Analysis of memory and effector CD8+ T cell subsets in chronic graft-versus-host disease

In humans, the selective depletion of CD8+ cells may prevent GVHD after allogeneic transplantation. These cells can infiltrate and damage target tissues. It is of interest to investigate the phenotypical characteristics and cytotoxic properties of the different CD8+ subsets in cGVHD patients. In a preliminary study we found that patients with cGVHD had a markedly elevated percentage of peripheral blood CCR7-/CD45RA+ cells compared to patients without cGVHD; conversely, the CCR7+/CD45RA+ subsets of CD8+ cells was significantly decreased. In this study, we report in depth on the phenotype of effector T cell subsets in cGVHD patients, as well as their proliferative capability, cytotoxic properties and cellular turnover. We confirm a predominance of effector T cell subsets in cGVHD patients and show that a large fraction of these cells down-regulate CCR7 and re-express CD45RA, thus approaching end-stage differentiation. Moreover CD8+ cells of cGVHD patients have low CD8 coreceptor expression, reduced proliferative potential and a high content of perforin and granzyme A. They also have a lower cell turnover and have more propensity to apoptosis, as demonstrated by BrdU incorporation. Taken together, our findings indicate a perturbation of the balance between naive/memory and effector/CD45RA+ CD8+ T cells, and suggest an involvement of the latter compartment characterized by a high content of cytotoxic equipment, in the pathogenesis of cGVHD.

Calibration of the thermoelastic constants for quantitative thermoelastic stress analysis on composites

The application of thermoelastic stress analysis in composite materials is particularly complicated because of the anisotropy of the material, that determines the thermoelastic constant to be dependent on the direction of the fibers. A further difficulty depends on the constructive stratification of the material, whose mechanical properties vary with the depth from the surface and this causes thermoelastic constants to be dependent on the frequency of the load applied. By using an analytical two layer model, it has been possible to interpret experimental data, thus proposing an explanation of the dependence on the frequency of the measured thermoelastic constants. This has shown that the practical use of the thermoelastic effect for quantitative stress analysis on composites needs constants calibrated at the correct frequency, also considering the thin layer of superficial resin present in every composite material.

Immunomodulating role of bisphosphonates on human gamma delta T cells: an intriguing and promising aspect of their antitumour activity

Vgamma9Vdelta2 T cells have the ability to produce inflammatory cytokines involved in protective immunity against intracellular pathogens and tumours and to display strong cytolytic as well as bactericidal activities. This suggests a direct involvement of Vgamma9Vdelta2 T lymphocytes in immune control of cancer and infections. These observations have recently aided development of novel immunotherapeutic approaches aimed at Vgamma9Vdelta2 T cell activation. Nitrogen-containing bisphosphonates (N-BPs) play a crucial role in Vgamma9Vdelta2 T lymphocyte activation and in the acquisition of effector functions. The preliminary results of these innovative strategies are encouraging. Moreover, compelling evidence in the literature supports the hypothesis that the antitumour effect of bisphosphonates is exerted through direct as well as indirect mechanisms. An additional and not yet well explored mechanism by which N-BPs may display antineoplastic effect is related to their immunomodulatory properties. It is fascinating that N-BPs influence the immune system in various but interrelated ways, being able to enhance the innate and to promote the adaptive immune responses. For all these reasons, Vgamma9Vdelta2 T lymphocytes represent a particularly interesting target for immunotherapeutic protocols based on N-BP administration. All these unexpected effects of N-BPs on the immune system have opened new and intriguing possibilities of therapeutic use for these drugs.

[Medical, social and economics aspects in the sulphur mines in Sicily(1791 - 1964)]

In Sicily the sulphur extraction represented an occasion of economic growth and a development for the dignity of the workers. The "carusi", young boys from 6 to 14 years old, were given up by their parents in return of a hardly payed of loan; it was the so called "soccorso morto" (dead aid). They were submitted to an enormous very hard physical work that caused severe damage to the skeleton and this was the reason of their inability to military service. The anthropometric surveys of "carusi" and pupils highlight for the first ones a reduced increase of the height and for the second ones the presence of "gibbo". For this reasons the inhabitans of Racalmuto were called racalmutesi immiruti" which means that people who lives in Racalmuto were hunchbacked. Nowadays it's possible to say that dietary and nutritional causes determined metabolic damages to the skeleton. A comparison between people who have been declared unable for military service belonged to the two lower clones of farmers and miners showed a lower incidence of the first ones. The law of 1866 on child labour assigned to medical doctors the task of certifying their suitability to work: the first step of normalisation on a medical care basis.

Magnetically Driven Growth of Anthracene Thin Films by Organic Molecular Beam Deposition

The possible use of a static magnetic field during organic molecular beam deposition of thin molecular films for inducing some preferential growth is discussed and the magnetic properties of diamagnetic molecules and molecular crystals are recalled. Considering prototypical materials, namely anthracene molecules and potassium phthalate substrates, which interact and may give rise to polycrystalline films with specific orientations, we show that in the presence of a magnetic field the films display a macroscopic preferential orientation as a result of minimization of the magnetic energy contribution. A very good agreement between the results of optical spectroscopy, atomic force microscopy, and predictions made on the basis of the anisotropic magnetic susceptibility of anthracene is found.

A human leucocyte antigen-DR1 transgene confers susceptibility to experimental allergic encephalomyelitis elicited by an epitope of myelin basic protein

Much evidence now indicates that human leucocyte antigen (HLA) class I and class II transgenic (Tg) mice can be of value in analysing HLA-restricted presentation of T-cell epitopes relevant to experimental models of autoimmune diseases. One area where this has been applied is the characterization of myelin epitopes presented by HLA class II molecules in experimental model of multiple sclerosis (experimental allergic encephalomyelitis (EAE)). As a first step towards humanized disease models in HLA Tg mice, we have analysed immune response of lymph node cells of HLA-DR1 Tg mice immunized with the human myelin basic protein (MBP) peptides 13-33, 87-106 and 139-154 bound by HLA-DR1. We report here that HLA-DR1 Tg mice display a hierarchy of response in vivo and in vitro to MBP epitopes depending on the binding affinity to DRB*0101 molecule. In fact, the 13-33 epitope induced a strong T helper 1 (Th1) response accompanied by high T-cell precursor frequency and caused mild EAE, while the two other epitopes gave poor (139-154) or no disease (87-106), and these data correlate with in vitro Th1 response. These data could prove a useful tool in understanding the role played by different MBP epitopes in EAE.

