Transfusion science最新文献

Double dose leucodepleted PC without filtration is considered to be the most cost-effective way of preparing leucodepleted PC in a reasonable time. The procedure lends itself to a multicomponent system and production of hyperconcentrate and dry platelets, with <10–15 ml plasma in final product and viral inactivation without considerable loss of in vitro platelet functions.

Platelet concentrates obtained by various procedures are highly heterogeneous, even if a standard protocol is used for the preparation. Therefore, standard/standardisation in both production and testing procedures remain a challenging area in order to obtain comparative results.

Attention needs to be focused on growing and complex technical features of preparation and on the use of new filter material in terms of biocompatibility and the related effects of activated factors on function of platelets and leucocytes. Both the production process and storage containers appear to contribute to various cellular lesion and generation of some biological response modifiers such as complements, cytokines and microparticles. In this respect it is relevant to adopt a multiparameter analysis for the validation of platelet quality as some markers of platelet storage lesion have different affinity to various surfaces, leading to false under estimation.

Further development work is still needed in preparation and usage of dry platelet, platelet alternative and bacterially safe products.

The underlying conditions of the transfused patients is also an important issue in this respect, it is interesting to note that patients with high IL8 levels have a substantially lower platelet recovery.

Cold haemagglutination syndrome is difficult to treat. Fortunately it seldom needs treating. In most cases cold agglutinins are an incidental finding representing either normality or a benign chronic monoclonal gammopathy that does not cause ill health. Two sorts of symptoms are likely in the more severe cases. Acrocyanosis is usually treated by keeping the patient warm and if necessary removing him or her to Florida or the Canary Islands. In the rare cases of haemolytic anaemia, an underlying lymphoid tumour should be sought and treated. If none exists, then it is unlikely that the treatments that are useful in warm antibody haemolytic anaemia will be helpful. Plasma exchange ought to work but in practice there are frequently problems of red cell agglutination within the cell separator or the plastic tubes. For this reason plasma exchange within a heated room is advocated. When cardiac surgery is contemplated pre-operative plasma exchange is sometimes helpful, or the heart may be stopped by potassium solutions and the operation is carried out in the warm.

Idiopathic thrombocytopenic purpura (ITP) is characterized by the development of a specific anti-platelet autoantibody immune response mediating the development of thrombocytopenia. Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of a wide variety of autoantibodies. In 15–20% of SLE cases, patients develop thrombocytopenia which appears to be autoimmune in nature (SLE-TP). To better understand the pathogenesis of the thrombocytopenia associated with SLE, we investigated the overlapping platelet and cellular immune features between SLE and ITP. Thirty-one patients with SLE, eight with SLE-TP, and 17 with ITP, were studied and compared to 60 healthy controls. We evaluated platelet-associated IgG, platelet microparticles, reticulated platelets, platelet HLA-DR expression, in vivo cytokine levels, lymphocyte proliferation, and the T lymphocyte anti-platelet immune response in these patients. Patients with SLE-TP and those with ITP had increased platelet-associated IgG, an increased percentage of platelet microparticles, a higher percentage of reticulated platelets and larger platelets, suggesting antibody-mediated platelet destruction and increased platelet production. More than 50% of patients with ITP had increased HLA-DR on their platelet surface whereas subjects with SLE-TP did not. Analysis of serum cytokines demonstrated increased levels of IL-10, IL-15 and TNF-α in patients with SLE, but in those with ITP, only increased levels of IL-15 were seen, no increases in any of these cytokines were observed in patients with in SLE-TP. The ability of lymphocytes to proliferate in response to phorbol myristate acetate (PMA) stimulation was increased in SLE-TP, but was normal in both SLE and ITP. Lymphocytes from subjects with ITP displayed an increased ability to proliferate on exposure to platelets, in contrast, those with SLE-TP did not. While the number of subjects evaluated with SLE-TP was small, these data reveal a number of differences in the immunopathogenesis between SLE-TP and ITP.