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Drug resistance is generally accepted as an important cause of treatment failure for patients with neoplastic or infectious diseases. Molecular mechanisms underlying drug resistance include the action of drug efflux pumps belonging to the super-family of ATP binding cassette (ABC) proteins, which mediate the cellular extrusion of a large variety of therapeutic drugs, a phenotype that is referred to as multidrug resistance (MDR). Unlike neoplastic and infectious diseases, chronic inflammatory diseases have received little attention. The potential role of ABC transporters in determining the efficacy of anti-rheumatic drugs, notably disease modifying anti-rheumatic drugs (DMARDs), in patients with rheumatoid arthritis is unclear. Based on knowledge from the field of oncology and immunology, this review concentrates on the pharmacological role of MDR proteins in the (clinical) efficacy of several DMARDs, as well as the physiological role of MDR proteins in transporting signalling molecules important in inflammatory processes. [ABSTRACT FROM AUTHOR]

Using an experimental contact sensitivity model in guinea-pigs, evidence is presented that hapten (DNCB or oxazolone) specific T lymphocytes may persist for several months in previous sites of inflammation. Immunological memory, revealed by accelerated contact skin reactions upon retesting with ihe hapten. was limited to the original contact skin reaction sites. This 'local skin memory" to DNCB or oxazolone could be induced in both specific and non-specific skin inflammatory reactions, provided the animals had been sensitized to the hapten not longer than 2 weeks before. In animals which had been sensitized more than 1 month earlier. Local skin memory could be induced if the animals received a booster application of hapten shortly (0-2 days) before primary skin testing. from these results we conclude that recently activated T cells may enter inflammatory sites non-specifically, producing specific local immunological memory. This memory may last several months. Accumulation of hapten specific T cells at inflammatory sites may be important in retest reactivity, in flare-up reactivity and in chronic inflammation. [ABSTRACT FROM AUTHOR]

Different lymphocyte subpopulations were prepared from lymph nodes and spleen obtained from 2.4-dinitrofluorobenzene/Freund's complete adjuvant (DNFB/FCA) sensitized guinea-pigs. The capacity to react in vitro to secondary antigenic (dinitrophenyl- modified syngeneic macrophages, DNP-Mø) stimulation by an increased DNA synthesis, appeared to be restricted to those T cells which lack receptors for lgG-Fc (Tγ- ). We confirmed the existence in this species of an IgG-Fc receptor-positive T-cell subset, which is particularly represented in the spleen (up to 56%). These Tγ+ cells apparently are not of monocyte lineage as they show strong PHA-responsiveness and a lack of non-specific esterase staining, whereas the majority of these cells form RRBC-rosettes. Neither B nor Tγ+ cells appeared to act as suppressor cells in the secondary DNP-Mø-driven proliferative response. [ABSTRACT FROM AUTHOR]

Until now in vitro stimulation tests have failed to detect DNCB contact sensitivity in guinea-pigs sensitized epicutaneously without the use of adjuvants. In this study DNP-conjugates optimally inducing contact sensitivity in vivo were tested for their capacity to detect DNCB contact sensitivity in vitro in a lymphocyte transformation assay. In vivo contact sensitivity measurements in guinea-pigs which had been immunized with different hapten-cell conjugates, showed that (1) living cells should be used for conjugation with the allergen, (2) macrophages are optimal carriers and (3) syngeneity is not required. Therefore, DNFB-coated peritoneal macrophages (viable when conjugated) were used as an antigen for in vitro stimulation. Using this conjugate, a highly reproducible antigen-specific increase in DNA synthesis could be obtained in lymph node lymphocytes from guinea-pigs that had been sensitized to DNCB by epicutaneous application of the allergen without the use of adjuvants. [ABSTRACT FROM AUTHOR]

Rabbit erythrocyte (RRBC) and EAC rosette formation, for detection of T and B lymphocytes respectively, was studied in thymus, lymph nodes and peripheral blood of guinea-pigs. Using two different methods for preparation of RRBC rosette-forming cells (RFC) it was found that, without an incubation period at 37°, a smaller part of the pool of T cells is detected which is particularly sensitive to cyclophosphamide (cy). RRBC rosette formation was studied for 2 weeks after treatment with one high dose of cy and appeared to be minimal in the thymus after 1 week and maximal in the lymph nodes at about day 3. EAC rosette formation was completely blocked by cy treatment. Four days after contact sensitization with 2,4-dinitrochlorobenzene (DNCB) no percentual increase was found in RRBC-RFC, suggesting a parallel increase of B and T cells in stimulated lymph nodes. Cytological screening of the rosettes at day 4 after DNCB showed that of the RRBC-RFC approximately 17 per cent were blast cells, while no difference was detected in the number of blast cells participating in EAC rosette formation as compared to the unstimulated lymph nodes. In contrast to RRBC-RFC the percentage of EAC-RFC in draining lymph nodes is increased after contact sensitization. The mechanism of this increase is discussed. [ABSTRACT FROM AUTHOR]

DNP-guinea-pig erythrocyte rosette-forming cells (RFC), as found after contact sensitization of guinea-pigs with DNCB, were shown to be highly sensitive to pretreatment with cyclophosphamide or X-irradiation, which suggests that these cells are B cells. This finding was confirmed by rosette-blocking experiments using an anti-immunoglobulin serum. It has already been shown that they are not directly related to antibody production. Possibly they represent precursors of antibody -producing cells. An increase in rosette formation, using non-antigenically related erythrocytes, was shown to parallel development of cell-mediated immunity (CMI) in the lymph nodes. These non-specifically induced RFC were also found to be B cells. Data were obtained which make it improbable that either proliferation or influx of B cells during development of CMI plays a major role in this increase. An alternative mechanism is suggested, while a possible role for these non-specifically induced RFC is proposed.

Guinea-pigs have been sensitized with DNCB, DNP-guinea-pig serum and DNP-guinea-pig erythrocytes. Four, six and ten days after sensitization numbers of rosette-forming cells with DNP-erythrocytes were estimated in the draining lymph nodes. It was found that the numbers of DNP-erythrocyte RFC did not correlate with humoral immunity as estimated by haemagglutination assay, but did so with cell- mediated immunity estimated as delayed-type hypersensitivity. On the other hand histological examination of the draining lymph nodes gave no clear confirmation of such a relationship. Experiments on the antigenic specificity of RFC showed that after DNCB sensitization a clear increase iii oxazolone-erythrocyte RFC and SRBC RFC can be found. These latter data suggest formation of RFC to be at least partly a non- specific phenomenon. [ABSTRACT FROM AUTHOR]