Cytokine profile, HLA restriction and TCR sequence analysis of human CD4+ T clones specific for an immunodominant epitope of Mycobacterium tuberculosis 16-kDa protein

The identification of immunodominant and universal mycobacterial peptides could be applied to vaccine design and have an employment as diagnostic reagents. In this paper we have investigated the fine specificity, clonal composition and HLA class II restriction of CD4+ T cell clones specific for an immunodominant epitope spanning amino acids 91-110 of the 16-kDa protein of Mycobacterium tuberculosis. Twenty-one of the tested 28 clones had a Th1 profile, while seven clones had a Th0 profile. None of the clones had a Th2 profile. While the TCR AV gene usage of the clones was heterogeneous, a dominant TCR BV2 gene family was used by 18 of the 28 clones. The CDR3 regions of BV2+ T cell clones showed variation in lengths, but a putative common motif R-L/V-G/S-Y/W-E/D was detected in 13 of the 18 clones. Moreover, the last two to three residues of the putative CDR3 loops, encoded by conserved BJ sequences, could also play a role in peptide recognition. Antibody blockade and fine restriction analysis using HLA-DR homozygous antigen-presenting cells established that 16 of 18 BV2+ peptide-specific clones were DR restricted and two clones were DR-DQ and DR-DP restricted. Additionally, five of the 18 TCRBV2+ clones recognized peptide 91-110 in association with both parental and diverse HLA-DR molecules, indicating their promiscuous recognition pattern. The ability of peptide 91-110 to bind a wide range of HLA-DR molecules, and to stimulate a Th1-type interferon (IFN)-gamma response more readily, encourage the use of this peptide as a subunit vaccine component.

Autosomal microsatellite and mtDNA genetic analysis in Sicily (Italy)

DNA samples from 465 blood donors living in 7 towns of Sicily, the largest island of Italy, have been collected according to well defined criteria, and their genetic heterogeneity tested on the basis of 9 autosomal microsatellite and mitochondrial DNA polymorphisms for a total of 85 microsatellite allele and 10 mtDNA haplogroup frequencies. A preliminary account of the results shows that: a) the samples are genetically heterogeneous; b) the first principal coordinates of the samples are correlated more with their longitude than with their latitude, and this result is even more remarkable when one outlier sample (Butera) is not considered; c) distances among samples calculated from allele and haplogroup frequencies and from the isonymy matrix are weakly correlated (r = 0.43, P = 0.06) but such correlation disappears (r = 0.16) if the mtDNA haplogroups alone are taken into account; d) mtDNA haplogroups and microsatellite distances suggest settlements of people occurred at different times: divergence times inferred from microsatellite data seem to describe a genetic composition of the town of Sciacca mainly derived from settlements after the Roman conquest of Sicily (First Punic war, 246 BC), while all other divergence times take root from the second to the first millennium BC, and therefore seem to backdate to the pre-Hellenistic period. A more reliable association of these diachronic genetic strata to different historical populations (e.g. Sicani, Elymi, Siculi), if possible, must be postponed to the analysis of more samples and hopefully more informative uniparental DNA markers such as the recently available DHPLC-SNP polymorphisms of the Y chromosome.

Granulysin-dependent killing of intracellular and extracellular Mycobacterium tuberculosis by Vgamma9/Vdelta2 T lymphocytes

Contribution of Vgamma9/Vdelta2 T lymphocytes to immune protection against Mycobacterium tuberculosis is still a matter of debate. It was reported earlier that Vgamma9/Vdelta2 T lymphocytes kill macrophages harboring live M. tuberculosis through a granule-dependent mechanism that results in killing of intracellular bacilli. This study found that Vgamma9/Vdelta2 T lymphocytes reduce the viability of both extracellular and intracellular M. tuberculosis. Granulysin and perforin, both detected in Vgamma9/Vdelta2 T lymphocytes, play a major role, which indicates that Vgamma9/Vdelta2 T lymphocytes directly contribute to a protective host response against M. tuberculosis infection.

Biology of gammadelta T cells in tuberculosis and malaria

Tuberculosis and malaria remain the leading causes of mortality among human infectious diseases in the world. It is estimated that 3 to 5 million people die from tuberculosis and malaria each year. Although it is traditionally believed that CD4 and CD8 alphabeta T lymphocytes are mandatory for protective immune responses against Mycobacterium tuberculosis and Plasmodium falciparum (the ethiologic agents of tuberculosis and the most severe form of malaria, respectively), there is still incomplete understanding of the mechanisms of immune protection and of the causes of its failure in the affected patients. Several studies in humans and animal models have suggested that Vgamma9/Vdelta2 T cells may play an important role in the immune responses against Mycobacterium tuberculosis and Plasmodium falciparum. Vgamma9/Vdelta2 T cells represent about 75% of all circulating gammadelta T cells while they can be greatly expanded during the acute phase of Mycobacterium tuberculosis and Plasmodium falciparum malaria. Vgamma9/Vdelta2 T recognize a new class of antigenic molecules which are nonpeptidic in nature and contain critical phosphate moieties (phosphoantigens). Interestingly, phosphoantigens isolated from Mycobacterium tuberculosis and Plasmodium falciparum share strong structural homology and are probably identical. However, despite a large body of data reported in the literature, it is not yet clear whether Vgamma9/Vdelta2 T cells play a protective or pathogenic role in immune responses against Mycobacterium tuberculosis and Plasmodium falciparum. In this review we summarize our current knowledge of the biology of Vgamma9/Vdelta2 T cells in response to the two pathogens, Mycobacterium tuberculosis and Plasmodium falciparum, and provide evidence suggesting definition of a novel and important protective role through which Vgamma9/Vdelta2 T cells can contribute to the killing of microorganisms residing in intracellular compartments.

Differential activation of human gammadelta cells by nonpeptide phosphoantigens

Human T cells expressing Vgamma9Ndelta2-encoded TCR recognize several nonpeptide phosphoantigens in the absence of major histocompatibility complex restriction. As these cells respond differentially to increasing concentrations of structurally related phosphoantigens, such ligands constitute agonists of different strengths. By analyzing early cellular events and late effector responses of gammadelta T cells, we compared their patterns of stimulation by weak, medium and strong phosphoantigen agonists. We found that, although the early metabolic activation as assessed by cytosensor microphysiometry directly reflects the intensity of subsequent effector response by gammadelta cells, TCR down-modulation is dissociated from the latter. Weak and mid-range phosphoantigen agonists induce a time- and dose-dependent down-modulation of the gammadelta TCR, whereas strong phosphoantigen agonists induce little or no TCR down-regulation. This indicates that gammadelta TCR down-modulation does not match the extent of TCR signaling as assessed by microphysiometry or conventional effector responses (TNF-alpha production and cytotoxicity). This differential pattern of gammadelta cell activation by phosphoantigens could explain the stronger potencies of some of these agonists.

Short latency facilitation between pairs of threshold magnetic stimuli studied in amyotrophic lateral sclerosis

The aim of the present study was to investigate the effects of short latency facilitation between pairs of threshold magnetic stimuli on the motor cortex of amyotrophic lateral sclerosis (ALS) patients, at an interstimulus interval (ISI) of 1-5 ms. As compared to controls, the facilitatory effects normally recorded at ISI 1 and 3 ms were considerably reduced. This suggested that the neuronal circuitry responsible for these effects, which is supposed to be the same as those generating I-waves, is impaired in ALS.

