The granulomatous inflammatory response

Leishmania infantum antigens modulate memory cell subsets of liver resident T lymphocyte

In the recent years, the liver has been recognized as an important immune organ with major regulatory functions and immune memory, adding to the well-described vital metabolic functions. There are evidences from experimental infections performed with visceral Leishmania species that immune responses to parasite infection can be organ-specific. The liver is the compartment of acute resolving infection, with minimal tissue damage and resistance to reinfection, whereas the spleen is the compartment of parasite persistence. Control of hepatic infection in mice requires a coordinated immune response that involves the development of inflammatory granulomas. It is also described that the liver harbors populations of resident lymphocytes, which may exhibit memory characteristics. Therefore, the present study aims to address the role of the liver as an immune memory organ in the context of Leishmania infantum infection, by characterizing phenotypically resident liver T lymphocytes. The dynamics of memory T cells in L. infantum infected BALB/c mice and the effect of anti-leishmanial treatment in the differentiation of memory cell subsets were analyzed. The potential of recognition, differentiation and selection of memory lymphocytes by three L. infantum recombinant proteins were also explored. L. infantum infection generates effector and central memory T cells, but the cells did not expand when recalled, demonstrating a possible parasite silencing effect. The treatment with a leishmanicidal drug (antimoniate meglumine) increases the levels of memory and effector T cells, eliciting a more robust hepatic immune response. L. infantum parasites with a decreased sensitivity to the leishmanicidal drug favor the expansion of memory CD8⁺ T cell subset, but inhibit the proliferation of CD8⁺ T effector cells, possibly assuring their own survival. The recombinant proteins LirCyp1 and LirSOD are strongly recognized by memory cells of treated mice, indicating that these proteins might be used in a prophylactic or therapeutic vaccine formulation. Thus, L. infantum released antigens induce the development of immune memory subsets in the liver resident T cell population that specifically recognized parasite antigens, including recombinant proteins.

Immunohistochemical Detection of Toxocaral Antigens in Human Liver Biopsies

The distribution of Toxocara species larval antigens in tissue was studied by immunohis tochemical techniques in five human cases of toxocariasis. Patients had a clinical his tory suggestive of the infection, a positive enzyme-linked immunosorbent assay test for toxocaral antibodies, and histopathologic patterns of toxocariasis. Liver biopsies were taken from all five patients, usually under suspicion of liver abscess or of meta static or primary liver neoplasia. In one case a segment of the right colon adjacent to the liver lesions was also examined. Immunohistochemical techniques using polyclonal antiserum raised in rabbits against excretory secretory (TES) antigens of Toxocara canis larvae detected antigen deposits phagocyte ed by macrophages at the periphery of eosinophil-rich granulomas, in the portal inflammatory infiltrate, between epithelioid cells close to the areas of necrosis, and sequestered in the collagen of the periportal region. Both nonabsorbed and Strongyloides venezuelensis and Ascaris suum absorbed sera essentially detected similar antigenic sites, but these sites were more frequently observed and more evident when the former was used. The importance of antigen detection for the etiologic diagnosis of eosinophilic granulomatous inflammation and eosinophil-rich inflammatory infiltrates is stressed. Int J Surg Pathol 2(2):117-124, 1994

Expression of IFN-γ, IL-4, and IL-17 in cutaneous schistosomal granuloma

OBJECTIVES

Cutaneous schistosomal granuloma (CSG) is a rare dermatological disease, the clinical and histopathological features of which are well defined. Although a panoramic picture of its immunopathogenesis in humans is not yet available, it is believed to be induced by T helper 1 (Th1), Th2, or Th17 cytokines in animals. This study evaluated the expression of different types of Th cytokines, including Th1 cytokine interferon-γ (IFN-γ), Th2 cytokine interleukin-4 (IL-4), and Th17 cytokine IL-17, in human CSG.

METHODS

This study included nine patients with CSG. Dermatological examinations were conducted in all subjects. Skin biopsy specimens were stained with hematoxylin and eosin (H&E). Immunohistochemical examination was performed using three monoclonal anti-human antibodies against IFN-γ, IL-4, and IL-17 to evaluate Th1, Th2, and Th17 cytokines, respectively.

