Dithiothreitol treatment of red blood cells.

Dithiothreitol (DTT), a reducing reagent, has multiple applications in blood bank testing. DTT disrupts the bridging of the disulfide bonds between amino acid residues necessary for structural conformation of some proteins and the bonds holding an IgM molecule in the pentameric formation. DTT treatment of red blood cells (RBCs) can denature or modify certain blood group antigens-in particular, those in the Kell, Lutheran, YT, JMH, LW, Cromer, Indian, Dombrock, and Knops systems-and prevent recognition by the corresponding antibodies. It also destroys RBC CD38, allowing DTT-treated RBCs to be used to avoid testing interference by therapeutic anti-CD38 preparations. DTT treatment can be used to disperse spontaneous agglutination of RBCs caused by heavy IgM autoantibody coating that invalidates ABO/Rh cell grouping and direct antiglobulin tests.Dithiothreitol (DTT), a reducing reagent, has multiple applications in blood bank testing. DTT disrupts the bridging of the disulfide bonds between amino acid residues necessary for structural conformation of some proteins and the bonds holding an IgM molecule in the pentameric formation. DTT treatment of red blood cells (RBCs) can denature or modify certain blood group antigens­in particular, those in the Kell, Lutheran, YT, JMH, LW, Cromer, Indian, Dombrock, and Knops systems­and prevent recognition by the corresponding antibodies. It also destroys RBC CD38, allowing DTT-treated RBCs to be used to avoid testing interference by therapeutic anti-CD38 preparations. DTT treatment can be used to disperse spontaneous agglutination of RBCs caused by heavy IgM autoantibody coating that invalidates ABO/Rh cell grouping and direct antiglobulin tests.

Contrasting HCV and HIV seroepidemiology in 11 years of blood donors screening in Brazil.

BACKGROUND: Blood donors are, in principle, healthy individuals who may be revealed as infectious for blood-borne agents by the laboratory screening process, depicting the asymptomatic burden of the disease. Therefore, monitoring hepatitis C virus (HCV)-infected donor and human immunodeficiency virus (HIV)-infected donor and associating to their demographical and behavioural characteristics may shed light on the dynamics and contemporary changes in these viruses' epidemiology. METHODS: Donors presenting repeatedly reactive HCV or HIV serology/nucleic acid testing (NAT) screening results were submitted to confirmatory testing. Confirmed positive donors were invited to return to the blood bank for notification and counselling when a follow-up sample was obtained and an interview performed to eventually disclose potential risks. HCV- or HIV-infected donors identified over 11 years of screening (2004-2015) were evaluated for demographic and behavioural parameters. RESULTS: In the period, 139 160 donations were screened, and 36 (0.025%) were found positive for HIV, stemming from 29 male and 7 female donors. Among those, eight subjects were repeat donors. A total of 95 donations were found repeatedly reactive for HCV (0.068%), obtained from 60 men and 35 women. Noticeably, in despite of a higher HCV prevalence in the donor population, the incidence of HIV among repeat donors was 10 times that of HCV (18 × 1.6/100 000 persons-year, respectively). On average, HIV-seroreactive men were found to be younger (mean = 34 years old) than women (mean = 40 years old). A total of 10 donors acknowledged sexual behaviours not previously informed, including 2 who were aware of their HIV-positive status and another 2 who admitted to be seeking HIV testing. No window period donation was verified. DISCUSSION: The majority of the HIV-infected donors are young males who deny risk factors in the interview and also ignore the confidence self-exclusion opportunity. As they may reiterate this behaviour in serial donations, use of the most sensitive laboratory testing is justified in this setting.

The use of a potential novel tool in virtual crossmatching for platelet transfusion in platelet refractoriness.

BACKGROUND AND OBJECTIVES: Transfusion support for immune-mediated platelet refractoriness (PR) is clinically challenging, technically laborious and costly. The development of 'EpHLA/EpVix software' has been used successfully to select kidney donors. Here, we sought to evaluate this new software as a tool for platelet virtual crossmatch (VxM). MATERIALS AND METHODS: This is a prospective study from 2007 to 2014 of PR patients in a tertiary hospital. Platelet components selected by HLAMatchmaker program were crossmatched by EpHLA/EpVix, anti-human globulin complement-dependent lymphocytotoxicity test (AHG-CDC), flow cytometry platelet crossmatch (FCxM) and then compared. Effectiveness of platelet components transfused was evaluated by CCI. RESULTS: Ninety-seven crossmatched platelet transfusions for 27 patients were enrolled. Partial matches were analysed for 75 transfusions by the 3 methods, and 22% showed discrepant results among the assays. After further analysis, data showed that all divergent cases could be explained by HPA alloimmunization, prozone effect (FCxM), low sensitivity of AHG-CDC and possible interference in FCxM/AHG-CDC assays. Notably, sensitivity and specificity of VxM analysis was excellent (100%). Satisfactory CCI counts were obtained for the majority (22/30) of the transfusions. CONCLUSION: The new EpHLA/EpVix method showed to be effective, feasible and fast for VxM at no cost and able to minimize labour on donor identification. However, platelet crossmatching may be a necessary step because EpHLA/EpVix does not formally exclude HPA alloimmunization.