A novel rapid single nucleotide polymorphism (SNP)-based method for assessment of hematopoietic chimerism after allogeneic stem cell transplantation

A major end point of nonmyeloablative hematopoietic stem cell transplantation is the attainment of either mixed chimerism or full donor hematopoiesis. Because the majority of human genetic disparity is generated by single nucleotide polymorphisms (SNPs), direct measurement of SNPs should provide a robust tool for the detection and quantitation of chimerism. Using pyrosequencing, a rapid quantitative sequencing technology, we developed a SNP-based assay for hematopoietic chimerism. Based on 14 SNPs with high allele frequencies, we were able to identify at least 1 informative SNP locus in 55 patients with HLA-identical donors. The median number of informative SNPs in related pairs was 5 and in unrelated pairs was 8 (P <.0001). Assessment of hematopoietic chimerism in posttransplantation DNA was shown to be quantitative, accurate, and highly reproducible. The presence of 5% donor cells was reliably detected in replicate assays. Compared with current measures of engraftment based on identification of short tandem repeats (STRs), variable number of tandem repeats (VNTRs), or microsatellite polymorphisms, this SNP-based method provides a more rapid and quantitative assessment of chimerism. A large panel of SNPs enhances the ability to identify an informative marker in almost all patient/donor pairs and also facilitates the simultaneous use of multiple markers to improve the statistical validity of chimerism measurements. The inclusion of SNPs that encode minor histocompatibility antigens or other genetic polymorphisms that may influence graft-versus-host disease or other transplantation outcomes can provide additional clinically relevant data. SNP-based assessment of chimerism is a promising technique that will assist in the analysis of outcomes following transplantation.     

IL28B alleles associated with poor hepatitis C virus (HCV) clearance protect against inflammation and fibrosis in patients infected with non-1 HCV genotypes

Genetic polymorphisms near IL28B are associated with spontaneous and treatment-induced clearance of hepatitis C virus (HCV), two processes that require the appropriate activation of the host immune responses. Intrahepatic inflammation is believed to mirror such activation, but its relationship with IL28B polymorphisms has yet to be fully appreciated. We analyzed the association of IL28B polymorphisms with histological and follow-up features in 2335 chronically HCV-infected Caucasian patients. Assessable phenotypes before any antiviral treatment included necroinflammatory activity (n = 1,098), fibrosis (n = 1,527), fibrosis progression rate (n = 1,312), and hepatocellular carcinoma development (n = 1,915). Associations of alleles with the phenotypes were evaluated by univariate analysis and multivariate logistic regression, accounting for all relevant covariates. The rare G allele at IL28B marker rs8099917-previously shown to be at risk of treatment failure-was associated with lower activity (P = 0.04), lower fibrosis (P = 0.02) with a trend toward lower fibrosis progression rate (P = 0.06). When stratified according to HCV genotype, most significant associations were observed in patients infected with non-1 genotypes (P = 0.003 for activity, P = 0.001 for fibrosis, and P = 0.02 for fibrosis progression rate), where the odds ratio of having necroinflammation or rapid fibrosis progression for patients with IL28B genotypes TG or GG versus TT were 0.48 (95% confidence intervals 0.30-0.78) and 0.56 (0.35-0.92), respectively. IL28B polymorphisms were not predictive of the development of hepatocellular carcinoma. CONCLUSION: In chronic hepatitis C, IL28B variants associated with poor response to interferon therapy may predict slower fibrosis progression, especially in patients infected with non-1 HCV genotypes.     

Comparison of eight diagnostic algorithms for liver fibrosis in hepatitis C: new algorithms are more precise and entirely noninvasive

