Mast-cell activation augments the late phase reaction in experimental immune-mediated blepharoconjunctivitis

BACKGROUND

How the early phase allergic reaction affects the late phase reaction remains unclear. We examined this issue with an experimental model of allergic conjunctivitis that permits the two reactions to be disconnected from each other.

METHODS

Experimental immune-mediated blepharoconjunctivitis (EC) was initiated in Brown Norway rats by transferring ovalbumin (OVA)-specific T cells and then challenging with OVA-containing eye drops. To induce early phase reaction, a mast-cell activator, C48/80, was challenged together with or without OVA. Rats were evaluated clinically and eyes were harvested for histologic examination and for evaluation of chemokine expression by reverse-transcriptase PCR.

RESULTS

The rats challenged with OVA alone developed the T-cell-mediated late phase reaction histologically, but not clinically, in the absence of early phase reaction. While rats challenged with C48/80 with or without OVA exhibited clinical signs of the early phase reaction, the clinical late phase reaction was observed only in the OVA+C48/80 group. Eosinophilic infiltration into the conjunctiva during the late phase reaction of the OVA+C48/80 group markedly exceeded that of rats challenged with either OVA or C48/80 alone. RANTES (regulated on activation, normal T-cell expressed and secreted), an eosinophil attractant, was expressed both in the OVA+C48/80 and OVA groups, while eotaxin was expressed at equivalent levels in all three groups.

CONCLUSION

The mast-cell-mediated early phase reaction potentiates the T-cell-mediated late phase reaction, and RANTES is involved in eosinophilic infiltration induced by antigen-specific T cells. Other molecules induced by allergen-specific T cells activated in an as yet unknown manner by the mast cells may be responsible for the infiltration of eosinophils.

Worsening injection site reactions with continued use of etanercept

We report the case of a patient with persistent and worsening injection site reactions associated with subcutaneous etanercept therapy. Injection site reactions are well documented to occur early in therapy; however they typically decrease in frequency over time. This patient developed early injection site reactions that have persisted and worsened into his tenth month of treatment with etanercept.

Delayed-type hypersensitivity to lidocaine

BACKGROUND

Lidocaine hydrochloride is the preferred anesthetic agent used in outpatient surgical procedures. While type I hypersensitivity reactions to lidocaine are uncommon, type IV hypersensitivity is reported even less frequently.

OBSERVATIONS

Between January 1, 2001, and December 31, 2001, 183 patients were patch tested at the Penn State Milton S. Hershey Medical Center (Hershey, Pa) to the North American Contact Dermatitis Group tray. All patients who had a positive patch test reaction to lidocaine were challenged with 0.1 mL of preservative-free 1% lidocaine intradermally. Of the 183 patients patch tested, 4 had positive reactions to lidocaine, 2 of whom had histories of sensitivity to local injections of lidocaine manifested by dermatitis.

CONCLUSIONS

Delayed-type hypersensitivity to lidocaine may occur more frequently than previously thought. In cases of suspected lidocaine contact type IV sensitivity, patients should be patch tested to lidocaine. Positive patch test reactions should be confirmed by intradermal challenge with lidocaine. To provide the patient with alternative local anesthetics, patch testing should be performed with other injectable anesthetics. If positive patch test results occur, intradermal testing should follow.

Interleukin 10 induced augmentation of delayed-type hypersensitivity (DTH) enhances Mycobacterium bovis bacillus Calmette-Guérin (BCG) mediated antitumour activity

