High dose valacyclovir for cytomegalovirus prophylaxis following allogeneic hematopoietic cell transplantation.

INTRODUCTION: Cytomegalovirus (CMV) is one of the most common and clinically significant viral infections following allogeneic hematopoietic cell transplantation (HCT). Currently available options for CMV prophylaxis and treatment present challenges related to side effects and cost. METHODS: In this retrospective medical record review, the incidence of clinically significant CMV infection (CMV disease or reactivation requiring preemptive treatment) following allogeneic HCT was compared in patients receiving valacyclovir 1 g three times daily versus acyclovir 400 mg every 12 h for viral prophylaxis. RESULTS: Forty-five patients who received valacyclovir were matched based on propensity scoring to 35 patients who received acyclovir. All patients received reduced-intensity conditioning regimens containing anti-thymocyte globulin. Clinically significant CMV infection by day + 180 was lower in the valacyclovir group compared to the acyclovir group (18% vs. 57%, p = 0.0004). Patients receiving valacyclovir prophylaxis also had less severe infection evidenced by a reduction in CMV disease, lower peak CMV titers, delayed CMV reactivation, and less secondary neutropenia. CONCLUSION: Prospective evaluation of valacyclovir 1 g three times daily for viral prophylaxis following allogeneic HCT is warranted. Due to valacyclovir's favorable toxicity profile and affordable cost, it has the potential to benefit patients on a broad scale as an option for CMV prophylaxis.

A multicenter report on the safety and efficacy of plerixafor based stem cell mobilization in children with malignant disorders.

BACKGROUND: Pleraxifor for peripheral blood stem cell (PBSC) mobilization in children with malignancies is often given following failure of standard mobilization (SM) rather than as a primary mobilizing agent. STUDY DESIGN AND METHODS: In this retrospective multicenter study, we report the safety of plerixafor-based PBSC mobilization in children with malignancies and compare outcomes between patients who received plerixafor upfront with SM (Group A) with those who received plerixafor following failure of SM (Group B). In the latter pleraxifor was given either following a low peripheral blood (PB) CD34 (<20 cells/cu.mm) (Group B1) or as a second collection process due to an unsuccessful yield (CD34 + < 2 × 106 /kg) (Group B2) following failed SM and first apheresis attempts. RESULTS: The study cohort (n = 47) with a median age of 8 (range 0.6-21) year, comprised 19 (40%) Group A and 28 (60%) Group B patients (B1 = 12 and B2 = 16). Pleraxifor mobilization was successful in 87.2% of patients, similar between Groups A and B (84.2% vs 89.2%) and resulted in a median 4-fold increase in PB CD34. Median number of apheresis attempts was 2 in Groups A and B1 but 4 in Group B2. In Group B2, median total CD34+ yield post-plerixafor was 9-fold higher than after SM (P = .0013). Mild to moderate transient adverse events affected 8.5% of patients. Among patients who proceeded to autologous transplant (n = 39), all but one engrafted. CONCLUSION: Plerixafor-based PBSC collection was safe and effective in our cohort and supports consideration as a primary mobilizing agent in children with malignancies.

Dynamical System Modeling to Simulate Donor T Cell Response to Whole Exome Sequencing-Derived Recipient Peptides Demonstrates Different Alloreactivity Potential in HLA-Matched and -Mismatched Donor-Recipient Pairs.

Immune reconstitution kinetics and subsequent clinical outcomes in HLA-matched recipients of allogeneic stem cell transplantation (SCT) are variable and difficult to predict. Considering SCT as a dynamical system may allow sequence differences across the exomes of the transplant donors and recipients to be used to simulate an alloreactive T cell response, which may allow better clinical outcome prediction. To accomplish this, whole exome sequencing was performed on 34 HLA-matched SCT donor-recipient pairs (DRPs) and the nucleotide sequence differences translated to peptides. The binding affinity of the peptides to the relevant HLA in each DRP was determined. The resulting array of peptide-HLA binding affinity values in each patient was considered as an operator modifying a hypothetical T cell repertoire vector, in which each T cell clone proliferates in accordance with the logistic equation of growth. Using an iterating system of matrices, each simulated T cell clone's growth was calculated with the steady-state population being proportional to the magnitude of the binding affinity of the driving HLA-peptide complex. Incorporating competition between T cell clones responding to different HLA-peptide complexes reproduces a number of features of clinically observed T cell clonal repertoire in the simulated repertoire, including sigmoidal growth kinetics of individual T cell clones and overall repertoire, Power Law clonal frequency distribution, increase in repertoire complexity over time with increasing clonal diversity, and alteration of clonal dominance when a different antigen array is encountered, such as in SCT. The simulated, alloreactive T cell repertoire was markedly different in HLA-matched DRPs. The patterns were differentiated by rate of growth and steady-state magnitude of the simulated T cell repertoire and demonstrate a possible correlation with survival. In conclusion, exome wide sequence differences in DRPs may allow simulation of donor alloreactive T cell response to recipient antigens and may provide a quantitative basis for refining donor selection and titration of immunosuppression after SCT.

