Lysozyme localization in normal and diseased human gastric and colonic mucosa. A correlative histochemical, immunohistochemical and immunoelectron microscopic investigation.

The distribution of lysozyme in normal and pathological human gastric and colonic mucosa was studied by light and electron microscopic immunocytochemical techniques and compared with histological and histochemical features. Lysozyme was localized in pyloric glandular epithelial cells, mucous neck cells of fundic glands, Paneth cells and some crypt cells of the mature colonic mucosa. In addition, lysozyme was detected in a large spectrum of "immature" or "regenerative" epithelium: neck cells of the gastric regenerative zone, undifferentiated columnar cells of surface and hyperplastic interfoveolar crests of the stomach, regenerative cells in a healed gastric ulcer, some goblet cells in incomplete intestinal metaplasia, cells of the regenerative zone at the bottom of colonic crypts and, finally, fetal intestinal epithelium. Electron microscopically, we localized lysozyme in the central core of mucous granules in the pyloric gastric glandular epithelium and in the dense mucous granules in gastric mucous neck cells. Lysozyme was also detected in some immature mucin-producing cells of the gastric regenerative zone and in the rough endoplasmic reticulum of surface hyperplastic columnar gastric cells. At the electron microscopic level, a peculiar correlation between the immunopattern of lysozyme and the morphology of mucous granules has been postulated. All our data support and extend the view that the presence of lysozyme may be related to cell immaturity as well as to a regenerative state of the cell. Finally, the lysozyme distribution and its relation to mucosubstances in gastric and colonic carcinoma suggest that lysozyme should not be considered an exclusive marker of cells of gastric derivation.     

Beta-HCG aberrant expression in primary mediastinal large B-cell lymphoma.

We report on a primary mediastinal large B-cell lymphoma with aberrant expression of beta-human chorionic gonadotropin (beta-hCG). The patient, a 33-year-old man, had cough, dyspnea, fever, superior vena cava syndrome, and a mediastinal bulky tumor. A biopsy showed that the latter was characterized by large cells, sclerosis, and compartmentalization. The neoplastic elements expressed CD45, CD20, CD79a and, partially, CD30, whereas they were negative for CD3, epithelial membrane antigen and cytokeratins. Surprisingly, they displayed a clear-cut positivity for beta-hCG. The remaining oncofetal markers applied (PLAP and alpha1-fetoprotein) were negative. Electron microscopy demonstrated the presence of numerous nuclear pockets and the lack of intercellular junctions. DNA analysis by polymerase chain reaction showed clonal rearrangement of Ig heavy-chain genes. The patient responded promptly to the administration of MACOP-B. To the best of our knowledge, this is the first example of B-cell lymphoma showing positivity for beta-hCG; a similar aberrant expression was previously observed only in three Japanese patients with human T-cell lymphotropic virus type I+ adult T-cell lymphoma/leukemia. Because primary mediastinal large B-cell lymphoma has in the past been frequently confused with germ cell tumors, pathologists should be aware of possible beta-hCG expression by lymphomatous cells to avoid the risk of misdiagnosis.     

The Impact of IFN-γ Receptor on SLPI Expression in Active Tuberculosis: Association with Disease Severity

Interferon (IFN)-γ displays a critical role in tuberculosis (TB), modulating the innate and adaptive immune responses. Previously, we reported that secretory leukocyte protease inhibitor (SLPI) is a pattern recognition receptor with anti-mycobacterial activity against Mycobacterium tuberculosis (Mtb). Herein, we determined whether IFN-γ modulated the levels of SLPI in TB patients. Plasma levels of SLPI and IFN-γ were studied in healthy donors (HDs) and TB patients. Peripheral blood mononuclear cells from HDs and patients with TB or defective IFN-γ receptor 1* were stimulated with Mtb antigen and SLPI, and IFN-γR expression levels were measured. Both SLPI and IFN-γ were significantly enhanced in plasma from those with TB compared with HDs. A direct association between SLPI levels and the severity of TB was detected. In addition, Mtb antigen stimulation decreased the SLPI produced by peripheral blood mononuclear cells from HDs, but not from TB or IFN-γR patients. Neutralization of IFN-γ reversed the inhibition of SLPI induced by Mtb antigen in HDs, but not in TB patients. Furthermore, recombinant IFN-γ was unable to modify the expression of SLPI in TB patients. Finally, IFN-γR expression was lower in TB compared with HD peripheral blood mononuclear cells. These results show that Mtb-induced IFN-γ down-modulated SLPI levels by signaling through the IFN-γR in HDs. This inhibitory mechanism was not observed in TB, probably because of the low expression of IFN-γR detected in these individuals.Tuberculosis (TB) is among the most common causes of morbidity and mortality in patients with HIV infection. Although protective immunological mechanisms against Mycobacterium tuberculosis (Mtb) are not fully understood, resistance to mycobacterial infections is primarily mediated by the interaction of antigen-specific T cells and macrophages.^1,2 This interaction depends on the cross talk of cytokines produced by these cells, and interferon (IFN)-γ is essential for protection.^2,3 Thus, during the immune response of the host against Mtb, IFN-γ produced by type 1 helper T cells is recognized by its receptor on macrophages. The IFN-γ receptor (IFN-γR) is composed of two ligand-binding IFNGR1 chains associated with two signal-transducing IFNGR2 chains, and an associated signaling machinery.^2–5 IFN-γ binds to its receptor and activates macrophages to efficient killing of intracellular mycobacteria. In humans, the loss-of-function mutations in IFNGR1 or IFNGR2 genes are closely associated with severe susceptibility to poorly virulent mycobacteria highlighted in childhood.^4,6,7Secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor secreted by inflammatory and epithelial cells, mainly in the respiratory tract mucosa, and it is primarily active against neutrophilic elastase, cathepsin G, trypsin, and chymotrypsin.⁸ The expression and secretion of SLPI are down-modulated during chronic obstructive pulmonary disease.^9–11 In addition, cathepsins B, L, and S and cigarette smoke exposure result in the cleavage and inactivation of SLPI.^12,13 Moreover, it has been demonstrated that IFN-γ is a prominent stimulator of cathepsins and matrix metalloproteinase-12 and an inhibitor of SLPI.¹⁴ Remarkably, SLPI may also function as an endogenous immunomodulatory, anti-inflammatory, and/or antimicrobial substance.^15–18 The antimicrobial effects of SLPI against several bacteria have been demonstrated.¹⁵ In particular, Nishimura et al¹⁷ described that recombinant mouse SLPI inhibited the growth of bacillus Calmette-Guérin (BCG) and Mtb through the disruption of the mycobacterial cell wall structure. Furthermore, we reported that human SLPI is a secreted pattern recognition receptor for mycobacteria that increases both the phagocytosis and killing of the pathogen.¹⁸ Remarkably, exposure of murine peritoneal macrophages to Mtb led to an increase in SLPI secretion.¹⁹ Thus, given the anti-inflammatory and anti-mycobacterial roles of SLPI in humans and taking into account the fact that SLPI is inhibited by IFN-γ,²⁰ a crucial cytokine in the protective immunity against Mtb, herein we studied the effect of IFN-γ on the expression of SLPI during human active disease.     

