Biomedical subjects
Oystein Flesland
Publications and source records attributed to Oystein Flesland.
Microchimerism in immune competent patients related to the leukocyte content of transfused red blood cell concentrates.
BACKGROUND: Microchimerism may play a part in transfusion complications. The aim of this study was to examine whether establishment of post-transfusion microchimerism was related to leukocyte content. METHODS: Twenty non-pregnant female patients, without known malignant or immunological diseases, mean age 68 years, receiving 2-4 units of red blood cell concentrates during elective surgery, were included. One or two of the units were from male donors. Ten patients received buffy-coat depleted red blood cell concentrates, leukocyte count 108-109 per unit, and 10 patients received red blood cells leukoreduced by prestorage leukocyte filtration, with a leukocyte count of <106 per unit. EDTA samples were collected in vacuum tubes before and after 1 week and 6 months after transfusion. The tubes were frozen and stored at -400 degrees C. Genomic DNA was isolated and PCR performed using four primer sets amplifying markers on the Y-chromosome. RESULTS: Microchimerism was detected in a total of eight out of the 20 patients. In three patients microchimerism was detected only before transfusion. These patients had given birth to one or two boys each, and had no history of previous transfusion. Two patients receiving buffy-coat depleted red blood cell concentrates and two patients receiving leukoreduced red blood cell concentrates had detectable microchimerism 1 week after transfusion. The age of the transfused red blood cell concentrates was 6, 24, 8 and 7 days, respectively. One patient receiving leukoreduced red blood cell concentrates had detectable microchimerism after 6 months. The age of this concentrate was 22 days. DISCUSSION: This study demonstrates that microchimerism after transfusion does not seem to be dose dependent, and can be induced even by a >3 week old leukoreduced red blood cell concentrate with a very low leukocyte content.
Guidelines for transfusion in Norway.
The Norwegian guidelines for transfusion are harmonised in terms of standards with the European directives, but we have two areas where there are substantial differences. First, in Norway a blood donor is defined as a patient in legal terms. Secondly, we have stricter criteria for geographical origin of the people who are allowed to donate blood than most other countries. It is a challenge to provide information stating that these guidelines are related to the risk of transmitting infectious disease rather than discrimination. Increased focus on hemovigilance and closer contact between the blood banks and the national health authorities will be major issues in future work to improve the quality of Transfusion Medicine in Norway.
Donor lymphocytes transferred with the graft to kidney recipients. Potential for establishing microchimerism.
After solid organ transplantation donor lymphocytes have been shown to survive and multiply in the organ recipient for a prolonged period. It is not clear whether this chimerism detected is the result of immunosuppression or the cause of allograft acceptance. The number of cells transferred, as well as the type of cells, and the degree of activation are likely to be of importance for the establishment of microchimerism. The cells that are flushed out of the vascular tree may be of particular importance since when an antigen primarily bypasses or secondarily avoids organised lymphoid collections, the immune system in the recipient may remain or become "indifferent" to its presence. In the present study we examined the amount of residual donor blood cells that we could flush out from the vascular tree of living donor kidneys and cadaveric donor kidneys immediately prior to transplantation, with special emphasis on T and B lymphocytes. Our study shows that perfusion of donor kidneys just prior to transplantation releases from 0.1 to 1.8x10(6) B-lymphocytes, with an average of 0.7x10(6) and from 0.5x10(6) to 2.6x10(6) T-lymphocytes, with an average of 1.8x10(6), for CD kidneys, and somewhat less for LD kidneys. These cells would otherwise have been flushed out into the organ recipient's circulation, where they might play a role in the establishment of microchimerism.