Anti-leucocyte antibodies in platelet apheresis donors with and without prior immunizing events: implications for TRALI prevention.

BACKGROUND AND OBJECTIVES: Transfusion-related acute lung injury (TRALI) prevention strategies in platelet (PLT) apheresis donors focus on identifying antileucocyte antibody-positive donors. The use of microbead based assays for screening purposes is hampered by the lack of a consensus cut-off for TRALI prevention and the undefined role of anti-leucocyte antibodies in never-alloexposed donors. This study evaluated anti-leucocyte antibody assays in PLT apheresis donors with and without prior immunizing events with special focus on microbead assay cut-offs, antibody specificities and their potential significance in never-alloexposed donors. MATERIAL AND METHODS: Blood samples of male and female PLT apheresis donors with and without history of prior immunization were tested for anti-leucocyte antibodies. RESULTS: Of 262 female and 118 male PLT apheresis donors, 37·4% had prior immunizing events. Fifty-eight of 238 (24·4%) donors without prior immunizing event had anti-HLA antibodies confirmed in microbead single antigen assay (mean fluorescence intensity (MFI) >500). Even with a cut-off MFI >3000, anti-HLA antibodies were detected in 10·6% of female and 4·3% of male donors without history of immunization. Of the antibody specificities found, 6 of 17 (35·3%) anti-HLA-A, 4 of 8 (50·0%) anti-HLA-B and 4 of 6 (66·6%) anti-HLA class II antibodies have been detected in donors associated with TRALI cases in the literature. CONCLUSION: Platelet apheresis donors without history of immunization have anti-leucocyte antibodies that potentially can cause TRALI. In our opinion, this cohort should be included in screening strategies for TRALI prevention. As references and consensus cut-offs have not yet been established, it is premature to use microbead assays as standard for donor screening.

Beam quality of InGaAs ridge lasers at high output power.

The nonlinear behavior of the light-current characteristic of single quantum well, graded-index-separateheterostructure ridge laser diodes emitting at 980 nm is investigated. We have measured the beam-quality factor |M|(2) as a function of the output power, under continuous-wave and transient conditions.The time constant associated with beam degradation under the transient condition suggests that the temperature profile in the cavity plays a significant role in the lateral guiding of the lasing modes. The two-dimensional heat equation is solved for the device, and the time-resolved thermally induced refractive-index profile is computed. There is excellent agreement between the time required to reach a steady index profile and that required to degrade the beam. The small beam astigmatism (typically 2 µm) measured under CW operating conditions in the linear regime indicates that the mode is essentially index guided, which permits simple quantitative modeling of the waveguide.

Corticosterone secretion in the rat after DSP-4 treatment.

Functioning of the hypothalamo-pituitary-adrenocortical axis was assessed in rats treated with DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine), a selective noradrenergic neurotoxin. Although adrenal weights were slightly increased 10 days after DSP-4 injection, basal plasma corticosterone levels were unaltered compared to those of control animals. Moreover, the elevation of corticosterone levels induced by the stress of ether inhalation did not appreciably differ from that in control rats. These various results suggest that DSP-4 treatment has no marked effect on the normal functioning of the hypothalamo-pituitary-adrenocortical axis.