RESULTS

The most common site of CSG manifestation was the paraumbilical area, which was affected in 66.7% of patients. All lesional skin biopsy specimens revealed multiple dermal granulomas surrounding schistosomal eggs. Positive immunoreactivity for IFN-γ, IL-4, and IL-17 was present in dermal inflammatory infiltrate in 88.9, 11.1, and 88.9% of subjects, respectively. There were statistically significant negative correlations between the duration of disease and both IFN-γ and IL-17 (P ≤ 0.05), and a statistically significant positive correlation between IFN-γ and IL-17 (P ≤ 0.05).

CONCLUSIONS

This study suggests that CSG is formed by the action of both Th1 (IFN-γ) and Th17 (IL-17) cytokines, which have been shown to be directed against the schistosomal egg to induce a cell-mediated immune response.

Periprosthetic joint infection diagnosis: a complete understanding of white blood cell count and differential

Recent research has raised doubts regarding the utility of serum white blood cell count (WBC) for diagnosis of periprosthetic joint infection (PJI). As synovial WBC and neutrophil (PMN) percentage have been adopted as accurate markers of PJI, this study investigated the correlation of WBC in serum versus joint fluid and diagnostic value of all WBC levels for failed arthroplasty patients. 153 patients (73 PJI) undergoing revision knee arthroplasty were identified. Weak correlations between joint fluid and serum for WBC (R = 0.19), PMN count (R = 0.31), and lymphocyte count (R = -0.22) were observed. Diagnostic accuracy of PMN (93%) and WBC (93%) synovial count relative to serum was similar to synovial WBC (93%) and PMN% (95%) alone. Serum WBC analysis does little to improve the accurate diagnosis of PJI.

Hepatic granulomas in canine visceral leishmaniasis and clinical status

The histopathological description of intralobular hepatic granulomas in animals with a defined clinical status (asymptomatic, oligosymptomatic and symptomatic animals) was reported. Seventy-one mongrel dogs naturally infected with Leishmania chagasi were obtained from two Brazilian endemic areas: João Pessoa, PB and Belo Horizonte, MG. The hepatic parasite load was determined and compared to granuloma formation. Liver fragments from all infected animals showed remarkable leishmaniotic granulomatous inflammatory reaction. Granulomas with variable size were constituted by macrophages (parasitized or not with amastigotes of L. chagasi), some epithelioid cells, small numbers of lymphocytes, plasma cells, and rare neutrophils. Asymptomatic dogs had higher numbers of granulomas than oligosymptomatic and symptomatic animals from both geographical regions. However, the average diametric size of granulomas was very heterogeneous in all groups, independently of the geographic region (P>0.05). Parasite tissue load did not show any difference among liver fragments of all animals, especially when considering the defined clinical status and/or their geographic origin.

Histopathological and immunohistochemical study of type 3 complement receptors (CD11b/CD18) in livers and spleens of asymptomatic and symptomatic dogs naturally infected with Leishmania (Leishmania) chagasi

Leishmania promastigotes interact with macrophages through the association of multiple membrane surface receptors. Macrophage complement receptor CR3 (CD11b/CD18 or Mac-1) has been implicated in the interaction of both human and murine macrophages with serum-opsonized promastigotes. The aim of this study was to determine CR3 expression in the livers and spleens of dogs naturally infected with Leishmania (Leishmania) chagasi. CR3 expression in liver was higher in asymptomatic than in symptomatic animals. Moreover, the hepatic parasitism load determined by immunocytochemical analysis was lower in parallel with higher numbers of granulomas. In contrast, in spleens, CR3 expression was higher in symptomatic animals than in asymptomatic ones. However, the tissue parasite load was greater in spleens of symptomatic dogs. There was a strict correlation between the parasite load and cellular CR3 expression in the spleens of dogs naturally infected with L. chagasi. CR3 macrophage integrins could be essential receptors for Leishmania survival. Considering that the symptomatic animals showed higher parasite loads and higher CD11b/CD18 expression in their spleens, we can conclude that these splenic cells (monocyte-macrophages) might serve to perpetuate intracellular infection.

