Optical and electrical properties of Ga-doped ZnO nanorod arrays fabricated by thermal evaporation

Well-aligned Ga-doped ZnO nanorod arrays with high optical and electrical property were fabricated by catalyst-free thermal evaporation on p-silicon substrate. As the Ga/Zn atom ratio in the source material was tuned from 0 to 0.2, wurtzite structure ZnO nanorod arrays were realized with length of -6 microm and growth direction along c-axis. With the addition of Ga, the intensity of the near-band-edge emission was enhanced and the deep-level emissions maintained neglectable. As the Ga/Zn atom ratio increased from 0 to 0.1, the red shift of the near-band-edge emission occurred due to Ga-doping induced band gap renormalization effect related with the enhancement of the carrier density, while the blue shifts of the emission were found once the Ga/Zn ratio is higher than 0.1 resulting from Burstein-Moss effect. The configuration of the vertical-aligned Ga-doped ZnO nanorod arrays on p-Si substrate makes it straightforward for the fabrication of p-n nanodiode, which shows an excellent rectifying characteristic with threshold voltage as low as -4.7 V with the Ga/Zn atomic ratio of 0.2.

[Mutation analysis and prenatal diagnosis of 2 cases with mucopolysaccharidosis type I]

OBJECTIVE

Mucopolysaccharidosis type I (MPS I; MIM# 252800) is an autosomal recessive disease that results from the deficiency in the lysosomal enzyme α-L-iduronidase(IDUA). IDUA is one of the enzymes involved in degradation of glycosaminoglycans heparan sulphate and dermatan sulphate. The deficiency of IDUA leads to widespread accumulation of partially degraded mucopolysaccharides inside lysosomes, resulting in progressive cellular and multiorgan dysfunction. Up to now there is no definitely effective treatment for this disorder, therefore it is important to provide an accurate genetic diagnosis and prenatal diagnosis for the MPSI families. This study was conducted to detect IDUA gene mutation in patients with MPSIand make a definite diagnosis of homozygote or heterozygote and make first trimester prenatal diagnosis.

METHOD

The 2 male probands included in this study were diagnosed as MPSI patients in Peking Union Medical College Hospital, case 1 was 2 years old and case 2 was 5 years old. Genomic DNA was extracted from leucocytes in the 2 patients and 2 mothers' cultured amniocytes. IDUA gene DNA sequence was amplified by polymerase chain reaction (PCR) and the PCR products were sequenced directly. Novel mutations were analyzed in 100 normal chromosomes.

RESULT

The genotype of case 1 was p.L238R/c.883InsC, while of case 2 was c.531InsT/p.L346R. The fetal case 1 did not inherit the same pathogenic mutations as proband 1, the activity of the IDUA in amniocytes was 9.0 nmol/(h·mg pr). The fetal case 2 inherited the same pathogenic mutations with the proband, the genotype of fetal 2 was c.531InsT/p.L346R, the activity of the IDUA in amniocytes was 0.5 nmol/(h·mg pr).

CONCLUSION

Of the 4 mutations found in 2 MPS I patients, p. L238R, c.883InsC, c.531InsT were novel. The fetal case 1 was diagnosed as normal fetus while the fetus 2 was diagnosed as affected. The results of the two kinds of prenatal diagnostic methods were correspondent with each other.

Selective Growth of Vertical-aligned ZnO Nanorod Arrays on Si Substrate by Catalyst-free Thermal Evaporation

By thermal evaporation of pure ZnO powders, high-density vertical-aligned ZnO nanorod arrays with diameter ranged in 80–250 nm were successfully synthesized on Si substrates covered with ZnO seed layers. It was revealed that the morphology, orientation, crystal, and optical quality of the ZnO nanorod arrays highly depend on the crystal quality of ZnO seed layers, which was confirmed by the characterizations of field-emission scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and photoluminescence measurements. For ZnO seed layer with wurtzite structure, the ZnO nanorods grew exactly normal to the substrate with perfect wurtzite structure, strong near-band-edge emission, and neglectable deep-level emission. The nanorods synthesized on the polycrystalline ZnO seed layer presented random orientation, wide diameter, and weak deep-level emission. This article provides a C-free and Au-free method for large-scale synthesis of vertical-aligned ZnO nanorod arrays by controlling the crystal quality of the seed layer.

Schwannoma of the gastrointestinal tract: a clinicopathological, immunohistochemical and ultrastructural study of 33 cases

AIMS

Thirty-three cases of gastrointestinal schwannomas were analysed to elucidate their peculiar clinicopathological, immunohistochemical and ultrastructural features.