Immunohistochemical panels for differentiating epithelial malignant mesothelioma from lung adenocarcinoma: a study with logistic regression analysis

Immunohistochemistry provides an important indicator for differential diagnosis between pleural malignant mesothelioma and lung adenocarcinoma, which have complex therapeutic and medicolegal implications. To pinpoint a reliable, restricted panel of markers, the authors evaluated the efficacy of select commercial antibodies in a series of patients with confirmed clinicopathologic diagnosis of mesothelioma or lung adenocarcinoma with the aid of multiple logistic classification tables. Specimens of 46 mesotheliomas and 20 lung adenocarcinomas were examined with calretinin, thrombomodulin, cytokeratins (CKs) 5/6, and high-molecular weight CKs (indicators of mesothelioma), alongside MOC 31, Ber-EP4, and carcinoembryonic antigen (CEA; indicators of lung adenocarcinoma). Of the mesotheliomas, 40 of 46 (87%) were positive with calretinin, 29 of 46 (63%) with thrombomodulin, 40 of 46 (87%) with CKs 5/6, and 41 of 46 (89%) with high-weight CKs; five of 46 mesotheliomas (11%) were focally reactive with MOC 31, four of 46 (9%) with Ber-EP4, and two of 46 (4%) with CEA. Of the lung adenocarcinomas, 18 of 20 (90%) were positive with MOC 31, 20 of 20 (100%) with Ber-EP4, and 17 of 20 (85%) with CEA; and two of 20 (10%) were focally reactive with calretinin, one of 20 (5%) with thrombomodulin, none of 20 (0%) with CKs 5/6, and five of 20 (25%) with high-weight CKs. Multiple logistic modeling indicated two batteries of three antibodies permitting more than 98% overall accuracy: Ber-EP4 plus CKs 5/6 plus calretinin, and Ber-EP4 plus CKs 5/6 plus CEA.

[Spontaneous electromyographic activity. Practical importance]

Spontaneous activities are a major semeiologic sign in electromyography. The present article deals with the different aspects recorded in practice in normal and pathological cases. There are two types of spontaneous activities, those related to motor unit hyperactivity (fasciculations and myokymia) and those related to the hyperactivity of one or more muscle fibers: fibrillations, positive sharp waves, myotonic discharges and complex repetitive discharges. In the first case the lesion is located in the axone and in the second in the membrane of the muscle fibers; All theories related to the cells' abnormalities share a common feature: spontaneous activities result from abnormal firing of the membrane action potential of muscular fibers. This functional abnormality may results from different types of lesions within the cells' membrane and determines the aspects of spontaneous activities. Impaired function of muscular cells' membranes can be produced by denervation or lesion of the membrane structure itself. The latter can be multiple and linked with the membrane proteins (such as laminine or dystrophin as in AIDS diseases) or with ion channel disturbances. Multiple membrane cell alterations may produce the same kind of spontaneous activity; for instance, myotonic discharges have the same morphology in Thomsen and Steinert's disease despite their different mechanisms and fibrillations seen in denervations and myopathies. The practical consequences are discussed and a new classification of these spontaneous activities is proposed.

Whole body irradiation induces IFN-gamma production in BALB/c mice by preventing the appearance of a V alpha 14(+)NK T downregulatory population

Lymph node cells from TNCB-immune BALB/c mice fail to produce IFN-gamma when exposed to antigen in vitro. Conversely, lymph node cells of irradiated (550 rads) BALB/c mice produce IFN-gamma. Transfer experiments show that normal BALB/c mice contain cells which suppress IFN-gamma production. These downregulatory cells are CD4(+)alpha beta(+)and rearrange the invariant V alpha 14-J alpha 281 T cell receptor alpha chain, thus belonging to the NK T cell subset. Downregulatory cells probably act by producing IL-4 as their effect is blocked by mAb to IL-4.

Change of Th0 to Th1 cell-cytokine profile following tuberculosis chemotherapy

T cells mediate protection against tuberculosis, but little is known about their role during chemotherapy of patients with active disease. Here we examined the cytokine profile of CD4 T cells before and after four months of chemotherapy in six initial skin test anergic cases. Purified protein derivative (PPD) and 16-kDa antigen-reactive CD4 T-cell clones prior to therapy resided mostly in disease-associated body fluids and were of the Th0 (interferon (IFN)-gamma + interleukin (IL)-4) secreting profile. In contrast, the majority of postchemotherapy CD4 T-cell clones originated from blood and were of the IFN-gamma secreting Th1 type. However, the recognition of several peptides derived from the 16-kDa antigen was not significantly different between the Th1 and Th0 clones. We conclude that chemotherapy shifts CD4 T cells from the affected body fluids to the blood circulation, accompanied by a change from Th0 to Th1 cytokine profile.

Neuronal loss in Onuf's nucleus in three patients with progressive supranuclear palsy

Disorders of micturition have been reported only sporadically in patients with progressive supranuclear palsy (PSP). We report the results of a clinicopathological study of 3 patients with a definite diagnosis of PSP at various stages of their illness with sphincter abnormalities. Electromyography of the sphincter muscles was performed in all 3 patients and was abnormal in 2. Morphological and morphometric evaluation of Onuf's nucleus in the sacral spinal cord, which is involved in sphincter control, showed severe cell loss, presence of neurofibrillary tangles, neuropil threads, and glial inclusions. We conclude that bladder dysfunction and abnormal sphincter electromyographic results are due to pathological changes in Onuf's nucleus, and we propose that sphincter abnormalities should be included in the list of possible symptoms of PSP.

In vitro activity of rifaximin, metronidazole and vancomycin against Clostridium difficile and the rate of selection of spontaneously resistant mutants against representative anaerobic and aerobic bacteria, including ammonia-producing species

BACKGROUND

Rifaximin is a rifamycin derivative characterized by a wide antibacterial activity. This drug is neither absorbed by the gastrointestinal tract nor inactivated by gastric juices, and exerts its action entirely within the intestinal lumen.

METHODS

In this study, the activity of this antibiotic was compared with that of metronidazole and vancomycin against 93 Clostridium difficile isolates. The rate of emergence of bacteria spontaneously resistant to the new compound was also evaluated in relation to representative gram-positive and gram-negative strains. In terms of MIC(50) values, rifaximin showed an intrinsic activity superior to that of the other agents. The emergence of spontaneously resistant strains was assessed with 46 aerobic (staphylococci, enterococci, Proteus spp., Citrobacter freundii, Providencia rettgeri, enteropathogenic, enteroinvasive, enterotoxigenic and entero- hemorrhagic Escherichia coli, and Salmonella enteritidis) and anaerobic (Clostridium spp., Bacteroides spp., Fusobacterium nucleatum and Peptococcus spp.) pathogens, most of them also ammonium producers. Two different methods, broth and agar dilution, were employed.