Dynamical System Modeling of Immune Reconstitution after Allogeneic Stem Cell Transplantation Identifies Patients at Risk for Adverse Outcomes.

Systems that evolve over time and follow mathematical laws as they evolve are called dynamical systems. Lymphocyte recovery and clinical outcomes in 41 allograft recipients conditioned using antithymocyte globulin (ATG) and 4.5-Gy total body irradiation were studied to determine if immune reconstitution could be described as a dynamical system. Survival, relapse, and graft-versus-host disease (GVHD) were not significantly different in 2 cohorts of patients receiving different doses of ATG. However, donor-derived CD3(+) cell reconstitution was superior in the lower ATG dose cohort, and there were fewer instances of donor lymphocyte infusion (DLI). Lymphoid recovery was plotted in each individual over time and demonstrated 1 of 3 sigmoid growth patterns: Pattern A (n = 15) had rapid growth with high lymphocyte counts, pattern B (n = 14) had slower growth with intermediate recovery, and pattern C (n = 10) had poor lymphocyte reconstitution. There was a significant association between lymphocyte recovery patterns and both the rate of change of donor-derived CD3(+) at day 30 after stem cell transplantation (SCT) and clinical outcomes. GVHD was observed more frequently with pattern A, relapse and DLI more so with pattern C, with a consequent survival advantage in patients with patterns A and B. We conclude that evaluating immune reconstitution after SCT as a dynamical system may differentiate patients at risk of adverse outcomes and allow early intervention to modulate that risk.

Whole exome sequencing to estimate alloreactivity potential between donors and recipients in stem cell transplantation.

Whole exome sequencing (WES) was performed on stem cell transplant donor-recipient (D-R) pairs to determine the extent of potential antigenic variation at a molecular level. In a small cohort of D-R pairs, a high frequency of sequence variation was observed between the donor and recipient exomes independent of human leucocyte antigen (HLA) matching. Nonsynonymous, nonconservative single nucleotide polymorphisms were approximately twice as frequent in HLA-matched unrelated, compared with related D-R pairs. When mapped to individual chromosomes, these polymorphic nucleotides were uniformly distributed across the entire exome. In conclusion, WES reveals extensive nucleotide sequence variation in the exomes of HLA-matched donors and recipients.

Phase 2 Study of Sorafenib, Valproic Acid, and Sildenafil in the Treatment of Recurrent High-Grade Glioma.

Here we report the results of a single-center phase 2 clinical trial combining sorafenib tosylate, valproic acid, and sildenafil for the treatment of patients with recurrent high-grade glioma (NCT01817751). Clinical toxicities were grade 1 and grade 2, with one grade 3 toxicity for maculopapular rash (6.4%). For all evaluable patients, the median progression-free survival was 3.65 months and overall survival (OS) 10.0 months. There was promising evidence showing clinical activity and benefit. In the 33 evaluable patients, low protein levels of the chaperone GRP78 (HSPA5) was significantly associated with a better OS (p < 0.0026). A correlation between the expression of PDGFRα and OS approached significance (p < 0.0728). Five patients presently have a mean OS of 73.6 months and remain alive. This is the first therapeutic intervention glioblastoma trial to significantly associate GRP78 expression to OS. Our data suggest that the combination of sorafenib tosylate, valproic acid, and sildenafil requires additional clinical development in the recurrent glioma population.

New opportunities for control of dengue virus.

