Serologic Matching Research Articles

Lack of antibodies against the antigen domain 2 epitope of cytomegalovirus (CMV) glycoprotein B is associated with CMV disease after renal transplantation in recipients having the same glycoprotein H serotypes as their donors

Cytomegalovirus (CMV) reinfection of seropositive individuals has been associated with adverse outcomes in organ transplantation and is a frequent cause of congenital infection. Previously we demonstrated that mismatching of CMV glycoprotein H (gH) serotypes was associated with CMV disease after renal transplantation. Because the antigen domain 2 (AD2) epitope of glycoprotein B (gB) is conserved among CMV isolates and is one of the known targets of neutralizing antibodies, in this study we investigated whether antibodies against the epitope contribute to protection from CMV reinfection in renal transplantation, irrespective of gH serological matching. For this purpose, the gB and gH serology and clinical outcomes were analyzed retrospectively for 77 transplant recipients in the donor positive/recipient positive setting, who were managed by preemptive strategy. We found that there was a good negative correlation between the numbers of antigenemia-positive cells and the levels of antibodies against gB AD2 in the CMV-gH antibody matched group, but not in the CMV-gH antibody mismatched group. None of the recipients with antibodies against both gB AD2 and strain-specific epitopes of gH have experienced CMV disease during 6 month after transplantation, while 28% of those who lacked either/both antibody response needed preemptive therapy. Because the outcome was statistically significant, antibodies against gB AD2 can be a useful indicator to predict emergence of CMV disease for preemptive therapy, in addition to antibodies against the mismatched gH types.

Conditioning with 8 Gy Total Body Irradiation and Fludarabine for Allogeneic Hematopoietic Stem Cell Transplantation in Acute Myeloid Leukemia: Projected 4-Year Update.

Seventy-one patients with acute myeloid leukemia (AML), most of them (63/71) considered ineligible for conventional allogeneic hematopoietic stem cell transplantation (HSCT), were enrolled into a phase II study on reduced intensity myeloablative conditioning with fractionated 8 Gy total body irradiation (TBI) and fludarabine (120 mg/m2) (Blood. 2005 Nov 1;106(9):3314–21). Patients received mobilized peripheral blood stem cells (n=68) or bone marrow (n=3) from siblings (n=39) or unrelated donors (n=32). HLA-typing was performed for HLA-A, -B, -Cw (serological matching or intermediate resolution DNA typing), DRB1 and DQB1 (high resolution DNA typing). Three patients had unrelated donors with an allele mismatch in HLA DRB1 (2 with an additional mismatch in HLA Cw) and 7 patients were transplanted from unrelated donors with an antigen mismatch in HLA Cw. Thirty-six patients were transplanted in complete remission (CR) and 35 with untreated or refractory disease (non-CR). Median patient age was 51 years (range, 20–66). Sustained engraftment was attained in all evaluable patients. With a median follow-up of now 41.3 months (range, 20.4–70.4) in surviving patients, probabilities of overall survival for patients transplanted in CR and non-CR were 80% (95% CI, 66 to 94%) and 17% (95% CI, 5 – 29%) at 4 years, respectively. Relapse-free survival rates were 57% (95% CI, 39 – 75%) and 14% (95% CI, 2 – 26%). Of the 35 evaluable patients transplanted in CR, 10 patients suffered a relapse between days 68 and 868 after transplantation (cumulative incidence 29%). Five patients with late relapse (>1 year after transplantation) achieved a subsequent CR after conventional chemotherapy, blood stem cell boost and treatment with granulocyte-macrophage colony-stimulating factor, lasting 2000+, 1841+, 909+, 847+ and 480 days, respectively. Depending on donor type, relapse-free survival was similar in patients transplanted from unrelated or sibling donors. Overall survival in patients transplanted in complete remission from unrelated vs. sibling donors was 84% (95% CI, 73 – 95%) vs. 77% (95% CI, 68 – 86%). The cumulative incidence of non-relapse mortality (NRM) in CR patients was 11% at 4 years and beyond (3 patients deceased before day 100 and 1 patient 25 months after transplantation), but amounted to 37% at 4 years in non-CR patients. Nine of the 33 surviving patients (27%) have actually active chronic GvHD (5 limited and 4 extensive disease). This update confirms that allogeneic HSCT from related or unrelated donors with 8 Gy TBI/fludarabine conditioning is feasible with low NRM and preserved long-term antileukemic activity in AML patients in first or later CR.

Reduced Intensity Conditioning Regimens with Alemtuzumab Result in Low Treatment-Related Mortality and Low Relapse Rate in Unrelated and Related Allotransplantation Recipients.

