DNA amplification for DQ typing as an adjunct to serological prenatal HLA typing for the identification of potential donors for umbilical cord blood transplantation.

It has recently been demonstrated that umbilical cord blood from genotypically human leukocyte antigen (HLA)-matched donors can provide sufficient numbers of progenitor cells for hematopoietic reconstitution. This technique has been successfully applied in the treatment of two children affected with Fanconi anemia (FA). Fetal cells from the potential sibling donors were first tested to determine that the fetus was not affected with FA. Unaffected fetal cells were then tested for HLA type. Cord blood from compatible donors can be harvested at birth and used immediately or frozen for subsequent use in hematopoietic reconstitution. We now show that fetal cell DNA amplification and hybridization for DQ typing can be an important adjunct procedure to verify serologically determined HLA class II types and/or to establish class II haplotype identity with the affected sibling.

Splenic red cell pooling: a diagnostic feature in polycythaemia.

Total red cell volumes and splenic red cell pools were measured in 31 patients with polycythaemia. 22 had polycythaemia vera (PV), 12 of whom had clinically detectable splenomegaly, and nine patients had secondary polycythaemia (PS). The mean red cell pool was 192.8 ml (SD 126.6) in PV (all cases), and 130.9 ml (SD 28.4 ml) in PV without splenomegaly; it was 61.1 ml (SD 8.3 ml) in PS. When expressed relative to spleen size (in cm), differences were even more striking: PV (all cases)--mean 13.7 ml/cm (SD 4.3); PV without splenomegaly--mean 12.7 ml/cm (SD 2.2); PS--mean 6.6 ml/cm (SD 1.2). Measurement of splenic red cell pool thus appears to be a valuable diagnostic tool for distinguishing between PV and PS. The findings point to the presence in PV of a splenic structural abnormality which is not simply an effect of the increased circulating red cell mass.

Autonomous erythropoietin induced erythrocytosis.

Erythrocytosis in a young Sinhalese man is described. The patient was known to have had a raised Hb and PCV for at least 10 years. Subsequent investigations failed to support the diagnosis of polycythaemia vera or to reveal a cause for secondary polycythaemia. Blood erythropoietin values were raised, but no cause for inappropriate secretion could be identified. Although there was no evidence of erythrocytosis in the family, the findings in this patient appear to be those of a condition which has been called familial polycythaemia. The spleen was unusually large and was associated with hypersplenism and thrombocytopenia. Problems of diagnosis and management are described. Phlebotomy appears to be the treatment of choice, with a regimen of regular venesection for the control of symptoms due to hyperviscosity and vascular occlusion.