Mechanisms of programmed cell death associated to severe dengue in human renal lesions.

Dengue virus (DENV) is a global health problem. Severe dengue can manifest with hemorrhage and signs of organ dysfunction, including the kidneys. The innate immune system is an important barrier against arbovirus infection and, specifically in dengue, the cytokines IL1ß and IL18 and caspase-1 activation make up a set of host immune strategies. Cell death mechanisms include pyroptosis, necroptosis and autophagy, each with peculiar markers: gasdermin, RIPK3/MLKL, LC3, respectively. In DENV infection, necrosis and apoptosis are involved and, when infecting monocytes and macrophages in vitro, DENV is capable of inducing pyroptosis. Our objective was to explore the presence of markers of necroptosis, pyroptosis and autophagy in renal lesions caused by DENV. MATERIAL AND METHODS: twenty specimens of lesions from patients who died due to DENV infection, from the pathology department of Hospital Guilherme Álvaro, Santos, SP, were subjected to histological and immunohistochemical studies. Histological sections were stained with hematoxylin-eosin to evaluate tissue changes or collected for research with antibodies: anti-DENV (Instituto Evandro Chagas-PA), RIPK3 (NBP2-45592), MLKL (ab184718), gasdermin D (#36425 ), LC3 (14600-AP), caspase 1 (#98033), IL1ß (AF201-NA) and IL18 (SC6178). Semi-quantitative analysis was performed on 20 glomeruli and evaluation on tubules and mononuclear cells. This study was approved by the ethics committee of the USP Faculty of Medicine. RESULTS: histological analysis demonstrated glomerular congestion, glomerulitis (medium to severe), acute kidney injury and hyalinization of the glomeruli. Viral antigens were visualized on mononuclear cells. LC3 (autophagy) expression ranged from moderate to intense (++/+++) in glomeruli, tubules and mononuclear cells. The expression of gasdermin (pyroptosis) was mild (+) in most cases in the glomeruli and moderate (++) in the tubules. RIPK3 and MLKL (necroptosis) mild in tubules and mononuclear cells (+). The expression of the cytokines IL1ß and IL18 and caspase 1 was moderate (++). Statistical analysis showed greater expression of LC3 over the others. CONCLUSIONS: Our results contribute to the understanding of the pathogenesis of renal involvement in severe dengue, considering the likely anti-viral mechanism of autophagy. To a lesser extent, pyroptosis is also present, corroborating previous data.

Ordered mesoporous silica SBA-15 A new effective adjuvant to induce antibody response

The applicability of SBA-15 mesostructure as an adjuvant and evaluation of its efficiency to induce antibody response, was discussed. It was observed that better encapsulation of biomolecules of variable shape and size can be achieved using a antigen to SBA-15 weight ratio of 1: 2.5. Efficient antibody generation could be achieved because SBA-15 was able to attract antigens effectively due to its high surface area and proper mesopore size. The results show that SBA-15 and related silica mesostructures are promising nanosystems for vaccine delivery.

Immunocytochemical study of malignant lymphoma in serous effusions.

OBJECTIVE: To cytologically evaluate a large series of serous effusions associated with malignant lymphoma (ML), identify the immunoreaction patterns of the cells from selected positive cases and to investigate the correlation of cytomorphology with tissue section diagnosis. STUDY DESIGN: From 1966 to 1990, a review of the files of the Department of Anatomic Pathology, A. C. Camargo Hospital, disclosed 4,297 cases of serous effusions, 256 of which were associated with ML. Cytopathologically positive cases were selected for immunocytochemical study. All paraffin sections stained with hematoxylin and eosin were reviewed to confirm the malignancy of the cases. Immunostaining was performed on both cytocentrifuge slides previously stained with Papanicolaou stain and new sections of the biopsy samples using the immunoperoxidase method and avidin-biotin complex with monoclonal mouse antihuman B-cell marker L-26 and monoclonal (mouse) antihuman T-cell marker UCHL-1. RESULTS: Immunocytochemical reactions were performed in 54 cases: 22 were pan-B positive and 10 pan-T positive; 24 cases showed no reactivity for either monoclonal antibody. Immunohistochemical reactions were performed in 24 available cases: 15 were pan-B positive and pan-T positive; 3 cases showed no reactivity for either monoclonal antibody. Cytohistoimmunoreactions were similar in 11 pan-B positive cases and 2 pan-T positive cases. Three cases were negative for both markers, 4 cases were pan-T positive in tissue samples and negative in cytocentrifuge smears, 3 cases were pan-B positive in tissue and negative on cytology and 3 cases were negative for both markers in both tissue and cytologic specimens. CONCLUSION: Cytology is an effective method of evaluating serous effusions associated with malignant lymphoma: no false positive diagnosis was observed in this series. Immunophenotyping of lymphoid cells is useful to classify and confirm the cytologic diagnosis.

An evaluation of clinical, serologic, anatomopathologic and immunohistochemical findings for fifteen patients with mucosal leishmaniasis before and after treatment.

Treatment of mucosal leishmaniasis (ML) can be controlled by clinical examination and by serologic titers by the indirect immunofluorescence serologic reaction (IISR). We studied the correlation between the presence of antigen in tissue determined by immunohistochemistry, the IISR titers and the anatomopathologic findings in fifteen patients with ML before and after healing of the lesions as determined by otorhinolaryngologic evaluation, and evaluated these parameters to determine which of them could be useful during follow-up. Tissue antigens became negative in four patients (group A) after treatment, with a statistically significant reduction or negativity of IISR titers (p < 0.05). This did not occur in patients in whom the antigen persisted after treatment (group B), suggesting that serologic follow-up should be performed together with the search for tissue antigen, a combination which, to our knowledge, has not been used in previous studies. The negativity of tissue antigens and the behavior of IIRS titers in group A patients probably indicate a lower possibility of recurrence. Upon anatomopathologic examination the inflammatory process was found to persist after treatment even in group A, suggesting that the permanence of inflammatory activity even in clinically healed lesions is possibly correlated with the presence of the antigen or of some unknown factor.

Cytologic diagnosis of melanoma in serous effusions. A morphologic and immunocytochemical study.

The diversity of melanoma patterns greatly impairs the interpretation of malignant cells in effusion samples. The presence of melanin pigments greatly helps determine the histogenetic origin of the tumor, but unfortunately many cases do not exhibit this feature. We reviewed cases with a definitive diagnosis of melanoma in order to identify some useful characteristics of the morphologic examination of effusions. We also subjected the effusions to the HMB45 immunoreaction to determine the diagnostic usefulness of this monoclonal antibody. The study was performed on 21 effusion samples containing malignant cells, and the main cytologic findings were similar to those on other neoplasms except for the presence of melanin pigment. The HMB45 immunoreaction was very sensitive, confirming the diagnosis in 14 of 18 cases (77.8%). Melanin pigments seem to be useful markers for melanoma in effusions, and HMB45 can be used as an ancillary method in the differential diagnosis.