Effector functions of heparin-binding hemagglutinin-specific CD8+ T lymphocytes in latent human tuberculosis.

BACKGROUND: Most individuals infected with Mycobacterium tuberculosis do not develop tuberculosis (TB) and can be regarded as being protected by an appropriate immune response to the infection. The characterization of the immune responses of individuals with latent TB may thus be helpful in the definition of correlates of protection and the development of new vaccine strategies. The highly protective antigen heparin-binding hemagglutinin (HBHA) induces strong interferon (IFN)- gamma responses during latent, but not active, TB. Because of the recently recognized importance of CD8(+) T lymphocytes in anti-TB immunity, we characterized the CD8(+) T lymphocyte responses to HBHA in subjects with latent TB. RESULTS: HBHA-specific CD8(+) T lymphocytes expressed memory cell markers and synthesized HBHA-specific IFN- gamma .They also restricted mycobacterial growth and expressed cytotoxicity by a granule-dependent mechanism. This activity was associated with the intracellular expression of HBHA-induced perforin. Surprisingly, the perforin-producing CD8(+) T lymphocytes were distinct from the IFN- gamma -producing CD8(+) T lymphocytes. CONCLUSION: During latent TB, the HBHA-specific CD8(+) T lymphocyte population expresses all 3 effector functions associated with CD8(+) T lymphocyte-mediated protective immune mechanisms, which supports the notion that HBHA may be protective in humans and suggests that markers of HBHA-specific CD8(+) T lymphocyte responses may be useful in the monitoring of protection.

A feasibility study evaluating docetaxel-based sequential and combination regimens in the adjuvant therapy of node-positive breast cancer

BACKGROUND AND PURPOSE: Docetaxel is an active agent in the treatment of metastatic breast cancer. We evaluated the feasibility of docetaxel-based sequential and combination regimens as adjuvant therapies for patients with node-positive breast cancer. PATIENTS AND METHODS: Three consecutive groups of patients with node-positive breast cancer or locally-advanced disease, aged < or = 70 years, received one of the following regimens: a) sequential A-->T-->CMF: doxorubicin 75 mg/m2 q 3 weeks x 3, followed by docetaxel 100 mg/m2 q 3 weeks x 3, followed by i.v. CMF days 1 + 8 q 4 weeks x 3; b) sequential accelerated A-->T-->CMF: A and T were administered at the same doses q 2 weeks; c) combination therapy: doxorubicin 50 mg/m2 + docetaxel 75 mg/m2 q 3 weeks x 4, followed by CMF x 4. When indicated, radiotherapy was administered during or after CMF, and tamoxifen started after the end of CMF. RESULTS: Seventy-nine patients have been treated. Median age was 48 years. A 30% rate of early treatment discontinuation was observed in patients receiving the sequential accelerated therapy (23% during A-->T), due principally to severe skin toxicity. Median relative dose-intensity was 100% in the three treatment arms. The incidence of G3-G4 major toxicities by treated patients, was as follows: skin toxicity a: 5%; b: 27%; c: 0%; stomatitis a: 20%; b: 20%; c: 3%. The incidence of neutropenic fever was a: 30%; b: 13%; c: 48%. After a median follow-up of 18 months, no late toxicity has been reported. CONCLUSIONS: The accelerated sequential A-->T-->CMF treatment is not feasible due to an excess of skin toxicity. The sequential non accelerated and the combination regimens are feasible and under evaluation in a phase III trial of adjuvant therapy.

3-year results of docetaxel-based sequential and combination regimens in the adjuvant therapy of node-positive breast cancer: a pilot study.

BACKGROUND: Docetaxel has proven efficacy in metastatic breast cancer. In this pilot study, we explored the efficacy/feasibility of docetaxel-based sequential and combination regimens as adjuvant therapy of node-positive breast cancer. PATIENTS AND METHODS: From March 1996 till March 1998, four consecutive groups of patients with stages II and III breast cancer, aged < or = 70 years, received one of the following regimens: a) sequential Doxorubicin (A) --> Docetaxel (T) --> CMF (Cyclophosphamide+Methotrexate+5-Fluorouracil): A 75 mg/m q 3 wks x 3, followed by T100 mg/m2 q 3 wks x 3, followed by i.v. CMF Days 1+8 q 4 wks x 3; b) sequential accelerated A --> T --> CMF: A and T administered at the same doses q 2 wks with Lenograstin support; c) combination therapy: A 50 mg/m2 + T 75 mg/m2 q 3 wks x 4, followed by CMF x 4; d) sequential T --> A --> CMF: T and A, administered as in group a), with the reverse sequence. When indicated, radiotherapy was administered during or after CMF, and Tamoxifen after CMF. RESULTS: Ninety-three patients were treated. The median age was 48 years (29-66) and the median number of positive axillary nodes was 6 (1-25). Tumors were operable in 94% and locally advanced in 6% of cases. Pathological tumor size was >2 cm in 72% of cases. There were 21 relapses, (18 systemic, 3 locoregional) and 11 patients (12%) have died from disease progression. At median follow-up of 39 months (6-57), overall survival (OS) was 87% (95% CI, 79-94%) and disease-free survival (DFS) was 76% (95% CI, 67%-85%). CONCLUSION: The efficacy of these docetaxel-based regimens, in terms of OS and DFS, appears to be at least as good as standard anthracycline-based adjuvant chemotherapy (CT), in similar high-risk patient populations.

A novel syndrome of severe neutrophil dysfunction: unresponsiveness confined to chemotaxin-induced functions.

We have identified a patient with a number of neutrophil dysfunctions. The patient was a female baby who lived for 8 months. During her life, she developed severe bacterial infections and showed omphalitis, impaired wound healing, and a pronounced leukocytosis. She was not a patient with leukocyte adhesion deficiency, because all leukocyte CD18 complex proteins were expressed at normal levels. Yet, neutrophil polarization and chemotaxis to platelet-activating factor, leukotriene B4, or formyl-methionyl-leucyl-phenylalanine (FMLP) were completely absent. We found a strong defect in actin polymerization in response to chemotactic stimuli, but only a retarded or even normal reaction with other stimuli. This indicates that the cellular dysfunctions were not due to an intrinsic defect in actin metabolism. Instead, the regulation of actin polymerization with chemotactic stimuli seemed to be defective. We concentrated on FMLP-induced responses in the patient's neutrophils. Functions dependent on activation of complement receptor type 3, such as aggregation or adherence to endothelial cells, were normally induced. Binding to serum-coated coverslips was normal in cell number; however, spreading was not observed. Exocytosis from the specific granules was readily induced. In contrast, FMLP failed to induce a respiratory burst activity or degranulation of the azurophil granules. FMLP induced a normal increase in free intracellular Ca2+, but a decreased formation of diglycerides (especially the 1-O-alkyl,2-acyl compounds). Thus, we have described a patient whose neutrophils show a severe defect in functional activation via chemotaxin receptors, resulting in a selective absence of NADPH oxidase activity, exocytosis from the azurophil granules, and actin polymerization. Our findings show that actin polymerization for neutrophil spreading and locomotion is regulated differently from that for phagocytosis. Also, the release of azurophil and specific granule contents is clearly shown to be regulated in a different way.

Positive regularised solutions in electromagnetic inverse scattering

Fredholm integral equations of the first kind are the mathematical model common to several electromagnetic, optical and acoustical inverse scattering problems. In most of these problems the solution must be positive in order to satisfy physical plausibility. We consider ill-posed deconvolution problems and investigate several linear regularization algorithms which provide positive approximate solutions at least in the absence of errors on the data.