Tissue granuloma structure-function in experimental visceral leishmaniasis

In experimental visceral leishmaniasis in normal mice (BALB/c, C57BL/6) acquired resistance to Leishmania donovani, a protozoan which targets tissue macrophages, depends upon T cells, Th1 cell-type cytokine generation and activated mononuclear phagocytes. In the intact host, initial control and eventual resolution of L. donovani hepatic infection in normal mice is expressed by and accomplished within well-formed, mature tissue granulomas. In the liver, these immunologically active, inflammatory structures are assembled around a core of fused, parasitized resident macrophages (Kupffer cells) which come to be encircled by both cytokine-secreting T cells and influxing leishmanicidal blood monocytes. This pro-host defense granuloma structure-function relationship, in which histologically mature granulomas provide the microenvironment for intracellular L. donovani killing, however, is only one of seven which have been identified through experimental modifications in this model. This report reviews these structure-function relationships and illustrates the broad spectrum of additional possible responses. These responses range from structurally intact granulomas which provide no antileishmanial function (the 'ineffective' granuloma), to enlarged granulomas which show enhanced parasite killing (the 'hypertrophied' granuloma), to effective antileishmanial activity in the absence of any tissue reaction (the 'invisible' granuloma).

Chemokine expression dynamics in mycobacterial (type-1) and schistosomal (type-2) antigen-elicited pulmonary granuloma formation

Transcript expression of 24 chemokines (CKs) was examined throughout 8 days in mouse lungs with type-1 (Th1) or type-2 (Th2) cytokine-mediated granulomas induced by bead-immobilized mycobacterial purified protein derivative or Schistosoma mansoni egg antigens. Where possible, CK protein levels were also measured. In addition, we examined effects of in vivo cytokine depletions. Findings were as follows: 1) bead challenge induced increases in 18 of 24 CK transcripts with type-1 and type-2 responses displaying different patterns. CKs fell into four categories: a) type-1-dominant (gamma-interferon-inducible protein (IP-10), monokine induced by INF-gamma (MIG), macrophage inflammatory protein-2 (MIP-2), lipopolysaccharide-induced chemokine (LIX), rodent growth-related oncogene homologue (KP), macrophage inflammatory protein-1alpha (MIP-1alpha) and -1beta (MIP-1beta), lymphotactin), b) type-2-dominant (eotaxin, monocyte chemotactic protein-2 (MCP-2) and -3 (MCP-3), liver and activation-regulated chemokine (LARC), T cell activation protein-3 (TCA-3), c) type-1 and type-2 co-dominant (MCP-1, MCP-5, monocyte-derived chemokine (MDC), thymus and activation-related chemokine (TARC), C10), and d) constitutive (lungkine, secondary lymphoid-tissue chemokine (SLC), EBI1-ligand chemokine (ELC), fractalkine, macrophage inflammatory protein-1gamma (MIP1-gamma), and stromal cell derived factor-1alpha (SDF1-alpha). 2) CKs displayed characteristic temporal patterns. CXC (IP-10, MIG, MIP-2, LIX, KC) and certain CC (MCP-1, MCP-5, MIP-1alpha, MIP-1beta) CKs were produced maximally within 1 to 2 days. Others (MCP-2, MCP-3, eotaxin, lymphotactin, LARC, TCA-3) displayed peak expression later. 3) Interferon-gamma neutralization profoundly abrogated MIG, but had little effect on other CKs. Tumor necrosis factor-alpha neutralization caused up to 50% reduction in a range of CKs. These findings indicate that type-1 and type-2 granulomas display characteristic CK profiles with coordinated expression that is under cytokine-mediated regulation.

Tumor necrosis factor (TNF) and a TNF-mimetic peptide modulate the granulomatous response to Mycobacterium bovis BCG infection in vivo

Tumor necrosis factor (TNF) is a critical mediator in the immune response to mycobacteria, particularly in the formation and maintenance of granulomas. Treatment of Mycobacterium bovis BCG-infected mice with TNF and a TNF-mimetic peptide (TNF(70-80)) altered the number and cellular composition of granulomas. This change was associated with a moderate decrease in the bacterial burden.

