Clinically significant alloimmunization to red cell antigens occurred in 28 percent of transfused patients in a sickle cell clinic. Therefore, a prospective study was undertaken to determine whether matching donors carefully for 17 blood group antigens would diminish the risk of further alloimmunization in patients on a chronic transfusion program. Alloantibodies had developed previously in 8 of the 12 patients. After chronic transfusion with selected donors, four new antibodies developed in three patients. Three antibodies were due to errors in phenotyping or matching, and one was due to an antigen that was not tested for in the protocol. The incidence of developing antibodies per unit transfused was diminished tenfold when selected donors were used. Autoantibodies developed in five patients (42%), but these did not seriously interfere with the transfusion therapy. It was concluded that matching for red cell antigens may diminish the incidence of alloimmunization in patients with sickle cell anemia requiring transfusion.

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We describe a new method for the simultaneous assay of 3,4-dihydroxyphenylalanine (L-dopa) and dopamine in serum. Both compounds have been determined quantitatively at concentrations as low as 10 mug/liter with a coefficient of variation of less than 4%. Peak heights were linearly related to concentration up to 10 mg/liter for each compound. Assay of human sera gave within-run and day-to-day coefficients of variation of 2.8% and 3.1% for L-dopa, and 2.9% and 3.7% for dopamine. The linear relationship between readings nA, y-axis) and concentration (mug/liter) is described by the following equations: y = (21.0 +/- 0.082)x + (0.46 +/- 0.31 SD) for L-dopa and y = (17.0 +/- 0.10)x + (0.08 +/- 0.04 SD) for dopamine. The procedure combines liquid/solid extraction, liquid chromatography, and controlled-potential electrochemistry. The simplicity, sensitivity, and accuracy of this method make it suitable for routine clinical analysis of serum samples to optimize bioavailability for individual patients. After the extraction procedure is completed, samples can be analyzed at the rate of 10/h.

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