Skin granuloma formation in mice immunosuppressed by cyclosporine

Descriptive study on risk of increased morbidity of schistosomiasis and graft loss after liver transplantation

Solid-organ transplantation procedures have witnessed a surge in frequency. Consequently, increased attention to associated infections and their impact on graft success is warranted. The liver is the principal target for infection by the flatworm Schistosoma mansoni. Hence, rigorous screening protocols for this parasite should be implemented for liver transplantation donors and recipients. This study investigated the risks posed by schistosomiasis-infected liver tissues for successful liver transplantation (LT), considering donors and recipients, by analyzing reported cases. Among the 43 patients undergoing LT (donors = 19; recipients = 24), 32 were infected with S. mansoni, five were infected with other Schistosoma species, and no identification was made in four patients. Reported follow-up periods ranged from 1 to 132 months, and all patients achieved successful recovery. As these helminths do not replicate in their vertebrate hosts, immunosuppressive treatment is not expected to promote increased morbidity or reactivation. Moreover, suspected or confirmed schistosomiasis infections often have a benign course, and generally, should not prevent LT. The available literature was reviewed and a provisional screening protocol has been proposed.

Disseminated Granuloma Annulare: Efficacy of Cyclosporine Therapy

Granuloma annulare is an anatomo-clinical entity that is frequently encountered in everyday dermatological practice. We report our experience regarding 4 patients with disseminated granuloma annulare. Each patient was treated with a cycle of cyclosporine therapy for six weeks. A cycle of systemic cyclosporine therapy was started at a dose of 4 mg/kg/day for four weeks, subsequently reduced by 0.5 mg/kg/day every two weeks. The clinical picture more or less completely resolved within three weeks in all of the patients, and there were no relapses during the dose-tapering period or the following 12 months. Cyclosporine was optimally tolerated by all four patients, none of whom experienced any therapy-related side effects. Cyclosporine is a valid therapeutic option for the treatment of disseminated granuloma annulare, although we recommend its use in a protected hospital environment that facilitates patient monitoring.

Collagenolytic (necrobiotic) granulomas: part 1 - the ‘blue’ granulomas

A collagenolytic or necrobiotic non-infectious granuloma is one in which a granulomatous infiltrate develops around a central area of altered collagen and elastic fibers. The altered fibers lose their distinct boundaries and exhibit new staining patterns, becoming either more basophilic or eosinophilic. Within the area of altered collagen, there may be deposition of acellular substances such as mucin (blue) or fibrin (red), or there may be neutrophils with nuclear dust (blue), eosinophils (red), or flame figures (red). These color distinctions can be used as a simple algorithm for the diagnosis of collagenolytic granulomas, i.e. "blue" granulomas vs. "red" granulomas. Eight diagnoses are included within these two groupings, which are discussed in this two-part article. In this first part, the clinical presentation, pathogenesis, and histologic features of the "blue" collagenolytic granulomas are discussed. These are the lesions of granuloma annulare, Wegener's granulomatosis, and rheumatoid vasculitis. In the subsequent half of this two-part series, the "red" collagenolytic granulomas will be discussed; these are the lesions of necrobiosis lipoidica, necrobiotic xanthogranuloma, rheumatoid nodules, Churg-Strauss syndrome, and eosinophilic cellulitis (Well's syndrome).

Histological evaluation of the lesion induced by inoculation of Leishmania mexicana in the cheek pouch of the hamster

We have studied the role of the immune response in the morphology of the leishmaniotic granuloma induced in the cheek pouch of hamsters, an immunologically privileged site, after inoculation of 3 x 10(5) Leishmania mexicana. Animals were histologically and immunologically evaluated until 120 days after inoculation. Independent of the time of sacrifice, the animals were always non-reactors to the footpad test (FPT). At histology, the introduction of L. mexicana in the cheek pouch leads to an abscess that evolves to a granulomatous reaction rich in amastigote forms, and later it leads to resolution, even in the absence of immune response detectable by FPT. Our results demonstrate that the development of immune response is not preponderant for the control of infection induced by L. mexicana inoculated subcutaneously in the cheek pouch of the hamster. It also suggests that the macrophages present in the leishmaniotic granuloma are capable of eliminating this parasite, even in the absence of immune response evaluated by FPT.

The hamster cheek pouch: an immunologically privileged site suitable to the study of granulomatous infections

The hamster cheek pouch is an invagination of oral mucosa, characterized histologically as skin-like. In this paper we describe anatomical, histological and embriological features of the pouch and comment on the pouch as an immunologically privileged site since it lacks lymphatic drainage and has few Langerhans cells. We present the review from literature and our observations after inoculation in the pouch of mycobacteriae (BCG, Mycobacterium tuberculosis and Mycobacterium leprae) and a fungus (Paracoccidioides brasiliensis). Lesions in the pouch were granulomatous but smaller and long lasting; even granulomatous, the reaction was inefficient to control the proliferation of agents compared with inoculation in other sites, except for BCG. Appearance of immunity was also delayed or absent and, when it was detected, a sharp decrease in number of agents in pouch lesions was observed. These observations make the pouch an interesting site for the study of the role of immune system in infectious diseases and in granuloma formation.