METHODS AND RESULTS

The patients were 16 men and 17 women, whose ages ranged from 27 to 81 years (median 52.6 years). Tumour size ranged from 10 to 120 mm in diameter. Follow-up in 23 cases from 6 months to 13 years showed no recurrences or metastases. Microscopically, all tumours were composed of spindle cells with focal epithelioid cells in four cases. In all cases except one, there were peripheral cuff-like lymphoid aggregates. Immunohistochemically, tumours were strongly positive for S100 protein and vimentin, the tumours were variably positive for nestin (78.8%, 26/33) and glial fibrillary acidic protein (63.6%, 21/33), three tumours had CD34+ cells, but all were negative for CD117, alpha-smooth muscle actin and desmin. Ultrastructurally, the tumours were composed of elongated spindle shaped cells with prominent parallel membranous structures.

CONCLUSIONS

Gastrointestinal schwannomas have characteristic histological features, especially the presence of a lymphoid cuff, that are different from their soft tissue and central nervous system counterparts. Gastrointestinal tract schwannomas behave in a benign fashion.

Development of an immunochromatographic lateral flow test strip for detection of β-adrenergic agonist Clenbuterol residues

A rapid immunochromatographic lateral flow test strip was developed in a competitive format with the gold-conjugated monoclonal antibody to specifically determine the residues of Clenbuterol (CL), a beta-adrenergic agonist. The test strip is made up of a sample pad, a conjugate reagent pad, a test membrane containing a control line and a test line, and an absorbent pad. CL standard samples of 0, 0.1, 0.3, 0.9, 2.7, 8.1 ng/ml in swine urine were determined by the test strip. It was shown that detection limit of the test strip was as low as 0.1 ng/ml of CL and that the half of maximal inhibition concentration (IC50) in relative optical density was calculated to be 1.78+/-0.17 ng/ml under an optical density scanner. The sensitivity by eye measurement was 1.0 ng/ml. It takes 10 min to accomplish a test. Parallel analysis of urine samples from pigs fed with CL showed comparable results obtained from the test strip and GC-MS. Therefore, the test strip is very useful as a screening method for quantitative, semi-quantitative or qualitative detection of CL residues in swine urine.

Heat shock protein 70: correlation of expression with degree of graft-versus-host response and clinical graft-versus-host disease

BACKGROUND

The heat shock proteins are increasingly becoming associated with immunopathologic phenomena, being induced in response to inflammation. They are highly immunogenic and are postulated as playing a role in both innate and adaptive immunity. Their proposed role in peptide binding and antigen presentation could suggest a potential role in the alloreactive process that leads to graft-versus-host disease (GVHD) after bone marrow transplantation.

METHODS

In this study we examined the expression of the widely studied heat shock protein 70 (hsp70) in an in vitro-generated graft-versus-host reaction in human skin, using streptavidin biotin immunohistochemistry and laser scanning confocal microscopy.

RESULTS

Hsp70 expression was correlated with high graft-versus-host responses (P<0.001) and was confirmed using laser scanning confocal microscopy. Increased expression of hsp70 was further defined due to increases in the inducible form of hsp70. Expression of inducible hsp70 was predictive of both clinical acute GVHD (P=0.001) and incidence of chronic GVHD (P<0.001).

CONCLUSIONS

This investigation has demonstrated for the first time the expression of hsp70 in a human model of GVHD, suggesting involvement in the pathogenesis of the disease and providing the basis for further investigation. Increased expression of inducible hsp70 in the model could provide a biologic marker for the prediction of clinical acute and chronic GVHD.

The detection of apoptosis in a human in vitro skin explant assay for graft versus host reactions

AIMS

Keratinocyte apoptosis is a major pathogenic mechanism in dermal complications, such as graft versus host disease (GVHD), after allogeneic bone marrow transplantation. However, the mechanisms by which recipient target cells undergo apoptosis in GVHD are still unclear, but may result from DNA damage caused by chemotherapeutic agents and/or by direct cytokine action. The basis of this investigation was to correlate keratinocyte apoptosis with (1) the severity of graft versus host reactions (GVHR) in vitro and (2) the clinical grade (0--III) of GVHD.

METHODS

Skin sections generated from an in vitro skin explant model for detecting experimental or clinically relevant GVHR were investigated for the detection of apoptotic nuclei using the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) technique. This investigation also aimed to establish whether the TUNEL assay could be used as an additional, predictive method for the severity of GVHD before transplantation in potential patient/donor pairs given standard GVHD prophylaxis (cyclosporin A and methotrexate).

