Severe Symptomatic Primary Human Cytomegalovirus Infection despite Effective Innate and Adaptive Immune Responses.

Primary human cytomegalovirus (HCMV) infection usually goes unnoticed, causing mild or no symptoms in immunocompetent individuals. However, some rare severe clinical cases have been reported without investigation of host immune responses or viral virulence. In the present study, we investigate for the first time phenotypic and functional features, together with gene expression profiles in immunocompetent adults experiencing a severe primary HCMV infection. Twenty primary HCMV-infected patients (PHIP) were enrolled, as well as 26 HCMV-seronegative and 39 HCMV-seropositive healthy controls. PHIP had extensive lymphocytosis marked by massive expansion of natural killer (NK) and T cell compartments. Interestingly, PHIP mounted efficient innate and adaptive immune responses with a deep HCMV imprint, revealed mainly by the expansion of NKG2C+ NK cells, CD16+ Vδ2(-) γδ T cells, and conventional HCMV-specific CD8+ T cells. The main effector lymphocytes were activated and displayed an early immune phenotype that developed toward a more mature differentiated status. We suggest that both massive lymphocytosis and excessive lymphocyte activation could contribute to massive cytokine production, known to mediate tissue damage observed in PHIP. Taken together, these findings bring new insights into the comprehensive understanding of immune mechanisms involved during primary HCMV infection in immunocompetent individuals.IMPORTANCE HCMV-specific immune responses have been extensively documented in immunocompromised patients and during in utero acquisition. While it usually goes unnoticed, some rare severe clinical cases of primary HCMV infection have been reported in immunocompetent patients. However, host immune responses or HCMV virulence in these patients has not so far been investigated. In the present study, we show massive expansion of NK and T cell compartments during the symptomatic stage of acute HCMV infection. The patients mounted efficient innate and adaptive immune responses with a deep HCMV imprint. The massive lymphocytosis could be the result of nonadapted or uncontrolled immune responses limiting the effectiveness of the specific responses mounted. Both massive lymphocytosis and excessive lymphocyte activation could contribute to massive cytokine production, known to mediate tissue damage. Furthermore, we cannot exclude a delayed immune response caused by immune escape established by HCMV strains.

Favorable impact of allogeneic stem cell transplantation in patients with therapy-related myelodysplasia regardless of TP53 mutational status.

Therapy-related myelodysplastic syndrome is a long-term complication of cancer treatment in patients receiving cytotoxic therapy, characterized by high-risk genetics and poor outcomes. Allogeneic hematopoietic cell transplantation is the only potential cure for this disease, but the prognostic impact of pre-transplant genetics and clinical features has not yet been fully characterized. We report here the genetic and clinical characteristics and outcomes of a relatively large cohort of patients with therapy-related myelodysplastic syndrome (n=67) who underwent allogeneic transplantation, comparing these patients to similarly treated patients with de novo disease (n=199). The 5-year overall survival was not different between patients with therapy-related and de novo disease (49.9% versus 53.9%; P=0.61) despite a higher proportion of individuals with an Intermediate-2/High International Prognostic Scoring System classification (59.7% versus 43.7%; P=0.003) and high-risk karyotypes (61.2% versus 30.7%; P<0.01) among the patients with therapy-related disease. In mutational analysis, TP53 alteration was the most common abnormality in patients with therapy-related disease (n=18: 30%). Interestingly, the presence of mutations in TP53 or in any other of the high-risk genes (EZH2, ETV6, RUNX1, ASXL1: n=29: 48%) did not significantly affect either overall survival or relapse-free survival. Allogeneic stem-cell transplantation is, therefore, a curative treatment for patients with therapy-related myelodysplastic syndrome, conferring a similar long-term survival to that of patients with de novo disease despite higher-risk features. While TP53 alteration was the most common mutation in therapy-related myelodysplastic syndrome, the finding was not detrimental in our case-series.

Influence of Absorption, Distribution, Metabolism, and Excretion Genomic Variants on Tacrolimus/Sirolimus Blood Levels and Graft-versus-Host Disease after Allogeneic Hematopoietic Cell Transplantation.