RESULTS

When liquid medium was employed, bacteria capable of sustained growth in 100 microg/ml of rifaximin were obtained after 2-5 transfers with gram-positive aerobic cocci, 2-3 transfers with gram-negative aerobic strains and 2-5 transfers with anaerobic species. At the highest dose used with the agar dilution method (8 x MIC), the frequency of emergence of spontaneously resistant mutants ranged from <1 x 10(-9) to 1.6 x 10(-8) with gram-positive aerobic and anaerobic cocci, while with aerobic and anaerobic gram-negative bacteria, this value ranged from <1 x 10(-9) to 1.7 x 10(-7). C. difficile showed a particularly low incidence of spontaneously resistant mutants (<1 x 10(-9)). The low incidence of resistant subpopulations selected by levels of 8 x MIC of rifaximin suggests that the high levels of the drug which were reached in the gastrointestinal lumen may further prevent the selection of mutants.

CONCLUSION

The low toxicity, broad antibacterial activity and very poor absorption from the gastrointestinal tract of rifaximin suggest a potential therapeutic use for this drug in gastrointestinal diseases, as well as in the management of patients with cirrhosis and chronic portal-systemic encephalopathy.

T cells recognize an immunodominant epitope of heat shock protein 65 in Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute systemic vasculitis of infancy and early childhood that is characterized by endothelial cell damage associated with T-cell activation. Lymphocytes infiltrating damaged tissues might be responsible for the disease through secretion of cytokines, such as tumor necrosis factor (TNF)-alpha, that could cause fever, as well as endothelial tissue damage. Debate is growing about the nature of antigen responsible for T-cell activation in KD. Bacillus Calmette Guerin (BCG) and purified protein derivative (PPD) hyperresponsiveness was observed in KD patients and this phenomenon was hypothetically ascribed to cross-reactivity between mycobacterial Heat Shock Protein (HSP) 65 and human homologue HSP63.

MATERIALS AND METHODS

CD4+ and CD8+ T-cell clones were obtained from peripheral blood of KD patients in acute phase, or control subjects. The clones were tested for reactivity toward HSP65 and derived peptides. Both proliferation and cytokine production were analyzed.

RESULTS

A significant fraction of CD4 and CD8 T-cell clones from KD patients recognized an epitope from HSP65, spanning amino acids 65-85. T-cell clones cross-reacted with the corresponding 90-110 peptide sequence of human HSP-63.

CONCLUSIONS

Cross-reactivity between specific epitopes of mycobacterial and human HSP could play a role in the development of the tissue-damage characteristic of KD.

Motor cortical dysfunction disclosed by single and double magnetic stimulation in patients with fibromyalgia

OBJECTIVE

To investigate the motor cortex by single and double magnetic stimulation, in patients with fibromyalgia.

METHODS

Thirteen patients with fibromyalgia and 13 age-matched healthy subjects were examined. We evaluated, in both limbs, motor evoked potential (MEP) latency and amplitude and the MCA/MPA ratio, i.e. MEP cortical amplitude (MCA) /maximal peripheral amplitude of the M response (MPA), the central conduction time (TCC) and the length of the silent period (SP). With double magnetic stimulation, different time intervals between shocks were used: with delays between shocks of 4, 25, 55 and 85 ms, the intensities of the conditioning shock were 80% the relaxed threshold. With delays between shocks of 55, 85, 100, 155, 200, 255 and 355 ms, the intensities of the conditioning shocks were set at 150% the relaxed threshold. In all cases, the intensity of the test shock was 150% the relaxed threshold. The results were also compared with those obtained in 5 women affected by rheumatoid arthritis (RA).

RESULTS

As compared to control, the cortical relaxed threshold was enhanced on both sides and limbs (P<0.05). The cortical silent period recorded with single magnetic stimulation was reduced in the upper limbs (P = 2.7x10(-11)) and lower limbs (both sides P = 3.6x10(-5)). The other parameters investigated were normal. With double magnetic stimulation, facilitatory phenomena were absent in fibromyalgic patients and the inhibitory responses recorded with a delay of 155 ms were reduced (P = 0.0052). No significant differences were noted between FM and RA patients.

CONCLUSION

This study demonstrated motor cortical dysfunction in patients with fibromyalgia involving excitatory and inhibitory mechanisms. This indicates motor cortical involvement and supports the hypothesis of aberrant central pain mechanisms. The absence of differences between FM and RA suggest that the lesions were not specific and could be related to chronic pain disorders within the central nervous system.

Vgamma9/Vdelta2 T lymphocytes reduce the viability of intracellular Mycobacterium tuberculosis

An effective immune response against the intracellular pathogen Mycobacterium tuberculosis is strictly dependent on T cell activation. Although this protective response mainly depends on local release of pro-inflammatory cytokines by Th1 CD4(+) T cells, contribution of Vgamma9 / Vdelta2 T lymphocytes to immune protection against this pathogen is suggested by the antimycobacterial reactivity of this subset and its ability to produce large amounts of Th1 cytokines. Here we show that Vgamma9 / Vdelta2 T lymphocytes kill macrophages harboring live M. tuberculosis. The cytotoxic activity of Vgamma9 / Vdelta2 T lymphocytes was not MHC class I or class II restricted but was blocked by anti-TCR monoclonal antibodies, thus indicating that it involved specific interaction between the TCR and the target cell. The cytotoxicity of Vgamma9 / Vdelta2 T lymphocytes was not mediated by TNF-alpha or Fas-Fas ligand, but was shown to occur through a granule-dependent mechanism that resulted in reduction of the viability of intracellular bacilli. Perforin was shown to play an important role in killing of both infected macrophages and intracellular mycobacteria. These data strongly suggest that Vgamma9 / Vdelta2 T lymphocytes contribute to the host defense against M. tuberculosis infection.

Ligand-specific alphabeta and gammadelta T cell responses in childhood tuberculosis

The alphabeta and gammadelta T cell responses were analyzed in the peripheral blood of children affected by active tuberculosis (TB) and in healthy children who tested positive (PPD+) or negative (PPD-) for purified protein derivative. PPD+ healthy and diseased children responded equally well to PPD in vitro. In contrast, only 18% of PPD+ TB patients responded to peptide p38G derived from the 38-kDa protein of Mycobacterium tuberculosis. Analysis of the whole gammadelta T cell population and of its Vgamma9/Vdelta2 subset showed similar frequencies in PPD+ children with TB and in healthy PPD+ and PPD- children. Vgamma9/Vdelta2 cells from children with TB responded to 5 different phosphoantigens similarly to those from healthy PPD+ children, but healthy PPD- children responded very poorly. Chemotherapy had contrasting effects on the tested lymphocyte population, represented by increase of alphabeta and decline of Vgamma9/Vdelta2 T cell responses. T cell responses in childhood TB may be similar to those in adult TB.