PURPOSE OF REVIEW: Dengue is a rapidly spreading vector-borne disease estimated to infect 400 million people worldwide. To date, there are no licensed treatments or vaccines. The last few years have seen significant developments in dengue control strategies. In this review, we will address four key areas: vaccines, vector control, antivirals and immunotherapeutics. RECENT FINDINGS: The first generation of dengue vaccines is able to induce good serological responses in test individuals. However, the recent Sanofi-Pasteur trial in Thailand found that a good serological response did not correlate with clinical protection. This trial did not demonstrate an increase in cases of severe disease following immunization, suggesting that concerns over vaccine-related immune enhancement may have been overcome. The bacterium Wolbachia appears to control dengue proliferation in Aedes mosquitoes, and field studies are underway. A large number of antivirals are in early-stage development and may prove useful in epidemics. Monoclonal antibodies have been postulated to have a clinical role. Whether their clinical application is feasible has yet to be seen. SUMMARY: Marked improvements in our knowledge of dengue have been made over the recent years. Sadly, clinical application remains some years away.

Gametocyte carriage in Plasmodium falciparum-infected travellers.

BACKGROUND: Gametocytes are the sexual stage of Plasmodium parasites. The determinants of gametocyte carriage have been studied extensively in endemic areas, but have rarely been explored in travellers with malaria. The incidence of gametocytaemia, and factors associated with gametocyte emergence in adult travellers with Plasmodium falciparum malaria was investigated at the Hospital for Tropical Diseases in London. METHODS: Clinical, parasitological and demographic data for all patients presenting with P. falciparum malaria between January 2001 and December 2011 were extracted from a prospective database. These data were supplemented by manual searches of laboratory records and patient case notes. RESULTS: Seven hundred and seventy three adult patients with laboratory-confirmed P. falciparum malaria were identified. Four hundred and sixty five (60%) were born in a country where malaria is endemic. Patients presented to hospital a median of four days into their illness. The median maximum parasite count was 0.4%. One hundred and ninety six patients (25%) had gametocytes; 94 (12%) on admission, and 102 (13%) developing during treatment. Gametocytaemia on admission was associated with anaemia and a lower maximum parasitaemia. Patients with gametocytes at presentation were less likely to have thrombocytopenia or severe malaria. Patients who developed gametocytes during treatment were more likely to have had parasitaemia of long duration, a high maximum parasitaemia and to have had severe malaria. There was no apparent association between the appearance of gametocytes and treatment regimen. CONCLUSIONS: The development of gametocytaemia in travellers with P. falciparum is associated with factors similar to those reported among populations in endemic areas. These data suggest that acquired immunity to malaria is not the only determinant of patterns of gametocyte carriage among patients with the disease.

INTRAVENOUS VITAMIN C SUPPLEMENTATION IN ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANT RECIPIENTS: SALUTARY IMPACT ON CLINICAL OUTCOMES.

Intravenous (IV) vitamin C improves organ function and reduces inflammation in sepsis, an inflammatory state like the post-hematopoietic stem cell transplant (SCT) milieu. The safety and efficacy of parenteral vitamin C after allogeneic hematopoietic stem cell transplant (HSCT) were evaluated in a phase I/II trial and clinical outcomes compared with a propensity score - matched historical control. Methods: Patients with advanced hematologic malignancies were enrolled in a phase 2 clinical trial, receiving IV vitamin C, 50mg/kg/d, divided into 3 doses given on days 1-14 after HSCT, followed by 500 mg bid oral from day 15 until 6 months post-SCT. Results: 55 patients received IV vitamin C: these include 10/10 HLA-MRD and MUD (n=48) and 9/10 HLA MUD recipients (n=7). All patients enrolled were deficient in vitamin C at day 0 and had restoration to normal levels for the remainder of the course. Vitamin C recipients had lower non-relapse mortality (11% vs. 25%, p-value = 0.07) and consequently, improved survival compared to historical controls (82% vs 62% p=0.06), with no attributable grade 3 and 4 toxicities to vitamin C. Patients with myeloid malignancies had improved survival (83% vs. 54%, p=0.02) and non-relapse mortality (NRM) (10% vs. 37%, p=0.009), as well as chronic GVHD, with similar relapse rates compared to controls. Conclusions: In patients undergoing allogeneic HSCT the administration of IV vitamin C is safe and reduces non-relapse mortality improving overall survival. Randomized trials are needed to confirm the utility of this easily available and inexpensive therapy.

Epigenetic induction of adaptive immune response in multiple myeloma: sequential azacitidine and lenalidomide generate cancer testis antigen-specific cellular immunity.