In previous work, we have shown that local administration of active cyctophosphamide (CY) derivatives, or other cytostatic drugs, at the sensitixation site induced a similar immunopotentiation to that of systemic CY. Since it is well documented that CY can inhibit suppressor cells, it was proposed that immunoenhancement by locally administered drugs might be based on a similar principle. The objective of the present study was to test this hypothesis, using an experimental model of Ts mediated suppression of delayed type hypersensitivity to sheep erythrocytes. In this model, mice are made tolerant to sheep erythrocytes by i.v. injection of a high dose of sheep erythrocytes. Local treatment of sheep erythrocytes-tolerant mice with the active CY derivative Z7557 at the site of attempted sensitization reversed suppression in a dose-dependent manner. Local treatment with the cytostatic drug etoposide (VP-16) and systemic CY treatment were also effective. In transfer experiments, the function of afferently acting suppressor cells was blocked by local treatment with Z7557 or systemic CY. These data support the concept of anti-.suppressor cell activity of locally administered cytostatic drugs. As with CY the pharmacological basis of this effect remains to be determined. [ABSTRACT FROM AUTHOR]

The immunomodulating effects of two locally administered cytostatic drugs, the active cyclophosphamide- derivative Z 7557 and the plant alkaloid VP-16, were compared with the effects of systemically administered cyclophosphamide and several established adjuvants: Freund's complete adjuvant, dextran sulphate, and dimethyl dioctadecyl ammonium bromide (DDA). All agents tested promoted the development of delayed-type hypersensitivity (DTH) to keyhole limpet haemocyanin (KLH) in mice. Locally administered cytostatic drugs were the most effective immunostimulatory compounds, whereas DDA was the least toxic agent tested. In order to increase the effectiveness and/ or reduce the toxicity of these agents we tested the efficacy of combinations of cytostatic drugs and DDA to enhance DTH. The results show that DDA and suboptimal amounts of locally administered cytostatic drugs act synergistically on DTH. [ABSTRACT FROM AUTHOR]

Lymph node lymphocytes from guinea pigs sensitized with the hapten homogenized in Freund's complete adjuvant or pretreated with cyclophosphamide shortly before an epicutaneous sensitization are capable of responding in vitro to a larger set of antigenic preparations than the lymphocytes from only epicutaneously sensitized animals. This may be due to a formation of a larger set of antigenic determinants when the hapten was homogenized in Freund's complete adjuvant or to a formation of a larger repertoire of lymphocytes capable of recognizing these determinants as it might be the result of pretreatment with cyclophosphamide. These procedures may also change the proportion of responding cells in the lymphocyte suspensions. [ABSTRACT FROM AUTHOR]

During clinical trials, a clonidine transdermal device has been found to induce clonidine-specific allergic contact dermatitis in up to 25% of patients during a treatment period of year. Using 3 different guinea pig strains, development was attempted of an experimental guinea pig model that would allow for in-depth studies into the mechanism of sensitization, and a possible role of transdermal device components. Transient low-level clonidine allergy could be obtained only in a minority of animal, with severe sensitization procedures departing from epicutaneous applications, combined with intradermal (adjuvant) FCA injections. Sensitization was not potentiated by additional booster procedures, including cyclophosphamide pretreatment, nor any of the putative cofactors (UV-treatments. C. parvum or acetaldehyde involvement) studied. These results suggest that the persistent skin contacts in man, with transdermal devices for sustained drug delivery, generate unique conditions favouring the development of allergic contact dermatitis, which are difficult to mimic in experimental animal models. Thus, clinical allergy may develop even to extremely weak sensitizing drugs that can be safely used orally, and escape most currently available predictive contact allergy animal models. Clinical studies remain unavoidable for studying factors that may reduce sensitization rates to more acceptable levels. [ABSTRACT FROM AUTHOR]

Vaults are large ribonucleoprotein particles found in eukaryotic cells. They are composed of multiple copies of a Mr 100,000 major vault protein and two minor vault proteins of Mr 193,000 and 240,000, as well as small untranslated RNAs of 86–141 bases. The vault components are arranged into a highly characteristic hollow barrel-like structure of 35 × 65 nm in size. Vaults are predominantly localized in the cytoplasm where they may associate with cytoskeletal elements. A small fraction of vaults are found to be associated with the nucleus. As of yet, the precise cellular function of the vault complex is unknown. However, their distinct morphology and intracellular distribution suggest a role in intracellular transport processes. Here we review the current knowledge on the vault complex, its structure, components and possible functions. [ABSTRACT FROM AUTHOR]

The interference of two simultaneous skin test reactions of intermediate strength has been studied in the guinea-pig, using four different antigens, i.e. ovalbumin, horse cytochrome c, PPD and oxazolone. Skin test reactions were evaluated at 4, 24 and 48 h by measuring three parameters: increase in skin thickness, diameter of erythema and intensity of erythema. When an Arthus reaction was elicited simultaneously with a delayed hypersensitivity (DH) reaction, no effect on the DH reaction was observed. When two simultaneous DH reactions were elicited with different antigens, the risk of interference appeared to be rather small. When, however, the same antigen was used for both skirt tests, suppression of at least one parameter of a DH-reaction was found in almost all experiments. Suppression of one skin test by another one could not be reduced by introducing a larger distance between the two skin tests. As complete inhibition of either of the parameters never occurred, multiple skin testing may allow one to obtain a qualitative impression of the state of delayed hypersensitivity; when, however, reliable quantitative data are needed, the performance of mare than one skin test at a time should be avoided. [ABSTRACT FROM AUTHOR]

Suppressor cells were demonstrated in the spleen of guinea-pigs made specifically unresponsive to dinitrofluorobenzene (DNFB) with dinitrobenzene sulphonic acid (DNBSO3). Transfusion of these cells at the same time as sensitization with DNFB, produced a significant reduction in the immunoblasts proliferating in the draining lymph node 4 days later. Transfusion on the day of skin testing produced no greater suppression of skin reactivity than cells taken from animals made hyporeactive to DNFB by contact with dinitrothiocyanate benzene (DNTB). It is concluded that there are at least two sites that suppressor cells can act. In the case of total unresponsiveness induced by DNBSO3, action is both central and in the periphery. In the case of hyporeactivity induced by DNTB, in which there is no defect in proliferation of T cells in response to antigen, the action of these cells is confined to the periphery. Results of spleen weight studies suggest that suppressor cells homing in the spleen respond by proliferation to epicutaneously applied DNFB. [ABSTRACT FROM AUTHOR]

This report presents the characterization of three mouse monoclonal antibodies (mAb) reactive with the guinea-pig leucocyte common antigen (LCA); CD45 in the human nomenclature. One, IH-l, reacted with LCA on all leucocytes. The other two were more restricted: IH-2 recognized only the 220,000, 210,000 and 195,000 MW isoforms, and IH-4 the 220,000, 210,000 MW isoforms. Both IH-2 and IH-4 reacted with all B cells and all Kurloff cells [the putative guinea-pig natural killer (NK) cell]. IH-2, but not IH-4, reacted with monocytes and macrophages. Neither reacted with neutrophils. Most thymocytes expressed low levels of the IH-2 and IH-4 epitopes, with those expressing high levels located predominantly within the medulla. Most (90%) CD4+ T cells from newborn guinea-pigs expressed high levels of the IH-2 and IH-4 epitopes; this percentage decreased with age to 70% in 2-year-old animals. We have demonstrated that CD4+ T cells which express low levels of the IH-2 epitope also express low levels of the IH-4 epitope. CD8+ T cells can be divided into two subsets by IH-4 but not IH-2. The reactivities of IH-2 and IH-4 are remarkably similar to those of human anti- CD45RB and anti-CD45RA antibodies respectively. Analogies with man and other species suggest important functional differences for subpopulations of guinea-pig T lymphocytes defined by anti- CD45R antibodies. [ABSTRACT FROM AUTHOR]