Townes-Brocks syndrome and renal dysplasia: a novel mutation in the SALL1 gene

A 14-year-old African-American boy had chronic renal failure and Townes-Brocks syndrome (TBS). There were no affected family members. Features were imperforate anus, rectoperineal fistula, triphalangeal thumb, bifid thumb, rocker bottom feet, bilateral ear tags, satyr ear, sensorineural hearing loss, hypospadias, bilateral renal hypoplasia, and progressive chronic renal failure. Renal and urological anomalies in TBS include renal hypoplasia, renal dysplasia, unilateral renal agenesis, horseshoe kidney, posterior urethral valves, uretero-vesical reflux, and meatal stenosis. TBS is caused by a dominantly inherited defect in the gene encoding the SALL1 putative transcription factor, a protein possibly required for urological, renal, limb, ear, brain, and liver development. This patient had a novel mutation in this gene. The extent of renal involvement in patients with TBS should be evaluated for optimum treatment and prediction of prognosis.

Primary central nervous system lymphoma presenting with a parkinsonian syndrome of pure akinesia

The incidence of primary central nervous system lymphoma (PCNSL), once a rare tumour, has risen significantly in both immunocompetent and immunosuppressed patients. Although infiltration of the basal ganglia is not uncommon in PCNSL, extrapyramidal movement disorders are generally not recognised as a mode of clinical presentation of this type of cerebral tumour. We present the unusual case of a 75-year-old man who developed a parkinsonian syndrome of "pure akinesia" due to autopsy-confirmed PCNSL primarily involving the globus pallidus bilaterally. Parkinsonism due to bilateral pallidal lesions is known but rare, and such cases help in the understanding of basal ganglia function with regard to akinesia and freezing.

Induction and tolerization of anti-male CD8+ cytotoxic T lymphocytes by in vivo immunization with an H-Y-derived peptide

We have analyzed the immune response induced by a 9mer synthetic peptide derived from the male histocompatibility antigen H-Y and containing Db-binding motifs in C57BL/6 mice. In this study we report that a single, subcutaneous injection of the peptide emulsified in IFA gave rise to the development of male-specific CD8+ T cells which displayed H-Y-specific proliferative response in vitro and showed a Tc1-type pattern of cytokine production (i.e. they secreted IFN-gamma and IL-2, but not IL-4 and IL-10). Development of a strong cytotoxic activity required in vitro stimulation with specific peptide and IL-2: under these culture conditions, we were able to generate potent CD8+ CTLs that lysed both male cells and peptide-pulsed female cells. Continuous administration of soluble peptide, delivered over a 7-day period by a mini-osmotic pump implanted subcutaneously, inhibited proliferative and cytotoxic responses and IFN-gamma production in lymph node cells from C57BL/6 mice subsequently primed with peptide in adjuvant. This decreased responses were associated with a strong increase in the secretion of IL-4 by antigen-specific CD8+ T lymphocytes. Subcutaneous administration of the H-Y-peptide in adjuvant significantly accelerates rejection of male skin graft, while continuous administration of peptide in soluble form did not modify the time course of rejection.

Impaired contact hypersensitivity to trinitrochlorobenzene in interleukin-4-deficient mice

We have examined the role of endogenously produced interleukin-4 (IL-4) in the contact hypersensitivity (CH) reaction to the haptene trinitrochlorobenzene (TNCB). The CH reaction was abolished in IL-4 genetically deficient mice (IL-4 KO), when compared to wild-type (wt) mice. The CH reaction was restored by treatment with IL-4 and further analysis revealed that IL-4 exerted its action both at the induction and effector stages of the CH reaction. Despite failure to develop a CH reaction, IL-4 KO mice developed a T helper type 1 (Th1) response to TNCB, in terms of lymphokine production in vitro. Furthermore, the number of Vgamma3+ cells accumulating in the lymph nodes of TNCB-immune IL-4 KO mice was normal. The recruitment of mononuclear cells and vascular leakage at the challenge site were consistently reduced in IL-4 KO mice and were restored by injection of IL-4. This suggests that IL-4 acts as a proinflammatory mediator in CH, perhaps favouring the accumulation of mononuclear cells at the site of inflammation. Among Th2-type cytokines, IL-13, but not IL-10, was shown to restore the CH reaction to TNCB in IL-4 KO mice. However, IL-4 KO mice developed a normal CH response to oxazolone, indicating that IL-4 was required for the CH reaction to TNCB, but not for that to oxazolone.

Broad clonal heterogeneity of antigen-specific CD4+ T-cells localizing at the site of disease during tuberculosis

The repertoire of CD4+ T-lymphocytes was investigated in six patients affected by tuberculosis, who had a negative PPD skin test at diagnosis. Polyclonal CD4+ T-cell lines from the peripheral blood failed to proliferate to PPD and to the 16- or 38-kDa proteins of Mycobacterium tuberculosis, while CD4+ T-cell lines from the site of disease responded to PPD, and to the 16- and 38-kDa proteins, and derived epitopes in vitro. The repertoire of CD4+ T-cells accumulating at the site of disease was found to be widely heterogeneous as demonstrated by the finding that at least seven different peptides from the 16- and 38-kDa proteins were recognized by every patient. These results indicate that CD4+ T-cells localized at the site of disease in tuberculosis recognize a vast array of M. tuberculosis epitopes.

Different role of human HLA-DR and -DQ molecules in xenogeneic transplantation using transgenic mice

BACKGROUND

The role of T lymphocytes in graft rejection in xenotransplantation is still unclear. The ability of the human HLA class II molecules DR and DQ to function as xenoantigens was investigated in a murine model of skin grafting, using HLA-DR1 and -DQ6-transgenic mice.

METHODS

Skin from HLA-DR1- or -DQ6-transgenic mice was transplanted in control littermates. Spleen cells from donors or recipients were tested in mixed lymphocyte reaction and cytotoxic assay.

RESULTS

Skin from HLA-DR1-transgenic mice was rejected and spleen cells from rejecting mice were able to proliferate to donor cells, although no rejection was observed when the skin of HLA-DQ6-transgenic mice was engrafted in control littermates. No cytotoxicity was observed in any models.

CONCLUSIONS

Taken all together these results clearly suggest a hierarchy in the xenogeneic potency of human HLA class II molecules, with the HLA-DR1 molecule functioning as a potent xenoantigen when compared with the HLA-DQ6 molecule.

