Читать книгу Transfusion Medicine - Jeffrey McCullough - Страница 119

Instruments and procedures have been improved to minimize the leukocyte content in the product, and thus also avoid potential complications of lymphocyte depletion in the donor. As a result, most plateletpheresis procedures today remove about 1 × 10⁶ to 5 × 10⁷ leukocytes. Loss of this number of leukocytes is very unlikely to lead to leukocyte depletion or any clinical effects on the donor’s immune function and has the advantage of producing a leukodepleted product. This is true even after serial collections completed in a relatively short period [96, 97]. However, in studies using the previously employed methods, significant lymphocyte depletion was observed together with decrease in total lymphocyte count and B and T cells, lower T4/T8 ratio, and reduced mitogen response [98–100]. Separate studies indicated that at least 10⁹ lymphocytes must be removed daily to observe a significant decline in lymphocyte count and at least 10¹¹ lymphocytes total must be removed over a short time and/or the individual’s lymphocyte count must be less than 500/μL for clinical immunosuppression to occur [97, 101]. The most recent studies show that although there is variability in lymphocyte loss in serial donors with the two most common collection instruments, the loss does not appear to lead to any clinical predisposition to infection [102–104]. Although one study suggests a possible increased risk of immunosuppression related infections [105].