Allelic variants of genes implicated in drug absorption, distribution, metabolism, and excretion (ADME) determine the pharmacokinetic variability of many medications and are increasingly recognized as important factors determining the success or failure of medical treatments. Both tacrolimus and sirolimus have narrow therapeutic ranges maintained by therapeutic drug monitoring (TDM). Using an ADME panel that covers >99% of the PharmaADME working group core list (188 single nucleotide polymorphism [SNP] and 12 copy number variant [CNV] assays in 36 pharmacogenetically relevant genes), we studied 177 patients who underwent allogeneic hematopoietic cell transplantation (HCT) using tacrolimus/sirolimus-based graft-versus-host disease (GVHD) prophylaxis. We tested for possible associations between ADME variants and tacrolimus/sirolimus drug levels, concentration/dose (C/D) ratio, and clinical endpoints, including acute GVHD. A total of 62 SNP and 6 CNV assays were evaluable after removing the variants, which were homozygous in (nearly) all samples. For sirolimus, rs2032582 (ABCB1) T-carriers versus non-T-carriers were associated with higher blood levels (P = .01), with similar results for C/D ratio. Generalized estimating equation analysis supported these findings. For tacrolimus, rs776746 CYP3A5*3/*3 and CYP3A5*3/*1 were associated with higher blood levels than CYP3A5*1/*1 (P = .002). By multivariable analysis, rs776746 CYP3A5*3/*3 and CYP3A5*3/*1 were independently associated with decreased acute GVHD compared with CYP3A5*1/*1, after adjustment for conditioning, donor type, race/ethnicity, and age. We demonstrated association of specific ADME genetic polymorphisms with blood levels of tacrolimus/sirolimus, and incidence of acute GVHD after HCT, in spite of TDM and dose adjustment. A larger ongoing study will determine whether these associations have clinical utility beyond TDM.

KIR2DS5 in the presence of HLA-C C2 protects against endometriosis.

Endometriosis is defined as the presence of functional endometrial tissue outside the uterine cavity. Several hypotheses have attempted to explain the etiology and pathogenesis of endometriosis. Recently, it has been suggested that a defect of the natural killer (NK) activity in the recognition and lysis of endometrial cells is one of the crucial points in the development of this disease. Natural killer cells can express killer immunoglobulin-like receptors (KIR), which recognize class I human leukocyte antigens on target cells. We asked whether polymorphisms in KIR, HLA-C, and HLA-B genes are risk factors for endometriosis. We tested 153 women with endometriosis diagnosed on the basis of laparoscopic and histological examination, and 213 control healthy women, who gave birth to at least one child. The frequency of KIR genes in patients was similar to that in controls except for KIR2DS5, which exerted a protective effect only in HLA-C C2-positive individuals. Moreover, KIR2DS5-positive women with endometriosis had 13 times lower chance that the disease would occupy the peritoneum than KIR2DS5- and KIR2DS4del-negative ones (OR = 0.077, P = 0.0061). Similarly, KIR2DS4del-positive endometriotic persons had 11 times lower chance for peritoneal disease (OR = 0.094, P < 0.001). Negative linkage disequilibrium between KIR2DS5 and KIR2DS4del indicates that these genes are mutually exclusive. Our data suggest that KIR2DS5 may be associated with protection from endometriosis, whereas KIR2DS4del seems to be associated with higher disease stages, possibly by exclusion of protective KIR2DS5.

Both the nature of KIR3DL1 alleles and the KIR3DL1/S1 allele combination affect the KIR3DL1 NK-cell repertoire in the French population.

NK-cell functions are regulated by many activating and inhibitory receptors including KIR3DL1. Extensive allelic polymorphism and variability in expression can directly alter NK-cell phenotype and functions. Here we investigated the KIR3DL1(+) NK-cell repertoire, taking into account the allelic KIR3DL1/S1 polymorphism, KIR3DL1 phenotype, and function. All 109 studied individuals possessed at least one KIR3DL1 allele, with weak KIR3DL1*054, or null alleles being frequently present. In KIR3DL1(high/null) individuals, we observed a bimodal distribution of KIR3DL1(+) NK cells identified by a different KIR3DL1 expression level and cell frequency regardless of a similar amount of both KIR3DL1 transcripts, HLA background, or KIR2D expression. However, this bimodal distribution can be explained by a functional selection following a hierarchy of KIR3DL1 receptors. The higher expression of KIR3DL1 observed on cord blood NK cells suggests the expression of the functional KIR3DL1*004 receptors. Thus, the low amplification of KIR3DL1(high) , KIR3DL1*004 NK-cell subsets during development may be due to extensive signaling via these two receptors. Albeit in a nonexclusive manner, individual immunological experience may contribute to shaping the KIR3DL1 NK-cell repertoire. Together, this study provides new insight into the mechanisms regulating the KIR3DL1 NK-cell repertoire.

