'Spin, cool, and filter' red cells prepared in a regional blood center.

Red cells depleted of leukocytes by the "spin, cool, and filter" (SCF) method are effective in preventing most febrile, nonhemolytic transfusion reactions (FNHTR). To determine whether red cell concentrates may be centrifuged in a blood center and filtered subsequently at an outlying facility, the authors examined how leukocyte removal was affected by the transport and storage of centrifuged red cells before microaggregate filtration (MAF). One hundred fourteen red cell units were each divided into two aliquots. After centrifugation, one aliquot from each unit was retained in the blood center, and the other was transported on a truck for 2 to 12 hours. Aliquots were stored for variable periods, after which the residual leukocytes were counted. Neither transportation nor storage significantly affected leukocyte removal by MAF. However, an unacceptable proportion of all SCF units failed to meet American Red Cross standards for leukocyte-poor blood and studies of factors influencing leukocyte depletion were undertaken. A relative centrifugal force of 6700 X g was needed to produce consistently acceptable units when blood was 8 to 15 days old. These results show that making SCF red cells is a practical, inexpensive way for blood centers to provide hospitals with products that prevent most FNHTR; however, each facility that prepares these products must perform quality control carefully.

Selective IgA deficiency in blood donors.

The frequency of selective IgA deficiency was determined in a healthy population of 6,240 blood donors. Screening for IgA deficiency was performed by double-diffusion analysis in agarose gel. Confirmation testing was performed with the more sensitive passive hemagglutination inhibition assay. Prevalence of IgA deficiency, characterized by a serum level of below 50 mg/L, was 0.30% (1 in 328), which is the highest prevalence of selective IgA deficiency reported in a healthy population. Antibodies to IgA were detected in sera of 36.8% of the blood donors with selective IgA deficiency, which also is the highest prevalence of anti-IgA antibodies reported in any previous study. The literature on IgA deficiency in healthy populations is reviewed. Current concepts in treatment of IgA-deficient patients requiring blood products are described.