Experimental paracoccidioidomycosis of hamster inoculated in the cheek pouch

We compared the granuloma morphology and immune response of hamsters inoculated with Paracoccidioides brasiliensis (Pb) into the cheek pouch, which lacks lymphatic drainage, and into the footpad, which is rich in lymphatics. Our objective was to better understand the modulation of Pb granuloma in an immunocompetent animal inoculated in an immunologically privileged site. The humoral immune response (ELISA) and cell mediated immunity (footpad test) became positive on days 7 and 14, respectively in animals inoculated into footpad and on days 35 and 60 in animals inoculated into the pouch. Typical epithelioid granulomas were observed at both sites on day 14. The number of fungi gradually decreased from the beginning of the experiment in footpad lesions, but only after day 35 in pouch granulomas, when cell mediated immunity was detectable. The results indicate that typical epithelioid paracoccidioidomycotic granulomas may develop in the absence of a detectable immune response; however, they are incapable of controlling fungal reproduction. Lack of lymphatic drainage delays the appearance of a detectable immune response, but with time fungi escape from the pouch, elicit an immune response and reach other organs. Our results further indicate the importance of the lymphatics in the pathogenesis of paracoccidioidomycosis.

Cyclosporin A: antiparasite drug, modulator of the host-parasite relationship and immunosuppressant

Cyclosporin A (CsA), a cyclic undecapeptide with powerful properties of immunosuppression, acts on parasitic infections in laboratory animals in various ways. The outcome of drug administration in vivo varies with timing of treatment relative to infection, route of administration, dose and number of treatments applied. CsA is clearly antiparasitic against malaria, schistosomes, adult tapeworms, metacestodes and filarial nematodes. By contrast, it acts as an immunomodulator against trypanosomes and Giardia, by exacerbating infection; in the case of Leishmania spp. the drug acts variously. In some other infections CsA acts both as an antiparasite drug and as an immunosuppressant (Toxoplasma, avian coccidiosis and gastrointestinal nematodes). This range of activities is reviewed and possible modes of action discussed in the light of emerging data on in vitro drug activity and on putative receptor binding. The potential value of a non-immunosuppressive analogue of CsA in the control of parasitic infections of humans and domestic animals is considered but this paper lays particular stress on the seminal role of CsA as a laboratory tool.

An improved noninfectious murine skin model of organized granulomatous inflammation

An improved model of granulomatous inflammation in skin was developed by second passage skin grafting of isolated, lyophilized skin granulomas, originally elicited in naive mice by inoculations of lyophilized hepatic schistosome egg granulomas. The tissue reaction is caused by a single exposure to a noninfectious, acellular granulomagenic stimulus and occurs in healthy mice free of systemic disease. The model should prove useful for isolation of granuloma initiation factor(s). Furthermore, because there is a time lag before new granuloma formation begins, a window exists for analytical dissection of the initiation process. In this study we described the responses of host cells by autoradiography, and light and electron microscopy. The activity of angiotensin-converting enzyme and proline-specific endopeptidase showed a modulation during granuloma formation. In addition we found that severe immunosuppression with high dose cyclosporine therapy did not alter granuloma formation, supporting the idea that initiation of organized granulomas is T-cell independent.

Effect of the immune modulating agents cyclophosphamide, methotrexate, hydrocortisone, and cyclosporin A on an animal model of granulomatous bowel disease

This study was undertaken to determine the effect of cyclophosphamide, methotrexate, hydrocortisone, and cyclosporin A on a model of granulomatous infiltration in the terminal ileum and draining lymph nodes of the guinea pig. Treatment groups of six animals were used and compared to untreated groups of 12. Epithelioid cell granulomas and primary macrophage granulomas were induced by the inoculation of BCG (Pasteur) and irradiated Mycobacterium leprae respectively into the terminal ileum of the guinea pig. The response to purified protein derivative of tuberculin was reduced in both groups of animals receiving any of these agents. Cyclophosphamide and methotrexate treated animals inoculated with BCG or M leprae showed a significant reduction of granulomatous infiltration at the inoculation site (p less than 0.05 and p less than 0.001 respectively). BCG inoculated animals treated with either hydrocortisone or cyclosporin A showed no reduction in granulomatous infiltration at either the inoculation site or the draining lymph nodes. By contrast M leprae inoculated animals receiving either of these agents showed a significant reduction of granulomatous infiltration at both the inoculation site (p less than 0.001) and in the primary draining lymph node (p less than 0.001). Ziehl Neelsen staining showed an increased proportion of animals with detectable acid fast bacilli (AFB) at the inoculation site in the groups receiving hydrocortisone (50%) and methotrexate (67%) compared to untreated controls (8%). No AFB were observed in any of the animals inoculated with M leprae. In conclusion, this model may be helpful in elucidating the mechanism of T lymphocyte response in Crohn's disease and the variable clinical response seen with the use of immunosuppressive agents in this condition.