Sequestration of T lymphocytes to body fluids in tuberculosis: reversal of anergy following chemotherapy

The specificity of CD4 T lymphocytes was investigated in 6 patients affected by tuberculosis who had negative tuberculin purified protein derivative (PPD) skin tests at diagnosis. Polyclonal CD4 T cell lines from the peripheral blood failed to proliferate to PPD and to the 16- or 38-kDa proteins of Mycobacterium tuberculosis, while CD4 cell lines from the disease site responded to PPD and to the 16- and 38-kDa proteins and derived epitopes in vitro. Four months after chemotherapy, the patients became responsive to PPD. The proliferative response to PPD and to the 16- or 38-kDa proteins and their derived peptides decreased in CD4 T cell lines from the disease site and increased in lines from the peripheral blood. These results indicate that CD4 T cells recognizing a vast array of M. tuberculosis epitopes are compartmentalized at the site of disease in anergic patients but appear in peripheral blood after chemotherapy.

In vivo gammadelta T cell priming to mycobacterial antigens by primary Mycobacterium tuberculosis infection and exposure to nonpeptidic ligands

BACKGROUND

The recognition of phosphorylated nonpeptidic microbial metabolites by Vgamma9Vdelta2 T cells does not appear to require the presence of MHC molecules or antigen processing, permitting rapid responses against microbial pathogens. These may constitute an important area of natural anti-infectious immunity. To provide evidence of their involvement in immune reactivities against mycobacteria, we measured the responsiveness of peripheral blood Vgamma9Vdelta2 T cells in children with primary Mycobacterium tuberculosis (MTB) infections.

MATERIALS AND METHODS

Peripheral blood mononuclear cells from 22 children with MTB infections and 16 positivity of tuberculin (PPD)-negative healthy children were exposed to nonpeptidic antigens in vitro and the reactivity of the Vgamma9Vdelta2 T cell subset with these antigens was determined using proliferation and cytokine assays. Also, responses of gammadelta T cells from rhesus monkeys stimulated with phosphoantigens in vivo were measured.

RESULTS

The Vgamma9Vdelta2 T cell responses were highly increased in infected children in comparison with age-matched controls. This augmented Vgamma9Vdelta2 T cell reactivity subsided after successful antibiotic chemotherapy, suggesting that persistent exposure to mycobacterial antigens is required for the maintenance of gammadelta T cell activation in vivo. The in vivo reactivity of Vgamma9Vdelta2 T cells to phosphoantigens was also analyzed in a rhesus monkey model system. Intravenous injections of phosphoantigens induced an activated state of simian Vgamma9Vdelta2 T cells which decreased after 2 months, i.e., with a time course similar to that seen in MTB-infected children.

CONCLUSIONS

The increased reactivity of Vgamma9Vdelta2 T cells to phosphoantigens appears to be dependent on constant antigenic exposure. Consequently, the assessment of Vgamma9Vdelta2 responses may be useful for monitoring the efficacy of antimycobacterial therapies.

High-performance liquid chromatographic determination of n-methylformamide, a biological index for occupational exposure to dimethylformamide

This report describes an analytical method for the biological monitoring of workers exposed to N,N-dimethylformamide (DMF), a solvent widely used in the chemical industry. The human main metabolites of DMF are N-hydroxymethyl-N-methylformamide (HMMF) and the minor metabolites N-methylformamide (NMF) and N-acetyl-S-(N-methylcarbamoyl)cysteine. The metabolite selected by the American Conference of Governmental Hygienists for occupational biomonitoring purposes, is NMF measured by gas chromatographic analysis, as during it HMMF may be converted to the minor metabolite NMF. HMMF and NFM can be measured independently using HPLC analysis. The procedure proposed here involves the thermal transformation of the primary metabolite HMMF into the minor metabolite NMF, which is then determined by HPLC. This method makes it possible to determine, using HPLC, both metabolites of DMF by measuring only one peak, thus offering two major advantages: (i) it increases the sensitivity of the test and (ii) it deploys only one reference standard.

[Evoked motor potentials obtained with double magnetic cortical stimulation: techniques and interpretation]

The technique of motor evoked potentials (MEP) obtained with single and double magnetic stimulation of the motor cortex in man has considerably improved over the past decade. We present the techniques and parameters involved in double magnetic stimulation for clinical purposes.

METHOD

The conditioning-test design is used to study modifications in the amplitudes of the muscular responses to the "test" shock, recorded on the first dorsal interosseus muscle. Enhanced amplitudes of conditioned responses indicate facilitation, reduced response inhibition.

RESULTS

The effects vary according to the shock intensity, the delay between shocks and the position of the conditioning coil. The latter may be located at the same place as the test shock (to test interneural circuitry related to pyramidal tract), on the hand area opposite the test shock (to test interhemispheric influences), or over the cerebellar area contralateral to the test side (to test the effect of cerebellar stimulations over the motor cortex). When the coils were located on the same cortical hand area there was facilitation when the intensities were both set at the threshold with an interstimulus interval (ISI) between 1 and 2.5-3 ms. At conditioning shock intensities below the threshold and the test shock 150% above, inhibition occurred at ISI 1-5 ms followed by facilitation at ISI 15-35 ms. When the intensities of both shocks were 150% above threshold, there were two clear cut individual responses at ISI above 10 ms; facilitation was recorded at ISI 15-35 ms, and inhibition between 55 and 255 ms. When the conditioning coil was located on the opposite hand area from the test shock (conditioning shock intensity supramaximal, test shock intensity above the threshold), ISI 1-5 ms facilitation occurred followed by inhibition up to ISI 30 ms. When the conditioning shock (intensity supramaximal) was located on the cerebellar area contralateral to the test side (intensity above the threshold), inhibition occurred at ISI 5 ms.

CONCLUSIONS

Double magnetic stimulations delivered over the same cortical area reflect facilitatory and inhibitory influences over the pyramidal tract controlled by interneurons, i.e., these tests investigate the intrinsic circuitry of the motor strip. Double magnetic stimulations delivered on each motor area study interhemispheric influences mediated by the corpus callosum, which are facilitatory and inhibitory. Double magnetic stimulations delivered on the cerebellar area demonstrates inhibitory influences over the contralateral cerebral motor cortex.

Selection of distinct Valpha/beta T-cell receptor families during in vivo and in vitro T-cell maturation

The experimental conditions influencing the use of Valphabeta TCR families were examined in lymph node (LN) cells from peptide-immunized C57BL/6 and Vbeta8.2 transgenic mice. Expanded proportions of Vbeta5, Vbeta8.2, Vbeta9, Vbeta12 and Vbeta14 positive cells and an association of Vbeta8.2 with Valpha11 was found in freshly harvested 8-day or 34-day immune LN cells. In contrast, peptide-specific T-cell lines generated in vitro from 8-day immune lymph node cells were found to be almost exclusively of the Valpha2/Vbeta12 family. However, T-cell lines originating from Vbeta8.2 transgenic mice did not show preferential Valpha usage. Anti-Vbeta8.2 antibody produced different effects: when added to cultures of LN cells from C57BL/6 or Vbeta8.2 transgenic strains, the peptide-induced proliferation was suppressed; however, following the injection of mice, subsequent in vitro proliferation and cytokine production induced by both peptide and Concanavalin A was suppressed in Vbeta8.2 transgenic, but much less in C57BL/6 mice. Hence, compensatory expansion of different Vbeta gene products occurred in vivo, but not under the employed in vitro conditions. In conclusion, these results suggest that the TCR family usage is influenced by the experimental conditions in which the T cells are selected and expanded and by the genetic potentials of the precursor pool.

