A disturbed hypothalamus-pituitary-adrenal gland axis and alterations at the immune system level have been observed in patients with chronic fatigue syndrome (CFS). Glucocorticoids are known to modulate T cell responses; therefore, purified CD4 T cells from CFS patients were studied to determine whether they have an altered sensitivity to dexamethasone (DEX). CD4 T cells from CFS patients produced less interferon-gamma than did cells from controls; by contrast, interleukin-4 production and cell proliferation were comparable. With CD4 T cells from CFS patients (compared with cells from controls), a 10- to 20-fold lower DEX concentration was needed to achieve 50% inhibition of interleukin-4 production and proliferation, indicating an increased sensitivity to DEX in CFS patients. Surprisingly, interferon-gamma production in patients and controls was equally sensitive to DEX. A differential sensitivity of cytokines or CD4 T cell subsets to glucocorticoids might explain an altered immunologic function in CFS patients.

Background and Objectives: Our requirements for leukocyte–depleted platelet concentrates (LD–PC) for an adult patient are: platelets >240×10⁹, leukocytes <5×10⁶, volume of 150–400 ml; and at the end of storage a pH between 6.8 and 7.4 and presence of the swirling effect. Our aim was to develop a standardized, semiautomated method for the production of LD–PC, by pooling of buffy coats (BC), and prestorage leukoreduction by filtration. Materials and Methods: Whole blood was collected in Top and Bottom systems, and separated automatically with the Compomat^™ G3 equipment into a red cell concentrate, a plasma and a BC. Subsequently, a pool of 5 BC was made, and 200 g plasma from one of the donors was added. Then, after soft spin centrifugation, the platelet rich plasma was leukocyte depleted by filtration using the Autostop^™BC filter, and stored in a 1,000 ml polyolefin platelet storage bag. Results: BC (n = 60) had a volume of 51±2 ml (mean ± SD) with a hematocrit of 0.44±0.03 l/l and contained 80±5% of the platelets and 74±12% of the leukocytes of the whole blood. Routinely prepared LD–PC (n = 15,037) contained a median of 341×10⁹ platelets (range 49–599×10⁹), with only 104/15,037 (0.7%) containing fewer than 240×10⁹ platelets; the median volume was 263 ml (range 134–373 ml). In 118/917 (13%) LD–PC leukocytes were observed in the Nageotte hemocytometer, but only twice exceeding 1×10⁶ leukocytes per unit, and none exceeding 5×10⁶ (median <0.6×10⁶; range <0.6–1.41×10⁶). Storage experiments of the LD–PC (n = 12) revealed adequate oxygenation and maintenance of pH and swirling effect up to 9 days. Conclusions: This method warrants with 99% confidence that LD–PC contain more than 240×10⁹ platelets; with 97.5% confidence that 100% of the LD–PC contain <5×10⁶ leukocytes, and with 95% confidence that more than 99% of the LD–PC contain fewer than 1×10⁶ leukocytes; these LD–PC can be stored satisfactorily for up to 9 days.

Background and Objectives: Whole blood can be separated by hard spin centrifugation into layers of blood components according to their specific gravity. The aim was to develop a program for an automatic separator to subsequently express the various components into their respective satellite bags in top and bottom systems with the following requirements: a red cell concentrate with a low leukocyte and platelet contamination, a 'cell–free' plasma, and a buffy coat with a volume of about 50 ml with an acceptable loss of red cells. Materials and Methods: The Compomat G4 possesses an independently moving upper and lower press, to automatically express plasma or red cells to satellite bags of top and bottom systems. The influence of the extension of the lower press was studied by pooling and dividing two units of whole blood, and separating these units after centrifugation (2,960 g, 10 min) either with a program where the lower press was completely extended (program C), or with a program that left approximately 1 mm between the door and the lower press (program D). Results: The program (program D), where the lower press was not completely extended, yielded a buffy coat with a volume of 52±1 ml (mean ± SD, n = 36), which contained >75% leukocytes and >90% platelets of the original whole blood unit, with a red cell loss in the buffy coat of 21±1 ml (10.8±0.8% of the original volume). The leukocyte content of the red cell concentrates was 775±379×10⁶ per unit, whereas the plasma contained 3±3×10⁶ leukocytes and 4±3×10⁹ platelets per unit. The pooling experiment indicated that complete extension of the lower press (program C) resulted in a significantly higher leukocyte contamination of the red cell concentrate (788±431×10⁶ vs. 658±419×10⁶; n = 12; p = 0.03), while there was no difference in the yield of red cells or plasma. The buffy coat produced with program D contained significantly more leukocytes (2,242 ±396×10⁶ vs. 2,065±327×10⁶, p = 0.005) and more platelets (96±14×10⁹ vs. 92±17×10⁹, p = 0.02) per unit than with program C, probably because buffy coat cells sticking to the container wall are not expressed to the red cell concentrate, and thus remain in the buffy coat bag. Therefore, program D met our specifications for blood products. Conclusions: The Compomat G4 warrants reproducible separation of whole blood in top and bottom bags into red cells, buffy coat and plasma meeting our specifications.

This method warrants with 99% confidence that LD-PC contain more than 240x10(9) platelets; with 97.5% confidence that 100% of the LD-PC contain <5x10(6) leukocytes, and with 95% confidence that more than 99% of the LD-PC contain fewer than 1x10(6) leukocytes; these LD-PC can be stored satisfactorily for up to 9 days.

Background and Objectives: Whole blood can be separated by hard spin centrifugation into layers of blood components according to their specific gravity. The aim was to develop a program for an automatic separator to subsequently express the various components into their respective satellite bags in top and bottom systems with the following requirements; a red cell concentrate with a low leukocyte and platelet contamination, a ‘cell‐free’ plasma, and a buffy coat with a volume of about 50 ml with an acceptable loss of red cells. Materials and Methods: The Compomat G4 possesses an independently moving upper and lower press, to automatically express plasma or red cells to satellite bags of top and bottom systems. The influence of the extension of the lower press was studied by pooling and dividing two units of whole blood, and separating these units after centrifugation (2,960 g, 10 min) either with a program where the lower press was completely extended (program C), or with a program that left approximately 1 mm between the door and the lower press (program D). Results: The program (program d), where the lower press was not completely extended, yieded a buffy coat with a volume of 52±1 ml (mean ± SD, n = 36), which contained >75% leukocytes and >90% platelets of the original whole blood unit, with a red cell loss in the buffy coat of 21±1 ml (10.8±0.8% of the original volume). The leukocyte content of the red cell concentrates was 775±379 × 106 per unit, whereas the plasma contained 3±3×106 leukocytes and 4±3 × 109 platelets per unit. The pooling experiment indicated that complete extension of the lower press (program C) resulted in a significantly higher leukocyte contamination of the red cell concentrate (788±431 × 106 vs. 658±419 × 106; n = 12; p = 0.03), while there was no difference in the yield of red cells or plasma. The buffy coat produced with program D contained significantly more leukocytes (2,242±396 × 106 vs. 2,065±327 × 106, p × 0.005) and more platelets (96±14 × 109 vs. 92±17 × 109, p 0.02) per unit than with program C, probably because buffy coat cells sticking to the container wall are not expressed to the red cell concentrate, and thus remain in the buffy coat bag. Therefore, program D met our specifications for blood products. Conclusions: The Compomat G4 warrants reproducible separation of whole blood in top and bottom bags into red cells, buffy coat and plasma meeting our specifications.