Case report: Anti-U caused mild haemolytic disease of the newborn

Background

In pregnancy, antibodies directed against blood group antigens may be transmitted diaplacental and may cause haemolytic disease of the foetus and newborn (HDFN). For most of the common specificities, the risk is now well known. The risk assessment for rare specificities often is poor due to the lack of data. The DGTI Working Party Rare Blood Groups therefore had called to report cases of pregnancies with rare antibodies. We here report on the postnatal course of a newborn with a maternal anti-U.

Methods

Antibody identification and determination of the titres were done with the antiglobulin test in column agglutination technique (Bio-Rad and Grifols). Bilirubin was tested either with Siemens ADVIA Chemistry XPT (laboratory) or with Radiometer ABL90 FLEX (point-of-care device, POC). Haemoglobin was tested with the Sysmex XN-1000 device (laboratory) or with the Radiometer ABL 90 FLEX (POC). Haptoglobin and lactate dehydrogenase (LDH) were tested with Siemens ADVIA Chemistry XPT.

Results

At 24th week of pregnancy, anti-U (MNS system) was detected, titre was 32. At delivery, the titre was 128. The newborn's red cells were tested positive for the antigen U and were reactive in the DAT (4+). Anti-U was eluated, it was also detectable in the newborn's plasma (titre 1). Doppler of the middle cerebral artery did not indicate foetal anaemia at any time. Postnatal haemoglobin decreased from 15.6 g/dl to 12.9 g/dl on day 4 (Tab. 1). On day 8, it reached the nadir of 11.2 g/dl, but increased continuously thereafter without therapy. Bilirubin increased to 24.6 mg/dl on day 4. Intensified phototherapy for 18 h on day 4 and phototherapy for 24 h on day 7 lowered bilirubin to 15.5 mg/dl. Thereafter it decreased without further therapy.

Conclusion

In Germany, it is extremely difficult to provide U-negative red cell units, most often support of foreign blood services is required. In the case reported here, HDFN due to anti-U was relatively mild and did not require transfusion therapy, provision of U-negative units was not necessary. This case may not be representative, but the more cases are reported, the better the assessment of the HDFN risk due to anti-U and due to other rare blood group antibodies.

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