Irritant reactions to sodium lauryl sulfate were induced on the backs of 20 volunteers by means of patch test occlusion for 24 h. Different concentrations ranging from 0.25% to 2% were used, the lowest concentration being borderline irritant. The skin tests were read at 24, 48 and 72 h. Both the 96 of responding individuals and the intensity of the skin reactions were maximal at 48 h for all test concentrations. It is concluded that irritants may provoke inflammatory reactions which are not completely developed after 24 h. and are thus very similar to allergic patch test reactions. [ABSTRACT FROM AUTHOR]

The article focuses on oncogenic mucosal human papillomaviruses in erosive vulval lichen planus. Erosive vulval lichen planus (LP) is a rare, difficult-to-treat inflammatory disease of unknown aetiology. One hypothesis is that a hypersensitivity reaction to a yet unidentified (intraepidermal) antigen may play a role. CD8+ lesional T cells are shown to be more cytotoxic against autologous lesional keratinocytes than clones isolated from nonlesional T-cell lines; the possible antigen may be associated with major histocompatibility complex class I on lesional keratinocytes. The absence of high-risk HPV in erosive vulval LP may also indicate that these HPV types play no role in causing malignancies in this form of LP.

Recently, a crucial role of Th2 responses in nickel allergic contact dermatitis ( ACD) was demonstrated. As palladium allergy is an issue of growing interest, the diagnostic potential of Th2 parameters for palladium sensitization was investigated. Palladium (Na2[PdCl4])-induced lymphocyte proliferation ( LPT), Th1 and Th2 cytokine production were correlated with skin test ( ST) reactivity in 16 positive and 21 negative controls. Furthermore, the diagnostic potential of these assays was evaluated using receiver operating characteristics ( ROC) analysis. For comparison, same experiments were carried out for nickel (Ni SO4). Correlation coefficients between palladium ST reactivity and IFN-γ, LPT, IL-5, and IL-13 were 0.34, 0.51, 0.69, and 0.78, and overall test accuracies were 68%, 81%, 89%, and 95%, respectively. Both palladium- and nickel-mediated Th2 responses tightly correlate with ST reactivity, supporting recent findings on the crucial role of Th2 involvement in ACD. Therefore, these assays may have great potential as diagnostic tools for future in vitro sensitization testing. [ABSTRACT FROM AUTHOR]

Background Various anti-inflammatory drugs are available for the treatment of skin disorders. In these diseases, untoward immune responses to endogenous and/or environmental antigens are initiated by maturation and polarization of dendritic cells (DC). Objective To explore the suppressive effects of anti-inflammatory drugs on DC maturation and, in particular, polarization. Methods Exposure of DC to nickel in vitro results in DC maturation and secretion of both type 1 and type 2 cytokines, thereby providing a model to study the effects of anti-inflammatory drugs on DC responses. The inhibitory effects of anti-inflammatory drugs (ciclosporin, dexamethasone, diclofenac, dimethylfumarate, hydrocortisone, lactoferrin, 1-α,25-dihydroxyvitamin D3) on DC maturation (CD83, CD86, HLA-DR, CXCL8) and polarization (type 1: IL-12p70, TNF-α; type 2: IL-10, CCL17) were studied. Results All anti-inflammatory drugs, except for lactoferrin, had inhibitory effects on DC maturation. Hydrocortisone and dexamethasone exclusively suppressed the release of type 1 cytokines. A less pronounced, but similar profile was observed for dimethylfumarate and 1-α,25-dihydroxyvitamin D3. Ciclosporin suppressed both type 1 and 2 cytokines. In contrast, diclofenac suppressed only type 2 DC cytokine secretion. Conclusion The present results give more insight into the pharmacological effects of immunosuppressive drugs on the immune system, and can thereby contribute to a more rational selection of anti-inflammatory drugs for the treatment of inflammatory skin disorders. [ABSTRACT FROM AUTHOR]

Background There is an increasing demand for the clinical application of human skin substitutes (HSSs) for treating ulcers, burns and surgical wounds. Due to this increasing demand and due to the simultaneous requirement for the administration of topical antiseptic medications, there is a need to determine potential cytotoxic effects of these medications on HSSs compared with autograft skin. Objectives To perform such an evaluation. Methods Two different HSSs were used (autologous reconstructed epidermis on fibroblast-populated human dermis and allogeneic reconstructed epidermis on a fibroblast-populated rat collagen gel) and were compared with conventional full-thickness autograft. Twelve different antiseptics were applied topically to the stratum corneum in vitro for 24 h. The degree of cytotoxicity was analysed as detrimental changes in histology, metabolic activity (MTT assay) and RNA staining of tissue sections. Results The antiseptic medications tested showed different degrees of cytotoxicity. Acticoat®, Aquacel Ag®, Dermacyn®, Fucidin®, 0·5% silver nitrate solution and chlorhexidine digluconate were not cytotoxic for either HSS or autograft, and can therefore be used as required. Flamazine® and zinc oxide cream resulted in moderate cytotoxicity. However, application of Betadine®, cerium-silver sulfadiazine cream, silver sulfadiazine cream with 1% acetic acid and Furacine® resulted in a substantial decrease in cell viability and a detrimental effect on tissue histology when applied to autograft and especially to HSS. Conclusions Due to the potential cytotoxic effect of some antiseptics on HSS, it is advised that clinicians balance the cytotoxicity of the medication, its antiseptic properties and the severity of colonization in choosing which one to apply. [ABSTRACT FROM AUTHOR]

Tumor-derived vascular endothelial growth factor (VEGF) has previously been identified as a causative factor in the disturbed differentiation of myeloid dendritic cells (DC) in advanced cancer patients. Here, we investigated the potential of vascular endothelial growth factor receptor (VEGFR) tyrosine kinase (TK) inhibition to overcome this defective DC differentiation. To this end, peripheral blood DC (PBDC) precursor and subset frequencies were measured in 13 patients with advanced cancer before and after treatment with AZD2171, a TK inhibitor (TKI) of VEGFR, coadministered with gefitinib, and an epidermal growth factor receptor (EGFR) TKI. Of note, not only myeloid DC but also plasmacytoid DC frequencies were significantly reduced in the blood of the cancer patients prior to treatment, as compared to healthy controls. Moreover, besides an accumulated population of immaturemyeloid cells (ImC), a population ofmyeloid suppressor cells (MSC) was significantly increased. Upon systemic VEGFR TK inhibition, DC frequencies did not increase, whereas the rate of circulating MSC showed a slight, but not significant, decrease. In conclusion, TK inhibition of VEGFR with AZD2171 does not restore the defective PBDC differentiation observed in advanced cancer patients. [ABSTRACT FROM AUTHOR]