From September, 2003, to July, 2006, 29 adult patients with hematological malignancies received reduced intensity conditioning (RIC) instead of standard conditioning for allogeneic transplant. The RIC regimens used in our program employ an ablative dose of melphalan and patients become cytopenic and transfusion-dependent. Patients were transplanted for a variety of malignancies including multiple myeloma, AML, CML, NHL, MDS, one renal cell carcinoma and one CLL. Eleven (38%) were in CR at time of transplant while 18 (62%) had relapsed or refractory disease. With a median follow-up of 8 mon (range 1–27 mon) we have completed a retrospective analysis of treatment-related mortality, d+100 and overall survival, engraftment, grades I-II and III-IV acute GVHD, and relapse rate. Two RIC regimens were used consecutively, consisting of either: fludarabine 30 mg/m2 × 5 d and melphalan 140 mg/m2 × 1 d in both groups, and Alemtuzumab 20 mg/d × 3d (Group 1) and × 2d (Group 2). Group 1 was 10 patients and Group 2 was 19. Median age was 53, range 24–66. Median age of Group 1 was 47 (range 24–59) and of Group 2 was 54 (range 34–66). Seventeen patients received MUD products (4 in Group 1 and 13 in Group 2) and twelve received MRD products. Cell source was bone marrow (8 patients), PBSC (18 patients) cord blood (2 patients) and combined products in 2 transplants (2 patients). All patients received an adequate C34+ cell dose or TNC dose (cord blood) and none of the products was manipulated. HLA matches were 6/6 antigen matches or better in Group 1 except for a 4/6 allele matched cord blood. All products were 6/6 or better in Group 2 except for two who were 8/10 allele matches, one 5/6 antigen match and a 4/6 serological match (cord). GVH prophylaxis was tacrolimus tapering after d+100 and MMF tapering after d+30. All patients except one achieved a WBC graft, and the ANC >500/dl occurred at a median of 12 d (range 10–48 d). The graft failure was a CML in Group 2 who received the 8/10 marrow product followed by a cord blood transplant that also failed. Eight (28%) of the cohort developed acute GVHD grades I-II (one from Group 1, 7 from Group 2) and two developed grades III-IV (one from each group). Five (17%) went on to develop chronic GVHD (one from Group 1, 4 from Group 2). Relapse or disease progression occurred in only 38% (4 in Group 1 and 7 in Group 2). Seven from the cohort were treated with one or more DLI to accelerate conversion to full chimerism and two from each group developed acute GVHD following the treatment. Incidence of treatment-related mortality by d+100 was low at 21%, with two patients in Group 1 and 4 in Group 2. Overall survival was 41%, 3 in Group 1 and 9 in Group 2. Most surprising was the overall survival of MUD patients, 41%, all from Group 2, which is higher than that reported by NMDP for unrelated transplants. In summary, we plan to continue accruing patients to both Alemtuzumab dosing regimens in order to compare the incidence of GVHD and relapse rate in each treatment arm. We conclude that a RIC regimen utilizing Alemtuzumab allows for a relatively low treatment-related mortality (21%), a low relapse rate (38%) and a superior survival (41%), especially in MUD transplants.

HLA-DR matching reduces rejection rate in heart transplantation.

We have studied the influence of serological matching for ten HLA-DR antigens on the occurrence of acute cellular rejection in heart transplantation by correlating the findings in routine endomyocardial biopsies taken during the first posttransplant year with the results of HLA typing of all recipients of a first cardiac graft and their donors during 1983-1994 at our center. We found that recipients of HLA-DR matched hearts had a lower frequency of acute cellular rejection, especially so for the moderate/severe rejection grades. Also, rejection appeared earlier in the DR-mismatched combinations. Whether the mismatch was for one or two DR antigens did not make a significant difference, neither could we demonstrate any influence of HLA-A or -B mismatches. The survival of DR-matched cardiac grafts tended to be higher at 1 year than DR-mismatched grafts, but the difference did not reach statistical significance.

HLA matching in pediatric recipients of a first kidney graft. A single center analysis.

We retrospectively examined the effect of HLA-A, -B, and -DR serological matching on graft survival in 88 pediatric end-stage renal disease patients who underwent primary renal transplantation. Actuarial graft survivals (GS) at 2 and 6 years in patients with zero DR mismatches (MM) (12 patients) or 1 DR MM (58 patients) were significantly higher than those in patients with 2 DR MM (18 patients) (2-year GS: 100% vs. 90% vs. 59%; 6-year GS: 100% vs. 79% vs. 59%, respectively). Because of the low number of patients in the zero DR MM group, only the GS difference between 1 DR MM and 2 DR MM had a significant result at 1 year (92% vs. 68%). No clear HLA matching effect was obtained in the HLA-A and -B loci. When DR were combined with A or B antigens (0-2 MM vs. 3-4 MM), significantly higher GS at 1, 2, and 6 years persisted for patients with 0-2 MM only in the A, DR group (96%, 94%, and 85% vs. 68%, 63%, and 56%, respectively). It is suggested that avoidance of mismatching for DR alleles at the serological level, in the selection of pediatric recipients of first cadaveric renal transplantation, leads to an improvement of both short- and longterm graft outcome.

HLA-DRB1 matching as a recipient selection criterion in cadaveric renal transplantation.

