Reports have shown a worse outcome for donor-recipient pairs mismatched for ABO blood groups in bone marrow transplantation (BMT). These studies, however, included small and heterogeneous study populations, and not all considered bidirectional ABO incompatibility separately. Because the issue remains controversial, we analyzed the effect of ABO mismatch on the overall survival, transplant-related mortality, and occurrence of acute and chronic graft-versus-host disease (GVHD) in a large homogenous group of patients undergoing allogeneic BMT. A total of 3103 patients with early-stage leukemia who underwent transplantation between 1990 and 1998 with bone marrow from an HLA-identical sibling and who were reported to the Center for International Blood and Marrow Transplant Research were studied. The median follow-up was 54 months. A total of 2108 (67.9%) donor-recipient pairs were ABO identical, 451 (14.5%) had a minor mismatch, 430 (13.9%) had a major mismatch, and 114 (3.7%) had a bidirectional ABO mismatch. The groups did not differ significantly in patient or donor characteristics except for more female-to-male sex mismatch in the bidirectional ABO mismatch group (P = .017). In multivariate models of overall survival, transplant-related mortality, and grade II to IV acute GVHD, there were no significant differences among the 4 groups. Bidirectional ABO mismatch was associated with a significantly higher risk of grade III or IV acute GVHD (hazard ratio, 1.869; 95% confidence interval, 1.192-2.93; P = .006). Patients with major ABO mismatch received red blood cell transfusions (P = .001) for a longer timer after transplantation and had a slightly slower neutrophil recovery (P < .001). There was no evidence of a substantial effect of ABO blood group incompatibility on the outcome of conventional BMT among patients with leukemia.

SummarySeveral methods to detect anti-A/B antibodies based on haemagglutination and haemolysis have been described. These methods measure predominantly anti-A/B immunoglobulin (Ig)M, whereas anti-A/B IgG and IgG subclasses are less well examined. We established a flow cytometry method (ABOfluorescence-activated cell sorting; ABO-FACS) to quantify binding of anti-A/B IgM, IgG and IgG subclasses to human A or B red blood cells. Anti-A/B IgM were present in the majority of 120 blood donors, as expected from blood group typing. The sensitivity and specificity of anti-A/B IgM to predict the blood group was 93% and 96% respectively. Anti-A/B IgG was found in 34/38 blood group O samples (89%). Anti-B IgG in blood group A or anti-A IgG in blood group B was present in 4/28 (14%) and 1/28 (4%) samples, respectively, and absent in 26 AB sera. IgG2 was the predominant IgG subclass. The correlation of anti-A/B IgM and IgG in the ABO-FACS with haemagglutination titres was 0AE870 and 0AE783, respectively (n ¼ 240; P < 0AE001) whereas the comparison of ABO-FACS with ABO-enzymelinked immunosorbent assay was less significant. In conclusion, ABO-FACS is a valid method to quantify anti-A/B IgM, IgG and IgG subclasses. It opens the possibility of isotype-specific monitoring of anti-A/B antibodies levels after ABO-incompatible solid organ and stem cell transplantation.

Objective. To identify the determinants of antibody responses to adjuvanted split influenza A (H1N1) vaccines in patients with inflammatory rheumatic diseases.Methods. One hundred seventy-three patients (82 with rheumatoid arthritis, 45 with spondylarthritis, and 46 with other inflammatory rheumatic diseases) and 138 control subjects were enrolled in this prospective single-center study. Controls received 1 dose of adjuvanted influenza A/09/H1N1 vaccine, and patients received 2 doses of the vaccine. Antibody responses were measured by hemagglutination inhibition assay before and 3-4 weeks after each dose. Geometric mean titers (GMTs) and rates of seroprotection (GMT >40) were calculated. A comprehensive medical questionnaire was used to identify the determinants of vaccine responses and adverse events.Results. Baseline influenza A/09/H1N1 antibody levels were low in patients and controls (seroprotection rates 14.8% and 14.2%, respectively). A significant response to dose 1 was observed in both groups. However, the GMT and the seroprotection rate remained significantly lower in patients (GMT 146 versus 340, seroprotection rate 74.6% versus 87%; both P < 0.001). The second dose markedly increased antibody titers in patients, with achievement of a similar GMT and seroprotection rate as elicited with a single dose in healthy controls. By multivariate regression analysis, increasing age, use of disease-modifying antirheumatic drugs (DMARDs) (except hydroxychloroquine and sulfasalazine), and recent (within 3 months) B cell depletion treatment were identified as the main determinants of vaccine responses; tumor necrosis factor ␣ antagonist treatment was not identified as a major determinant. Immunization was well tolerated, without any adverse effect on disease activity.Conclusion. DMARDs exert distinct influences on influenza vaccine responses in patients with inflammatory rheumatic diseases. Two doses of adjuvanted vaccine were necessary and sufficient to elicit responses in patients similar to those achieved with 1 dose in healthy controls.

Xenotransplantation is one promising approach to bridge the gap between available human cells, tissues, and organs and the needs of patients with diabetes or end-stage organ failure. Based on recent progress using genetically-modified source pigs, improving results with conventional and experimental immunosuppression, and expanded understanding of residual physiologic hurdles, xenotransplantation appears likely to be evaluated in clinical trials in the near future for some select applications. This review offers a comprehensive overview of known mechanisms of xenograft injury, a contemporary assessment of preclinical progress and residual barriers, and our opinions regarding where breakthroughs are likely to occur.