The biological relevance of polykaryons in the immune response

Peripheral blood monocyte-derived multinucleated giant cells are a well-known feature of chronic inflammatory conditions. Similarly, virus-induced syncytia derived from CD4+ cells are considered to be typical of human immunodeficiency virus infection under culture conditions. Here, Stefano Fais and colleagues summarize recent experimental results comparing the mechanisms underlying the formation and fate of these two different polykaryons, discussing their putative role in the immune response.

Rejection of discordant neovascularized xenografts: is it similar to the response against metazoan parasites?

Allotransplantation is now widely successful but is increasingly limited by a shortage of human organ donors. Xenografts could solve this shortage but hyperacute rejection due to preformed antibodies that react with graft endothelial cells in primarily vascularized xenografts that cannot be controlled with current immunosuppressants causes graft loss and negates this approach. In the absence of hyperacute rejection, the host mounts a vigorous cellular response but its nature is poorly understood. In contrast, the cellular immune response against allografts is usually reversible with immunosuppression. The anti-xenograft response is similar to that generated against metazoan parasites but they often survive. Perhaps the host perceives a xenograft in a manner similar to the recognition of a parasite and reacts in a similar way but with parasites the response is often inadequate. Perhaps there are lessons to be learnt from parasitology that may be applicable to xenotransplantation.

Interferon expression in Crohn's disease patients: increased interferon-gamma and -alpha mRNA in the intestinal lamina propria mononuclear cells

The in vivo interferon (IFN) activation in Crohn's disease was evaluated by measuring the relative amounts of IFN-alpha and -gamma mRNA in freshly isolated human lamina propria mononuclear cells (LPMC) from patients with Crohn's disease and controls. Both IFN-gamma and IFN-alpha mRNA, as estimated by dot blot analysis, were increased in Crohn's disease (LPMC), although the relative amounts of IFN mRNA appeared to differ among patients. Appreciable amounts of IFN-gamma mRNA were found in Crohn's disease peripheral blood mononuclear cells (PBMC) extracts, whereas the same cells were negative for IFN-alpha mRNA. Only minute amounts of IFN-gamma RNA were found sporadically in control LPMC while no IFN-alpha was detected. Control PBMC were shown to be virtually negative for both IFN-alpha and IFN-gamma mRNA. These data suggest that IFN induction in the normal human gut is a well-controlled function and that in Crohn's disease tissues, both IFN-gamma and IFN-alpha production are dysregulated. The increased IFN activity may represent a major feature in the induction and perpetuation of the chronic inflammatory process in Crohn's disease.

Cutaneous sarcoid-like granulomas in primary immunodeficiency disorders

We report the occurrence of cutaneous sarcoid-like granulomas in one patient with common variable immunodeficiency and another with 'thymoma and hypogammaglobulinaemia'. To our knowledge, this is the first time that such skin lesions have been described in patients with primary immunodeficiency. These granulomas may be attributed to a combination of interleukin-2 deficiency and a profound CD4 lymphopenia. The lesions are similar to the non-infectious 'papular eruption' associated with human immunodeficiency virus infection, and might reflect a common pathogenic mechanism.

An ultrastructural and cytochemical study of the pulmonary lesions and multinucleate giant cells in porcine dermatosis vegetans

The pulmonary lesions and multinucleate giant cell formations in porcine dermatosis vegetans were studied ultrastructurally and cytochemically in seven affected pigs that ranged from one to 120 days of age. At birth, no pulmonary lesions were observed. By seven days of age, there was a moderate infiltration of monocytes/macrophages in the alveoli and interstitium. These changes progressed, and by two weeks of age there was pronounced infiltration of macrophages and lymphocytes in the alveoli. Close apposition of macrophages and lymphocytes was observed, and cellular contact was demonstrated. By three to four weeks of age, small aggregates with epithelioid cells, macrophages, and lymphocytes resembling granulomas were present. In an older pig, aged four months, the inflammatory changes waned. Large macrophages, and large and small multinucleate cells shared common morphological characteristics of cytoplasm endowed with organelles, primary and secondary lysosomes, Golgi profiles, and granular endoplasmic reticulum. Cytochemically, macrophages and MGCs were positive for acid phosphatase. The present study showed that the initial pulmonary changes share morphological characteristics with a granulomatous inflammatory response, and evolve into small granulomas with macrophages, epithelioid cells and lymphocytes. Morphologically, these changes share characteristics with epithelioid cell granulomas. Macrophages and MGCs share common ultrastructural traits, and are positive for acid phosphatase. MGCs seem to evolve in the course of the granulomatous inflammatory response and are probably of monocyte/macrophage origin.

