Infantile pyknocytosis: A cause of intrauterine haemolysis in two siblings

Abstract

Pyknocytosis is a rare cause of haemolytic anaemia in utero and in the neonatal period. Two unusually severe cases of infantile pyknocytosis in 2 siblings are described. The first sibling, a male infant, was delivered prematurely at 37 wk. At birth the child had moderately severe jaundice and hepatosplenomegaly. The cord blood film showed marked pyknocytosis with numerous nucleated red cells. During the first 6 h of life the child developed clinical and laboratory evidence of disseminated intravascular coagulation. An attempt was made to do exchange transfusion but the child died 6 h after birth. The autopsy showed evidence of marked extramedullar erythropoiesis consistent with intrauterine haemolytic anaemia. The second infant of the parents was closely monitored during pregnancy as the history in the first infant had suggested severe intrauterine haemolysis. Amniocentesis was performed at 33 wk and 35 wk of gestation and showed an increase in bilirubin suggestive of a moderately severely affected infant. The baby was delivered by caesarean section at 35 wk and at birth showed evidence of haemolytic anaemia. Cord blood:haemoglobin 11.2 g/dl; PCV 36%; MCV 104 μ m 3 ; MCHC 32.7%; MCH 34 pg; reticulocyte count 21.3%; 126 nucleated red cells per 100 white cells; WCC 12,900 × 10 3 and platelet count 273 × 10 3 . Peripheral blood showed marked pyknocytosis very similar to the blood film of the first infant. The investigations to exclude enzyme deficiencies such as G6-PD, P-K. and glutathione reductase were normal. β -lipoproteins were also normal. No Heinz bodies were detected. To control hyperbilirubinaemia, the baby required 3 exchange transfusions. Despite exchange transfusions pyknocytosis persisted with evidence of recurrence of anaemia. The pyknocytosis and haemolytic anaemia persisted until 4 mth of age. A previous report suggested that the erythrocyte abnormality may have resulted from a plasma factor present in the affected infants. However, in our patient red cell morphology was not corrected by incubating the red cells with fresh plasma, nor were normal erythrocytes affected when incubated with the infant’s plasma. It would appear therefore that the erythrocyte abnormality is a transient but intrinsic abnormality of red cell membrane.