The sequential algorithm for fibrosis evaluation (SAFE) and the Bordeaux algorithm (BA), which cross-check FibroTest with the aspartate aminotransferase-to-platelet ratio index (APRI) or FibroScan, are very accurate but provide only a binary diagnosis of significant fibrosis (SAFE or BA for Metavir F ≥ 2) or cirrhosis (SAFE or BA for F4). Therefore, in clinical practice, physicians have to apply the algorithm for F ≥ 2, and then, when needed, the algorithm for F4 ("successive algorithms"). We aimed to evaluate successive SAFE, successive BA, and a new, noninvasive, detailed classification of fibrosis. The study included 1785 patients with chronic hepatitis C, liver biopsy, blood fibrosis tests, and FibroScan (the latter in 729 patients). The most accurate synchronous combination of FibroScan with a blood test (FibroMeter) provided a new detailed (six classes) classification (FM+FS). Successive SAFE had a significantly (P < 10(-3) ) lower diagnostic accuracy (87.3%) than individual SAFE for F ≥ 2 (94.6%) or SAFE for F4 (89.5%), and required significantly more biopsies (70.8% versus 64.0% or 6.4%, respectively, P < 10(-3) ). Similarly, successive BA had significantly (P ≤ 10(-3) ) lower diagnostic accuracy (84.7%) than individual BA for F ≥ 2 (88.3%) or BA for F4 (94.2%), and required significantly more biopsies (49.8% versus 34.6% or 24.6%, respectively, P < 10(-3) ). The diagnostic accuracy of the FM+FS classification (86.7%) was not significantly different from those of successive SAFE or BA. However, this new classification required no biopsy. CONCLUSION: SAFE and BA for significant fibrosis or cirrhosis are very accurate. However, their successive use induces a significant decrease in diagnostic accuracy and a significant increase in required liver biopsy. A new fibrosis classification that synchronously combines two fibrosis tests was as accurate as successive SAFE or BA, while providing an entirely noninvasive (0% liver biopsy) and more precise (six versus two or three fibrosis classes) fibrosis diagnosis.     

Safety and efficacy of denileukin diftitox in patients with steroid-refractory acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Denileukin diftitox (Ontak), a recombinant protein composed of human interleukin 2 (IL-2) fused to diphtheria toxin, has selective cytotoxicity against activated lymphocytes expressing the high-affinity IL-2 receptor. We conducted a phase 1 study of denileukin diftitox in 30 patients with steroid refractory acute graft-versus-host disease (GVHD). Seven patients received 9 microg/kg intravenously on days 1 and 15; 18 received 9 microg/kg intravenously on days 1, 3, 5, 15, 17, and 19; and 5 received 9 microg/kg intravenously on days 1 to 5 and 15 to 19. Hepatic transaminase elevation was the dose-limiting toxicity (DLT), and dose level 2 was the maximum tolerated dose (MTD). Overall, 71% of patients responded with complete resolution (12 of 24; 50%) or partial resolution (5 of 24; 21%) of GVHD. Eight of 24 patients (33%) are alive at 6.3 to 24.6 months (median, 7.2 months). Denileukin diftitox is tolerable and has promising activity in steroid-refractory acute GVHD.     

Graft-versus-tumor response in patients with multiple myeloma is associated with antibody response to BCMA, a plasma-cell membrane receptor

Donor lymphocyte infusions (DLIs) induce effective graft-versus-tumor responses in patients with multiple myeloma who relapse after allogeneic hematopoietic stem-cell transplantation. The graft-versus-myeloma response is presumably mediated primarily by donor T cells, but recent studies have also demonstrated the presence of antibodies specific for a variety of myeloma-associated antigens in patients who achieve complete remission after DLI. One of the B-cell antigens identified in these studies was B-cell maturation antigen (BCMA), a transmembrane receptor of the tumor necrosis factor (TNF) superfamily that is selectively expressed by mature B cells. The present studies were undertaken to characterize the functional significance of antibodies to BCMA in vivo. Using transfected cells expressing BCMA, antibodies in patient serum were found to react with the cell-surface domain of BCMA. Post-DLI patient serum was able to induce complement-mediated lysis and antibody-dependent cellular cytotoxicity (ADCC) of transfected cells and primary myeloma cells expressing BCMA. BCMA antibodies were only found in post-DLI responders and not in other allogeneic transplant patients or healthy donors. These results demonstrate that BCMA is a target of donor B-cell immunity in patients with myeloma who respond to DLI. Antibody responses to cell-surface BCMA may contribute directly to tumor rejection in vivo.     