Patients with multiple myeloma (MM) undergoing high dose therapy and autologous stem cell transplantation (SCT) remain at risk for disease progression. Induction of the expression of highly immunogenic cancer testis antigens (CTA) in malignant plasma cells in MM patients may trigger a protective immune response following SCT. We initiated a phase II clinical trial of the DNA hypomethylating agent, azacitidine (Aza) administered sequentially with lenalidomide (Rev) in patients with MM. Three cycles of Aza and Rev were administered and autologous lymphocytes were collected following the 2nd and 3rd cycles of Aza-Rev and cryopreserved. Subsequent stem cell mobilization was followed by high-dose melphalan and SCT. Autologous lymphocyte infusion (ALI) was performed in the second month following transplantation. Fourteen patients have completed the investigational therapy; autologous lymphocytes were collected from all of the patients. Thirteen patients have successfully completed SCT and 11 have undergone ALI. Six patients tested have demonstrated CTA up-regulation in either unfractionated bone marrow (n = 4) or CD138+ cells (n = 2). CTA (CTAG1B)-specific T cell response has been observed in all three patients tested and persists following SCT. Epigenetic induction of an adaptive immune response to cancer testis antigens is safe and feasible in MM patients undergoing SCT.

Non-tuberculous slow-growing mycobacterial pulmonary infections in non-HIV-infected patients in south London.

BACKGROUND: UK data on slow-growing non-tuberculous mycobacterial (NTM) pulmonary infections are sparse and there is little consensus on optimal treatment regimens. METHODS: This was a retrospective study of NTM pulmonary infections in a London teaching hospital. Inclusion criteria were culture of slow-growing mycobacteria between 2000 and 2007, age > 18 y, HIV-negative, and meeting American Thoracic Society criteria. RESULTS: Fifty-seven patients were included; 68% were males and the median age was 61 y. Predisposing factors were smoking (70%), alcohol abuse (28%), and chronic obstructive pulmonary disease (37%). Cavitation (56%) and infiltrates (42%) were common radiological findings. The predominant organism was Mycobacterium kansasii (70%). Ninety-three percent of patients with M. kansasii, 63% with Mycobacterium avium intracellulare, 60% with Mycobacterium malmoense, and 25% with Mycobacterium xenopi had clinical disease. Of the 57 patients, 37 were treated and had follow-up data available. Most patients received 3 drugs: rifampicin, ethambutol, and clarithromycin or ciprofloxacin for at least 9 months. Thirty percent experienced drug side effects. M. kansasii treatment had a 100% cure and 10% relapse rate, but 15% died. CONCLUSIONS: M. kansasii was the most common NTM and its isolation was predictive of clinical disease. Compared with other studies, treatment with 3 agents had a similar rate of cure and did not appear to reduce the relapse rate of disease, but did increase the risk of side effects.

Digital Polymerase Chain Reaction Paired with High-Speed Atomic Force Microscopy for Quantitation and Length Analysis of DNA Length Polymorphisms.

DNA length polymorphisms are found in many serious diseases, and assessment of their length and abundance is often critical for accurate diagnosis. However, measuring their length and frequency in a mostly wild-type background, as occurs in many situations, remains challenging due to their variable and repetitive nature. To overcome these hurdles, we combined two powerful techniques, digital polymerase chain reaction (dPCR) and high-speed atomic force microscopy (HSAFM), to create a simple, rapid, and flexible method for quantifying both the size and proportion of DNA length polymorphisms. In our approach, individual amplicons from each dPCR partition are imaged and sized directly. We focused on internal tandem duplications (ITDs) located within the FLT3 gene, which are associated with acute myeloid leukemia and often indicative of a poor prognosis. In an analysis of over 1.5 million HSAFM-imaged amplicons from cell line and clinical samples containing FLT3-ITDs, dPCR-HSAFM returned the expected variant length and variant allele frequency, down to 5% variant samples. As a high-throughput method with single-molecule resolution, dPCR-HSAFM thus represents an advance in HSAFM analysis and a powerful tool for the diagnosis of length polymorphisms.

A Preliminary Investigation towards the Risk Stratification of Allogeneic Stem Cell Recipients with Respect to the Potential for Development of GVHD via Their Pre-Transplant Plasma Lipid and Metabolic Signature.