Intravesical BCG therapy is effective in the treatment of superficial bladder cancer. Both clinical and experimental results suggest a role for cytokines and delayed-type hypersensitivity (DTH) in BCG-induced antitumour immunity. We characterized the modulatory effects of BCG on bladder cytokine expression and determined the relationship between DTH and BCG antitumour activity. The bladders of mice were instilled with BCG through a catheter. Bladder tissue RNA and urine were collected for evaluation of cytokine expression using reverse transcriptase-polymerase chain reaction (RT-PCR) and/or ELISA. IFN-gamma and TNF-alpha, the two major cytokines associated with DTH, were efficiently induced by BCG. IL10, an important down-regulator of DTH, was also induced by BCG. Constitutive levels of IL4 and IL5 were observed, but neither IL4 nor IL5 were modulated by BCG. Similar results were observed in the kinetic analysis of urinary cytokines in patients after intravesical BCG therapy. Production of Th1 (T helper type 1) cytokines (IFN-gamma, IL2 and IL12) preceded that of the Th2 (T helper type 2) cytokine IL10. A tendency toward higher ratios of IFN-gamma versus IL10 for BCG responders also was observed. In animal studies the absence of IL10 abrogated either by antibody inhibition or the use of genetically modified, IL10 deficient (IL10-/-) mice resulted in enhanced DTH responses. Under conditions of enhanced DTH, a significant enhancement in antitumour activity was observed. These data demonstrate that DTH and its associated mononuclear infiltration and cytokine production are important to the antitumour activity of intravesical BCG therapy, and suggest that effects to diminish IL10 production may have therapeutic value.

MD41, a novel T helper 0 clone, mediates mast-cell dependent delayed-type hypersensitivity in mice

In a previous study on mouse, we have shown that delayed-type hypersensitivity (DTH) could be classified into two types according to MC requirement. The first type of DTH could be elicited by sensitization with methylated human serum albumin (MHSA) in complete Freund's adjuvant (CFA) in both wild type and mast-cell deficient (W/Wv) mice. The second type could be elicited by MHSA in incomplete Freund's adjuvant (IFA) sensitization in wild type but not W/Wv mice. While the former was related to classic tuberculin (tbc)-type DTH, the latter appeared to be a novel mast-cell dependent DTH (MD-DTH). In order to investigate the mechanism of MD-DTH, in this study, we generated an effector T-cell clone (MD41) from lymph node cells of MHSA in IFA-sensitized mice and analysed its pattern of cytokine production. Our results from cytokine assays show that following antigen stimulation, MD41 cells produce significant amounts of the T helper 1 (Th1) cytokine interferon-gamma (IFN-gamma) as well as the Th2 cytokines interleukin (IL)-4 and IL-10. In addition, double staining for IL-4 and IFN-gamma revealed that MD41 cells produce both Th1- and Th2-type cytokines simultaneously, which suggest that MD41 represents a Th0 clone rather than a mixture of Th1 and Th2 clones. Adoptive transfer of MD41 cells into wild-type mice resulted in the development of DTH skin reactions similar to those produced by active sensitization, with very similar histological findings. However, DTH skin reactions could not be induced in W/Wv mice unless first reconstituted with normal bone marrow MC (BM-MC). Therefore, our study suggests that in conjunction with tissue MC, MD41, a less-polarized MD-DTH-derived Th0 clone, is capable of developing murine DTH to the same extent as strongly polarized Th1 cells and mediates MD-DTH rather than tbc-type DTH.

Ocular surface inflammation induced by Propionibacterium acnes

PURPOSE

In the eye, is commonly isolated in the lid, conjunctiva, and meibomian gland secretion. Well known as a causative bacterium of granulomatous endophthalmitis and a potent inflammatory stimulus, reportedly induces a delayed-type hypersensitivity (DTH) response and forms granulomas in the liver and lung in animal models. In this study, we examined whether can induce a DTH response in the cornea.

METHODS

Six- to 8-week-old female Lewis rats were immunized with heat-killed suspension of and assessed as to DTH response via ear challenge at 2 weeks after immunization. At 3 weeks after immunization, suspension was injected in the rat corneal stroma, which was then observed biomicroscopically at 6, 24, and 48 hours after injection. Phenol-killed suspension was also used for the comparison. Histological examination was also performed on the corneal tissues, using hematoxylin and eosin staining as well as immunohistochemical staining against CD4 and CD8 T cells.