Role of gamma delta T lymphocytes in immune response in humans and mice

T lymphocytes recognize antigen through the T cell receptor. T cells expressing the gamma delta T cell receptor have been found in many species. Whereas murine alpha beta T cells are concentrated in the lymphoid organs, gamma delta T cells represent only a minor population in the adult thymus and peripheral lymphoid organs (less than 5% of the population). However, murine gamma delta cells predominate in epidermis, in epithelial layers of small intestine, in lung, and in female reproductive organs. In contrast, human gamma delta cells predominate in lymphoid organs. Despite extensive progress in the molecular characterization of the gamma delta T cell receptor and its genes, the physiological role of gamma delta T cells has remained elusive for many years. It is becoming now clear that, in contrast to alpha beta cells that recognize peptide/MHC complexes, gamma delta T cells appear to recognize unprocessed proteic antigens and, in humans, also a class of widely represented nonproteic antigens containing critical phosphate moieties. Similarly, it is now known that gamma delta cells can perform a vast array of immune effector functions and appear to play important roles in antimicrobial immunity as well as in chronic inflammatory reactions.

Double magnetic stimulation of the motor cortex in amyotrophic lateral sclerosis

OBJECTIVES

To study the motor cortex circuitry and the motor interhemispheric influences with double magnetic stimulation in patients affected by amystrophic lateral sclerosis.

METHODS

We investigated the motor cortex in 21 amyotrophic lateral sclerosis patients (ALS, 10 with bulbar and 11 with spinal onset) with double magnetic stimulation (one shock in each hand area) with 2, 4, 6, 11 and 15 ms delay between shocks and paired magnetic stimulation (both shocks in the same area), with 4, 15, 25, 35, 55, 85, 100, 155, 200 and 255 ms delays, and compared the results with those obtained in normal subjects.

RESULTS

Double magnetic stimulation showed reduced interhemispheric facilitatory influences (maximal at 4 ms delay between shocks) when the test shock was applied on the left hemisphere in all patients; whereas no significant differences were observed compared to control (P > 0.05) when it was applied on the right hemisphere in both forms. Inhibitory effects (maximal at 11 ms delay between shocks) were reduced in all patients for both hemispheres (P < 0.05). Paired magnetic stimulations showed decreased inhibitory influences at 100-155 ms delay between shocks. Compared to control, the difference was significant in bulbar (P < 0.05) and spinal onset, but not between onset forms (P > 0.05). Inhibitory effects recorded with a short delay between shocks (4 ms) were not significantly modified in both forms of onset (P > 0.05) as compared to control. There were no facilitatory influences at 15 and 35 ms delays between shocks.

CONCLUSIONS

The results suggest that under these test conditions inhibition and facilitation were reduced in the motor cortex in ALS. As inhibitory effects were affected differently, two distinct cortical circuitries could be involved for short and long delays. As GABA neurons altered in ALS have been identified as a subpopulation reactive to parvalbumin, and since only inhibitory effects recorded with long delay between shocks were impaired in ALS, we suggest that this subpopulation of GABA neurons may be involved in the genesis of inhibitory effects recorded with a long delay between shocks.

Behaviour of human osteoblasts cultured on bioactive glass coatings

Two new formulations of bioactive glasses were used as coatings on titanium alloy (TiAl6V4) implants for prosthetic applications in the orthopaedic field. The biocompatibility of these bioglasses, as well as their osteoconductive properties, were assessed by employing primary cultures of human osteoblasts. A nonbioactive glass, the titanium alloy and polystyrene surface were used as controls. The results obtained demonstrated that the two bioglasses elicited a rapid and strong proliferative response by osteoblasts, which spread, formed a close layer and then expressed the specific osteoblastic marker i.e. osteocalcin. In comparison, cells grew on the nonbioactive glass to a much minor extent, similar to that of polystyrene control, showing individual cellular elements not forming a compact sheet, but expressed levels of osteocalcin clearly higher than both the polystyrene control and the two bioglasses. Finally, a very low proliferative rate of osteoblasts and the synthesis of hardly detectable osteocalcin amounts were observed with the titanium alloy. In conclusion, our studies indicate that the new bioactive glasses are effective in stimulating osteoblast growth and differentiation.

Early spontaneous improvement and deterioration of ischemic stroke patients. A serial study with transcranial Doppler ultrasonography

BACKGROUND AND PURPOSE

The purpose of our study was to investigate whether emergency transcranial Doppler (TCD) findings and their modifications over the first 48 hours are related to early neurological changes in acute ischemic stroke patients.

METHODS

Ninety-three patients underwent CT scan within 5 hours of a first-ever ischemic hemispheric stroke, and TCD serial examinations at 6, 24, and 48 hours after stroke onset. We classified TCD findings as follows: normal; middle cerebral artery (MCA) asymmetry (asymmetry index between affected and contralateral MCAs below -21%); and MCA no-flow (absence of flow signal from the affected MCA in the presence of ipsilateral anterior and posterior cerebral artery signals through the same acoustic window). We considered early deterioration and early improvement to be a decrease or an increase of 1 or more points, respectively, in the Canadian Neurological Scale score over the same period.

RESULTS

At 6-hour TCD examination, MCA asymmetry and MCA no-flow were present in 6 (22%) and 2 (7%), respectively, of 27 improving patients; in 20 (43%) and 10 (22%) of 46 stable patients, and in 9 (45%) and 8 (40%) of 20 deteriorating patients. TCD findings were normal in the remaining patients (P = 0.001). At serial TCD, we detected early (within 24 hours) recanalization (from no-flow to asymmetry or normal and from asymmetry to normal) in 2 (25%) improving patients, in 7 (23%) stable patients, and in 5 (29%) deteriorating patients and late (between 24 and 48 hours) recanalization in 4 (50%) improving patients, in 6 (20%) stable patients, and in none of the deteriorating patients (P = 0.03, chi 2 for trend, improving versus nonimproving irrespective of the timing of recanalization). One deteriorating patient (5%) developed a non-flow from an initial MCA asymmetry. Logistic regression selected normal TCD (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.06 to 0.46) as an independent predictor of early improvement and abnormal TCD (asymmetry plus no-flow) (OR, 5.02; 95% CI, 1.31 to 19.3) as an independent predictor of early deterioration.