Application of Petersen Index Score for Dukes’B colorectal cancer in a population of 103 consecutive resected patients

Dukes' B colorectal cancer (CRC) represents a wide spectrum of disease from early penetration through the bowel wall to aggressive and extensive tumours with extramural venous spread and involvement of the serosa, surgical margins or adjacent organs. Among Dukes' B cancers, Petersen Index allows stratification to identify those patients whom chemotherapy may benefit. One hundred and three resected patients with CRC Dukes' B were included prospectively in a database and considered in the present study. According to Petersen Index, a score (from 0 to 4) for each patient was calculated on the basis of peritoneal and margin involvement, venous invasion and tumour perforation. Twenty-four out of 103 tumours were located in the rectum and 79 in the colon. According to PI score 59 patients had a score of 0, 30 of 1 and 14 of ≥2. The overall R0 resection was achieved in 95.1?% of cases and the majority of patients with PI score of ≥2 were R1-2. The mean of harvested lymph nodes was 23.6 (±10.7) with no difference according to the PI score. Patients in the high-risk group had a worse 5-year survival rate (66.3?%) compared with the other group (P?相似文献   

Hepatitis B virus DNA in mononuclear blood cells. A frequent event in hepatitis B surface antigen-positive and -negative patients with acute and chronic liver disease

We have investigated 38 hepatitis B surface antigen (HBsAg)-positive and 34-negative patients with acute and chronic liver disease for the presence of hepatitis B virus (HBV) DNA in peripheral mononuclear blood cells. Among the HBsAg-positive subjects HBV DNA was detected in the mononuclear cells of asymptomatic HBV carriers (2/6), patients with acute hepatitis (8/8), chronic active hepatitis (18/21), and with hepatocellular carcinoma (2/3); the viral DNA sequences were also identified in the mononuclear cells of patients with HBsAg-negative acute hepatitis (2/3), chronic active hepatitis (5/15) and hepatocellular carcinoma (5/16), some of these showing no evidence of HBV by conventional serological markers. By contrast HBV DNA was not detected after resolution of the acute viral infection. For 7 patients different mononuclear cell-enriched subpopulations were assayed and the viral DNA was observed in T lymphocytes (both OKT4+ and OKT8+ enriched subsets) and/or in B enriched lymphocytes; the restriction DNA patterns showed in some patients a genetic organisation of the viral DNA similar to those observed in the liver (including free monomeric and oligomeric HBV DNA and results consistent with integrated viral sequences); however, no HBV DNA replicative forms were detected. These results show that the hepatitis B virus infection of mononuclear blood cells (including lymphoid cells) is a frequent event at all stages of the viral infection which might be related to immunological abnormalities observed in HBV carriers; in addition the mononuclear blood cells analysis may provide an insight to the liver cells status.     

Hepatitis B virus (HBV) sequence variation of cytotoxic T lymphocyte epitopes is not common in patients with chronic HBV infection.

It has been suggested that immune selection pressure exerted by the cytotoxic T lymphocyte (CTL) response could be responsible for viral persistence during chronic hepatitis B virus infection. To address this question, in the current study we compared the DNA and amino acid sequences of, and the CTL responses to, multiple HLA-A2-restricted CTL epitopes in the hepatitis B virus in several HLA-A2-positive patients with acute and chronic hepatitis. Our results indicate that the CTL response to these epitopes is barely detectable in the majority of patients with chronic hepatitis. Further, we show that the weak CTL response is not secondary in infection by mutant viruses lacking these epitopes, and we show that the CTL response did not select for escape mutants in any of these patients. We conclude that an ineffective hepatitis B virus specific CTL response is the primary determinant of viral persistence in chronic hepatitis and that immune selection of viral variants is not a common event in the majority of patients.