Expression of pattern recognition receptors in liver biopsy specimens of children chronically infected with HBV and HCV.

Pattern recognition receptors (PRRs) constitute a pivotal arm of innate immunity. Their distribution is widespread and not limited to cells of the immune system. Following our previous findings concerning the expression of Toll-like receptors (TLRs) 2, 3 and 4 in chronic viral hepatitis C of children, we wished to search for other PRRs, including other TLRs, NOD-like receptors (NLRs) and RIG-1-like helicase receptors (RLR) in infected hepatocytes. Liver biopsy fragments from ten children with chronic hepatitis B and C were used and two others in which hepatotropic virus infection was excluded. Frozen sections of liver samples were subjected to ABC immunohistochemistry (IHC) following incubation with a set of antibodies. Results of IHC findings were screened for correlation with clinical/laboratory data of patients. It was found that several PRRs could be shown in affected hepatocytes, but the incidence was higher in hepatitis C than in B. In hepatitis C, TLR1, 2, 4, NALP and RIG-1 helicase showed the most marked expression. In hepatitis B, TLR1, 3, 9, NOD1 and NALP expression were the most conspicuous. Expression PRRs in liver from hepatitis of unknown origin was much lower. It was also the case in cytospins from human hepatoma cell line. Several correlations between PRRs expression and clinical findings in patients could be shown by statistical exploration. In conclusion, this data suggests some role for PRRs in the pathogenesis of chronic viral hepatitis.

Toll-like receptors 2, 3 and 4 (TLR-2, TLR-3 and TLR-4) are expressed in the microenvironment of human acquired cholesteatoma.

Human toll-like receptors (TLR 1-10) are crucial in the induction and activation of innate immunity in the course of an infection. They are expressed mainly on the cells of the immune system, and also on some epithelia and endothelia. Their ligands so called pathogen associated molecular patterns are abundant on invading microbes. TLR-ligand binding results in cell signal transduction and subsequent production of various proinflammatory cytokines such as IL-1 and TNF-alpha. Acquired cholesteatoma is formed during chronic otitis media in the proportion of cases. It has adverse effects on ear structures, resulting in osteolysis and bone resorption. Its formation and pathogenesis are not fully understood. The current study attempted to search the possible role of TLRs in this somewhat awkward pathological condition. Surgical specimens of human acquired cholesteatoma (n=15) and normal external auditory canal skin (n=5, control tissues) were tested by immunohistochemistry for the presence of TLRs. Three TLRs were examined: TLR-2, TLR-3 and TLR-4. All TLRs tested were demonstrated in matrix (layer of keratinizing epithelium) and perimatrix (granulation tissue) of this inflammatory tumour. Expression of particular TLRs within the keratinizing epithelium was distinct and uneven. In the perimatrix, numerous T (CD3+) cells were seen and relatively few macrophages (CD11c+, HLA-DR+). There was a weak expression of all TLRs on normal (non-inflammatory) skin. Expression of TLR-3 both on the epithelium and some cells within the perimatrix and the presence of T cells may suggest that apart from innate immune responses, mechanisms of adaptive immunity also operate in cholesteatoma. Weak expression of these receptors on normal skin may also suggest the important role of TLRs in the etiopathogenesis of cholesteatoma.

Immunosuppressive mechanisms in the microenvironment of malignant pleural effusions.

Malignant effusions in serous cavities constitute a unique milieu for direct contact of tumor cells with host lymphoid cells in a fluid phase. The aim of this study was to depict agents responsible for suppression of lymphoid cells with putative anti-tumor potential. Pleural effusions drawn from 44 (18 non-malignant and 26 malignant) patients were tested for selected cytokines--interleukin-10 (IL-10), transforming growth factor beta (TGF-beta1) and soluble Fas ligand (sFasL) and nuclear membrane proteins (NMPs) content by ELISA. TCR-zeta expression of T cells and TUNEL reaction for apoptosis were evaluated by three color flow cytometry. Both cytokine concentrations were found to be significantly elevated in malignant pleural effusions (MPE) as compared to non-malignant ones. It was also true for sFasL content. Moreover, NMPs corresponding to decoy cell fragments, were also heightened in MPE. Concentrations of NMPs correlated with the percent of apoptotic (TUNEL+) T CD3+ lymphocytes and inversely correlated with the percent of T cells. The low expression of TCR-zeta chain on T cells corresponded to high concentration of sFasL in MPE. In conclusion, the above data suggest that out of three suppression agents tested, only sFasL appears to show correlation with the downregulation of T cells in MPE.