CONCLUSIONS

TCD examination within 6 hours after stroke can help to predict both early deterioration and early improvement. Serial TCD shows that propagation of arterial occlusion is rarely related to early deterioration, whereas the fact that it can detect early recanalization (within 24 hours) in deteriorating patients and both early and late recanalization (after 24 hours) in improving patients suggests the existence of individual time frames for tissue recovery.

Cross-talk between V beta 8+ and gamma delta+ T lymphocytes in contact sensitivity

We have previously reported that T lymphocytes proliferating in vitro to the hapten trinitrochlorobenzene (TNCB) exhibit a very restricted V beta gene usage and response to TNCB is limited to T-cell receptors (TCR) composed of V beta 8.2 in combination with V alpha 3.2, V alpha 8 and V alpha 10. This paper investigates the role played by T lymphocytes expressing the V beta 8.2 gene segment in the contact sensitivity (CS) reaction to TNCB in the intact mouse and in its passive transfer into naive recipient mice. Mice injected with monoclonal antibodies to V beta 8 are unable to develop CS upon immunization with TNCB and 4-day TNCB-immune lymph node cells from mice that had been depleted in vivo or in vitro of V beta 8+ T lymphocytes fail to transfer CS. However, when separated V beta 8+ and V beta 8- cells were used for passive transfer, it was found that V beta 8+ T lymphocytes failed to transfer CS when given alone to recipient mice and a V beta 8- population was absolutely required. Further analysis revealed that within the V beta 8- population, T lymphocytes expressing the gamma delta TCR were fundamental to allow transfer of the CS reaction. These gamma delta cells were found to be antigen non-specific, genetically unrestricted and to rearrange the V gamma 3 gene segment. This indicates that transfer of the CS reaction requires cross-talk between V beta 8+ and gamma delta+ T lymphocytes, thus confirming our previous results obtained using TNCB-specific T-cell lines. Time-course experiments showed that V beta 8+ lymphocytes taken 4-24 days after immunization with TNCB were able to proliferate and produce interleukin-2 (IL-2) in response to the specific antigen in vitro. Similar time-course experiments were then undertaken using the passive transfer of the CS reaction system. The results obtained confirm that TNCB-specific V beta 8+ T lymphocytes are present in the lymph nodes of immunized mice from day 4 to day 24, and reveal that gamma delta+ T lymphocytes are active for a very short period of time, i.e. days 4 and 5 after immunization. In fact, TNCB-specific V beta 8+ cells are able to transfer CS when taken 4-24 days after immunization, providing the accompanying V beta 8- or gamma delta+ T lymphocyte are obtained 4 days after immunization. In contrast, injection of V beta 8+ T lymphocytes together with V beta 8- or gamma delta+ T lymphocytes that had been taken 2 or 6 days after immunization, failed to transfer significant CS into recipient mice. Taken together, our results confirm that cross-talk between V beta 8+ and gamma delta+ T lymphocytes is necessary for full development of the CS reaction and may explain why the CS reaction in the intact mouse lasts up to 21 days after immunization while the ability of immune lymph node cells to transfer CS is limited to days 4 and 5 after immunization.

The effect of cyclosporin A, FK506 and rapamycin on the murine contact sensitivity reaction

We have evaluated the effects of three potent immunosuppressive agents, cyclosporin A (CsA), FK506 and rapamycin, on the murine contact sensitivity (CS) reaction to the hapten trinitrochlorobenzene. Development of CS reaction requires participation of three distinct T cell subsets: alphabeta+, CD4+ T lymphocytes, which are the classical effector cell of the CS reaction, gammadelta+ T lymphocytes, and alphabeta+, double-negative (CD4- CD8-) T lymphocytes that express the B220 molecule and produce IL-4. We found that all three drugs inhibit the development of the CS reaction, but they affect different target cells. In fact, rapamycin and FK-506 block both alphabeta+, CD4+ and gammadelta+ T lymphocytes, while CsA inhibits only the alphabeta+, CD4+ T lymphocyte. None of the three drugs exerted any inhibitory activity on the alphabeta+, double-negative (CD4- CD8-) T lymphocytes. Hapten-immune lymph node cells from mice treated in vivo with CsA or FK506 failed to proliferate and to produce IL-2 when re-exposed to the specific antigen in vitro. In contrast, immune lymph node cells from mice that had been treated in vivo with rapamycin gave optimal antigen-specific proliferation and IL-2 production in vitro. The implications of these observations are discussed in relation to the use of these immunosuppressive agents for prevention of allograft rejection.

Development of hapten-induced IL-4-producing CD4+ T lymphocytes requires early IL-4 production by alphabeta T lymphocytes carrying invariant V(alpha)14 TCR alpha chains

This paper investigates the mechanisms responsible for the generation of IL-4-producing CD4+ T cells during contact sensitization with the hapten trinitrochlorobenzene (TNCB). Lymph node cells taken 1 day after immunization spontaneously released IL-4 while lymph node cells taken 2 and 3 days after immunization did not produce IL-4. A second wave of IL-4 production that was both antigen-specific and MHC class II (I-A)-restricted was observed 4 days after immunization. The spontaneous release of IL-4 at day 1 was due to the alphabeta+ double-negative (CD4- CD8-) T lymphocytes that also expressed NK1.1 and showed V(alpha)14 rearrangement, while alphabeta+ CD4+ T lymphocytes were the source of the antigen-specific IL-4 production at day 4. Early IL-4 production was required for the development of IL-4-producing CD4+ T cells as mice injected with anti-V(alpha)14 or anti-IL-4 mAb produced little IL-4 and IL-10, while production of IFN-gamma was increased approximately 2-fold. These results indicate that the development of IL-4-producing CD4+ T lymphocytes in the TNCB system requires early production of IL-4 by alphabeta+ double-negative cells carrying invariant V(alpha)14 TCR alpha chain.

Gluten stimulation induces an in vitro expansion of peripheral blood T gamma delta cells from HLA-DQ2-positive subjects of families of patients with celiac disease

The intestinal gluten sensitivity formally known as celiac disease (CD) is characterized by an evident involvement of local immune response and it is associated with the expression of HLA-DQ2 allele. The major role in the disease seems to be played by the T lymphocyte population bearing gamma delta T cell receptor (T gamma delta cells) which are increased both in peripheral blood and intestinal mucosae of celiac patients. In this paper data on the effects of in vitro gluten stimulation on lymphocytes expressing the T gamma delta phenotype are reported. Gluten seems to be able to induce the expansion of the T gamma delta cell population both in CD patients and their HLA-DQ2-positive asymptomatic relatives, in spite of the absence of clinical evidence of the disease. In addition, the evaluation of gluten-induced cytokine production shows that interleukin-4 could be implied in the early phases of pathogenesis of CD.