Significance of ethnicity in the risk of acute graft-versus-host disease and leukemia relapse after unrelated donor hematopoietic stem cell transplantation.

The significance of patient and donor ethnicity on risk of acute graft-versus-host disease (GVHD) and disease relapse after unrelated donor hematopoietic cell transplantation (HCT) is not known. A total of 4335 patient-donor pairs from the International Histocompatibility Working Group in HCT met the following 3 criteria: (1) HLA-A, -B, -C, -DRB1, and -DQB1 allele matched donor, (2) diagnosis of leukemia, and (3) non-T cell depleted GVHD prophylaxis. Posttransplantation risks of acute GVHD and leukemia relapse were defined in Asian/Pacific Islander, white, African American, Hispanic, and Native American patients that underwent transplantation from donors with the same self-described background. Asian patients had a significantly lower incidence of acute GVHD (Japanese patients: 40.0% grades II to IV and 15.3% grades III to IV; non-Japanese Asian patients: 42.1% grades II to IV and 15.7% grades III to IV) compared with white patients (56.5% grades II to IV and 22.6% grades III to IV) (P < .001). The hazard ratio of acute GVHD for white patients was significantly higher than for Japanese patients. Unexpectedly, the hazard ratio of leukemia relapse in white patients with early disease status was also significantly higher than that in Japanese patients. These results provide a platform for future investigation into the genetic factors for unrelated donor HCT and clinical implications of diverse ethnic background.

Hematopoietic cell transplantation with cord blood for cure of HIV infections.

Hematopoietic cell transplantation (HCT) using CCR5-Δ32/Δ32 stem cells from an adult donor has resulted in the only known cure of human immunodeficiency virus (HIV) infection. However, it is not feasible to repeat this procedure except rarely because of the low incidence of the CCR5-Δ32 allele, the availability of only a small number of potential donors for most patients, and the need for a very close human leukocyte antigen (HLA) match between adult donors and recipients. In contrast, cord blood (CB) transplantations require significantly less stringent HLA matching. Therefore, our hypothesis is that cure of HIV infections by HCT can be accomplished much more readily using umbilical CB stem cells obtained from a modestly sized inventory of cryopreserved CCR5-Δ32/Δ32 CB units. To test this hypothesis, we developed a screening program for CB units and are developing an inventory of CCR5-Δ32/Δ32 cryopreserved units available for HCT. Three hundred such units are projected to provide for white pediatric patients a 73.6% probability of finding an adequately HLA matched unit with a cell dose of ≥2.5 × 10(7) total nucleated cells (TNCs)/kg and a 27.9% probability for white adults. With a cell dose of ≥1 × 10(7) TNCs/kg, the corresponding projected probabilities are 85.6% and 82.1%. The projected probabilities are lower for ethnic minorities. Impetus for using CB HCT was provided by a transplantation of an adult with acute myelogenous leukemia who was not HIV infected. The HCT was performed with a CCR5-Δ32/Δ32 CB unit, and posttransplantation in vitro studies indicated that the patient's peripheral blood mononuclear cells were resistant to HIV infection.

Genetic susceptibility to anthracycline-related congestive heart failure in survivors of haematopoietic cell transplantation.

Haematopoietic cell transplantation (HCT) survivors are at increased risk for developing congestive heart failure (CHF), primarily due to pre-HCT exposure to anthracyclines. We examined the association between the development of CHF after HCT and polymorphisms in 16 candidate genes involved in anthracycline metabolism, iron homeostasis, anti-oxidant defence, and myocardial remodelling. A nested case-control study design was used. Cases (post-HCT CHF) were identified from 2950 patients who underwent HCT between 1988 and 2007 at City of Hope and had survived ≥1 year. This cohort formed the sampling frame for selecting controls (without CHF) matched on: age, race/ethnicity, cumulative anthracycline exposure, stem cell source (allogeneic, autologous), and length of follow-up. Seventy-seven cases with pre-HCT germline DNA and 178 controls were genotyped. Multivariate analysis revealed that the odds of CHF was higher in females [Odds Ratio (OR) = 2·9, P < 0·01], individuals with pre-HCT chest radiation (OR = 4·7, P = 0·05), hypertension (OR = 2·9, P = 0·01), and with variants of genes coding for the NAD(P)H-oxidase subunit RAC2 (rs13058338, 7508T→A; OR = 2·8, P < 0·01), HFE (rs1799945, 63C→G; OR = 2·5, P = 0·05) or the doxorubicin efflux transporter ABCC2 (rs8187710, 1515G→A; OR = 4·3, P < 0·01). A combined (clinical and genetic) CHF predictive model performed better [area under the curve (AUC), 0·79] than the genetic (AUC = 0·67) or the clinical (AUC = 0·69) models alone.