Antibody responses to H-Y minor histocompatibility antigens correlate with chronic graft-versus-host disease and disease remission

Minor histocompatibility antigens (mHAs) are known targets of donor T cells after allogeneic hematopoietic stem cell transplantation (HSCT). In contrast, B-cell responses to mHAs have not been extensively characterized and the clinical significance of antibodies to mHAs is unknown. We tested 121 patients who underwent HSCT and 134 healthy donors for immunoglobulin G (IgG) antibodies against 5 mHAs encoded by genes on the Y chromosome (DBY, UTY, ZFY, RPS4Y, and EIF1AY). Antibodies to at least one H-Y protein developed in 52% of male patients with female donors compared with 8.7% of male patients with male donors (P < .0001), and in 41.4% of healthy females compared with 7.8% of healthy males (P < .0001). H-Y antibodies develop 4 to 12 months after transplantation and persist for long periods. The clinical significance of H-Y antibodies was characterized in 75 male patients with hematologic malignancies who received stem cells from female donors (F --> M HSCT). The presence of H-Y antibodies correlated with chronic graft-versus-host disease (GVHD) by univariate (odds ratio [OR] = 15.5; P < .0001) and multivariable logistic regression analysis (OR = 56.5; P < .0001). Antibody response to Y-chromosome encoded histocompatibility antigens (H-Y antigens) was also associated with maintenance of disease remission (P < .0001). B cells may provide a new target for immune intervention in chronic GVHD.     

Sequential infusion of donor‐derived dendritic cells with donor lymphocyte infusion for relapsed hematologic cancers after allogeneic hematopoietic stem cell transplantation

Donor lymphocyte infusion (DLI) is often given to induce a graft‐versus‐leukemia (GVL) effect after allogeneic hematopoietic stem cell transplantation (HSCT). However, efficacy of DLI is limited in most hematologic cancers. As antigen presenting cells, dendritic cells (DC) bolster immune responses. We conducted a Phase I trial testing the coinfusion of DC followed by DLI. DC were generated by culturing peripheral blood mononuclear cells from HLA matched‐related donors in GM‐CSF and IL‐4 for 7 days, followed by TNF‐α for 3 days. DC were administered intravenously on 3 dose levels (5 × 10⁶; 1 × 10⁷; 5 × 10⁷ cells). DLI (3 × 10⁷ CD3+ cells/kg) was administered intravenously 1 day after the DC. Sixteen patients with hematologic cancers relapsed after HSCT were treated. A maximum tolerated dose for DC was not reached. Two of 16 patients met criteria for DLT within 10 weeks of the infusion: 1 idiopathic respiratory failure, 1 ventricular cardiac arrest. None developed grade III/IV GVHD. One patient developed grade II acute intestinal graft‐vs.‐host disease (GVHD) and 1 chronic GVHD within 6 months of the infusion. Both resolved with corticosteroids. Four of 14 patients evaluable for disease response achieved durable remissions and are alive and cancer free 6.7, 8.4, 8.8, and 10.1 years from infusion. Sequential infusion of donor‐derived DC with DLI is feasible in patients with relapsed hematologic cancers after allogeneic HSCT. Future studies may consider donor DC preloaded with tumor antigens to investigate whether DC infusion could augment the GVL effect. Am. J. Hematol. 89:1092–1096, 2014. © 2014 Wiley Periodicals, Inc.     

HIV infection in haemophilia--a European cohort

Ten haemophilia centres in northern Europe have pooled data on 202 haemophilic children who were infected with HIV between 1979 and 1986. All cases were under 16 years of age on 1 July 1985. The age at infection ranged from 1-15 years. Thirty seven cases (18%) had progressed to AIDS by 1 July 1991 and 15 of these have died. Persistent generalised lymphadenopathy has been noted in 102 patients of whom 18 (17%) have developed AIDS. Twenty three of the remaining patients (23%) have not. CD4+ T cell counts have fallen steadily. Of 36 patients who have had shingles since seroconversion, 19 (53%) had counts below 0.2 x 10(9)/l. Thirty five out of 145 patients without shingles (24%) had similar values. The mean IgA concentration in patients with CD4+ T cell counts above 0.5 x 10(9)/l was 2.38 g/l, between 0.2 and 0.5 was 3.07 g/l, and in those with CD4+ T cell counts below 0.2 x 10(9)/l the mean IgA concentration was 4.58 g/l. Treatment patterns have altered between 1989 and 1991, with increased use of zidovudine in patients without AIDS and a marked increase in primary prophylaxis against pneumocystis pneumonia. This has been associated with a decline in the incidence of pneumocystis as an indicator disease in new AIDS cases from 56% in 1989 to 20% in 1991. These observations indicate that persistent generalised lymphadenopathy does not worsen the outlook, but shingles does. Rising IgA concentrations are markers for disease progression. Modern prophylactic regimens are delaying the onset of indicator disease, but CD4 values continue to fall steadily.