RESULTS

Rats immunized with suspension showed significantly higher ear swelling values at both the 24- and 48-hour measurements than did the naïve controls (p < 0.005). Massive cellular infiltration with stromal edema was observed biomicroscopically at 48 hours after injection of suspension in the corneal stroma. Histological study showed that the cell infiltration pattern was similar to that of DTH in the skin, i.e., neutrophils infiltrated at 6 hours, followed by mononuclear cells that, including macrophages and lymphocytes, increased and mixed with neutrophils, accompanied by stromal edema at 48 hours. Immunohistochemical study revealed that CD4 T-cell infiltration in the corneal stroma appeared to predominate over CD8 T-cell infiltration.

CONCLUSIONS

These results indicate that can induce a DTH response in the cornea and may be a causative bacterium of ocular surface inflammation.

Susceptibility to T cell-mediated injury in immune complex disease is linked to local activation of renin-angiotensin system: the role of NF-AT pathway

FcR provides a critical link between ligands and effector cells in immune complex diseases. Emerging evidence reveals that angiotensin (Ang)II exerts a wide variety of cellular effects and contributes to the pathogenesis of inflammatory diseases. In anti-glomerular basement membrane Ab-induced glomerulonephritis (GN), we have previously noted that FcR-deficient mice (gamma(-/-)) surviving from lethal initial damage still developed mesangial proliferative GN, which was drastically prevented by an AngII type 1 receptor (AT1) blocker. We further examined the mechanisms by which renin-Ang system (RAS) participates in this immune disease. Using bone marrow chimeras between gamma(-/-) and AT1(-/-) mice, we found that glomerular injury in gamma(-/-) mice was associated with CD4(+) T cell infiltration depending on renal AT1-stimulation. Based on findings in cutaneous delayed-type hypersensitivity, we showed that AngII-activated renal resident cells are responsible for the recruitment of effector T cells. We next examined the chemotactic activity of AngII-stimulated mesangial cells, as potential mechanisms coupling RAS and cellular immunity. Chemotactic activity for T cells and Th1-associated chemokine (IFN-gamma-inducible protein-10 and macrophage-inflammatory protein 1alpha) expression was markedly reduced in mesangial cells from AT1(-/-) mice. Moreover, this activity was mainly through calcineurin-dependent NF-AT. Although IFN-gamma-inducible protein-10 was NF-kappaB-dependent, macrophage-inflammatory protein 1alpha was dominantly regulated by NF-AT. Furthermore, AT1-dependent NF-AT activation was observed in injured glomeruli by Southwestern histochemistry. In conclusion, our data indicate that local RAS activation, partly via the local NF-AT pathway, enhances the susceptibility to T cell-mediated injury in anti-glomerular basement membrane Ab-induced GN. This novel mechanism affords a rationale for the use of drugs interfering with RAS in immune renal diseases.

Hypersensitivity reactions after respiratory sensitization: effect of intranasal peptides containing T-cell epitopes

BACKGROUND

The intranasal administration of peptides containing T-cell epitopes has been shown to inhibit T-cell and antibody responses of mice injected with allergen, but responses to respiratory sensitization might be regulated differently.

OBJECTIVE

This study was designed to examine the effect of intranasal peptide on antigen-induced lung inflammatory responses and delayed hypersensitivity after sensitization by the respiratory mucosa or without sensitization.

METHODS

Mice were treated with an intranasal tolerizing regimen of a peptide containing the major T-cell epitope of Der p 1. Delayed hypersensitivity and lung inflammation to challenge with Der p 1 was measured either without further treatment or after sensitization induced by means of the intranasal administration of Der p 1 with a mutated enterotoxin adjuvant. Lung inflammatory responses were examined by means of lavage and histologic section, and delayed hypersensitivity responses were measured on the basis of ear swelling.

RESULTS

Delayed hypersensitivity reactions were induced in mice treated with intranasal peptide, and large reactions were found in mice given intranasal peptide and sensitized with intranasal Der p 1 and adjuvant. Mice pretreated with peptide and sensitized with Der p 1 had an increased lymphocytic infiltration after allergen-specific challenge, as measured by means of bronchoalveolar lavage and shown histologically. These hypersensitivity results are in contrast to previous data that show tolerance to injected antigen.