A phase II pilot study of tacrolimus/sirolimus GVHD prophylaxis for sibling donor hematopoietic stem cell transplantation using 3 conditioning regimens.

Combination tacrolimus and sirolimus graft-versus-host disease (GVHD) prophylaxis for allogeneic transplant in patients conditioned with a fractionated total body irradiation-based regimen has shown encouraging results. We studied this prophylaxis combination in 85 patients receiving a matched-sibling transplant conditioned with 3 different regimens:fludarabine-melphalan (n = 46); total body irradiation-etoposide (n = 28), and busulfan-cyclophosphamide (n = 11). The conditioning regimens were completed on day -4. Sirolimus and tacrolimus were started on day -3 to avoid overlap with conditioning therapy. All patients engrafted, with a median time to neutrophil engraftment of 15 days. The cumulative incidence of acute GVHD grades II to IV and III to IV was 43% and 19%, respectively, with no significant difference by conditioning regimen. The 2-year cumulative incidence of chronic GVHD was 46%. With a median follow-up of 26 months, disease-free survival was 58% and overall survival, 66%. The day-100 and 2-year nonrelapse mortality was 4.8% and 10.2%, respectively. The overall incidence of thrombotic microangiopathy was 19%, and it was significantly higher with busulfan/cyclophosphamide (55%, P = .005). Tacrolimus plus sirolimus is an effective combination for acute GVHD prophylaxis and is associated with very low nonrelapse mortality. Thrombotic microangiopathy is a significant complication with this regimen, particularly in patients receiving busulfan/cyclophosphamide.

Expression of activating KIR2DS2 and KIR2DS4 genes after hematopoietic cell transplantation: relevance to cytomegalovirus infection.

The important role of activating killer immunoglobulin-like receptors (KIRs) in protecting against cytomegalovirus (CMV) reactivation has been described previously in patients undergoing hematopoietic cell transplantation (HCT). More specifically, the presence of multiple activating KIRs and the presence of at least KIR2DS2 and KIR2DS4 in the donor genotype identified a group of HCT patients at low risk for CMV reactivation. However, CMV infection still occurs in patients with the KIR protective genotype, and the question has been raised as to whether this is related to the lack of KIR expression. In this report, expression of the KIR2DS2 and KIR2DS4 genes, as measured by mRNA-based quantitative polymerase chain reaction in both the donor cells and the HCT recipient cells, was studied relative to CMV reactivation. In the control samples from healthy donors, the median range for KIR2DS2 and KIR2DS4 expression was low, with 35% of donors considered null-expressers. Interestingly, KIR2DS2 and KIR2DS4 expression was elevated after HCT compared with donor expression before HCT, and was significantly elevated in CMV viremic compared with CMV nonviremic HCT recipients. The CMV seropositivity of donors was not associated with activating KIR expression, and donor null expression in those with the KIR2DS2 or KIR2DS4 genotype was not predictive for CMV reactivation in the recipient. After controlling for other transplant factors, including donor type (sibling or unrelated), transplant source (bone marrow or peripheral blood stem cells), and acute GVHD grade, regression analysis of elevated KIR gene expression found an association for both KIR2DS2 and KIR2DS4, with a 7-fold increase in risk for CMV reactivation. We speculate that the elevated activating KIR expression in CMV-viremic HCT recipients is either coincidental with factors that activate CMV or is initiated by CMV or cellular processes responsive to such CMV infection reactivation.

One-antigen mismatched related versus HLA-matched unrelated donor hematopoietic stem cell transplantation in adults with acute leukemia: Center for International Blood and Marrow Transplant Research results in the era of molecular HLA typing.

