Implementation and outcomes of a transfusion-related acute lung injury surveillance programme and study of HLA/HNA alloimmunisation in blood donors.

BACKGROUND: Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-associated mortality. Antibodies against human leucocyte antigens (HLA) and human neutrophil antigens (HNA) are often detected in the implicated donors. We investigated the incidence and aetiology of TRALI in Lombardy. Moreover, we determined the rate of HLA and HNA alloimmunisation and the HNA genotype in a cohort of local blood donors. MATERIALS AND METHODS: During a 2-year observational study in eight blood transfusion services, suspected TRALI cases were collected and characterised by means of HLA and HNA antibody screening of implicated donors, donor/recipient cross-matching and HLA/HNA molecular typing. In addition, 406 Italian donors were evaluated for alloimmunisation and in 102 of them HNA gene frequencies were determined. RESULTS: Eleven cases were referred to the central laboratory, of whom three were diagnosed as having TRALI, seven as having possible TRALI and one as having transfusion-associated circulatory overload. Seven TRALI cases were immune-mediated whereas in three we did not find either alloantibodies in implicated donors or a positive reaction in the cross-match. The most frequently implicated blood component was red blood cells (in 5 males and in 1 female), whereas four cases of TRALI were associated with transfusion of fresh-frozen plasma (in 3 females and in 1 male). The frequency of reported TRALI/possible TRALI cases was 1:82,000 for red blood cells and 1:22,500 for fresh-frozen plasma. No cases were observed for platelets. Overall, the frequency of HLA or HNA alloimmunisation in blood donors was 29% for females and 7% for males. The latter could be related, at least in part, to natural antibodies. HNA gene frequencies showed that HNA-1b is more frequent than HNA-1a in our sample of donors. DISCUSSION: The recently adopted national policy to prevent TRALI, i.e. using only plasma donated by males, would have had a positive impact in our setting.

Increased tissue factor pathway inhibitor and homocysteine in Alzheimer's disease.

We investigated the possible involvement of vascular damage in the pathogenesis of Alzheimer's disease (AD), by assessment of plasma levels of tissue factor pathway inhibitor (TFPI), a serine protease inhibitor induced by endothelial injury, and homocysteine (Hcy), a known risk factor for cerebrovascular disorders, folate levels were also measured. 110 probable AD, 38 mild cognitive impairment, 31 patients affected by idiopathic Parkinson's disease (without dementia) and 100 healthy controls, who displayed no vascular disorders were enrolled. TFPI and Hcy were significantly higher in AD patients with respect to other groups. The levels of TFPI and Hcy were positively correlated in hyperhomocysteinemic AD and mild cognitive impairment subjects, and were negatively correlated with folate levels. Our findings suggest that an impairment of endothelial function associated with high Hcy levels may occur in AD patients, despite the absence of manifest cerebrovascular lesions. Therefore, TFPI may represent a candidate marker of endothelial damage in AD and might be used for the identification and monitoring of patients that would benefit from folate supplementation treatment.

Circulating endothelial cells and endothelial activation in essential thrombocythemia: results from CD146+ immunomagnetic enrichment--flow cytometry and soluble E-selectin detection.

Circulating endothelial cells (CECs) have been studied in cardiovascular disorders and as a marker of angiogenetic activity; clinical applications are limited by a lack of consensus on their phenotypic identification and quantification. We determined CECs in essential thrombocythemia (ET) patients, to investigate their possible pathogenetic role. We considered CECs as CD146⁺/CD45⁻ nucleated cells, detected in peripheral blood from 21 healthy controls and 39 ET patients, performing a combination of pre-enrichment of CD146⁺ circulating cells and multiparametric flow cytometry measurement (FCM). Levels of CECs in ET patients were higher with respect to controls (median 2844 CECs/mL vs. 121.3 CECs/mL, P < 0.0001). Apparently hydroxyurea treatment did not influence the levels of CECs. As another established marker of endothelial activation, we also assessed soluble E-selectin (sE-selectin) levels in 31 of the ET patients and compared with 39 healthy volunteers: median sE-selectin level in ET patients was 35.3 ng/mL, higher with respect to controls (24.48 ng/mL), P = 0.0369. Our data suggest that endothelium in ET is activated, reflecting a significant role of angiogenesis in this disorder and suggesting an important endothelial contribution in the hypercoagulable state of ET patients.

Platelet activation during plasma-reduced multicomponent PLT collection: a comparison between COBE Trima and Spectra LRS turbo cell separators.

BACKGROUND: The wide diffusion of multicomponent collection in donor apheresis has led to the yielding of different components, such as plasma-reduced platelet-pheresis at high PLT concentration. We investigated whether this collection modality could induce more PLT activation compared to standard plateletpheresis. STUDY DESIGN AND METHODS: Forty-one plateletpheresis collections (20 Trima and 21 Spectra LRS Turbo v.7.0, COBE) were evaluated. Donor, procedure, and product data were recorded. ADP, collagen, and U46619 (a thromboxane-A2 analog)-induced PLT aggregation was investigated in basal (donor) and final (plateletpheresis unit) samples. The expression of PLT activation marker P-selectin (CD62P) was studied using flow cytometry in basal and final samples. In all cases, P-selectin was investigated in final samples after stimulation with ADP to assess for a possible further release of the antigen. Four additional plateletpheresis procedures were performed in donors from Group A, using the traditional, nonplasma-reduced program. RESULTS: Plateletpheresis obtained by means of the Trima device showed a lower response to in-vitro induced PLT aggregation and a higher percentage of P-selectin-expressing PLT when compared to products obtained using the Spectra device. Moreover, P-selectin release after ADP stimulation was reduced in plateletpheresis units obtained using the Trima device. These differences disappeared when a nonplasma-reduced collection program was used. In-vivo evaluation did not detect any difference between plateletpheresis obtained by means of the two cell separators. CONCLUSIONS: Plateletpheresis units obtained by means of multicomponent collection show a higher degree of PLT activation compared to traditional plateletpheresis procedures when high-concentration plasma-reduced products are collected. Randomized clinical studies are needed to assess the real impact of these findings in terms of in-vivo efficacy of plasma-reduced plateletpheresis units.