CONCLUSIONS

Although the intranasal administration of a peptide containing a T-cell epitope markedly inhibits responses to sensitization produced by the injection of allergen, the peptide induces immune responses and increases hypersensitivity to respiratory sensitization.

Gene expression levels of cytokine profile and cytotoxic markers in non-immediate reactions to drugs

Drugs can induce IgE mediated or T cell dependent immunological reactions. T cell dependent reactions are poorly understood, although T lymphocytes have been proposed as a protagonist in a number of non-immediate immunological reactions (NIR). The objective was to study in vivo different regulatory and proinflammatory cytokines and cytotoxic markers in patients with NIR to drugs. Twenty patients with NIR after drug intake were classified into two groups: Group A (severe), Stevens-Johnson syndrome and toxic epidermal necrolysis; and Group B (mild), maculopapular exanthema and desquamative exanthema. Another 25 subjects taking the same drugs but without reactions formed a control group. Samples were obtained within 24 hours of the reaction and 30 days later. IL-2, IL-4, IFN, TNF, perforin, granzyme B (GrB), and FasL mRNA expression levels were determined in peripheral blood mononuclear cells by competitive RT-PCR. There were 9 patients in Group A and 11 in Group B. The drugs involved were betalactams (8), anticonvulsants (6), allopurinol (1), sulfamethoxazole (1), amiodarone (1) dypirone (2), and erythromicine+paracetamol (1). At the acute stage there was a high increase of IL-2, IFN, and TNF mRNA expression in both groups vs. controls, perforin and GrB varied in each group with patients in Group A having the highest values, and FasL was only expressed in Group A. Relationships between the cytokines were only significant in Group B (p < 0.05). Only the relation between IFN-gamma and TNF-alpha was significant in Group A. There was a significant correlation between cytotoxic markers in both groups (A: p < 0.001, B: p < 0.01). These data demonstrate the complexity of the Th1 phenotype in NIR after drug intake. In patients with mild NIR, cytokines appear to play a closely related role, whereas cytotoxic markers appear more relevant in severe reactions.

Spontaneous induction of immunoregulation by an endogenous retinal antigen

PURPOSE

Ocular immune deviation studies have relied on intraocular injections of antigen to induce altered immune responses. Contributions of the injection process itself have complicated study of the mechanisms and interpretations of biological significance. In the current study, transgenic mice were used to determine the presence of immune deviation or other evidence of immunoregulation, elicited by endogenous Escherichia coli beta-galactosidase (beta-gal) expressed through a retinal arrestin promoter.

METHODS

Mice that express beta-gal in the retina and various control mice were immunized with beta-gal and tested for immune responsiveness by the ear-swelling test for delayed-type hypersensitivity (DTH), in vitro proliferation assays, and cytokine assays. Spleen cells from transgenic mice were also transferred to normal recipients to test for transfer of immune deviation.

RESULTS

Endogenous retinal beta-gal expression depressed the DTH response and proliferation assays after beta-gal immunization. The ability to depress DTH was transferred by naïve spleen cells from transgenic mice to nontransgenic mice. Use of an immunization protocol that included high-dose Mycobacterium tuberculosis (M tb) H37Ra adjuvant and concurrent administration of pertussis toxin reversed the inhibition of DTH.

CONCLUSIONS

An endogenous neo self-retinal antigen alters subsequent immune responses without intraocular injection, suggesting that normal retinal proteins in quiet eyes induce immunoregulatory responses. Based on cytokine assays, there were similarities to the immune deviation induced by intraocular inoculation in the IL-4 response, but the IL-10, IFN-gamma, and TGF-beta1 results were not similar, indicating that the mechanisms differ. The ability of supplemented adjuvant to overcome endogenous tolerance may be related to the requirement for supplemented adjuvants in the induction of experimental autoimmune uveoretinitis.

