Blood transfusion for haemolytic disease as a cause of leukocytosis in the fetus

Increased monocytes and bands following a red blood cell transfusion

OBJECTIVE

The objective of this study is to analyze the white blood cell changes that occur after a transfusion of red blood cells in order to identify a subclinical inflammatory response in neonates.

STUDY DESIGN

Retrospective analysis of infants who received a red blood cell transfusion in an intensive care nursery. White blood cell results within 24 h pre- to 48 h post-transfusion were collected and analyzed. Statistical analysis included ANOVA, T-test, Mann-Whitney U test, Pearson's correlation and multivariable linear regression.

RESULT

Monocytes (P=0.02) and bands (P=0.035) were increased post-transfusion. There were no differences in monocytes (P=0.46) or bands (P=0.56) between groups who did or did not have blood cultures obtained. There was no difference in monocytes between groups who did or did not have sepsis (P=0.88).

CONCLUSION

We identified an elevation in monocytes and bands in the 48 h following a transfusion in premature infants. Our findings support a possible pro-inflammatory response related to transfusion of red blood cells.

Intrauterine transfusion for rhesus alloimmunization elevates fetal beta2-microglobulin levels

BACKGROUND

Intrauterine transfusions for rhesus alloimmunization leads to alterations in circulating T-cell populations. Given that elevations in circulating beta2-microglobulin are a marker of T-cell-mediated organ transplant rejection, we evaluated the effect of intrauterine transfusion on fetal beta2-microglobulin levels.

METHODS

Umbilical venous samples were obtained immediately prior to initial transfusion in ten anemic fetuses and in 12 fetuses with prior transfusions. Samples were also obtained from 18 gestational age-matched non-anemic fetuses and eight healthy neonates.

RESULTS

The median concentration of beta2-microglobulin was significantly higher in fetuses with prior transfusions compared with non-anemic controls. In non-anemic controls, and in transfused fetuses, beta2-microglobulin levels decreased throughout gestation (r = -0.69, p = 0.01; and r = -0.80, p = 0.01, respectively). Among anemic and transfused fetuses, beta2-microglobulin levels displayed a negative correlation with fetal hematocrit (r = -0.62, p < 0.05; and r = -0.58, p = 0.04, respectively).

CONCLUSIONS

We conclude that intrauterine transfusion for fetal anemia is associated with increased beta2-microglobulin levels, suggesting immunomodulatory effects of intrauterine transfusion on host immune responses to donor leukocyte antigens.

Transfusion in premature infants impairs production and/or release of red blood cells, white blood cells and platelets

OBJECTIVE

To examine whether red blood cell transfusion in infants with anaemia of prematurity alters peripheral counts of red blood cell precursors, total white blood cells and white cell differential and platelets.

METHODOLOGY

In 18 consecutive stable premature infants with anaemia of prematurity, peripheral cell counts were prospectively recorded immediately before transfusion of 20 mL/kg packed red blood cells (given over 6 h), and at 48 h after completion of the transfusion.

RESULTS

The median (interquartile range) haematocrit increased from 22.0% (21.3-24.0%) pre-transfusion to 37.0% (36.0-38.0%) post-transfusion (P < 0.001). Red-cell precursors decreased: median (interquartile range) reticulocytes from 3.7% (3.0-7.7%) to 3.7% (2.6-4.1%) (P = 0.03); and median (interquartile range) nucleated red blood cells from 0 G/L (0-0.2 G/L) to 0 G/L (0-0 G/L) (P = 0.03). The mean (SD) platelet count decreased from 420 G/L (154 G/L) to 313 G/L (101 G/L) (P = 0.001). The total white blood cell count and neutrophils did not change significantly; however, median (interquartile range) immature neutrophils decreased from 0.12 G/L (0.06-0.74 G/L) to 0.08 G/L (0.01-0.24 G/L) (P = 0.03). Lymphocytes, eosinophils, basophils and plasma cells remained unchanged. Monocytes increased (P = 0.01).

CONCLUSIONS

Forty-eight hours after red blood cell transfusion to premature infants, there is an absolute decrease in red blood cell precursors, immature white blood cells and platelets, probably due to erythropoietin-suppression.

Immunological aspects of blood transfusions

Donor selection based on blood group phenotypes, and blood processing such as leukocyte-depletion, gamma-irradiation or washing to remove plasma, are approaches for therapeutic or preventive use to manage the immunological complications of transfusion. Indications for specific components are prescribed in guidelines provided by (inter)national Transfusion Societies. Although the use of guidelines and protocols is in line with modern medicine, these can create a state of tension with the political sense of values to improve the viral safety of blood products and with the commercial exploitation of pooled plasma-products.A century of blood transfusion therapy has facilitated cancer treatment and advanced surgical interventions. The transfusion product has improved progressively, although mostly in response to disasters such as wars and AIDS. Every blood transfusion interacts with the immune system of the recipient. There are, however, very few quantitative figures to estimate the consequences. This review is based on the available literature on the clinical consequences of transfusion induced immunization and modulation. To a large degree the clinical consequences of transfusion induced immune effects are still a mystery.A blood transfusion is a medical intervention, which in many cases remains experimental with respect to the benefit/risk ratio. Ideally, this uncertainty should be communicated to patients and every transfusion included in a study. Such studies preferentially should be randomized because the perceived need for transfusion is associated with clinical conditions with a worse prognosis than those that do not receive transfusion. This difference may mask the interpretation of the transfusion effect. Since the blood supply services in almost all Western countries have been reorganized and nationalized, or at least operate to national quality standards, the measurement of risk: benefit of transfusion, whether political or evidence-based, needs to be reconsidered. Differences in emphasis and responsibilities between transfusion providers and transfusion prescribers will drive the providers to political and liability criteria - ever safer products - that will increase hospital costs with undetermined clinical benefits.

Immunomodulation induced by intrauterine transfusions

Intrauterine transfusion (IUT) therapy offers a unique model to study the immunological consequences of fetal exposure to donor alloantigens. IUT can result in immediate and short effects. Directly after IUT a relative leukocytosis was observed, which was evenly distributed among the different leukocyte subsets. After the course of IUT treatment a memory response against donor antigens was generated. This was also reflected by an increase in CD3/CD45RO+ T-cells and modulation of T cell receptor Vbeta (TCRBV) repertoire. However, a long term clinical follow-up study on IUT patients who received this treatment in the 1960's revealed no evidence of serious side effects. Furthermore, persistence of donor leukocytes and in vitro immunomodulation could not be observed.