Two new Scianna variants causing loss of high prevalence antigens: ERMAP model and 3D analysis of the antigens.

BACKGROUND: Scianna (Sc) antigens, seven high and two of low prevalence, are expressed on erythrocyte membrane-associated protein (ERMAP). We investigated SC (ERMAP) in individuals who made antibodies to high prevalence Scianna antigens, and propose a 3D model for ERMAP to precisely localize the residues associated with the known antigens. METHODS: Serological testing and DNA sequencing was performed by standard methods. A 3D structural model was built using a multi-template homology approach. Protein structures representing missense variants associated with the loss or gain of an antigen were generated. Residue accessibility and intraprotein interactions were compared with the wild-type protein. RESULTS: Two new SC alleles, one with c.349C > T (p.Arg117Cys) in a woman from South India with anti-Sc3 in her plasma, and a c.217_219delinsTGT (p.Arg73Cys) in an African-American woman with an antibody to a new high prevalence antigen, termed SCAC, were identified. Six structural templates were used to model ERMAP. 3D analysis showed that residues key for Scianna antigen expression were all exposed at the surface of the extracellular domain. The p.Arg117Cys change was predicted to abolish interactions between residues 93 and 117, with no compensating interactions. CONCLUSION: We confirm the extracellular location of Scianna residues responsible for antigen expression which predicts direct accessibility to antibodies. Loss of intraprotein interactions appear to be responsible for a Sc null and production of anti-Sc3 with p.117Cys, SC*01 N.03, and for loss of a high prevalence antigen with p.73Cys, termed SCAC for Sc Arg to Cys. Comparative modeling aids our understanding of new alleles and Scianna antigen expression.

Decreasing preoperative autologous blood donation: collaboration between a hospital and a blood center to prompt change in physician ordering behavior.

OBJECTIVE: To describe the collaborative efforts of a large healthcare institution and its local blood center in reducing preoperative autologous blood donation (PABD). METHODS: Through an educational letter-based campaign, we contacted physicians who historically had ordered PABD units. Follow-up educational efforts occurred at departmental and individual meetings. RESULTS: Our educational campaign to reduce PABD achieved complete elimination of PABD orders and the resultant waste of PABD units within 3 years of the start of the program. These changes were sustained for at least 2 subsequent years without the need for additional educational efforts. CONCLUSION: Targeted educational efforts directed at practitioners of PABD were successful in significantly decreasing the use and waste of PABD at the health care institution we studied and may yield the same results in comparable institutions.

Epidemiologic and laboratory findings from 3 years of testing United States blood donors for Trypanosoma cruzi.

BACKGROUND: At most blood centers in the United States routine testing of donations for Trypanosoma cruzi using an enzyme-linked immunosorbent assay (ELISA) is followed by supplemental testing by radioimmunoprecipitation assay (RIPA). The objective of this study was to report the results of routine testing and risk factor data from allogeneic blood donors. STUDY DESIGN AND METHODS: T. cruzi testing data from January 2007 through December 2009 were analyzed, and risk factor interviews and follow-up studies were conducted on seroreactive donors. Prevalences of confirmed infection and risk factors associated with infection were assessed using logistic and multivariable logistic regression. RESULTS: Of 2,940,491 allogeneic donations from 1,183,076 donors, 305 (0.01% per donation tested and 0.026% per blood donor) were repeat reactive (RR) and 89 of those were confirmed positive by RIPA, yielding an overall seroprevalence of 1 per 33,039 donations and 1 per 13,292 donors. Country of birth and US blood center location differences in the seroprevalence of T. cruzi were evident. The odds of confirmed infection were highest if the donor reported having been bitten by the reduviid (kissing) bug (odds ratio [OR], 76.1; 95% confidence interval [CI], 11.1-3173) followed by having lived in a rural area of Latin America (OR, 38.6; 95% CI, 15.1-102.5). In multivariable analyses, having spent 3 months or more in Mexico or Central and/or South America was associated with the highest odds of RIPA-confirmed infection (OR, 8.5; 95% CI, 2.7-26.5). Polymerase chain reaction (PCR) testing of ELISA RR donors exhibited low sensitivity (1/22 [4%] RIPA-confirmed donors was PCR positive). CONCLUSION: Risk factors for confirmed infection in US blood donors are consistent with the known epidemiology of Chagas disease. Blood donors or transfusions do not substantially contribute to the burden of T. cruzi infection in the United States.

Delayed adverse reactions to blood donation.

BACKGROUND: Blood donation is safe, but a small proportion of donors have delayed and/or off-site reactions that have the potential to lead to serious injury. This retrospective study sought to identify risk factors for delayed reactions (DRs). STUDY DESIGN AND METHODS: The records of 793,293 allogeneic whole blood and apheresis donations in 2007 were assessed for vasovagal reactions. Donor demographic, biometric, and clinical measurements were captured. Incidents related to needle insertion and mild reactions were excluded. Based on the reaction onset time relative to the procedure end time, reactions were classified as delayed (>15 min) or immediate (

Low CD34 collection from a healthy blood progenitor cell donor: a case report.

BACKGROUND: Transplantation of hematopoietic progenitor cells is widely used to ameliorate the consequences of bone marrow failure. In allogeneic transplantation, peripheral blood progenitor cells (PBPCs) from an HLA-matched donor are collected by apheresis and then identified using flow cytometric methods as being CD34 marker positive cells. CASE REPORT: A 25-year-old healthy male was matched with an obese 106 kg 23-year-old female diagnosed with acute lymphoblastic lymphoma. After a routine course of G-CSF induction, a 2-day PBPC collection procedure with a collection volume of 12 L/day was planned. All samples for CD34 estimation were shipped, stored, and tested according to the laboratory standard regulations. Testing was performed per International Society for Hematotherapy and Graft protocol, and CD34+ cells were immunophenotyped using monoclonal antibody against CD34 and CD45 by multicolor flow cytometry. RESULTS: The cumulative yield of both collections was 70.6 x 10(6) CD34+ cells (0.67 x 10(6) CD34+ cells/kg), which fell short of the requested dose of 530 x 10(6) (5 x 10(6) CD34+ cells/kg). Surprisingly, the recipient engrafted successfully and 12 days posttransplant short tandem repeat testing demonstrated only T cells of donor origin in the peripheral blood. CONCLUSION: To our knowledge, no successful engraftment has been reported as yet with such a poor collection of PBPC. The amountof transfused CD34+ cells (0.67 x 10(6)/kg) was significantly less than the minimum required amount (5x 10(6)/kg).