Approximately 13% of patients lacking an HLA-identical sibling have a one-antigen-mismatched related donor (MMRD). Historically, outcomes from the use of a one-antigen MMRD were considered equivalent to those from the use of a matched unrelated donor (UD). Recent improvements in UD stem cell transplantation (SCT) resulting from better molecular HLA matching justifies investigating whether UD should be preferred over MMRD in adult patients with acute leukemia. Here, we compared the outcomes of MMRD (n = 89) and HLA-A, -B, -C, and -DRB1 allele-matched UD (n = 700) SCT reported to the Center for International Blood and Marrow Transplant Research between 1995 and 2005. The patients underwent transplantation for acute myelogenous leukemia or acute lymphoblastic leukemia in first or second complete remission. Donor type was not associated with hematologic recovery. Univariate and multivariate comparisons of MMRD versus HLA-matched UD transplants showed no statistically significant differences in overall survival, disease-free survival, treatment-related mortality, relapse, or 100-day grade III-IV acute graft-versus-host disease (GVHD). MMRD SCT was associated with a lower rate of chronic GVHD at 1 year (35% vs 47%; P = .03), which was confirmed by multivariate analysis (relative risk, 0.58; 95% confidence interval, 0.39-0.85; P < .01). According to our data, HLA-matched UD and MMRD SCT are associated with comparable survival. Given that less chronic GVHD was observed in the MMRD transplantations, this option, when available, remains the first choice in patients with acute leukemia without an HLA-identical sibling in need of allogeneic SCT.

Rapid, flow cytometric assay for NK alloreactivity reveals exceptions to rules governing alloreactivity.

Alloreactive NK cells lyse target cells lacking self-HLA-C or the HLA-B-Bw4 epitope. Prior to haploidentical stem cell transplants, donor alloreactivity toward the patient is evaluated by natural killer (NK) cloning followed by testing of the clones in the (51)Cr-release assay. As only a few percent of NK clones are alloreactive, a large number of NK clones must be established and evaluated. This approach is laborious and time consuming, with a complete evaluation taking up to 6 weeks. We developed a flow cytometry-based cytotoxicity assay utilizing CD107a expression on 12-day polyclonally expanded NK cells and showed that NK alloreactivity mediated by inhibitory and activating KIR can be detected by measuring CD107a expression following incubation with targets lacking the appropriate class I epitope. The percentage of alloreactive NK cells varied greatly between individuals and was easily estimated by the CD107a assay. For each epitope (C1, C2, Bw4), donors were found who did not have alloreactivity, although alloreactivity was predicted by the current rules thought to govern alloreactivity. The data emphasize the importance of demonstrating alloreactivity in a functional assay.

Killer immunoglobulin-like receptor ligand HLA-Bw4 protects against multiple sclerosis.

OBJECTIVE: Multiple sclerosis (MS) is a chronic inflammatory disease affecting the central nervous system. A human leukocyte antigen (HLA) class II association is well established (DRB1*1501-DQB1*0602), but more recently HLA class II-independent associations with HLA class I variants have also been reported. The HLA class I (HLA-A, -B, -C) molecules serve as ligands for both T-cell receptors and killer immunoglobulin-like receptors (KIRs). We investigated the HLA class I alleles defined by their KIR binding motifs and the KIR genes to evaluate whether these genes could influence MS susceptibility or severity, alone or in combination. METHODS: We typed Norwegian MS patients (n = 631) and controls (n = 555) for HLA-A, -B, -C and -DRB1 alleles as well as the presence or absence of genes encoding inhibitory (KIR2DL1, KIR2DL2, KIR2DL3, KIR2DL5, KIR3DL1, KIR3DL2, KIR3DL3) and activating (KIR2DS1, KIR2DS2, KIR2DS3, KIR2DL4, KIR2DS4, KIR2DS5, KIR3DS1) KIRs. RESULTS: The frequency of the HLA-Bw4 specificity, which is the ligand for the inhibitory KIR3DL1, was significantly reduced in MS patients as compared with controls (41.4% vs 55.1%, p(uncorrected (uc)) = 4.6 x 10(-6)). Also after stratifying for known HLA class II associations, the HLA-Bw4 association was seen (p(uc) = 0.002). No significant differences in gene carrier frequencies of inhibitory and activating KIRs were observed. However, our data indicate that MS patients who carry the activating KIR2DS2 and the inhibitory KIR2DL2 genes have more severe disease than patients not carrying these genes. INTERPRETATION: Carriage of the ligand of the inhibitory KIR3DL1 receptor, HLA-Bw4, was found to protect against MS in an HLA-DRB1 independent manner.

