anti-Kell undetectable in low-ionic-strength solutions

Low-ionic-strength solution (LISS) reagents and methodologies have become popular in recent years in hospital transfusion service laboratories for alloantibody detection and compatibility testing of blood recipients. It has been the experience with all other hemagglutination technics that some examples of alloantibodies unpredictably fail to react. Such is the case with this patient's alloantibody with respect to LISS. The patient had a significant hemolytic transfusion reaction due to Kell incompatibility of one unit of packed human erythrocytes. Using various LISS reagents and methodologies, the anti-Kell was undetectable in pretransfusion and posttransfusion samples through the fifth day. The anti-Kell was of immunoglobulin class IgG, and it was detected in saline solution or albumin at room temperature, at 37 C and by the antiglobulin technic.

[Hydrops fetalis caused by isoimmunization against Kell factor (author's transl)]

The article reports on a case of hydrops fetalis caused by Kell antibodies, antibody formation having been triggered by pregnancy. Since the relative frequency of Kell (and rhesus sub-group) intolerance is increasing due to the successes achieved by anti-D-immunoglobulin prophylaxis, the question arises, on account of the possibly severe course of the disease, whether the Kell factor should be taken into consideration in all blood transfusions in girls during their childhood and in women of childbearing age.

[Diagnosis of transfusion reactions]

The diagnosis of the haemolytic transfusion reaction in the immunhaematological and clinical-chemical laboratory is described. The origin of haemolysis and disseminated intravascular coagulation and the possibilities to diagnose these disorders are pointed out.

Changes in amniotic fluid optical density at 450 millimicron in Rh-sensitized patients after maternal hydrocortisone treatment

In anticipation of elective premature delivery (32 to 34 weeks of gestation), five Rh-sensitized pregnant women were given hydrocortisone succinate for enhancement of fetal lung maturation. Serial amniocenteses were performed and an abrupt drop in the optical density at 450 millimicron (OD450) was observed in all cases immediately after administration of the steroid. Two infants in whom the OD450 remained low were followed safely to term. The others were delivered prematurely. All infants were Rh-sensitized and required one or more exchange transfusions, and all survived. It is tempting to speculate that glucocorticoids alter the antigen-antibody affinity and inhibit splenic macrophage sequestration, thus reducing erythrocyte destruction. Maternal steroid administration may prove to be therapeutic in the management of Rh-sensitization, but until its mechanisms are further delineated, extreme caution must be used in the interpretation of OD450 changes.

Delayed hemolytic transfusion reactions. Evidence of the need for an improved pretransfusion compatibility test

Delayed hemolytic transfusion reactions were diagnosed with a frequency of 1 per 4,000 units of whole blood or erythrocytes transfused, which represents an increased frequency of detection for those reported in other studies. The reasons for this increase, as well as the current detection of relatively milder reactions, appear to be related to the careful monitoring of the transfusion process, along with an increased clinical awareness of the problem and more sensitive laboratory detection methods. The increased frequency of detection emphasizes the need for more sensitive pretransfusion crossmatch methods to prevent those delayed hemolytic transfusion reactions that are the result of secondary immune responses.