We retrospectively examined the effect of HLA-DRB1 matching at the DNA level compared with serological HLA-DR matching on acute rejection and graft survival in patients who underwent primary cadaveric renal transplantation. For patients with serological HLA-DR zero mismatch, the incidence of acute rejection in patients with zero DRB1 mismatch (3/20; 15%) was significantly lower than in those with one or two DRB1 mismatches (10/21; 48%). Five-year graft survival in patients with zero DRB1 mismatch was 100%, whereas that in those with one or two DRB1 mismatches was 76%, although the difference was not statistically significant. The fact that HLA-DRB1 matching at the DNA level influenced incidence of graft rejection after cadaveric renal transplantation is analogous to results in living-related renal transplantation. It is suggested that avoidance of mismatching for DRB1 alleles at the DNA level in recipient selection of cadaveric renal transplantation leads to an improvement of graft outcome.

Transplantation rénale et compatibilité HLA-DR évaluée par analyse génomique : étude unicentre

The actual effect of HLA-DR matching in renal transplantation remains controversial. Since DNA analysis has been shown to be more reliable than serological typing, a re-evaluation of the impact of DR-matching on graft prognosis is required. In this study, 224 cadaver kidney transplantations performed in our center were retrospectively matched according to Restriction Fragment Length Polymorphism DR incompatibilities and compared to prospective serological DR-matching. Transplant outcome was evaluated using graft survival, first rejection onset and rejection frequency. In 18.8% individuals, a discrepancy between serology and DNA typing for at least one antigen was noted. Serology particularly failed to type recipients (21.7%) and 43.2% of the total missed antigens were serologically "blank" or unidentified ("X") alleles. A graft survival rate of 100% after one year was observed for transplantations with no DNA DR mismatch (n = 31). Furthermore, there was a definite correlation between DNA matching and (i), the percentage of individuals with one or more than one acute rejection episode (18% and 41.8% at one year for O incompatibility and pooled 1 and 2 incompatibilities respectively, p < 0.05); (ii), the mean of acute rejection per individual (p < 0.001); and (iii), the rejection onset time (p < 0.01). No correlation between serological matching and the acute rejection episodes parameters was noted. Since HLA typing could be performed in less than 2 hrs using new molecular biology techniques, we conclude that prospective DNA typing should improve kidney transplantation outcome in the near future.

Serological responses in volunteers to inactivated trivalent subunit influenza vaccine: Antibody reactivity with epidemic influenza A and B strains and evidence of a rapid immune response

A study of the immunogenicity of the inactivated trivalent subunit influenza vaccine for the 1989/90 season was performed in what proved to be an influenza epidemic year. One hundred student volunteers at The London Hospital Medical College participated in the study and the findings indicated that there was an excellent serological match between the epidemic strain of influenza A (H3N2) and the vaccine strain. Before vaccination, the geometric mean titre (GMT) to A/England/308/89, a representative H3N2 epidemic strain in the United Kingdom from the 1989/90 season, was 46. Post-vaccination the antibody levels rose and 99% of vaccinees had HI titres of greater than or equal to 40, the GMT being 131. The serological responses were also investigated against other circulating influenza A (H3N2 and H1N1) and B strains. Preliminary results of an evaluation of the rapidity of the immune response showed that in three of six subjects rises in HI antibody appeared within two days of vaccination.

Latex agglutination and enzyme-linked immunosorbent assays for cytomegalovirus serologic screening of transplant donors and recipients.

The effectiveness of three serologic assays (two enzyme-linked immunosorbent assays [ELISAs] and latex agglutination) for cytomegalovirus (CMV) serologic matching of donors and recipients was assessed over a 2-year period in a major organ transplant program. Sera with equivocal test results were investigated by repeat testing of serum samples and additional specimens from the individuals involved and monitoring of CMV infection in recipients. An in-house ELISA identified all CMV-infective donors as seropositive. Of 63 ELISA-positive donors, 5 were negative by latex agglutination; recipients from 3 of these donors developed primary CMV infection posttransplant. The in-house ELISA and a commercial ELISA (Abbott enzyme immunoassay; Abbott Laboratories, North Chicago, Ill.) had a 93% concordance of results; follow-up testing indicated that the Abbott assay was sensitive but had a false-positive rate of about 11%. One recipient with a false-positive result developed symptomatic primary CMV infection after receiving a seropositive organ. Thus, performance characteristics of currently used screening assays affect recipient outcome.

Serological matching for D locus antigens improves kidney allograft survival in rhesus monkeys.

A prospective study performed in unrelated, unimmunized rhesus monkeys revealed that serological matching for D-associated Ia1 antigens improves kidney allograft prognosis, provided that the recipients are nonreactive in mixed lymphocyte cultures (MLC) against their donors. MLC-negative host-donor combinations showed a more than 3-fold increase in the mean survival time as compared with MLC-positive combinations. Apparently, compatibility for the most important MLC-stimulating determinants is required for a significant improvement in graft survival. On the other hand, matching for A and B loci antigens did not play a decisive role. Since the relatively simple matching on the basis of identity for Ia1 (or DR) antigens yields a rather high proportion of MLC-nonreactive combinations, this method is likely to become an essential addition to the conventional matching procedures, also in clinical organ transplantation.