RESULTS

By comparing mean values of apoptosis for each GVHR grade in a cohort of 83 retrospective skin sections it was shown that as the severity of GVHR increased there was a parallel increase in the percentage of apoptotic cells (p < 0.0001). However, the correlation between clinical GVHD grade II--III and overall keratinocyte apoptosis (> 2.6%) did not reach this degree of significance (chi(2): 4.2; degrees of freedom, 1; p = 0.04; Fisher's exact test: p = 0.06).

CONCLUSIONS

The detection of apoptosis correlated with degree of GVHR using an in vitro assay and a higher degree of apoptosis tended to correlate with more severe GVHD. Further studies in a larger cohort of patients, using other methods to detect apoptosis in conjunction with the TUNEL assay, may give additional insight into the complex immunopathophysiology of GVHD.

Expression of human vascular endothelial growth factor (VEGF165) in Pichia pastoris and its biological activity

OBJECTIVE

To express human vascular endothelial growth factor (hVEGF165) cDNA in Pichia pastroris, purify the expressed product and detect the biological activity of it.

METHODS

By inserting hVEGF165 cDNA coding 165 amino acid residues into Pichia pastoris expression vector pPIC9K containing AOX1 promoter and the sequences of alpha secreting signal peptides, a recombinant expression plasmid pPIC9K/hVEGF165 was constructed and transformed to yeast host strain KM71, then multiple-copy insert transformants were screened out and cultured in flasks, and hVEGF165 was expressed under the induction of 1% methanol.

RESULTS

SDS-PAGE showed that after being induced with 1% methanol for 4 d, the expressed product existed in supernatant in the form of soluble molecule and contained 60% of total protein expressed. Western blot showed good antigenicity and specificity of expressed product. After being purified by Heparin-Sepharose CL6B affinity chromatography, the purity of expressed product reached above 90%. Biological assays proved that the expressed product could stimulate the proliferation of HUVEC.

CONCLUSION

hVEGF165 was successfully expressed. The study opened up a wide prospect for the application of VEGF165 in the prevention and treatment of ischemic heart disease and other tissue ischemic diseases such as secondary arterial occlusion in limbs.

Expression of human vascular endothelial growth factor receptor Flt-1 extracellular domain 1-3 loop cDNA in Pichia pastoris, purification of the expressed product and detection of its biological activity

OBJECTIVE

To express human vascular endothelial growth factor receptor Flt-1 extracellular domain 1-3 loop cDNA in Pichia. pastroris, and to purify the expressed product and detect its biological activity.

METHODS

By inserting human Flt-1 (1-3 loop) cDNA coding 316 amino acid residues into Pichia pastoris expression vector pPIC9K containing AOX1 promoter and the sequences of alpha secreting signal peptides, a recombinant expression plasmid pPIC9K/Flt-1 (1-3) was constructed and transformed to yeast host strain GS115, then His+ Muts phenotype transformant was screened out and cultured in flasks, and Flt-1 (1-3) was expressed under the induction of 1% methanol.

RESULTS

SDS-PAGE showed that after being induced with 1% methanol for 4d, the expressed product existed in supernatant in the form of soluble molecule and contained 60% of total protein expressed. Western blot showed good antigenicity and specificity of expressed product. After being purified by CM-Sepharose FF and Sephacryl S-100 chromatography, the purity of the expressed product reached above 90%. Biological assay proved that the expressed product could bind to hVEGF165 and inhibit the proliferation of HUVEC stimulated by hVEGF165.

CONCLUSION

Human vascular endothelial growth factor receptor Flt-1 extracellular domain 1-3 loop was successfully expressed. The study lays a foundation for further application of the expressed product in the treatment of vasoformation related diseases, such as tumor and diabetic retinopathy.

GvHD risk assessment in hematopoietic stem cell transplantation: role of cytokine gene polymorphisms and an in vitro human skin explant model

This present review concentrates on the recent results investigating the role of certain cytokine gene polymorphisms, including tumor necrosis factor alpha, interferon gamma, interleukin-6 (IL-6), IL-10, and IL-1 receptor antagonist, in allogeneic stem cell transplantation. The review discusses their potential role in predicting outcome and the development of a genetic risk index for graft-versus-host disease in human leukocyte antigen matched sibling transplants. By the comparative use of an in vitro human skin explant model, initial results suggest that certain polymorphisms may be associated with more severe disease.