Using tolerance induced via the anterior chamber of the eye to inhibit Th2-dependent pulmonary pathology

Anterior chamber-associated immune deviation (ACAID), a manifestation of ocular immune privilege, prevents Th1-dependent delayed hypersensitivity from developing in response to eye-derived Ags, thereby preserving vision. Since Th2-type cells have recently been shown to mediate destructive inflammation of the cornea, we wondered whether pre-emptive induction of ACAID could inhibit Th2 responses. Using a murine model of OVA -specific, Th2-dependent pulmonary inflammation, we pretreated susceptible mice by injecting OVA alone into the anterior chamber, or by injecting OVA-pulsed, TGF-beta2-treated peritoneal exudate cells i.v. These mice were then immunized with OVA plus alum strategy that generates Th2-mediated OVA-specific pulmonary pathology. When pretreated mice were challenged intratracheally with OVA, their bronchoalveolar lavage fluids contained far fewer eosinophils and significantly less IL-4, IL-5, and IL-13 compared with that of positive, nonpretreated controls. Similarly, lung-draining lymph node cells of pretreated mice secreted significantly less IL-4, IL-5, and IL-13 when challenged in vitro with OVA. Moreover, sera from pretreated mice contained much lower titers of OVA-specific IgE Abs. We conclude that Ags injected into the anterior chamber of the eye impair both Th1 and Th2 responses. These results reduce the likelihood that ACAID regulates Th1 responses via a Th2-like mechanism. Thus, immune privilege of the eye regulates inflammation secondary to both Th1- and Th2-type immune responses.

Stage-dependent changes in trabecular bone turnover and osteogenic capacity of marrow cells during development of type II collagen-induced arthritis in mice

Rheumatoid arthritis (RA) is a disease characterized by inflammatory polyarthritis leading to destruction of the joints and reduction in bone mass. However, the relationship between bone mass and turnover is not yet clear in RA patients. To clarify the effect of bone turnover and marrow osteogenic capacity on mass and structure during the development of arthritis, we examined DBA1/J mice for 8 weeks after the first immunization with bovine type II collagen at the age of 9 weeks. Localized arthritis developed at 4 weeks and advanced arthritis at 6 weeks postimmunization. Urinary deoxypyridinoline levels in arthritic mice were significantly higher at 4 weeks, and levels were maintained thereafter. Their serum osteocalcin levels were significantly reduced compared with controls at 2 and 6 weeks, but did not differ significantly from those in the control group at 4 and 8 weeks. Three-dimensional (3D) trabecular bone volume of the proximal tibia measured by 3D microcomputed tomography (micro-CT) in the arthritic mice became significantly lower at 4 weeks and decreased further at 6 weeks compared with controls. Parameters of 3D trabecular bone structure, such as structure model index and trabecular bone pattern factor, were increased at 4 and 6 weeks, respectively. Trabecular osteoclast number increased and bone formation rates decreased at 8 weeks. The number of total bone marrow cells (BMCs), adherent stromal cells, and area of mineralized nodule formation in the tibia of arthritic mice were significantly reduced compared with controls at 6 weeks. Numbers of total fibroblastic colony-forming units (CFU-f) and alkaline phosphatase (ALP)-positive CFU-f colonies also decreased. However, the values of these osteogenic parameters corrected for the total BMCs and/or adherent stromal cells did not differ significantly between the arthritic and control groups. These data indicate that an increase in bone resorption led to the reduction in trabecular bone mass and deterioration of 3D structure during the localized arthritic stage. The reduction in bone marrow osteogenic potential in the advanced arthritic stage was due to the reduction in the number of total bone marrow cells, and differentiation of osteogenic cells was apparently unaffected. The reduction in bone formation may not be substantial in this arthritic model.

Langerhans cells within the follicular epithelium and the intradermal sweat duct in equine insect hypersensitivity "Kasen"

Histopathologic and electron microscopic observations were given on Langerhans cells (LCs) within the follicular epithelium (FE) and intradermal sweat duct (ISD) of equine "Kasen". By light microscopy, LCs were present in the greatest numbers within the FE and ISD than within the epidermal layer and the normal skin, with an occasional formation of several aggregated foci. By electron microscopy, LCs within the FE and ISD widely extended their dendritic processes between the keratinocytes and contained Birbeck granules (Bgs), mitochondria, rough endoplasmic reticula and ribosomes in the cytoplasm. Numerous Type 2 LCs, with a number of Bgs and endocytosis, and Type 3 LCs, with multivesicular bodies and endosomes of various sizes, were recognized within the FE and ISD, although inactive Type 1 LCs, with a narrow and lucid cytoplasm, were rarely seen. LCs observed within the FE and ISD in the "Kasen" skin lesions might express the particular stage corresponded to recognize, intake and process the antigens which permeate them.

