Immunological imbalance between IFN-³ and IL-10 levels in the sera of patients with the cardiac form of Chagas disease

The immune response is crucial for protection against disease; however, immunological imbalances can lead to heart and digestive tract lesions in chagasic patients. Several studies have evaluated the cellular and humoral immune responses in chagasic patients in an attempt to correlate immunological findings with clinical forms of Chagas disease. Moreover, immunoglobulins and cytokines are important for parasitic control and are involved in lesion genesis. Here, cytokine and IgG isotype production were studied, using total epimastigote antigen on sera of chagasic patients with indeterminate (IND, n = 27) and cardiac (CARD, n = 16) forms of the disease. Samples from normal, uninfected individuals (NI, n = 30) were use as controls. The results showed that sera from both IND and CARD patients contained higher levels of Trypanosoma cruzi-specific IgG1 (IgG1) antibodies than sera from NI. No difference in IgG2 production levels was observed between NI, IND and CARD patients, nor was a difference in IL-10 and IFN-³ production detected in the sera of IND, CARD and NI patients. However, IND patients displayed a positive correlation between IL-10 and IFN-³ levels in serum, while CARD patients showed no such correlation, indicating an uncontrolled inflammatory response in CARD patients. These findings support the hypothesis that a lack of efficient regulation between IFN-³ and IL-10 productions in CARD patients may lead to cardiac immunopathology.CNP

Feasibility of dosimetry-based high-dose I-131-meta-iodobenzylguanidine with topotecan as a radiosensitizer in children with metastatic neuroblastoma

Introduction: I-131-meta iodobenzylguanidine ((131I)-mIBG) therapy is established palliation for relapsed near-oblastoma. The topoisomerase-1 inhibitor, topotecan, has direct activity against neuroblastoma and acts as a radiation sensitiser. These 2 treatments are synergistic in laboratory studies. Theoretically, the benefit of I-131-mIBG treatment could be enhanced by dose escalation and combination with topotecan. Haeniatological support would be necessary to overcome the myelosuppression, which is the dose-limiting toxicity. Aims: Firstly, one aim of this study was to establish whether in vivo dosimetry could be used to guide the delivery of a precise total whole-body radiation-absorbed dose of 4 Gy accuratelyfroin 2 I-131-mIBG treatments. Secondly, the other aim. of this study was to determine whether it is feasible to combine this treatment with the topotecan in children with metastatic neuroblastoma. Material and Methods: An activity of I-131-mIBG (12 mCi/kg, 444 MBq/kg), estimated to give a whole-body absorbed-radiation dose of approximately 2 Gy, was administered on day 1, with topotecan 0.7 mg/m(2) administered daily from days 1-5. In vivo dosimetry was used to calculate a 2nd activity of I-131-mIBG, to be given on day 15 which would give a total whole-body dose of 4 Gy. A further 5 doses of topotecan were given from days 15-19. The myeloablative effect of this regimen was circumvented by peripheral blood stein cell or bone marrow support. Results: Eight children with relapsed stage IV neuroblastoma were treated. The treatment was delivered according to protocol in all patients. There were no unanticipated side-ffects. Satisfactory haematological reconstituition occurred in all patients. The measured total whole-body radiation-absorbed dose ranged from 3.7 Gy to 4.7 Gy (mean, 4.2 Gy). Conclusions: In vivo dosimetry allows for a specified total whole-body radiation dose to be delivered accurately. This schedule of intensification of I-131-mIBG therapy by close escalation and radiosensitization with topotecan with a haemopoietic autograft is safe and practicable. This approach should now be testedfor efficacy in a phase II clinical trial

Detection of Leishmania RNA virus in Leishmania parasites.

BACKGROUND: Patients suffering from cutaneous leishmaniasis (CL) caused by New World Leishmania (Viannia) species are at high risk of developing mucosal (ML) or disseminated cutaneous leishmaniasis (DCL). After the formation of a primary skin lesion at the site of the bite by a Leishmania-infected sand fly, the infection can disseminate to form secondary lesions. This metastatic phenotype causes significant morbidity and is often associated with a hyper-inflammatory immune response leading to the destruction of nasopharyngeal tissues in ML, and appearance of nodules or numerous ulcerated skin lesions in DCL. Recently, we connected this aggressive phenotype to the presence of Leishmania RNA virus (LRV) in strains of L. guyanensis, showing that LRV is responsible for elevated parasitaemia, destructive hyper-inflammation and an overall exacerbation of the disease. Further studies of this relationship and the distribution of LRVs in other Leishmania strains and species would benefit from improved methods of viral detection and quantitation, especially ones not dependent on prior knowledge of the viral sequence as LRVs show significant evolutionary divergence. METHODOLOGY/PRINCIPAL FINDINGS: This study reports various techniques, among which, the use of an anti-dsRNA monoclonal antibody (J2) stands out for its specific and quantitative recognition of dsRNA in a sequence-independent fashion. Applications of J2 include immunofluorescence, ELISA and dot blot: techniques complementing an arsenal of other detection tools, such as nucleic acid purification and quantitative real-time-PCR. We evaluate each method as well as demonstrate a successful LRV detection by the J2 antibody in several parasite strains, a freshly isolated patient sample and lesion biopsies of infected mice. CONCLUSIONS/SIGNIFICANCE: We propose that refinements of these methods could be transferred to the field for use as a diagnostic tool in detecting the presence of LRV, and potentially assessing the LRV-related risk of complications in cutaneous leishmaniasis