Recurrent intra-cranial granulomata presenting as space-occupying lesions in a patient with common variable immunodeficiency

A patient with profound panhypogammaglobulinaemia due to common variable immunodeficiency developed two discrete intra-cranial space-occupying lesions, 10 years apart, requiring craniotomy. Histological examination revealed the intra-cranial masses to be granulomata of unknown aetiology on both occasions.

Analysis of adhesion molecules in the immunopathogenesis of giant cell arteritis

To explore the role of adhesion molecules in mediating mononuclear cell localisation, development of the granulomatous reaction, and cell mediated damage to the arterial wall in giant cell arteritis, 17 temporal artery biopsy specimens were examined. Eleven showed the histological features of giant cell arteritis and six showed no evidence of arteritis. All were examined for the expression of LFA-3, ICAM-1 and its receptor LFA-1, and HLA-DR. Temporal arteries with early features of arteritis, as well as histologically unaffected skip areas, showed a regional induction of ICAM-1 expression, but not HLA-DR, on smooth muscle cells of the media. ICAM-1 expression was detected in areas where a clinically important mononuclear cell infiltrate had not yet developed. In more florid cases of giant cell arteritis there was an additional widespread induction of ICAM-1 expression on intimal myofibroblasts. Strong expression of ICAM-1, HLA-DR, and LFA-3 was found on macrophages, epithelioid cells, and giant cells comprising the granulomatous lesion. The pattern of expression of these adhesion molecules suggests that they have a role in leucocyte traffic into the vascular lesion as well as in mediating the intercellular interactions which constitute the granulomatous response.

Granulomatous sialadenitis

Granulomatous inflammation in salivary tissues is most often a response to liberated ductal contents, particularly mucin, in various degrees of obstructive sialadenopathy. Far less often is a granulomatous sialadenitis the result of specific infective granulomas or systemic granuloma-forming diseases. In these instances, the salivary parenchymal involvement is usually secondary to disease localization in regional lymph nodes.

Epithelial macrophages secrete a deactivating factor for superoxide release

The release of superoxide anion (O2-) by inflammatory macrophages, multinucleated giant cells, and epithelioid cells, obtained by the insertion of round glass coverslips into the subcutaneous tissue of mice, was investigated. O2- was shown to be spontaneously released by cells on the surface of glass coverslips implanted up to 7 days, but not by cells obtained 14 or 21 days after coverslip implantation. The former showed increased O2- release when stimulated by phorbol myristate acetate, whereas cells harvested after 14 or 21 days implantation did not. The induction of delayed type hypersensitivity around coverslips implanted for 5 days increased spontaneous O2- release by these cells by 40%. On the other hand, when the same protocol was used with coverslips implanted for 14 days, O2- release was not detected. These results were viewed in regard to the composition of the cell population at each time point. When coverslips were removed after 14 days of implantation and the cells incubated for 30 minutes in vitro, the medium so conditioned inhibited O2- release by cells of 5 day old preparations. This indicates the release by cells on the longer term coverslips of a substance that inhibits O2- production by cells of coverslips implanted for 5 days only. This inhibitory activity could be suppressed by treating the conditioned medium with proteases. The factor was, however, heat stable and exerted its effects even when the test cells were exposed to phorbol myristate acetate.

Granulomatous inflammation of the spleen in infectious mononucleosis

Granulomatous inflammation of the spleen has not previously been recorded in infectious mononucleosis. We report two cases and describe further morphological features more often associated with malignant lymphoid conditions.