The role of Langerhans cells in Pseudomonas aeruginosa infection

PURPOSE

Previous experimental studies have shown that extended-wear contact lens usage results in a centripetal migration of Langerhans cells from the conjunctiva into the central cornea. To test the consequences of this, Langerhans cells were induced into the cornea before Pseudomonas aeruginosa infection in BALB/c mice that are normally resistant (the cornea heals) and in C57BL/6 mice that are susceptible (the cornea perforates) to bacterial challenge.

METHODS

Mean clinical scores, slit lamp examination, adenosine diphosphatase (ADPase), and acid phosphatase staining as well as immunostaining with DEC-205, B7-1, CD4, and interleukin-2 receptor (IL-2R) antibodies and histopathologic, RT-PCR, and delayed-type hypersensitivity (DTH) analyses were used to examine the effects on bacterial disease after polystyrene bead induction of Langerhans cells into the cornea before bacterial challenge.

RESULTS

No difference in disease response was observed in bead- versus sham-treated C57BL/6 mice after bacterial infection; however, significant differences leading to corneal perforation were seen in BALB/c mice that included an increased number of Langerhans cells in the central cornea at 1 and 6 days after infection, an increased number of B7-1+ (mature) Langerhans cells at 6 days after infection, CD4+ and IL-2R+ T cells at 5 days after infection, enhanced DTH, and increased mRNA levels for IFN-gamma in cornea and cervical lymph nodes. Alternately, levels of IL-4 were significantly higher in the cornea and cervical lymph nodes of sham- versus bead-treated animals.

CONCLUSIONS

These data provide evidence that Langerhans cells are critical in the innate immune response to P. aeruginosa and provide new information regarding the mechanisms governing resistance versus susceptibility to bacterial infection with this opportunistic pathogen.

[The oral mucosa and delayed hypersensitivity]

Buccal mucosal allergies are rare because the conditions for sensitization are less favourable in the buccal environment. Clinical presentation is dominated by subjective manifestations (hardening, hypersialorrhea, "burning mouth" syndrome). Extradental etiologies are linked with cosmetic and medicinal topics, as well as dental etiologies caused by metals, alloys of mercury and resins.

Viral IL-10 gene transfer inhibits DTH responses to soluble antigens: evidence for involvement of genetically modified dendritic cells and macrophages

Expression of the viral interleukin-10 (vIL-10) gene within one joint of an animal with polyarticular, inflammatory arthritis suppresses disease in both treated and untreated joints (the "contralateral effect"). We used a mouse delayed-type hypersensitivity (DTH) model to investigate this phenomenon. Adenoviral delivery of the vIL-10 gene suppressed DTH reactions in injected and contralateral paws. T lymphocytes recovered from immunized mice injected with the adenoviral vector (ad-vIL-10) were unable to transfer the DTH response, but were not inhibitory. Peritoneal exudate cells recovered from mice injected intraperitoneally with ad-vIL-10 inhibited DTH reactions in recipient mice, but only when the donor mice had been sensitized to the antigen used to incite the DTH response. Dendritic cells (DCs) recovered from the draining lymph nodes of mice injected with ad-vIL-10 behaved similarly. Bone-marrow-derived DCs cultured ex vivo with ad-vIL-10 or recombinant mouse IL-10 also suppressed DTH reactions by adoptive transfer when pulsed with the inciting antigen. Collectively, these data suggest a mechanism for the contralateral effect in which genetically modified macrophages and DCs present antigen in the context of high, local concentrations of vIL-10, thereby generating unresponsive T lymphocytes. These findings suggest new ways in which to treat immune-driven diseases by gene and cell therapy.

