RESUMO

In this study, we assessed the effectiveness of a live, attenuated Salmonella enterica serovar Typhi (S. Typhi) vaccine strain as a cancer immunotherapy in a mouse model of metastatic T-cell lymphoma. EL4 tumor-bearing C57BL/6J mice immunized with S. Typhi strain CVD 915, by injection into the tumor and the draining lymph node areas, displayed a significant decrease in tumor growth, a reduction in the mitotic index (MI) of tumors, a delayed development of palpable lymph node metastases and most importantly improved survival, compared to untreated mice. Besides, complete tumor regression was achieved in a small number of bacteria-treated mice. A successful therapeutic response associated with a significant reduction of tumor mass was evident as early as 5 days after treatment. The administration of Salmonella to tumor-bearing mice promoted early cellular infiltration (mainly neutrophils) within the tumor, and was accompanied by a decreased intratumoral interleukin 10 production as well as by leukocyte expansion in tumor draining lymph nodes. A tumor-specific memory immune response was induced in most of cured animals, as evidenced by the lack of tumor growth after a rechallenge with the same tumor. EL4 cells cultured with live Salmonella failed to proliferate and underwent apoptosis in a dose-dependent, time-dependent, and contact-dependent manner. To our knowledge, these results demonstrate for the first time the efficacy of a S. Typhi vaccine strain as an oncolytic and immunotherapeutic agent against a highly malignant tumor and support the use of S. Typhi-based vaccine strains in cancer therapy.

Assuntos

RESUMO

Rhodotorula sp. are commensal yeasts that may cause opportunistic infections. There have been only a few case reports of Rhodotorula fungemia in children with cancer, and in all of them the patients had a central venous catheter inserted. The authors report three nonfatal cases of fungemia by Rhodotorula in patients with post-chemotherapy neutropenia. Two of three patients required catheter removal, and a response was achieved with systemic antifungal therapy. Aggressive therapy may be required for selected high-risk patients.

Assuntos

Assuntos

RESUMO

Epstein-Barr virus is universally associated with endemic Burkitt's lymphoma (BL) and undifferentiated nasopharyngeal carcinoma and can be detected in a significant proportion of cases of Hodgkin's disease (HD) and peripheral T-cell lymphoma, but only rarely in sporadic B-NHL. The frequency of EBV-positivity in certain neoplasms shows important geographic variations. Both HD and sporadic BL from Latin America have shown higher rates of EBV-association than cases from Western countries. In T-NHL, the frequency of EBV-positivity is influenced by the site of the primary tumor and the phenotype of the neoplastic cells. Nasal and nasal-type T-NHL, which show a T/NK-cell phenotype with expression of CD56 are virtually always EBV-associated, whereas only a proportion of nodal, gastrointestinal and pulmonary T-NHL are EBV-infected. A recent investigation of primary intestinal lymphomas of Mexican origin demonstrated EBV-positivity in all examined cases of T-NHL and BL and a proportion of other B-NHLs. The presence of EBV was independent of the presence or absence of enteropathy. Two of 6 cases studied showed CD56 expression. The high rate of EBV-positivity independent of histologic subtype is in contrast to the low to intermediate rates of EBV-positivity found in cases of intestinal T-NHL from Western countries and indicates that geographic differences in the frequency of EBV-association of lymphoid neoplasms might also extend to a fraction of peripheral T-cell lymphomas.

Assuntos

RESUMO

We describe an unusual case of Sezary syndrome which transformed into a large T-cell non Hodgkin's lymphoma (immunoblastic) in a black man of Caribbean descent with negative HTLV-I serology and no evidence of HTLV-I infection by DNA analysis using sensitive techniques. The disease presented as a small-cell Sezary syndrome and transformed in an inguinal lymph node one year from diagnosis. Immunological markers in the small and large cells showed a mature T-cell phenotype CD4+, CD8- with expression of T-cell activation markers and a high proliferative rate. Ultrastructural analysis confirmed small Sezary cells with serpentine nucleus in the peripheral blood and immunoblasts in the lymph node. Cytogenetics demonstrated complex clonal chromosome abnormalities with involvement of 7q35, the locus for the beta chain of the T-cell receptor (TCR). Southern-blot analysis showed the same rearrangement of the TCR beta, gamma, delta chain genes in lymph node and peripheral blood cells. Antibodies to HTLV-I were not detected in the serum by ELISA and particle agglutination (PA) nor HTLV-I specific sequences were demonstrated by nested polymerase chain reaction with primers to the envelope proteins, LTR and tax/rex of HTLV-I in both tissues, blood and lymph node. The disease had an aggressive course and was refractory to therapy; the patient died of progressive disease 28 months from presentation. Two unusual features characterised this patient's illness: immunoblastic transformation of a Sezary syndrome in a patient of Afro-Caribbean origin without evidence of HTLV-I DNA sequences and negative HTLV-I serology and the atypical lymph node histology resembling ATLL.

Assuntos