Background Chronic wounds represent a major problem to our society. Therefore, advanced wound-healing strategies for the treatment of these wounds are expanding into the field of tissue engineering. Objectives To develop a novel tissue-engineered, autologous, full-thickness skin substitute of entirely human origin and to determine its ability to heal chronic wounds. Methods Skin substitutes (fully differentiated epidermis on fibroblast-populated human dermis) were constructed from 3-mm punch biopsies isolated from patients to be treated. Acellular allodermis was used as a dermal matrix. After a prior 5-day vacuum-assisted closure therapy to prepare the wound bed, skin substitutes were applied in a simple one-step surgical procedure to 19 long-standing recalcitrant leg ulcers (14 patients; ulcer duration 0·5–50 years). Results The success rate in culturing biopsies was 97%. The skin substitute visibly resembled an autograft. Eleven of the 19 ulcers (size 1–10 cm2) healed within 8 weeks after a single application of the skin substitute. The other eight larger (60–150 cm2) and/or complicated ulcers healed completely ( n = 5) or continued to decrease substantially in size ( n = 3) after the 8-week follow-up period. Wound healing occurred by direct take of the skin substitute ( n = 12) and/or stimulation of granulation tissue/epithelialization ( n = 7). Skin substitutes were very well tolerated and pain relief was immediate after application. Conclusions Application of this novel skin substitute provides a promising new therapy for healing chronic wounds resistant to conventional therapies. [ABSTRACT FROM AUTHOR]

Purpose: To study the effect of autologous tumor cell vaccinations on the presence and numbers of circulating CD8+ T cells specific for tumor-associated antigens (TAA) in metastatic melanoma patients. To investigate the correlation between the presence of tumor-infiltrating lymphocytes (TIL) and circulating TAA-specific CD8+ T cells before and after autologous tumor cell vaccination with overall survival. Experimental design: Twenty-five stage III and resected stage IV metastatic melanoma patients were adjuvantly treated with a series of intracutaneously injected autologous tumor cell vaccinations, of which the first two contained BCG as an immunostimulatory adjuvant. Tumor samples and blood samples obtained before and after vaccination of these patients were studied for the presence of TAA-specific T cells using HLA-tetramers and results were correlated with survival. Results: In 5 of 17 (29%) melanoma patients, circulating TAA-specific T cells were detectable prior to immunizations. No significant changes in the frequency and specificity were found during the treatment period in all patients. Presence of circulating TAA-specific T cells was not correlated with survival (log rank, P=0.215). Inside melanoma tissue, TAA-specific TIL could be detected in 75% of 16 available tumor samples. In case of detectable TAA-specific TIL, median survival was 22.5 months compared to median survival of 4.5 months in case of absence of TAA-specific T cells (log rank, P=0.0094). In none of the patients, TAA-specific T cells were found both in tumor tissue and blood at the same time. Conclusions: These data suggest that the presence of TAA-specific TILs forms a prognostic factor, predicting improved survival in advanced-stage melanoma patients. The absence of TAA-specific T cells in the circulation suggests that homing of the tumor-specific T cell population to the tumor site contributes to the effectiveness of antitumor immunity. [ABSTRACT FROM AUTHOR]

Multidrug transporters, such as P-glycoprotein (P-gp), multidrug-resistance associated protein 1 (MRP1) and breast cancer resistance protein (BCRP), are associated with multidrug resistance in cancers; other molecules, such as major vault protein (MVP), have a similar association with drug-resistant cancer. These proteins are postulated to generate drug resistance in epilepsy. They have been shown individually to be up-regulated in epileptogenic brain tissue. In any consideration of the function, inhibition or evasion of the activity of such proteins, the colocalization of such proteins needs to be understood. We systematically determined the presence of such colocalization, focusing on microvascular endothelium from epileptogenic human brain tissue. Double labelling immunofluorescence and confocal laser scanning microscopy were used to determine colocalization of P-gp, MRP1, BCRP and MVP in one case of hippocampal sclerosis and two cases of focal cortical dysplasia type IIb. Endothelial colocalization was examined with double labelling using antibodies to CD34 and Factor VIII. The presence of P-gp, BCRP and MVP in microvascular endothelium was confirmed. P-gp, BCRP and MVP colocalized in microvascular endothelium, though not all proteins appeared to be identically distributed within this tissue. MRP1 did not colocalize to endothelium. These findings were not unexpected but required formal confirmation. The demonstrated colocalization of P-gp, BCRP and MVP in microvascular endothelium in epileptogenic human brain tissue has important implications for functional experiments (including single knock-out mice studies), work with specific and broad-spectrum inhibitors of transport function, and any eventual trials of treatment of refractory epilepsy involving modulation of the function of these proteins. [ABSTRACT FROM AUTHOR]

In this study, we investigated the capacity of CD4+CD25+ regulatory T cells to suppress nickel-specific effector T cells, both in nickel-allergic patients and healthy controls. CD4+ cells isolated from allergic patients showed an increased proliferative response to nickel, whereas CD4+ cells from negative controls did not respond to allergen. When CD4+CD25+ cells were depleted, nickel-specific responsiveness was strongly increased both in allergic and in non-allergic individuals, with the most pronounced effect in allergic patients. These regulatory T cells were anergic to nickel but inhibited nickel-specific CD4+CD25– effector T cells in coculture experiments. CD4+CD25+ cells from nickel-allergic patients showed only a limited capacity to suppress effector T-cell responsiveness, because an increased nickel reactivity could still be detected in these cocultures. None of the isolated CD4+CD25+ cells, either isolated from healthy controls or allergic patients, produced IL-10 in response to nickel. Overall, these results support the view that CD4+CD25+ cells can control the activation of nickel-specific effector T cells in non-allergic individuals, whereas this regulatory capacity is impaired in allergic patients. To investigate the presence of allergen-specific regulatory T cells in truly naïve, non-sensitized individuals, T-cell reactivity should also be studied with non-environmental contact allergens, such as para-phenylenediamine. [ABSTRACT FROM AUTHOR]

Spiekstra SW, Toebak MJ, Sampat-Sardjoepersad S, van Beek PJ, Boorsma DM, Stoof TJ, von Blomberg BME, Scheper RJ, Bruynzeel DP, Rustemeyer T, Gibbs S. Induction of cytokine (interleukin-1α and tumor necrosis factor-α) and chemokine (CCL20, CCL27, and CXCL8) alarm signals after allergen and irritant exposure.The immune system is called into action by alarm signals generated from injured tissues. We examined the nature of these alarm signals after exposure of skin residential cells to contact allergens (nickel sulfate and potassium dichromate) and a contact irritant[sodium dodecyl sulfate (SDS)].Nickel sulfate, potassium dichromate, and SDS were applied topically to the stratum corneum of human skin equivalents. A similar concentration-dependent increase in chemokine (CCL20, CCL27, and CXCL8) secretion was observed for all three chemicals. Exposure to nickel sulfate and SDS was investigated in more detail: similar to chemokine secretion, no difference was observed in the time- and concentration-dependent increase in pro-inflammatory cytokine[interleukin-1α (IL-1α) and tumor necrosis factor-α (TNF-α)] secretion. Maximal increase in IL-1α secretion occurred within 2 h after exposure to both nickel sulfate and SDS and prior to increased chemokine secretion. TNF-α secretion was detectable 8 h after chemical exposure. After allergen or irritant exposure, increased CCL20 and CXCL8, but not CCL27, secretion was inhibited by neutralizing human antibodies to either IL-1α or TNF-α.Our data show that alarm signals consist of primary and secondary signals. IL-1α and TNF-α are released as primary alarm signals, which trigger the release of secondary chemokine (CCL20 and CXCL8) alarm signals. However, some chemokines, for example, CCL27 can be secreted in an IL-1α and TNF-α independent manner. Our data suggest that skin residential cells respond to both allergen and irritant exposure by releasing mediators that initiate infiltration of immune responsive cells into the skin. [ABSTRACT FROM AUTHOR]