T-cell- and macrophage-mediated axon damage in the absence of a CNS-specific immune response: involvement of metalloproteinases

Recent evidence has highlighted the fact that axon injury is an important component of multiple sclerosis pathology. The issue of whether a CNS antigen-specific immune response is required to produce axon injury remains unresolved. We investigated the extent and time course of axon injury in a rodent model of a delayed-type hypersensitivity (DTH) reaction directed against the mycobacterium bacille Calmette-Guérin (BCG). Using MRI, we determined whether the ongoing axon injury is restricted to the period during which the blood-brain barrier is compromised. DTH lesions were initiated in adult rats by intracerebral injection of heat-killed BCG followed by a peripheral challenge with BCG. Our findings demonstrate that a DTH reaction to a non-CNS antigen within a CNS white matter tract leads to axon injury. Ongoing axon injury persisted throughout the 3-month period studied and was not restricted to the period of blood-brain barrier breakdown, as detected by MRI enhancing lesions. We have previously demonstrated that matrix metalloproteinases (MMPs) are upregulated in multiple sclerosis plaques and DTH lesions. In this study we demonstrated that microinjection of activated MMPs into the cortical white matter results in axon injury. Our results show that axon injury, possibly mediated by MMPs, is immunologically non-specific and may continue behind an intact blood-brain barrier.

Immunohistochemical characterization of the perivascular infiltrate cells in tissues adjacent to stainless steel implants compared with titanium implants

Metallic orthopaedics implants are composed of elements that are known to be skin sensitizers in the general population. In this study, we analyzed the cells of perivascular infiltration in the tissue adjacent to titanium (n = 23) and steel (n = 8) implants after explantation of the metals by immunohistochemical methods. The following panel of monoclonal antibodies were used as parameters: CD 1a (Langerhans cells), CD 4 (T-helper cells), CD 8 (T-suppressor cells), CD 11c (monocytes and macrophages), CD 45 RO (memory cells), CD 45 RA (naive cells), eosinophil cationic proteins (ECP), neutrophil elastase, and HLA-DR. The number of perivascular total cells did not differ significantly. All cells were identified in both metal subgroups, but a statistical difference was not seen in the above-mentioned parameters. We conclude that sensitization to metals is possible in the tissue adjacent to steel and titanium implants, because all cells which play an important role in allergic delayed-type hypersensitivity (type IV) reactions are present. This phenomenon may be called a 'pre-sensitization' phase, because no sensitization or allergic reactions were seen in our cases. Second, in the present study, a statistical difference was not seen in the number of infiltrate cells in the tissue adjacent to steel compared with titanium implants.

Clinical, histological, and immunophenotypic characteristics of injection site reactions associated with etanercept: a recombinant tumor necrosis factor alpha receptor: Fc fusion protein

OBJECTIVE

To study injection site reactions (ISRs) associated with etanercept therapy.

DESIGN

Retrospective chart review, along with prospective analysis of selected patients experiencing ISRs associated with etanercept therapy.

SETTING

Academic rheumatology/immunology unit and dermatology clinic.

SUBJECTS

Patients with rheumatoid arthritis, juvenile rheumatoid arthritis, inflammatory seronegative arthritis, psoriatic arthritis, psoriasis, or inflammatory bowel disease.

INTERVENTIONS

Skin biopsy specimens were taken from selected patients experiencing ISRs.

MAIN OUTCOME MEASURES

Incidence of IRSs and histological and immunophenotypic analysis of ISRs in 3 patients undergoing prospective study.

RESULTS

Twenty-one (20%) of 103 of all patients receiving etanercept reported ISRs, all within the first 2 months of inception of therapy. The reactions occurred 1 to 2 days after the last injection and resolved within a few days. Moreover, eventual waning of reactions was observed, with none proving to be dose limiting. Histological examination of all biopsy specimens showed an inflammatory infiltrate composed of predominantly lymphoid cells and some eosinophils, in a perivascular cuffing pattern, without evidence of leukocytoclastic vasculitis. The infiltrating lymphoid cells were predominantly activated mature (HLA-DR(+)/CD3(+)/CD4(-)/CD8(+)) cytotoxic T lymphocytes, with a small number of CD4(+) cells. A biopsy specimen from a recall ISR showed strong HLA-DR expression by epidermal keratinocytes.

