Use of a PCR-based assay for fetal Cw antigen genotyping in a patient with a history of moderately severe hemolytic disease of the newborn due to anti-Cw

Anti- c(w): in a young female patient. A case report with review of literature and frequency of low incidence c(w) (rh8) antigen in north India

If the patient has antibody to low incidence antigen providing compatible blood for transfusion is not a problem. It is however necessary to identify such antibodies to assess their potential to cause hemolytic transfusion reaction and hemolytic disease of newborn. We identified anti C(w) in patient's serum while investigating the cause of incompatible cross match in a female thalassemia patient. Anti C(w) is an antibody against C(w) (Rh8) antigen, which is a low incidence antigen of Rh system. This case also prompted us to study frequency of C(w) antigen in our donor population as the frequency of C(w) antigens in our population is not reported. Frequency of C(w) antigens in north Indian donors was found to be 1.2 %.

Severe Hemolytic Disease of the Newborn Due to Anti-Cw

BACKGROUND

Pregnancies complicated by Rh isoimmunization have decreased significantly since the widespread use of Rh immune globulin. Uncommon red blood cell antigens have therefore become more clinically evident. We report a case of anti-Cw immunization that resulted in severe fetal anemia that required multiple transfusions.

CASE

A 28-year-old multigravida presented to our service at 18 weeks of gestation with her fourth pregnancy. Her pregnancy was complicated by anti-Cw isoimmunization that resulted in severe fetal anemia requiring in utero fetal blood transfusions.

CONCLUSION

While previous reports recommend only postpartum surveillance when Cw isoimmunization is present, we report a case resulting in severe fetal anemia.

Anti-C(w) alloimmunization presenting as hydrops fetalis

C(w) is a low frequency red cell antigen that belongs to the Rh blood groups system. While not uncommon, anti-C(w) is rarely associated with clinically significant haemolytic disease of the newborn (HDN). When it does occur, it is often subclinical or of mild to moderate clinical severity. In the majority of pregnancies it is considered to be a naturally occurring antibody and has not been reported to cause hydrops fetalis or stillbirth. We report a case of anti-C(w) alloimmunization, which was associated with significant anaemia and hydrops fetalis, presenting at 35 wk gestation.

CONCLUSION

Pregnancies affected by anti-C(w) merit closer scrutiny. Consideration should be given to performing more frequent antenatal ultrasound assessments to detect hydrops fetalis. This may help to support the need for more invasive procedures (cordocentesis and intrauterine transfusions).