Roles of tumour localization, second signals and cross priming in cytotoxic T-cell induction.

The vertebrate immune system has evolved to protect against infections that threaten survival before reproduction. Clinically manifest tumours mostly arise after the reproductive years and somatic mutations allow even otherwise antigenic tumours to evade the attention of the immune system. Moreover, the lack of immunological co-stimulatory molecules on solid tumours could result in T-cell tolerance; that is, the failure of T cells to respond. However, this may not generally apply. Here we report several important findings regarding the immune response to tumours, on the basis of studies of several tumour types. First, tumour-specific induction of protective cytotoxic T cells (CTLs) depends on sufficient tumour cells reaching secondary lymphatic organs early and for a long enough duration. Second, diffusely invading systemic tumours delete CTLs. Third, tumours that stay strictly outside secondary lymphatic organs, or that are within these organs but separated from T cells by barriers, are ignored by T cells but do not delete them. Fourth, co-stimulatory molecules on tumour cells do not influence CTL priming but enhance primed CTL responses in peripheral solid tumours. Last, cross priming of CTLs by tumour antigens, mediated by major histocompatibility complex (MHC) class I molecules of antigen-presenting host cells, is inefficient and not protective. These rules of T-cell induction and maintenance not only change previous views but also rationales for anti-tumour immunotherapy.

Rapid peptide turnover and inefficient presentation of exogenous antigen critically limit the activation of self-reactive CTL by dendritic cells.

This study evaluated to what extent presentation of exogenously acquired self-Ags via MHC class I molecules on DC might contribute to the activation of self-reactive CTL and subsequent development of autoimmune disease. We show here by using the rat insulin promotor lymphocytic choriomeningitis virus glycoprotein model of autoimmune diabetes that the activation of self-reactive CTL by DC after uptake of exogenous Ag is very limited, first by the short half-life of MHC class I-associated peptides on DC in vitro and in vivo, and second by the rather inefficient MHC class I presentation of cell-associated self-Ags by DC. These two mechanisms are probably crucial in establishing high thresholds for the induction of self-reactive CTL that prevent autoimmune sequelae after release of sequestered and previously immunologically ignored tissue Ags.

In vivo antigen loading and activation of dendritic cells via a liposomal peptide vaccine mediates protective antiviral and anti-tumour immunity.

Initiation of antiviral and anti-tumour T cell responses is probably achieved mainly by dendritic cells (DC) transporting antigen from the periphery into organised lymphoid tissues. To develop T cell vaccines it is, therefore, important to understand the accessibility of the antigen to DC in vivo and whether DC are activated by vaccination. Here we have evaluated the immunogenicity of a liposomal vaccine formulation with antigenic peptides derived from the glycoprotein of the lymphocytic choriomeningitis virus. Liposome-encapsulated peptides were highly immunogenic when administered intradermally and elicited protective antiviral immunity. After intradermal injection, liposomes formed antigen depots which facilitated long-lasting in vivo antigen loading of dendritic cells almost exclusively in the local draining lymph nodes. The immunogenicity of the liposomal peptide vaccine was further enhanced by incorporation of immunostimulatory oligonucleotides leading to activation of DC. This optimised liposomal peptide vaccine elicited also anti-tumour immunity and induced CTL responses comparable to adoptively transferred, peptide-presenting DC. Thus, our data show that liposomal formulations of peptide vaccines are highly effective at direct in vivo antigen loading and activation of DC leading to protective antiviral and anti-tumour immune responses.

Periarteritis nodosa presenting as a breast lesion: report of a case and review of the literature.

We describe a 34-year-old woman with periarteritis nodosa (PAN) presenting as a breast lesion. Localized involvement of the breast is an unusual manifestation of PAN. To date, 10 cases have been reported: all were in women with an age range of 45-78 years (mean 63). In most cases, breast lesions were an isolated finding, and the prognosis was favourable, setting them apart from the more common form of systemic PAN. The case presented is unusual in that vasculitis developed in the postpartum period, and was associated with cutaneous PAN-like lesions elsewhere on the body, and digital artery occlusion. The most important differential diagnoses of PAN of the breast are infectious mastitis, mammary malignancy and other forms of idiopathic vasculitides of the breast, e.g. giant cell arteritis and Wegener granulomatosis.

Immune surveillance against a solid tumor fails because of immunological ignorance.

Many peripheral solid tumors such as sarcomas and carcinomas express tumor-specific antigens that can serve as targets for immune effector T cells. Nevertheless, overall immune surveillance against such tumors seems relatively inefficient. We studied immune surveillance against a s.c. sarcoma expressing a characterized viral tumor antigen. Surprisingly, the tumor cells were capable of inducing a protective cytotoxic T cell response if transferred as a single-cell suspension. However, if they were transplanted as small tumor pieces, tumors readily grew. Tumor growth correlated strictly with (i) failure of tumor cells to reach the draining lymph nodes and (ii) absence of primed cytotoxic T cells. Cytotoxic T cells were not tolerant or deleted because a tumor antigen-specific cytotoxic T cell response was readily induced in lymphoid tissue by immunization with virus or with tumor cells even in the presence of large tumors. Established tumors were rejected by vaccine-induced effector T cells if effector T cells were maintained by prolonged or repetitive vaccination, but not by single-dose vaccination. Thus, in addition to several other tumor-promoting parameters, some antigenic peripheral sarcomas-and probably carcinomas-may grow not because they anergize or tolerize tumor-specific T cells, but because such tumors are immunologically dealt with as if they were in a so-called immunologically privileged site and are ignored for too long.