CONCLUSIONS

Injection site reactions associated with etanercept therapy are common, and may be an example of a T-lymphocyte-mediated delayed-type hypersensitivity reaction, with waning over time due to eventual induction of tolerance.

Brain-derived gangliosides suppress the chronic relapsing-remitting experimental autoimmune encephalomyelitis in NOD mice induced with myelin oligodendrocyte glycoprotein peptide

Chronic relapsing-remitting experimental autoimmune encephalomyelitis (CREAE) induced with myelin oligodendrocyte glycoprotein peptides 35-55 (MOG(35-55)) in NOD mice was successfully treated with brain-derived gangliosides (GA). The GA treatment suppressed the development and severity of CREAE, both clinically and histologically. Spleen cells from the GA-treated mice displayed markedly inhibited levels of MOG(35-55) specific proliferation and interferon-gamma production. Delayed-type hypersensitivity reactions to MOG(35-55) were suppressed by the GA treatment. GA modulate various T cell effector functions in CREAE and may be an effective therapeutic agent for autoimmune demyelinating diseases such as multiple sclerosis.

Dominance of autoreactive T cell-mediated delayed-type hypersensitivity or antibody-mediated demyelination results in distinct forms of experimental autoimmune neuritis in the Lewis rat

The role of anti-myelin antibodies in the pathogenesis of experimental autoimmune neuritis (EAN) induced in the Lewis rat by immunization with peripheral nerve myelin has been assessed. Passive transfer with lymph node cells (LNC) or purified serum immunoglobulin from rats with EAN was employed to directly measure the contribution of B cells and anti-myelin antibodies to demyelination and disease. Lewis rats with EAN transferred by LNC or purified serum immunoglobulin from EAN donors in conjunction with a low dose of P2-specific CD4+ T cells demonstrated profound histopathological and neurophysiological evidence of demyelination during disease. In contrast, the classical adoptive transfer model of EAN in the Lewis rat induced by the injection of P2-specific CD4+ T cells was characterized by histopathological and neurophysiological evidence of axonal dysfunction and degeneration with limited demyelination. These findings demonstrate that the synergistic action of T cells and anti-myelin antibodies mediating demyelination or purely T cell mediated axonal dysfunction and degeneration are distinct pathways by which a specific autoimmune response in the peripheral nervous system can cause neurological disease.

Peribronchiolar accumulation of dendritic cells and their close association with CD4(+) T cells in the murine lung hypersensitivity

In order to understand the interaction between dendritic cells (DCs) and helper T (Th) cells in the region exposed to antigens during pulmonary delayed-type hypersensitivity (DTH), which is considered to be mediated by Th1 cells, we immunohistochemically investigated their spatial relationship in the cellular infiltrate. At 24 hours after intratracheal instillation of hapten in sensitized mice, DCs were preferentially accumulated around the bronchioles, whereas macrophages were more abundant around the accompanying arteries. DCs often formed a cluster, in which they were interconnected with each other by projections. Serial section analysis revealed that clustered DCs made a close apposition to Th cells but much less frequently to cytotoxic T cells and B cells. Immunoelectron microscopy demonstrated that lymphocytes extravasated the capillaries in the peribronchiolar interstitium and made conjugation with DCs. In the interstitial tissue, DCs often adhered to the fibroblasts, suggesting the supportive role of the latter cells in DC migration. Eosinophils were also frequent around the arteries, representing the possible involvement of Th2 cytokines. By contrast, in a chronic type of airway inflammation induced by repeated challenges of aerosolized ovalbumin, DCs were densely and diffusely accumulated around the arteries in the same way as macrophages. The present study demonstrated a close association of DCs with Th cells around the bronchioles during pulmonary DTH, suggesting that local interaction between them in the lung may play important roles in the development of this disorder.