Diagnostic patch testing in allergic contact dermatitis faces the risk of boosting existing hypersensitivities or active sensitization. Risk-free and reliable in vitro assays using peripheral blood are, therefore, wanted. Here, we studied new approaches for in vitro monitoring of nickel-specific effector ad regulatory cell functions in allergic patients and potentially tolerized individuals. Lymphocyte proliferation assays were carried out with the allergen and additional IL-12/IL-7 or IL-4/IL-7 cytokine supplements. Release of IFN-γ and IL-5 were assessed as measures for type-1 and type-2 effector T cell function, respectively, and IL-10 and TGF-β1 to monitor possible regulatory T cell function reflecting immunological tolerance. After optimization of in vitro cut-off values, potency of these parameters was evaluated as compared with conventional nickel patch testing. One hundred and fifty six outpatients were included in this study, 74 of whom presenting with a positive history of nickel allergy. Nickel-sulphate patch test results showed positive reactions in 43 patients, of whom 40 had a positive history (test sensitivity 54%; specificity 96%; overall accuracy 76%). Proliferation tests without cytokine supplementation showed an accuracy of 68%, which was further improved by supplementing IL-4/IL-7 (82%). IFN-γ and IL-5 cytokine production, as revealed in IL-12/IL-7 and IL-4/IL-7 supplemented cultures, respectively, showed accuracies of 70% and 83%. As to the production of putatively immunoregulatory cytokines, IL-10 was most informative, with highest production rates in nickel-skin test negative individuals with long-lasting mucosal metal contact preceding skin piercing. These results indicate that measuring both T cell proliferation and cytokine secretion profiles, in particular IL-5 release using IL-4/IL-7 supplemented medium, offers a promising improvement of the in vitro diagnostic options in monitoring nickel contact sensitization. Since oral nickel contact has been shown earlier to induce active tolerization, nickel-induced in vitro IL-10 production may help identify nickel-tolerized individuals. [ABSTRACT FROM AUTHOR]

Whereas T lymphocytes are widely accepted as effector cells determining the pathogenesis of allergic contact dermatitis, contradictory results have been found regarding the roles of different T-cell subsets. The use of various experimental models, involving long-term cultured T-cell lines or clones, may explain these contradictory results. To investigate the involvement of distinct T-cell subsets in patients with nickel contact allergy. Different T-cell subsets were directly isolated from peripheral blood mononuclear cells (PBMCs) of nickel-allergic patients, and their proliferative capacity, type-1 or type-2 cytokine secretion [measured by interferon (IFN)-γ or interleukin (IL)-5 release] and phenotypical marker expression were analysed after stimulation with nickel. Only CD4+ CLA+ CD45RO+ and not CD8+ T cells proliferate and produce both type-1 (IFN-γ) and type-2 (IL-5) cytokines in response to nickel. Moreover, cells expressing the marker CLA in combination with CD4, CD45RO or CD69 are increased after nickel-specific stimulation. Interestingly, in addition, CD45RA+ CLA+ cells showed an increased frequency after allergen-specific stimulation. Analysis of nickel-reactive T cells for expression of distinct chemokine receptors showed that both proliferative capacity and cytokine production are restricted to subsets expressing CXCR3, CCR4 but not CCR6. Fluorescence-activated cell sorting analysis of chemokine receptors expressed on nickel-stimulated T cells confirmed these results; a subset of T cells expressing CLA and CXCR3, CCR4 and, most importantly, CCR10 increased in response to allergen, while these CLA+ nickel-reactive T cells were all negative for CCR6. These findings demonstrate that freshly isolated nickel-reactive T cells can be characterized as CD4+ CLA+ memory T cells which express the chemokine receptors CXCR3, CCR4 and CCR10, but not CCR6. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor in response to the article "TNF-X Receptor 1 Expression on Acute Myeloid Leukemic Blasts Predicts Differentiation Into Leukemic Dendtric Cells," published in the April 2004 issue of "Leukemia."

Severe trauma can lead to a compromised immune response, thereby increasing susceptibility to infections. Here we will study to what extent these early changes in the immune status upon trauma affect a primary immune response to keyhole limpet haemocyanin (KLH). Because glutamine is the preferred respiratory substrate for immune competent cells and known to be depleted after trauma, we studied the immune status and the primary sensitization in relation to the glutamine plasma concentration in a group of severe trauma patients [injury severity score (ISS) >17]. Trauma patients ( n = 31) were sensitized with KLH within 12 h after trauma; plasma glutamine concentrations and immune parameters were determined, after which KLH-specific immune responsiveness was evaluated on days 9 and 14. Low plasma glutamine concentrations were found after trauma. Significantly elevated numbers of granulocytes and CD14-positive leucocytes were found, whereas the HLA-DR expression on CD14-positive cells was significantly lower in trauma patients than in healthy controls. Trauma did not change the in vitro proliferative capacity of lymphocytes when cultured with glutamine; however, when lymphocytes were cultured without glutamine, trauma resulted in lower proliferation than healthy controls. Phytohaemagglutinin-(PHA)-induced interferon (IFN)- γ and interleukin (IL)-10 production was significantly lower after trauma, whereas IL-4 production was not affected. KLH sensitization following trauma resulted in poor skin test reactivity and low in vitro KLH-induced lymphocyte proliferation compared to controls. In contrast, the development of anti-KLH IgM, IgG, IgA, IgG1, IgG2, IgG3 and IgG4 production on days 9 and 14 following trauma was not different from that in healthy controls. Major trauma was associated with a reduced cell-mediated immune response, correlating with low plasma glutamine concentrations, while no effects of trauma were found on the development of a primary humoral immune response. [ABSTRACT FROM AUTHOR]

