Immunohistochemistry as an adjunct in the differential diagnosis of radiation-induced atypia versus urothelial carcinoma in situ of the bladder: a study of 45 cases.

Muscle invasive urothelial carcinoma has been treated with cystectomy ± adjuvant therapy. Recently, a bladder-sparing protocol has been offered to selected patients closely followed with surveillance biopsies. In this setting, radiation-induced changes (RAD-Ch) may be very difficult to distinguish from carcinoma in situ, and failing to recognize them may lead to overtreatment. We ascertained the role of immunohistochemistry using cytokeratin (CK) 20, p53, and CD44s in bladder biopsies from 28 patients with a history of bladder radiation and 17 with carcinoma in situ without radiation. Negative or weak multifocal nuclear p53 staining was seen in 24 of 28 RAD-Ch cases, whereas strong and diffuse nuclear p53 staining was found in 8 of 17 carcinoma in situ cases and moderate and focal to multifocal in 3. CK20 showed strong cytoplasmic staining of only umbrella cells in 22 of 28 RAD-Ch cases. In contrast, 11 of 17 carcinomas in situ showed diffuse and strong CK20 positivity and 5 moderate and focal to multifocal positivity. All carcinomas in situ with weak or no p53 showed significant CK20 staining except 1. CD44s displayed diffuse membranous positivity in 7 of 17 RAD-Ch cases and up to mid-third in 8. Only 1 of 17 carcinomas in situ had diffuse membranous CD44s staining. Diffuse and significant CK20 expression was seen in most carcinomas in situ. Strong and diffuse p53 expression was only seen in carcinoma in situ (~50%), whereas diffuse CD44s staining was typically only seen in RAD-Ch. Our data suggest that a CK20(-) p53(-) CD44a panel proves to be very helpful (CK20 more reliable than p53 or CD44s) in the diagnosis of RAD-Ch.

Leishmania infection impairs beta 1-integrin function and chemokine receptor expression in mononuclear phagocytes.

Leishmania spp. are intracellular parasites that cause lesions in the skin, mucosa, and viscera. We have previously shown that Leishmania infection reduces mononuclear phagocyte adhesion to inflamed connective tissue. In this study, we examined the role of adhesion molecules and chemokines in this process. Infection rate (r = -0.826, P = 0.003) and parasite burden (r = -0.917, P = 0.028) negatively correlated to mouse phagocyte adhesion. The decrease (58.7 to 75.0% inhibition, P = 0.005) in phagocyte adhesion to connective tissue, induced by Leishmania, occurred as early as 2 h after infection and was maintained for at least 24 h. Interestingly, impairment of cell adhesion was sustained by phagocyte infection, since it was not observed following phagocytosis of killed parasites (cell adhesion varied from 15.2% below to 24.0% above control levels, P > 0.05). In addition, Leishmania infection diminished cell adhesion to fibronectin (54.1 to 96.2%, P < 0.01), collagen (15.7 to 83.7%, P < 0.05), and laminin (59.1 to 82.2%, P < 0.05). The CD11b(hi) subpopulation was highly infected (49.6 to 97.3%). Calcium and Mg(2+) replacement by Mn(2+), a treatment that is known to induce integrins to a high state of affinity for their receptors, reverted the inhibition in adhesion caused by Leishmania. This reversion was completely blocked by anti-VLA4 antibodies. Furthermore, expression of CCR4 and CCR5, two chemokine receptors implicated in cell adhesion, was found to be downregulated 16 h after infection (2.8 to 4.1 times and 1.9 to 2.8 times, respectively). Together, these results suggest that mechanisms regulating integrin function are implicated in the change of macrophage adhesion in leishmaniasis.

The modelling of mononuclear phagocyte-connective tissue adhesion in vitro: application to disclose a specific inhibitory effect of Leishmania infection.

In this work, we have developed an adhesion assay to study interactions between mononuclear phagocytes and connective tissue in vitro and show its potential use to study diseases caused by intracellular microorganisms. The assay reproduces most of the characteristics of macrophage adhesion to connective tissue in vivo, such as: preferential adhesion to inflamed connective tissue, divalent cation and integrin dependence, and up-regulation upon cell activation. The phagocyte adhesion to connective tissue was inhibited by infection with Leishmania (58+/-22%, p < 0.05) and was not affected by infection with Mycobacterium or by endocytosis of latex beads. Manganese partially reverted the loss in adherence produced by Leishmania infection, indicating that the mechanisms regulating the function of integrins are affected by cell infection with Leishmania. This assay might be a useful tool for the study of the mechanisms by which mononuclear phagocytes play a role in the immune-inflammatory response and in the development of lesions.