The clinical outcome of allogeneic hematopoietic stem cell transplantation (SCT) may be influenced by the metabolic status of the recipient following conditioning, which in turn may enable risk stratification with respect to the development of transplant-associated complications such as graft vs. host disease (GVHD). To better understand the impact of the metabolic profile of transplant recipients on post-transplant alloreactivity, we investigated the metabolic signature of 14 patients undergoing myeloablative conditioning followed by either human leukocyte antigen (HLA)-matched related or unrelated donor SCT, or autologous SCT. Blood samples were taken following conditioning and prior to transplant on day 0 and the plasma was comprehensively characterized with respect to its lipidome and metabolome via liquid chromatography/mass spectrometry (LCMS) and gas chromatography/mass spectrometry (GCMS). A pro-inflammatory metabolic profile was observed in patients who eventually developed GVHD. Five potential pre-transplant biomarkers, 2-aminobutyric acid, 1-monopalmitin, diacylglycerols (DG 38:5, DG 38:6), and fatty acid FA 20:1 demonstrated high sensitivity and specificity towards predicting post-transplant GVHD. The resulting predictive model demonstrated an estimated predictive accuracy of risk stratification of 100%, with area under the curve of the ROC of 0.995. The likelihood ratio of 1-monopalmitin (infinity), DG 38:5 (6.0), and DG 38:6 (6.0) also demonstrated that a patient with a positive test result for these biomarkers following conditioning and prior to transplant will be at risk of developing GVHD. Collectively, the data suggest the possibility that pre-transplant metabolic signature may be used for risk stratification of SCT recipients with respect to development of alloreactivity.

The influence of lymphoid reconstitution kinetics on clinical outcomes in allogeneic stem cell transplantation.

Lymphoid recovery following myeloablative stem cell transplantation (SCT) displays a logistic pattern of exponential growth followed by a plateau. Within this logistic framework, lymphoid recovery is characterized by the parameters R (slope of ascent), a (time of maximal rate of ascent) and K (plateau), the 'steady-state' lymphocyte count. A retrospective analysis of allogeneic SCT performed from 2008 to 2013 was undertaken to compare lymphoid recovery and clinical outcomes in 131 patients with acute myelogenous leukemia, acute lymphocytic leukemia, and myelodysplastic syndromes. Using Prism software, a logistic curve was successfully fit to the absolute lymphocyte count recovery in all patients. Patients were classified according to the magnitude and rate of lymphoid recovery; pattern A achieved an absolute lymphocyte counts (ALC) of >1000/µL by day 45, pattern B an ALC 500 < x < 1000/µL, and pattern C an ALC <500/µL. Pattern A was characterized by a higher mean K (p < .0001) compared with patterns B and C. Patients with patterns B and C were more likely to have mixed T cell chimerism at 90 d following SCT (p = .01). There was a trend towards improved survival (and relapse-free survival) in those with pattern A and B at 1 year compared to pattern C (p = .073). There was no difference in cGVHD (p = .42) or relapse (p = .45) between pattern types. Cytomegalovirus (CMV), aGVHD, and all relapse were heralded by deviation from logistic behavior. Pattern C patients were more likely to require donor lymphocyte infusion (DLI) (p = .017). Weaning of tacrolimus post-transplant was associated with a second, separate logistic expansion in some patients. This study demonstrated that lymphoid reconstitution follows a prototypical logistic recovery and that pattern observed correlates with T cell chimerism and need for DLI, and may influence survival.

Sequence homology between HLA-bound cytomegalovirus and human peptides: A potential trigger for alloreactivity.

Human cytomegalovirus (hCMV) reactivation may often coincide with the development of graft-versus-host-disease (GVHD) in stem cell transplantation (SCT). Seventy seven SCT donor-recipient pairs (DRP) (HLA matched unrelated donor (MUD), n = 50; matched related donor (MRD), n = 27) underwent whole exome sequencing to identify single nucleotide polymorphisms (SNPs) generating alloreactive peptide libraries for each DRP (9-mer peptide-HLA complexes); Human CMV CROSS (Cross-Reactive Open Source Sequence) database was compiled from NCBI; HLA class I binding affinity for each DRPs HLA was calculated by NetMHCpan 2.8 and hCMV- derived 9-mers algorithmically compared to the alloreactive peptide-HLA complex libraries. Short consecutive (≥6) amino acid (AA) sequence homology matching hCMV to recipient peptides was considered for HLA-bound-peptide (IC50<500nM) cross reactivity. Of the 70,686 hCMV 9-mers contained within the hCMV CROSS database, an average of 29,658 matched the MRD DRP alloreactive peptides and 52,910 matched MUD DRP peptides (p<0.001). In silico analysis revealed multiple high affinity, immunogenic CMV-Human peptide matches (IC50<500 nM) expressed in GVHD-affected tissue-specific manner. hCMV+GVHD was found in 18 patients, 13 developing hCMV viremia before GVHD onset. Analysis of patients with GVHD identified potential cross reactive peptide expression within affected organs. We propose that hCMV peptide sequence homology with human alloreactive peptides may contribute to the pathophysiology of GVHD.