The effect of single and combined activating killer immunoglobulin-like receptor genotypes on cytomegalovirus infection and immunity after hematopoietic cell transplantation.

It has been shown that activating killer Ig-like receptor (aKIR) genes are important for control of cytomegalovirus (CMV) reactivation after hematopoietic cell transplantation (HCT). To date, using the broad classification of KIR haplotypes A and B, the precise role of individual KIR genes in the control of infection cannot be discerned. To address this, a consecutive case series of 211 non-T cell-depleted HCT patients all at risk for CMV were monitored biweekly for CMV DNA in plasma by quantitative polymerase chain reaction (Q-PCR) and at intervals for CMV-specific T cell immunity. Comparing patients with CMV reactivation (n = 152) to those with no reactivation (n = 59), the presence of specific aKIR haplotypes in the donor, but not in the recipient, were associated with protection from CMV reactivation and control of peak plasma CMV DNA (P < .001). A donor aKIR profile, predictive for low risk of CMV reactivation, contained either aKIR2DS2 and aKIR2DS4 or had >/=5 aKIR genes. Neither donor nor recipient inhibitory KIR (iKIR) played a role in a protective effect. CD4(+)- and CD8(+)-specific CMV immunity did not explain reduced CMV infection. The initial control of CMV infection after HCT is managed by aKIR functions, and donor aKIR haplotypes deserve further evaluation in donor selection for optimized HCT outcome.

Reduced-intensity conditioning followed by peripheral blood stem cell transplantation for adult patients with high-risk acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) with high-risk features has a poor prognosis in adults despite aggressive chemotherapy. Reduced-intensity conditioning (RIC) is a lower toxicity alternative for high-risk patients requiring hematopoietic cell transplantation (HCT); however, it has not been widely used for ALL. We conducted a retrospective study of 24 high-risk adult ALL patients who received an RIC regimen of fludarabine (Flu)/melphalan (Mel) prior to allogeneic peripheral blood stem cell transplantation (PBSCT) between 6/14/02 and 6/15/07 at the City of Hope. Indications for the RIC regimen were: (1) aged 50 years or older (42%), (2) compromised organ function (54%), or (3) recipient of a previous HCT (37.5%). Patients had a median age of 47.5 years and the median follow-up was 28.5 months for living patients. Both overall survival (OS) and disease-free survival (DFS) at 2 years was 61.5%. Relapse incidence was 21.1% and nonrelapse mortality (NRM) was 21.5% at 2 years. Chronic graft-versus-host (cGVHD) developed in 86% of evaluable patients. In this series, no significant correlations were made between outcomes and patient age, presence of Philadelphia chromosome, relatedness of donor source, or prior HCT. These high survival rates for high-risk ALL patients following RIC HCT may offer a promising option for patients not eligible for a standard myeloablative transplant.

Influence of donor KIR genotypes on reduced relapse risk in acute myelogenous leukemia after hematopoietic stem cell transplantation in patients with CMV reactivation.

Multiple retrospective studies have demonstrated an association between cytomegalovirus (CMV) reactivation and reduced risk of AML relapse. However, the potential mechanism explaining this association remains elusive. We investigated a homogeneous cohort of 288 adult patients with AML in remission who received allogeneic hematopoietic stem cell transplantation (HCT) from matched sibling/unrelated donors between 1995 and 2011. The 5-year cumulative incidence of relapse was greater in patients without CMV reactivation compared with those with reactivation (30.2% vs. 12.1%, p = 0.001) in a landmark analysis. In multivariate analyses CMV reactivation was independently associated with reduced relapse risk (HR: 0.49 [0.25-0.95], p = 0.036) and increased non-relapse mortality (26.5% vs. 13.1%, p = 0.002) resulting in similar 5-year overall survival (64.5% vs. 59.1%, p = 0.8). In further subgroup analyses the protective effect of CMV reactivation was significant in patients who received HCT from donors with KIR Bx compared to KIR AA (11.7% vs. 29.5%, p = 0.01). Likewise, the protective effect of CMV reactivation was more significant when the donors had 2DS1 activating KIR (11.5% vs. 30.7%, p = 0.05) compared with those without 2DS1 (14.3% vs. 27.5%, p = 0.12). Our data independently confirmed the association between CMV reactivation and AML relapse, suggesting the involvement of donor KIR genotypes and NK cell-mediated graft-versus-leukemia effect.

