Exuberant verrucous carcinoma arising from a burn scar

Verrucous carcinoma (VC) is an unusual, well-differentiated, and low-grade type of squamous cell carcinoma, characterized by slow growth, low metastatic spread, local invasion, and little dysplasia. It occurs predominantly on the genitals, in the oropharynx, or in the palmoplantar region, being less frequent at other sites; however, it can occur on any part of the body. Many factors have been associated with its pathogenesis, including the presence of previous skin lesions, such as varicose, decubitus, traumatic, or neuropathic plantar ulcers. VC arising from a burn scar is rare. We report the case of a patient who developed exuberant VC on his knee many years after having burn injuries at that site.

Molecular model for studying the uncultivated fungal pathogen Lacazia loboi

Lacazia loboi is an uncultivated fungal pathogen of humans and dolphins that causes cutaneous and subcutaneous infections only in the tropical areas of the Americas. It was recently found by phylogenetic analysis that this unusual pathogen is closely related to Paracoccidioides brasiliensis and to the other fungal dimorphic members of the order Onygenales. That original phylogenetic study used universal primers to amplify well-known genes. However, this approach cannot be applied to the study of other proteins. We have developed a strategy for studying the gene encoding the gp43 homologous protein of P. brasiliensis in L. loboi. The gp43 protein was selected because it has been found that this P. brasiliensis antigen strongly reacts when it is used to test sera from patients with lacaziosis. The principle behind this idea was to obtain the gp43 amino acid sequence of P. brasiliensis and other homologous fungal sequences from GenBank and design primers from their aligned conserved regions. These sets of primers were used to amplify the selected regions with genomic DNA extracted from the yeast-like cells of L. loboi from experimentally infected mice. Using this approach, we amplified 483 bp of the L. loboi gp43-like gene. These sequences had 85% identity at the nucleotide level and 75% identity with the deduced amino acid sequences of the P. brasiliensis gp43 protein. The identity of the 483-bp DNA fragment was confirmed by phylogenetic analysis. This analysis revealed that the L. loboi gp43-like deduced amino acid sequence formed a strongly supported (100%) sister group with several P. brasiliensis gp43 sequences and that this taxon in turn was linked to the other fungal sequences used in this analysis. This study shows that the use of a molecular model for investigation of the genes encoding important proteins in L. loboi is feasible.

Immunohistochemical characterization of the cellular infiltrate in Jorge Lobo's disease

Few studies have been conducted to evaluate the cellular composition of the granulomatous lesions induced by Lacazia loboi. Thus, the objective of the present study was to characterize the mononuclear cell population present in cutaneous lesions obtained from 15 patients with Jorge Lobo's disease. Histological sections were stained with hematoxylin-eosin and methenamine silver and the following mononuclear cells were identified by immunohistochemistry: T lymphocytes (CD3+), helper T lymphocytes (CD4+), cytotoxic T lymphocytes (CD8+), B lymphocytes (CD20+), plasma cells (CD79+), natural killer cells (CD57+) and histiocytes (CD68+). This study showed that the inflammatory infiltrate mainly consists of histiocytes and multinucleated giant cells, in addition to the presence of a large number of fungal cells. The identified inflammatory cells showed the following frequency: CD68+ histiocytes > CD3+ T lymphocytes > CD4+ T > CD8+ T lymphocytes > CD57+ natural killer cells > CD79+ plasma cells > CD20+ B lymphocytes. Based on the findings of a large number of fungal cells in the infected tissues and the disorganized cell arrangement in the granuloma, we hypothesize that patients with Jorge Lobo's disease present immunoregulatory disturbances, which are likely to be specific and perhaps responsible for the lack of containment of the pathogen.

Cytokine quantification in the supernatant of mononuclear cell cultures and in blood serum from patients with Jorge Lobo's disease

Few studies are available about the participation of the immune response in the control or the development of Jorge Lobo's disease. Thus, the objective of the present study was to quantify macrophage and lymphocyte cytokines in the supernatant of cell cultures and in blood serum from patients with this disease. The study was conducted on 15 patients with the mycosis and on 15 healthy adult individuals (control group). Blood samples were collected in order to obtain serum and mononuclear cells. Monocytes were cultured for 24 h in the presence or absence of LPS and L. loboi, and lymphocytes were cultured for 48 h in the presence or absence of PHA and L. loboi. Cytokines IL-1beta, TNF-alpha and IL-6 were quantified by ELISA in the supernatants of monocyte cultures and in serum. Cytokines IL-2, IFN-gamma, IL-4 and IL-10 were quantified by FLISA in the supernatants of lymphocyte cultures and in serum. The quantification of the cytokines in the culture supernatant revealed a greater IL-4 and IL-6 production and lower IL-2 levels in patients compared to control. The production of IL-1beta, TNF-alpha, IL-10 and INF-gamma was similar in patients and controls. The mononuclear cells from patients with the non-localized form of the disease produced higher INF-gamma levels than those of patients with the localized form. The results suggest that patients with Jorge Lobo's disease show altered cytokine profiles represented by a predominance of the Th2 profile. However, further studies are needed to assess the participation of cytokines in the cell-fungus interaction in situ.