Histological correlation between different centers using the skin explant model to predict graft-versus-host disease following bone marrow transplantation

Acute graft-versus-host disease (GVHD) remains the major complication of allogeneic stem cell transplantation (SCT) with an incidence of 40-60% and a mortality of up to 50%. Several assays have been developed to try to predict the development of GVHD including the mixed lymphocyte culture reaction, cytotoxic and helper T lymphocyte precursor frequency assays. In the Northern region of England we have used an in vitro skin explant model for predicting GVHD in MHC compatible bone marrow transplant recipients since 1988. The aims of the present study was to test the reproducibility of the model in two other bone marrow transplant centers in Europe. The assay consists of incubating patient skin explants with effector cells from mixed donor versus recipient lymphocyte cultures and the subsequent detection of graft-versus-host reactions by histopathological grading (0-IV) of the skin explants. 503 slides from 134 patients were evaluated. All were graded for negative GVHR grade 0-I or positive grade II-IV. Results from control and test slides significantly correlated between centers to the p value of 0.0001 by Fisher's exact probability test. These results show that the skin explant assay is reproducible between centers and supports the continued use of the assay to predict GVHD in allogeneic stem cell transplant recipients.

Parton energy loss with detailed balance

Stimulated gluon emission and thermal absorption, in addition to induced radiation, are considered for an energetic parton propagating inside a quark-gluon plasma. In the presence of thermal gluons, stimulated emission reduces, while absorption increases, the parton's energy. The net effect is a reduction of the parton energy loss. Though decreasing asymptotically as T/E with the parton energy, the relative reduction is found to be important for intermediate energies. The modified energy dependence of the energy loss will affect the shape of suppression of moderately high p(T) hadrons due to jet quenching in high-energy heavy-ion collisions.

Kinetic equation with exact charge conservation

A kinetic master equation for multiplicity distributions is formulated for charged particles which are created or destroyed only in pairs due to the conservation of their Abelian charge. It allows one to study time evolution of the multiplicity distributions in a relativistic many-body system with arbitrary average particle multiplicities. It is shown to reproduce the equilibrium results for both canonical (rare particles) and grand canonical (abundant particles) systems. For canonical systems, the equilibrium multiplicity is much lower and the relaxation time is much shorter than the naive extrapolation from grand canonical results. Implications for chemical equilibration in heavy-ion collisions are also discussed.

Energy and centrality dependence of rapidity densities at RHIC energies

The energy and centrality dependence of the charged multiplicity per participant nucleon is shown to be able to differentiate between final state saturation and fixed scale perturbative QCD models of initial entropy production in high-energy heavy-ion collisions. The energy dependence is shown to test the nuclear enhancement of the minijet component of the initial conditions, while the centrality dependence provides a key test of whether gluon saturation is reached at RHIC energies. The HIJING model predicts that the rapidity density per participant increases with centrality, while the saturation model prediction is essentially independent of centrality.

High p(T) azimuthal asymmetry in noncentral A + A at RHIC

The high p(T)>3 GeV azimuthal asymmetry, v(2)(p(T)), in noncentral nuclear collisions at RHIC is shown to be a sensitive measure of the initial parton density distribution of the produced quark-gluon plasma. A generalization of the Gyulassy-Lévai-Vitev non-Abelian energy loss formalism including Bjorken (1+1)D expansion as well as important kinematic constraints is used.

Multiple scattering, parton energy loss, and modified fragmentation functions in deeply inelastic eA scattering

Modified quark fragmentation functions in deeply inelastic eA collisions and their QCD evolution equations are derived for the first time in the framework of multiple parton scattering. Induced radiation gives rise to additional terms in the evolution equations and thus softens the modified quark fragmentation functions. The results in the next-leading-twist depend on both diagonal and off-diagonal twist-four parton distributions and the combination of which clearly manifests the LPM interference pattern. The predicted modification depends quadratically on the nuclear size ( A2/3). Generalization to the case of hot QCD medium is also discussed.

Can cord blood cells support the cytokine storm in GvHD?

Cord blood has a high number of proliferating hematopoietic progenitors and is therefore used as an alternative source of hematopoietic cells for allogeneic transplantation. In addition there is a wider availability of cord blood and a lower cost of procurement compared to bone marrow. However one of the most interesting immunological benefits of a cord blood transplant that has been proposed is the low severity of Graft versus Host Disease (GvHD). This review aims to address some of the immunological reasons why this may be the case by assessing the role of cord blood cytokines in the cytokine storm of GvHD.