Abstract: Allergen-induced emigration and maturation of dendritic cells (DC) are pivotal steps in sparking off allergic contact dermatitis. In vitro models, reflecting these steps, may provide tools for assessment of sensitizing capacities of putative contact allergens. Here, we evaluated the applicability of such models for a panel of methacrylate congeners, the sensitizing properties of which were established previously in clinical and experimental animal studies. First, using interleukin-4 (IL-4)/granulocyte–macrophage colony-stimulating factor (GM-CSF)-induced, blood monocyte-derived DC, hapten-induced up-regulation of maturation/activation markers, including CD80, CD83, CD86, chemokine receptors CXCR4 and CCR5, as well as the drug resistance related molecules P -glycoprotein (Pgp) and lung resistance protein (LRP), were monitored by flow cytometry. Of note, whereas CD86 and CXCR4 were most sensitive in discriminating between the contact sensitizers and irritants included in the panel, i.e. sodium dodecyl sulphate (SDS) and croton oil (CO), assessment of CD83 and LRP expression reflected the relatively lower sensitizing capacity of methyl methacrylate. Second, using ex vivo skin explant cultures, allergen-induced LC migration from epidermal to basal membranous and dermal skin structures was most reliably monitored by CD1a, as compared with Pgp, LRP, HLA-DR or CD54 staining. The extent of CD1a[sup +] LC migration was found to closely correlate with the sensitizing capacities of the panel of test compounds. These results support the view that both in vitro models can provide valuable data on contact sensitizing properties, and add chemokine receptors and drug resistance related molecules to the list of DC membrane markers revealing allergenic signaling. [ABSTRACT FROM AUTHOR]

This study was undertaken to investigate the expression and predictive value for outcome of multidrug resistance-associated (MDR) proteins P-glycoprotein (Pgp), MRP1, BCRP, and LRP, in advanced testicular germ-cell tumours (TGCT). Paraffin-embedded sections from 56 previously untreated patients with metastatic TGCT were immunostained for Pgp, MRP1, BCRP, and LRP. All patients received platinum-based chemotherapy after orchidectomy. Immunostaining was related to clinicopathological parameters, response to chemotherapy, and outcome. Strong and intermediate expressions of the different MDR-related proteins were: 27 and 41% (Pgp), 54 and 37% (MRP1), 86 and 7% (BCRP), and 14 and 29% (LRP). P-glycoprotein and MRP1 associated, respectively, to low AFP (P=0.026) and high LDH levels (P=0.014), whereas LRP expression associated with high beta-hCG levels (P=0.003) and stage IV tumours (P=0.029). No correlation was found between Pgp, MRP1, and BCRP expression and response to chemotherapy and survival. In contrast, patients with LRP-positive tumours (strong or intermediate expression) had shorter progression-free (P=0.0006) and overall survival (P=0.0116) than LRP-negative patients, even after individual log-rank adjustments by statistically associated variables. Our data suggest that a positive LRP immunostaining at the time of diagnosis in metastatic TGCT is associated with an adverse clinical outcome. [ABSTRACT FROM AUTHOR]

In the present study, we addressed the question of a putative relevance of Rho proteins in tumour progression by analysing their expression on protein and mRNA level in breast turnouts. We show that the level of RhoA, RhoB, Racl and Cdc42 protein is largely enhanced in all turnout samples analysed (n=15) as compared to normal tissues originating from the same individual. The same is true for [sup 32]P-ADP-ribosytation of Rho proteins which is catalysed by Clostridium botulinum exoenzyme C3. Also the amount of Rho-GDI and ERK2 as well as the level of overall [sup 32]P-GTP binding activity was turnout-specific elevated, yet to a lower extent than Rho proteins, Although the amount of Rho proteins was enhanced in tumours, most of them did not show changes in rho mRNA expression as compared to the corresponding normal tissue. Thus, elevated gene expression seems not to be the underlying mechanism of tumour-specific overexpression of Rho proteins. Sequence analysis of RhoA, RhoB, RhoC and Racl failed to detect any mutations in both the GTP-binding site and effector binding region, By analysing > 50 tumour samples, the amount of RhoA-like proteins (i,e, RhoA, B, C), but not of Racl, was found to significantly increase with histological grade and proliferation index. Rho protein expression was neither related to p53 nor to HER-2/neu oncogene status. Expression of rho mRNAs did not show a significant increase with histological grade. Overall the data show that (1) Rho proteins are overexpressed in breast tumours (2) overexpression is not regulated on the mRNA level (3) the expression level of RhoA-Iike proteins correlates with malignancy and (4) Rho proteins are not altered by mutation in breast tumours. [ABSTRACT FROM AUTHOR]

Summary Background Surgery induces a postoperative immunosuppression, thereby possibly facilitating the outgrowth of pre-existing occult metastases or the seeding of disseminated tumour cells in patients with primary colorectal carcinoma operated on with curative intent. The hypothesis that adjuvant therapy with perioperative recombinant human granulocyte–macrophage colony-stimulating factor (rhGM-CSF) would minimize postoperative immunosuppression was investigated in this pilot study. Methods Patients were allocated randomly to receive daily subcutaneous injections with either saline (n = 8) or rhGM-CSF 2·8 μg per kg body-weight (n = 8) from 3 days before operation until 4 days afterwards. Phytohaemagglutinin (PHA) skin test reactivity, monocyte human leucocyte antigen (HLA) DR expression and the extent of the acute-phase response, by determination of white blood cell count and differentiation, plasma interleukin (IL) 6 levels and body temperature in the perioperative period, were examined. Results rhGM-CSF treatment minimized postoperative suppression in PHA skin test reactivity and increased the numbers of neutrophils and monocytes while enhancing the expression of HLA-DR in the postoperative period. Additionally, both postoperative plasma IL-6 levels and the incidence of fever tended to be higher in the rhGM-CSF group. Conclusion In this pilot study, perioperative administration of low-dose rhGM-CSF stimulated certain immune functions that are normally depressed after operation. The implications for the antitumour responses directly after operation and the formation of liver metastases are currently under investigation. [ABSTRACT FROM AUTHOR]

The multidrug resistance protein 1 (MRP1) is an ATP-dependent transport protein for organic anions, as well as neutral or positively charged anticancer agents. In this study we show that flavopiridol, a synthetic flavonoid currently studied in phase 1 trials for its antiproliferative characteristics, interacts with MRP1 in a potent way. Flavopiridol, as well as other (iso)flavonoids stimulate the ATPase activity of MRP1 in a dose-dependent way at low micromolar concentrations. A new specific monoclonal antibody against MRP1 (MIB6) inhibits the (iso)flavonoid-induced ATPase activity of plasma membrane vesicles prepared from the MRP1 overexpressing cell line GLC4/ADR. The accumulation of daunorubicin in GLC4/ADR cells is increased by flavopiridol and by other non-glycosylated (iso)flavonoids that interact with MRP1 ATPase activity. However, flavopiridol is the only tested compound that affects the daunorubicin accumulation when present at concentrations below 1 microM. Glycosylated (iso)flavonoids do not affect MRP1-mediated transport or ATPase activity. Finally, MRP1 overexpressing and transfected cells are resistant to flavopiridol, but not to other (iso)flavonoids tested. These findings may be of relevance for the development of anticancer therapies with flavopiridol. [ABSTRACT FROM AUTHOR]