Evaluation of the phagocytic activity of peripheral blood monocytes of patients with Jorge Lobo's disease

Studies on host-parasite interaction in Jorge Lobo's disease are scarce, with no report in the literature on the phagocytosis of Lacazia loboi by phagocytic mononuclear cells. Thus, the objective of the present study was to assess the phagocytic activity of blood monocytes in the presence of L. loboi in patients with the disease and in healthy subjects (controls) over 3 and 24 hours of incubation. Statistical analyses of the results showed no significant difference in percent phagocytosis of the fungus between patient and control monocytes. With respect to incubation time, however, there was a significant difference, in that percent phagocytosis was higher at 3 hours than at 24 hours (p <0.01). These results suggest that monocytes from patients with the mycosis are able to phagocyte the fungus, as also observed in control individuals.

Evaluation of the vital staining method for Lacazia loboi through the experimental inoculation of BALB/c mice

The viability of the currently unculturable fungal pathogen Lacazia loboi can be determined by means of fluorescein diacetate-ethidium bromide (FD-EB) staining. This technique can be used in experimental study of the mycosis, in attempts to cultivate the fungus and in attempts to gauge the success of therapies. In the present study, the potential applications of FD-EB vital staining were studied using a proposed murine experimental model of lobomycosis. BALB/c mice were inoculated in the footpads with an L. loboi suspension that appeared in FD-EB staining to have lost viability after being held for 15 days at room temperature, whereas a control group of mice was inoculated with apparently viable fungi. The animals were killed after 1, 2, 4, 6, 8, 11 and 13 months. Both inoculated footpads were excised, one for determination of viability and the other for histological examination. In the group injected with nonviable material, no active infection was noted; inoculation sites showed small quantities of macrophage-laden infiltrate and no viable fungal cells. In the control group, the infection progressed with exuberant infiltrates surrounding copious fungal growth, most of which consisted of cells staining as viable in FD-EB. These results suggest that the FD-EB vital staining is a sensitive and specific method that can reliably be used for viability determination in L. loboi.

Experimental reproduction of the Jorge Lobo's disease in BAlb/c mice inoculated with Lacazia loboi obtained from a previously infected mouse

Long-term maintenance of Lacazia loboi in the laboratory has not been reported. We report here the use BALB/c mice to maintain the Lacazia loboi for extended period of time. Eight to ten week-old mice were inoculated intradermally in both hind footpads with a fungal suspension from a macerated footpad obtained from an original mouse previously infected with the fungi and sacrificed 8 months after inoculation. The inoculated animals were sacrificed at different time intervals, footpads were excised, the right one was submitted to histopathological examination and the left one was macerated in sterile saline for fungal count and viability index determination. The inoculated animals presented the histopathological picture identical to the mice previously inoculated with material from human lesion. Granulomatous infiltrates with predominance of macrophages and giant cells were observed. The granulomas evolved progressively as observed in the different times of sacrifice. After 7 months of inoculation, macroscopic lesions were observed, and the number of fungi obtained from macerated footpads was higher than the number of inoculated fungi. The pattern of lesion development was similar to what was observed in animals infected with a fungal suspension obtained from a human lesion. Considering the histopathological findings, the clinical manifestations, and the finding of a higher number of fungi obtained than the inoculated into footpads of each mice, we believe the BALB/c mice strain is as an excellent way to maintain L. loboi in laboratory. Moreover, even after serial passages of the fungi, the granulomatous lesions are reproduced consistently in laboratory conditions.

Drug resistance and genotypes of strains of Mycobacterium tuberculosis isolated from human immunodeficiency virus-infected and non-infected tuberculosis patients in Bauru, São Paulo, Brazil

Little is known about transmission and drug resistance of tuberculosis (TB) in Bauru, State of S o Paulo. The objective of this study was to evaluate risk factors for transmission of Mycobacterium tuberculosis strains in this area. Strains were collected from patients attended at ambulatory services in the region and susceptibility towards the main first line antibiotics was determined and fingerprinting performed. A total of 57 strains were submitted to susceptibility testing: 23 (42.6%) were resistant to at least one drug while 3 (13%) were resistant against both rifampicin and isoniazide. Resistant strains had been isolated from patients that had not (n = 13) or had (n = 9) previously been submitted to anti-TB treatment, demonstrating a preoccupying high level of primary resistance in the context of the study. All strains were submitted to IS6110 restriction fragment length polymorphism (IS6110-RFLP) and double repetitive element PCR (DRE-PCR). Using IS6110-RFLP, 26.3% of the strains were clustered and one cluster of 3 patients included 2 HIV-infected individuals that had been hospitalized together during 16 days; clustering of strains of patients from the hospital was however not higher than that of patients attended at health posts. According to DRE-PCR, 55.3% belonged to a cluster, confirming the larger discriminatory power of IS6110-RFLP when compared to DRE-PCR, that should therefore be used as a screening procedure only. No clinical, epidemiological or microbiological characteristics were associated with clustering so risk factors for transmission of TB could not be defined in the present study.