T-cell frequency analysis does not predict the incidence of graft-versus-host disease in HLA-matched sibling bone marrow transplantation

BACKGROUND

Graft-versus-host disease (GVHD) is a major and sometimes fatal complication of allogeneic bone marrow transplantation (BMT). The prediction of GVHD remains an important issue in preventing morbidity and mortality after allogeneic BMT. In the past 10 years, there has been great interest in using the frequency analysis of alloreactive helper and cytotoxic T lymphocyte precursors (HTLp and CTLp) to detect recipient-specific alloreactivity and thus predict GVHD in HLA-matched related and unrelated BMT. However, the results remain controversial. The intention of the present study was to investigate whether alloreactive HTLp and CTLp frequencies measured in donor peripheral blood before BMT would be a useful predictor for the occurrence of acute GVHD after HLA-matched sibling BMT.

METHOD

A combined limiting dilution assay was used to determine alloreactive HTLp and CTLp frequencies for 42 HLA-matched sibling patient/donor pairs. The pretransplantation host-reactive HTLp and CTLp frequencies were then correlated with post-transplantation clinical outcomes of acute GVHD. The association between HTLp/CTLp frequencies and the incidence of acute GVHD was determined using the Fisher's exact test.

RESULTS

The mean values of HTLp and CTLp frequencies for this cohort of HLA-matched sibling patient/donor pairs were 1:321,322 (range 1:71,000 to 1:1000,000) and 1:195,260 (range 1:3,717 to 1:1000,000), respectively. Acute GVHD (> or =II) was observed in one of four patients with high (>1:100,000) HTLp frequencies and 20 of 36 patients with low (<1:100,000) HTLp frequencies. Similarly, 6 of 10 patients with high (>1: 100,000) CTLp frequencies and 14 of 29 patients with low (<1:100,000) CTLp frequencies developed acute GVHD (> or =II). The overall correlation between hostreactive HTLp/CTLp frequencies and the incidence of acute GVHD in this cohort of patients was 42.5% and 53.9%, respectively. There was no significant difference in the incidence of acute GVHD between the patients with either high or low host-reactive HTLp/ CTLp frequencies (P=0.331 and 0.716, respectively). The data were also analyzed separately for the adult patient group based on GVHD prophylaxis with either cyclosporine alone or the combination of cyclosporine and methotrexate. Within these two prophylaxis groups, neither HTLp nor CTLp frequencies correlated with acute GVHD.

CONCLUSION

Host-reactive HTLp and CTLp frequency analysis did not provide informative prediction for the occurrence of acute GVHD after HLA-matched sibling BMT.

[Expression and characterization of human vascular endothelial growth factor receptor Flt-1 extracellular domain in Pichia pastoris]

By inserting VEGF receptor Flt-1(1-3 loop) cDNA into Pichia pastoris expression vector pPIC9K containing AOX1 promotor and the sequences of alpha secreting signal peptides, the expression plasmid pPIC9K/Flt-1(1-3) was constructed and transformed into GS115. The multi-copy insert transformants were selected and cultivated in flasks. After 4 days of 1% methanol induction, the expressed Flt-1(1-3) accumulated up to 30% of total proteins in supernatant. The expressed Flt-1(1-3) was further proved with good antigenicity and high specificity by ELISA and Western blot. They can bind to VEGF and inhibit HUVEC proliferation stimulated by VEGF.

Skeletal muscle oxidative capacity, fiber type, and metabolites after lung transplantation

Lung transplant (LTx) recipients have a low peak work rate, peak oxygen consumption (V O2peak), and early lactate threshold on incremental exercise. We hypothesized that LTx recipients have reduced oxidative function and altered fiber type proportion in peripheral skeletal muscle. Seven stable LTx recipients and seven age- and sex-matched control subjects were studied. Incremental exercise testing with arterialized venous sampling and a resting quadriceps femoris punch muscle biopsy were performed. Muscle specimens were analyzed for fiber type proportion, metabolites, oxidative and glycolytic enzyme activities, and mitochondrial ATP production rate (MAPR) using standard techniques. The results showed that mean V O2peak in LTx recipients was 52% of control subjects. Compared with the control subjects, LTx skeletal muscle exhibited: (1) a lower MAPR; (2) lower activity of the mitochondrial enzymes glutamate dehydrogenase (GDH), citrate synthase (CS), 2-oxogluterate dehydrogenase (OGDH), and 3-hydroxyacyl-CoA-dehydrogenase (HAD). There was no difference in the activities of anaerobic enzymes, except for higher phosphofructokinase activity; (3) a lower proportion of type I fibers; (4) a higher lactate and inosine monophosphate (IMP) content and a lower ATP content at rest indicating a high reliance on anaerobic metabolism. The reduced type I fiber proportion and severely reduced mitochondrial oxidative capacity may play an important role in exercise limitation after LTx.