The association between HLA and non-Hodgkin lymphoma subtypes, among a transplant-indicated population.

Several studies have implicated HLA in non-Hodgkin lymphoma (NHL) subtype etiology. However, NHL patients indicated for stem cell transplants are underrepresented in these reports. We therefore evaluated the association between HLA and NHL subtypes among a transplant-indicated population. One thousand three hundred and sixty-six NHL patients HLA-typed and indicated for transplant at the City of Hope National Medical Center (Duarte, CA) were compared to 10,271 prospective donors. Odds ratios and 95% confidence intervals were calculated for HLA haplotype and alleles, adjusted for sex and age. The HLA-A*0201∼C*0602∼B*1302∼DRB1*0701∼DQB1*0201 haplotype was significantly associated with follicular lymphoma (FL) risk among Caucasians. Several haplotypes were associated with diffuse large B-cell lymphoma (DLBCL) risk among Caucasians, including the previously implicated DLBCL risk loci, HLA-B*0801. The HLA-A*0101 allele was also observed to be associated with mantle cell lymphoma (MCL) risk. Our results support the association between previously reported susceptibility loci and FL and suggest potentially new DLBCL and MCL risk loci.

Impact of graft cell dose on transplant outcomes following unrelated donor allogeneic peripheral blood stem cell transplantation: higher CD34+ cell doses are associated with decreased relapse rates.

Peripheral blood stem cells (PBSC) have been increasingly used in the matched unrelated donor (MUD) transplant setting, but the impact of CD34(+) cell dose on outcomes in this setting have not been well characterized. We analyzed 181 consecutive patients who underwent MUD-PBSC transplantation at the City of Hope between August 2000 to December 2004. Patients were conditioned with either full-intensity regimen or reduced-intensity regimen. There was a significant inverse relationship between higher CD34(+) cell dose and faster neutrophil engraftment (r = -0.16, P = .035). By univariate analysis, a CD34(+) cell dose > or =4.2 x 10(6)/kg (above the lowest quartile) was associated with significantly lower relapse risk (hazard ratio [HR] = 0.67, P = .0126), with a trend for corresponding improvement for disease-free survival (HR = 0.84, P = .12) but not overall survival (HR = 0.91, P = .46). The impact of the CD34(+) cell dose remained significant in multivariate analysis. The higher CD34(+) cell dose was significantly associated with faster recovery of absolute lymphocyte counts on day +30 posttransplant. Subset analysis demonstrated that the higher CD34(+) cell dose was associated with (1) greater reduction in relapse in myeloid malignancies than that in lymphoid malignancies, (2) greater reduction in reduced-intensity conditioning than in full-intensity conditioning, (3) greater reduction in relapse when there is a inhibitory killer-cell immunoglobulin-like receptor ligand (iKIRL)-mismatch in the gravft-versus-host (GVH) direction, and (4) greater reduction in relapse when there is a lack of iKIRL, suggesting that the protective effect of CD34(+) cell dose against relapse may be immune-mediated, possibly through NK cell recovery.

Common and well-documented HLA alleles: report of the Ad-Hoc committee of the american society for histocompatiblity and immunogenetics.

In histocompatibility testing some genotype ambiguities are almost always resolved into the genotype with the most common alleles. To achieve unambiguous assignments additional unwieldy tests are performed. The American Society for Histocompatibility and Immunogenetics formed a committee to define what human leukocyte antigen (HLA) genotypes do not need to be resolved in external proficiency testing. The tasks included detailed analysis of large datasets of high-resolution typing and thorough review of the pertinent scientific literature. Strict criteria were used to create a catalogue of common and well-documented (CWD) alleles. In total, 130, 245, 81, and 143 of the highly polymorphic HLA-A, -B, -C, and DRB1 loci fell into the CWD category; these represent 27%-30% of all alleles recognized. For the loci DRB3/4/5, DQA1, DQB1, and DPB1, a total of 29, 16, 26, and 52 CWD alleles were identified. A recommendation indicated that an acceptable report should only include one possible genotype; multiple genotypes can only be reported if only one of these includes two alleles of the CWD group. Exceptions in which resolution is not necessary are ambiguities involving functional alleles with identical sequences in the antigen recognition site. The criteria were established for proficiency testing, which could be a valuable tool when making clinical histocompatibility decisions.