In silico Derivation of HLA-Specific Alloreactivity Potential from Whole Exome Sequencing of Stem-Cell Transplant Donors and Recipients: Understanding the Quantitative Immunobiology of Allogeneic Transplantation.

Donor T-cell mediated graft versus host (GVH) effects may result from the aggregate alloreactivity to minor histocompatibility antigens (mHA) presented by the human leukocyte antigen (HLA) molecules in each donor-recipient pair undergoing stem-cell transplantation (SCT). Whole exome sequencing has previously demonstrated a large number of non-synonymous single nucleotide polymorphisms (SNP) present in HLA-matched recipients of SCT donors (GVH direction). The nucleotide sequence flanking each of these SNPs was obtained and the amino acid sequence determined. All the possible nonameric peptides incorporating the variant amino acid resulting from these SNPs were interrogated in silico for their likelihood to be presented by the HLA class I molecules using the Immune Epitope Database stabilized matrix method (SMM) and NetMHCpan algorithms. The SMM algorithm predicted that a median of 18,396 peptides weakly bound HLA class I molecules in individual SCT recipients, and 2,254 peptides displayed strong binding. A similar library of presented peptides was identified when the data were interrogated using the NetMHCpan algorithm. The bioinformatic algorithm presented here demonstrates that there may be a high level of mHA variation in HLA-matched individuals, constituting a HLA-specific alloreactivity potential.

Stem cell transplantation as a dynamical system: are clinical outcomes deterministic?

Outcomes in stem cell transplantation (SCT) are modeled using probability theory. However, the clinical course following SCT appears to demonstrate many characteristics of dynamical systems, especially when outcomes are considered in the context of immune reconstitution. Dynamical systems tend to evolve over time according to mathematically determined rules. Characteristically, the future states of the system are predicated on the states preceding them, and there is sensitivity to initial conditions. In SCT, the interaction between donor T cells and the recipient may be considered as such a system in which, graft source, conditioning, and early immunosuppression profoundly influence immune reconstitution over time. This eventually determines clinical outcomes, either the emergence of tolerance or the development of graft versus host disease. In this paper, parallels between SCT and dynamical systems are explored and a conceptual framework for developing mathematical models to understand disparate transplant outcomes is proposed.

Distinct oligoclonal T cells are associated with graft versus host disease after stem-cell transplantation.

BACKGROUND: In patients with hematologic malignancies who receive stem-cell transplantation, donors' T cells can recognize minor histocompatibility antigens on recipient cells and generate an objective response against the tumor. However, a major side effect of such therapy is graft-versus-host disease (GVHD). The purpose of this study was to characterize distinct T-cell clones that were frequently and exclusively involved in GVHD or graft-versus-tumor (GVT) effects. METHODS: We hypothesized that distinct GVHD-associated T-cell clones can be identified during the disease progression. To test this, we conducted comparative analysis of T-cell receptor (TCR) Vßs in donor-recipient pairs of patients with GVHD versus those with GVHD-free and relapse-free survival using quantitative reverse-transcriptase polymerase chain reaction and spectratyping analyses. RESULTS: We identified three sets of T-cell clones that were either frequently involved in GVHD (TCR Vß4, 11, and 23) or GVT effect (TCR Vß9, 16, and 20), or were increased at the time of GVHD and GVT effects in a patient-specific manner (TCR Vß2, 3, 7, 12, 15, and 17). Spectratyping analysis showed restricted clonality of the identified TCR Vßs. Polymerase chain reaction analysis also confirmed the presence of GVHD-associated T-cell clones at the site of the disease. CONCLUSIONS: These data suggest that GVHD- and GVT-associated clones can be distinguished by molecular analysis of TCR Vß to develop targeted therapy for GVHD.