Treatment of erythroblastosis fetalis, with special reference to sensitization to Rh-Hr factors other than Rh 0

Abstract

<h2>Summary</h2> To date, 166 babies with erythroblastosis fetalis caused by <b>Rh₀</b> sensitization have been treated by our latest modification of exchange transfusion by the radial artery-saphenous vein technique. In this latest modification, partially concentrated blood (hematocrit 0.5), preferably not more than three days old, is used. This is prepared by removing part of the citrated plasma after sedimentation has occurred. Depending on the severity of the disease and the size of the baby, from 450 to 900 ml. of such concentrated blood is used for the transfusion. In severe cases the exchange transfusion is repeated. In no instance are more than two exchange transfusions deemed necessary. Among the 166 babies treated this way, only five babies died or had neurological sequelae, a crude mortality rate of only 3.0±0.9 per cent. On the other hand, among babies treated by our earlier modifications, or by only simple transfusion, or receiving no treatment at all, the mortality rate ranged from 17 to 21 per cent. The difference in results is even more striking when the severity of the disease is taken into account. Thus, among severely affected babies who received no treatment the mortality rate was 65.5±10.6 per cent; among those receiving simple transfusion therapy the mortality rate was 42.1±7.8 per cent; among those treated by our previous methods of exchange transfusion the mortality rate was 19.8±2.6; while among those treated by our latest modification of exchange transfusion, the mortality rate was only 3.8±1.0 per cent. The cases of erythroblastosis fetalis caused by sensitization to Rh-Hr factors other than <b>Rh₀</b> pose an important problem, since the routine antenatal screening test for <b>Rh₀</b> sensitization does not take them into account. Such cases are rare, but when they occur they are just as serious as instances of <b>Rh₀</b> sensitization. Thus, among nine cases of erythroblastosis fetalis caused by <b>hr′</b> sensitization, one baby died before treatment could be instituted. Of the remainder, four were treated by exchange transfusion and recovered uneventfully, while among the four treated by simple transfusion one died and one of the three who survived had severe neurological sequelae. A simple screening test for <b>Rh₀</b> antibodies consists in testing the serum of the patient against ficin-treated cells of types Rh₁Rh₁, Rh₂, and rh, respectively. This test should be carried out on all patients in labor admitted to the obstetrical service, and on patients admitted to the surgical or other services, who might require blood transfusion therapy. Case histories are presented, which illustrate the value of this screening test. It is pointed out that in cases of <b>hr′</b> sensitization the antibodies, even when present in high titer, may react only in tests against enzyme-treated cells and may fail to react in the conglutination and antiglobulin tests. This accounts for puzzling, severe cases of erythroblastosis fetalis in which the direct antiglobulin test for coating of the baby's red cells by Rh-Hr antibodies is negative. It is emphasized that certain antibodies, such as anti-<b>F</b> and anti-<b>J</b> are not detected by the enzyme test, so that the screening test against ficin-treated cells should supplement and not replace the other tests for isosensitization.