Lymphocytic infiltrate is often present in cervical cancer lesions, possibly reflecting an ongoing, but ineffective, immune response to the tumour. Recently, evidence has accumulated for systemically impaired T-cell functions in cancer patients, associated with decreased expression of signal-transducing zeta ζ chain dimer molecules on circulating T-cells and NK-cells. Here, we report on the intralesional down-regulation of ζ chain expression on T-cells in cervical carcinoma. Paraffin-embedded or snap-frozen sections from 24 different cervical cancer specimens were studied. Paraffin-embedded tumour-positive (n = 7) and tumour-negative (n = 15) pelvic lymph nodes were also included in the study. Immunostaining was performed on consecutive sections with antibodies specific for CD3-ε or the CD3-associated ζ chain dimer. Antigen retrieval by sodium citrate/microwave treatment was essential for ζ staining of paraffin sections. The amount of ζ positive cells was quantitated and related to the number of CD3-ε+ cells in corresponding tumour areas. Of the 24 cervical cancer specimens studied, ζ chain dimer expression was reduced in seven cases and strongly reduced in the other 17 samples. In tonsil control sections, CD3-ε and CD3-ζ were always co-expressed in almost equal numbers. Also, both tumour-negative and -positive lymph nodes showed ζ chain expression which equalled that of CD3-ε expression. These data indicate that a decreased expression of signal-transducing ζ molecules on tumour-infiltrating T-cells is frequent in cervical cancer. The apparently unimpaired ζ chain expression within draining lymph nodes suggests that local tumour-derived factors at the primary site are instrumental in ζ chain down-regulation. [ABSTRACT FROM AUTHOR]

Summary The α‐galactosylceramide KRN7000 was reported to be presented by CD1d to natural killer (NK) T cells, cells that are thought to play an important role in the rejection of malignant tumours and in the regulation of several autoimmune diseases. Here we analysed human peripheral blood (PB) NK T cells (Vα24+ Vβ11+ T cells) before and after a short‐term culture in the presence of KRN7000. KRN7000 strongly activated PB Vα24+ Vβ11+ T cells and, when stimulated, the vast majority of these cells expressed interferon‐γ (IFN‐γ). Exposure of these KRN7000‐cultured Vα24+ Vβ11+ T cells to interleukin‐12 (IL‐12), but not to IL‐7, resulted in a relative increase in IFN‐γ‐expressing Vα24+ Vβ11+ T cells, compared with IL‐4‐expressing Vα24+ Vβ11+ T cells, indicating a shift towards a T‐helper type 1 (Th1) phenotype. KRN7000 strongly up‐regulated the expression of the cytotoxic molecule granzyme B (GrB) in Vα24+ Vβ11+ T cells. Although IL‐7 resulted in a decrease in GrB levels in KRN7000‐cultured Vα24+ Vβ11+ T cells, IL‐12 increased GrB levels in both Vα24+ Vβ11+ T cells and in Vα24+ Vβ11+ T‐cell clones and increased cytotoxicity against hCD1d‐transfected HeLa cells. Our data provide further insight into the characteristics of human Vα24+ Vβ11+ T cells and indicate that KRN7000 is a potent activator of Vα24+ Vβ11+ T cells. Combined with the established anti‐tumour effects of KRN7000 in mouse models, these results may support the use of KRN7000 as an anti‐tumour... [ABSTRACT FROM AUTHOR]

Guinea-pig lymphokines were shown to stimulate the migration of eosinophils from capillary tubes. Eosinophil migration stimulatory activity was produced by Freund's complete adjuvant (FCA)- sensitized lymph node or peritoneal exudate lymphocytes in the presence of purified protein derivative (PPD), as well as by Con A-stimulated lymph node lymphocytes. Like murine and human eosinophil-stimulation promoter lymphokine (ESP), the guinea- pig lymphokine activity is T cell-derived, non-dialysable and resistant to heating at 56°. In contrast to the migration inhibition factor (MIF) which could be adsorbed by macrophages, eosinophil migration stimulatory activity could not be removed by pre- adsorption to macrophages or eosinophils. [ABSTRACT FROM AUTHOR]

Studies were carried out in order to explain the often small contribution of eosinophils to immunologically mediated chronic inflammatory reactions. A chronic inflammation model was used in which large numbers of cosinophils accumulated in the peritoneal cavity of guinea-pigs following repeated intraperitoneal injections with PPD or ovalbumin (OA). Eosinophil accumulation could be strongly suppressed by pre-immunization with a mycobacteria- containing adjuvant, which induces delayed hypersensitivity to the stimulating antigen. Suppression of OA-induced eosinophil accumulation could be obtained in a non-specific way by concomitant delayed hypersensitivity reactions to PPD. The absence of eosinophil accumulation was not related to a lack of relevant antibodies. Histological studies suggested that similar numbers of basophils were locally available in both non-pre-immunized and pre- immunized groups to allow for the attraction of eosinophils by the expression of basophil anaphylactic reactivity. Skin tests and macrophage migration inhibition measurements provided further support for the hypothesis that local lymphokine release may suppress the accumulation of eosinophils in chronic inflammatory lesions. [ABSTRACT FROM AUTHOR]

A chronic inflammation model is described which allows the study of the relationship between the level of specific cell-mediated and humoral immunity to the triggering antigen, and the presence of cells or mediators in the inflammatory exudate. In the present study special attention is paid to the participation of lymphocytes and eosinophils. Normal or FCA-pre- immunized guinea-pigs received repeated intraperitoneal injections with PPD for periods up to 21 weeks. In non-pre-immunized animals the inflammation was characterized by a strong accumulation of eosinophils, whereas only a few lymphocytes were present. In contrast, the FCA-pre-immunized guinea-pigs showed a strong lymphocytic accumulation in the absence of eosinophils. Both peritoneal inflammations were shown to remain dependent on the continuous PPD administration. Therefore, the participation of either lymphocytes or eosinophils could be directly correlated to differences in the specific immune status. Both experimental groups developed similar strong anti- PPD antibody responses as assessed by haemagglutination and passive cutaneous anaphylaxis. Only the FCA-pre-immunized guinea-pigs, however, showed strong cell-mediated immunity. The development of CMI to the continuously administered antigen appears to be a prerequisite for the accumulation of lymphocytes, while it seems to prevent antibody- mediated eosinophil accumulation. [ABSTRACT FROM AUTHOR]

The detection of antigen-specific T cell responsiveness, particularly of resting memory lymphocytes, in cultures of peripheral blood mononuclear cells (PBMC) may be hampered by a less than optimal antigen presentation in vitro. Augmented sensitivity of the test system may be achieved by the addition of reagents with a beneficial effect on lymphocyte and antigen-presenting cell (APC) functions. In this study the effect of several biological response modifiers on antigen-specific T cell proliferation was determined, using nickel sulphate and tetanus toxoid as test antigens. IL-1α (100 U/ml), interferon-gamma (IFN-γ) (10 U/ml), and indomethacin (2 μM) were found to significantly enhance nickel-induced proliferation in PBMC cultures from nickel-hypersensitive donors (n = 6). Tetanus-induced proliferation (n = 5) was similarly enhanced, both by the above supplements and by the addition of polyethylene glycol (PEG) or a neuraminidase treatment of the PBMC before culture. The addition to PBMC cultures of a combination of IL-1α (30 U/ml), IFN-γ (10 U/ml), and indomethacin (2 μM) is recommended to specifically enhance antigen-induced lymphoproliferative signals. [ABSTRACT FROM AUTHOR]