Coordination of differential effects of primary estrogen and catecholestrogen on two distinct targets mediates embryo implantation in the mouse

In the mouse, estrogen is essential for blastocyst implantation in the progesterone (P4)-primed uterus. The mechanism(s) by which estrogen initiates this response still remains elusive. The present investigation, using delayed implantation in the mouse, examined the differential role of estradiol-17beta (E2) and its catechol metabolite 4-hydroxy-E2 (4-OH-E2) in uterine and blastocyst activation for implantation. The conditions of delayed implantation were induced by ovariectomizing mice on day 4 (day 1 = vaginal plug) of pregnancy or pseudopregnancy and maintaining them with P4 from days 5-7. The binding of EGF to blastocysts was used as a marker for blastocyst activation. Our results show that whereas E2 fails to activate dormant blastocysts (with respect to EGF binding in vitro), 4-OH-E2, cAMP, or prostaglandin E2, is effective in this response. Further, whereas 4-OH-E2 induced-activation is not blocked by an antiestrogen, an inhibitor of PG synthesis, adenylyl cyclase or protein kinase A effectively blocks this activation. These results suggest that 4-OH-E2 effects on blastocysts are mediated by PGs, which, in turn, stimulate cAMP production and thus activation of protein kinase A. Two-fluoro-E2 is a poor substrate and an inhibitor of catecholestrogen synthesis, but it is estrogenic, with respect to uterine growth and gene expression. Using blastocyst transfer experiments, we observed that dormant blastocysts incubated with 4-OH-E2 in vitro, but not with E2, are capable of implanting in P4-treated delayed implanting mice receiving two-fluoro-E2. The results suggest that whereas E2 is necessary for preparation of the uterus, uterine-derived catecholestrogen is important for blastocyst activation for implantation. Indeed, the receptive uterus has the capacity to synthesize 4-OH-E2. Collectively, we demonstrate that the primary ovarian estrogen E2, via its interaction with nuclear estrogen receptors, participates in the preparation of the P4-primed uterus to the receptive state in an endocrine manner, whereas its metabolite 4-OH-E2, produced from E2 in the uterus, mediates blastocyst activation for implantation in a paracrine manner. Our results also establish that these target-specific effects of primary estrogen and catecholestrogen are both essential for implantation and that successful implantation occurs only when the activated stage of the blastocyst coincides with the receptive state of the uterus.

Predicting graft-versus-host disease in HLA-identical bone marrow transplant: a comparison of T-cell frequency analysis and a human skin explant model

BACKGROUND

Graft-versus-host disease (GVHD) occurring after HLA-identical sibling bone marrow transplantation (BMT) is considered to be mainly caused by minor histocompatibility antigen (mHag) disparities between the recipient and donor. In our laboratory, a human skin explant model has been successfully used to predict acute GVHD in HLA-identical sibling BMT. More recently, the frequency analysis of host-reactive helper and cytotoxic T lymphocyte precursors (HTLp and CTLp, respectively) has been shown to have potential application for predicting GVHD. In the present study, HTLp and CTLp frequency analysis and the skin explant model were directly compared for their ability to predict acute GVHD in HLA-identical sibling BMT.

METHODS

Host-reactive HTLp and CTLp frequencies were determined using a combined limiting dilution assay. A human skin explant model was used to detect graft-versus-host reactions in vitro. The results from the skin explant model (graft-versus-host reaction grades I-IV) and T cell frequency analysis (>/< 1:100,000) were correlated with posttransplant GVHD outcome, respectively.

RESULTS

The skin explant model correctly predicted GVHD outcome in 77% of cases (P=0.03). HTLp frequencies were very low in all patient/donor pairs tested. None of them exceeded 1:100,000, although 9/18 recipients developed GVHD (> or =clinical grade II) after transplant. In all patients tested, the relationship between either high (>1:100,000) or low (<1:100,000) CTLp frequency and occurrence of GVHD appeared to be random (P=1.0).

CONCLUSIONS

HTLp and CTLp frequency analysis did not predict the occurrence of acute GVHD after HLA-identical sibling BMT. The human skin explant model, however, remained an accurate indicator of acute GVHD and probably detects mHag disparities.