Topical immunotherapy of severe alopecia areata with diphenylcyclopropenone: evaluation of 68 cases.

BACKGROUND: Currently, topical immunotherapy with diphenylcyclopropenone (DCP) represents the most accepted therapeutic modality in the treatment of severe alopecia areata (AA). OBJECTIVE: Efficacy, side effects and prognostic factors of DCP treatment in severe AA. METHODS: Retrospective study of 68 patients with severe AA (> 40% scalp hair loss), treated for at least 5 months at the Department of Dermatology, University Hospital of Zürich, between May 1989 and December 1996. RESULTS: The overall response rate was 70.6%, complete remission was obtained in 30.9% and partial remission in 39.7%. Among the investigated prognostic factors for the outcome of DCP therapy, only the extent of AA at the time of initiation of treatment was found to be of significance. CONCLUSION: DCP treatment of severe AA is an effective, albeit symptomatic therapy with frequent side effects and a relatively high relapse rate. The response rate depends on the type of AA.

Eosinophilic myositis/perimyositis: frequency and spectrum of cutaneous manifestations.

BACKGROUND: Eosinophilic myositis/perimyositis (EM/P) are a group of rare idiopathic muscle disorders associated with eosinophilia. OBJECTIVE: We describe the frequency and spectrum of cutaneous manifestations in EM/P and compare them with the idiopathic hypereosinophilic syndrome (HES). METHODS: We review the literature on EM/P and describe an additional case associated with angioedema. RESULTS: Of a total of 26 reported patients with EM/P, cutaneous manifestations were observed in 10. These were, in order of frequency, deep subcutaneous induration, erythema, angioedema, urticaria, and papular lesions. CONCLUSION: Skin lesions occur less frequently in EM/P than in HES. Although erythematous papulonodular lesions and urticaria/angioedema are most commonly observed in HES, the most frequent skin manifestations of EM/P are subcutaneous induration and erythema. In HES, angioedema has been correlated with a favorable prognosis. At least some of these patients apparently have an idiopathic eosinophilic disorder distinct from HES, including EM/P. In contrast to HES, the overall prognosis of EM/P is good, particularly when muscle lesions are focal, and the principal histopathologic finding is perimysial infiltrates.

[Tufted hair folliculitis]. / Bündelhaar-Follikulitis.

A case of tufted hair folliculutis presenting as circumscribed, tender and inflamed areas in the occiput with residual tufted follicles in a 28-year old man is reported. Tufted hair folliculitis is a characteristic localized scarring bacterial folliculitis of the scalp due to Staphylococcus aureus. Histopathological studies reveal perifollicular inflammation around the upper portions of the follicles sparing the hair root level. Within areas of inflammation, several follicles converge toward a common follicular duct with a widely dilated opening. Currently, tufted hair folliculitis is considered a variant of folliculitis decalvans of Quinquaud. Staphylococcal infection is believed to be an initial causative factor, and underlying differences in follicular anatomy or host response may be important in determining which reaction pattern occurs in an affected individual. The development of atrophy with loss of adnexal structures (in folliculitis decalvans) or of hair tufts (in tufting folliculitis) may depend upon the depth and destructive potential of the inflammatory process. The therapeutic approach is problematic; prolonged treatment with oral antibiotics may stabilize the disease, but good and at times more definitive results (as in the presented case) have been reported after radical surgical excision of the involved areas.

Necrotizing granulomatosis of the breast.

We describe a case of necrotizing granulomatosis of Wegener's type involving the breasts of a 40-year-old man. There were no signs of generalized disease. Involvement of the breast is rare in Wegener's granulomatosis (WG). To date, 17 cases have been reported, and all were women. They predominantly presented with a unilateral breast mass, and mammary malignancy was the principal concern. In the majority of cases, breast lesions of WG have been a presenting sign of, or preceded, disseminated disease. Our patient is unusual in that the necrotizing granulomas developed as an isolated finding in a site remote from those usually affected by WG, and, as far as we are aware, represents the first case of Wegener's type granulomatosis involving the male breast.

Interleukin 12, interferon gamma, and tumor necrosis factor alpha are the key cytokines of the generalized Shwartzman reaction.

The Shwartzman reaction is elicited by two injections of lipopolysaccharide (LPS) in mice. The priming LPS injection is given in the footpad, whereas the lethal LPS challenge is given intravenously 24 h later. The injection of interferon gamma (IFN-gamma) or interleukin 12 (IL-12) instead of the LPS priming injection induced the lethal reaction in mice further challenged with LPS. Antibodies against IFN-gamma when given together with the priming agent, prevented the lethal reaction in mice primed with either LPS, IL-12, or IFN-gamma. Antibodies against IL-12, when given together with the priming agent, prevented the lethal reaction in mice primed with either LPS or IL-12 but not with IFN-gamma. These results strongly suggest that LPS induces the release of IL-12, that IL-12 induces the production of IFN-gamma, and that IFN-gamma is the cytokine that primes macrophages and other cell types. Upon LPS challenge, the lethal Shwartzman reaction is induced by a massive production of inflammatory cytokines that act on the target sites already sensitized by IFN-gamma. If mixtures of TNF and IL-1 or mixtures of TNF and IFN-gamma are used to challenge mice previously primed with IFN-gamma or IL-12, mortality is induced. In the same conditions, the individual cytokines or a mixture of IL-1 and IFN-gamma do not replace the LPS challenge. When the mice are primed with LPS, the combination of TNF, IL-1, and IFN-gamma induced only a partial mortality incidence suggesting that the involvement of other LPS-induced factors.