In patients with head and neck carcinomas and in patients with chronic purulent upper airway infections, low molecular weight retroviral p15E-like factors are found. These factors are responsible for partial defects in the cellular immune response. We studied the distribution of these p15E-related proteins in neoplastic, inflamed and normal human tissues and related these findings with the presence of p15E-like factors in patients' sera. Demonstration of p15E-like proteins in sera of patients with upper airway infections and of patients with head and neck carcinomas correlated exclusively with the presence of p15E in normal and pathologic epithelium of the upper respiratory tract, p15E was not demonstrated in epithelia of other localizations. Our results suggest that chronic stimulation or neoplastic transformation of the epithelia of the upper respiratory tract stimulates the production of p15E-like proteins leading to their reported immunosuppressive actions. [ABSTRACT FROM AUTHOR]

From animal studies we know that oral administration of T-dependent antigens before sensitization effectively induces systemic immune unresponsiveness. Such 'oral tolerance' is persistent, dose dependent, antigen-specific and presumably T suppressor cell-mediated. Oral tolerance induction could be an effective way to prevent undesired T cell-mediated immune functions, such as playing a role in allograft reaction, autoimmune and allergic diseases. In the present study allergic contact hypersensitivity (ACH) to nickel, currently presenting the most frequent contact allergy in man, was chosen to establish the feasibility of oral prevention of undesired T cell-mediated immunity in man. Potentially tolerizing (oral nickel contacts via orthodontic braces) as well as sensitizing (ear piercing) events were studied retrospectively in 2176 patients attending nine European patch test clinics. Patients were interviewed by means of a confidential questionnaire. The results show that ear piercing strongly favoured development of nickel ACH, More importantly, patients having had oral contacts with nickel-releasing appliances (dental braces) at an early age, but only if prior to ear piercing, showed a reduced frequency of nickel hypersensitivity. Frequencies of other hypersensitivities, in particular to fragrance, were not affected. These results support our view that induction of specific systemic immunologic tolerance by timely oral administration of antigens is feasible in man. [ABSTRACT FROM AUTHOR]

A single systemic dose of cyclophosphamide (CY) has been shown to enhance cellular immunity in a variety of antigen models. The immunoenhancing effects of CY have been attributed to its ability to selectively abrogate suppressor cell function. Previous studies from our group have demonstrated that local administration of distinct cytostatic drugs at the sensitization site can induce a similar enhancement of delayed-type hypersensitivity as systemic CY, with the obvious advantage of avoiding systemic side-effects. In the present study we investigated the effects of local administration of an optimally immunopotentiating dose of the active CY-derivative Z 7557 and, in selected experiments, of etoposide (VP- 16) and systemic CY on mononuclear cells in draining lymph nodes. Whereas CY caused a long-lasting and marked depletion of B-cell areas, locally administered Z 7557 and VP- 16 relatively spared B cells and even induced an increase in B- and 1-cell numbers in (keyhole limpet haemocyanin-) sensitized mice. At Day 4 the CD4JCD8 ratio was slightly reduced in drug- treated mice. Interestingly, drug treatment reduced the proportion of interdigitating cells staining with the monoclonal antibodies NLDC-145 and MIDC-8. Upon isolation, dendritic cells (DC) from sensitized, Z 7557-treated mice showed longer dendritic protrusions and an enhanced accessory cell function compared to DC from saline-treated controls. These findings suggest that immunoenhancing effects of cytostatic drugs may occur via an effect on DC. [ABSTRACT FROM AUTHOR]

A monoclonal antibody is described which reacts with monocytes and macrophages of the guineaspig. The antibody recognizes a cytoplasmic component in the majority of tissue macrophages, as detected by histochemical analysis. It reacts positively with all macrophages in lymphoid organs, including Tingible body macrophages. In addition it recognizes the cells of Von Kupifer in the liver, and macrophages in bone marrow and peritoneal cavity. In comparison to other monoclonal antibodies that have been described in the guinea-pig, MR-1 shows a unique tissue distribution. The antibody is a useful tool to discriminate macrophages by immunohistochemical methods. [ABSTRACT FROM AUTHOR]

A prospective study of the development of hand eczema was initiated in 86 junior hairdressers and 217 junior nurses. Data obtained at the start of their apprenticeships are presented. None of the junior apprentices presented with hand eczema. but a history of hand eczema was reported by 22 303 (7%) of the students, Almost half of this group (10,22, 45%) could be classified as atopics. Students without a history of hand eczema showed a similar frequency of atopy (17%) as observed in the general population. History of hand eczema was not related In nickel hypersensitivity, as assessed by patch testing. The incidence of nickel hypersensitivity was high in junior hairdressers (26%), compared to junior nurses (12%). Information as to previous contacts with nickel suggested that development of nickel allergy had been promoted by ear-piercing. A lower incidence of nickel hypersensitivity was observed if this potentially sensitizing event had been preceeded by orthodontic treatment with nickel-containing materials. This phenomenon is discussed in terms of orally-induced tolerance. [ABSTRACT FROM AUTHOR]

Irrelevant reactions occurred in 68 of 157 patients (43%) with strong positive patch teat reactions and concomitant weak positive reactions. A lower figure, 13 of 45 (29%) was found in patients with only weak positive patch test reactions (0. 1 > P > 0.05). An allergen eliciting' a weak positive reaction should therefore be retested when a conclusion has to be drawn about the epidermal sensitivity of a patient. [ABSTRACT FROM AUTHOR]

The clinical relevance of multidrug resistance (MDR)-related proteins in childhood acute lymphoblastic leukemia (ALL) is largely unknown. The diversity of techniques, fixation methods, storage of cells (fresh or cryopreserved) etc, may contribute to discrepancies observed between several studies. We therefore optimized the detection of P-glycoprotein (P-gp), MDR-associated protein (MRP) and lung resistance-related protein (LRP) by immunocytochemistry and flow cytometry in childhood ALL cells. Thirteen fixation methods were compared using six antibodies in both immunocytochemistry and flow cytometry. The optimal fixation for P-gp (C219, MRK16), MRP (MRPr1) and LRP (LRP56) was a mixture of 2% (v/v) formaldehyde solution and acetone incubated for only 10 s at room temperature (FAc). For MRP recognized by MRPm6, the optimal fixation condition was acetone for 5 min at room temperature in immunocytochemistry, and methanol for 15 min at -20 degrees C in flow cytometry. P-gp staining by 4E3 was strongly antibody batch-dependent; on cytospins FAc fixation was optimal, but inconclusive data were obtained by flow cytometry. The optimized fixation conditions on fresh samples revealed a day-to-day variation in staining (both increasing and decreasing) in one third of the immunocytochemical tests. In flow cytometry the day-to-day variation in the fluorescence index was -1 +/- 22%. In both techniques, staining was comparable between fresh and cryopreserved cells. We recommend the use of the above mentioned fixation methods in order to study the clinical relevance of P-gp, MRP and LRP in childhood ALL. [ABSTRACT FROM AUTHOR]

Focuses on the vaccination of chronic myeloid leukemia patients with autologous in vitro cultured leukemic dendritic cells. Role of T-cell immunity in chronic myelogenous leukemia (CML); Reason for the T-cell anergy to leukemic cells occurring in CML; Clinical characteristics of of CML patients treated with leukemic dendritic cell vaccination.