[Fetomaternal anti-RH3, -4 (anti-E and anti-c) rhesus isoimmunization: a case report]

Hemolytic disease of the newborn caused by maternal isoimmunization has been decreasing over the past 10 years because of prophylactic treatment with anti-RH1 (anti-D) immunoglobulin. Nevertheless, there is an increase in the incidence of both relative and absolute numbers of non-RH1 red-cell maternofetal isoimmunizations, essentially anti-RH4 (anti-c), anti-RH3 (anti-E), and anti-Kell. In 8 to 14% of cases, multispecificity antibodies are present, the most common combination being the association of anti-RH3 and -4. Despite absence of specific prophylactic therapy, anti-RH4 isoimmunization could be as severe as anti-RH1 ; as for anti-RH3, it is usually associated with mild to moderate clinical manifestations. Nevertheless, there are few publications on anti-RH3, -4 maternofetal isoimmunization with a bias toward the most severe cases being reported. We report here a case of nonsevere maternofetal anti-RH3, -4 isoimmunization complicated with severe hyperbilirubinemia and delayed profound anemia. Hyperbilirubinemia was controlled using intensive phototherapy. Although anemia was absent at birth, it appeared progressively with a nadir at 7.8 g/dL at 1-month postnatal age. Blood counts were monitored for 3 months but the patient did not require red blood cell transfusion. This report underlines the need for a prolonged and rigorous pediatric follow-up of children born in the context of maternofetal isoimmunization after the acute neonatal period. Furthermore, it stresses the necessity of DAT testing in all pregnant women, even those who are RH1-positive.