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Four patients with chronic myelogenous leukemia (CML) that was refractory to interferon alpha (two patients) or imatinib mesylate (two patients), and who lacked donors for allogeneic stem cell transplantation, received autotransplants followed by infusions of ex vivo costimulated autologous T cells. At day +30 (about 14 days after T-cell infusion), the mean CD4+ cell count was 481 cells/microl (range 270-834) and the mean CD8+ count was 516 cells/microl (range 173-1261). One patient had a relative lymphocytosis at 3.5 months after T-cell infusion, with CD4 and CD8 levels of 750 and 1985 cells/microl, respectively. All the four patients had complete cytogenetic remissions early after transplantation, three of whom also became PCR negative for the bcr/abl fusion mRNA. One patient, who had experienced progressive CML while on interferon alpha therapy, became PCR- post transplant, and remained in a molecular CR at 3.0 years of follow-up. All the four patients survived at 6, 9, 40, and 44 months post transplant; the patient who remained PCR+ had a cytogenetic and hematologic relapse of CML, but entered a molecular remission on imatinib. Autotransplantation followed by costimulated autologous T cells is feasible for patients with chronic phase CML, who lack allogeneic donors and can be associated with molecular remissions.

Immunodeficiency is a barrier to successful vaccination in individuals with cancer and chronic infection. We performed a randomized phase 1/2 study in lymphopenic individuals after high-dose chemotherapy and autologous hematopoietic stem cell transplantation for myeloma. Combination immunotherapy consisting of a single early post-transplant infusion of in vivo vaccine-primed and ex vivo costimulated autologous T cells followed by post-transplant booster immunizations improved the severe immunodeficiency associated with high-dose chemotherapy and led to the induction of clinically relevant immunity in adults within a month after transplantation. Immune assays showed accelerated restoration of CD4 T-cell numbers and function. Early T-cell infusions also resulted in significantly improved T-cell proliferation in response to antigens that were not contained in the vaccine, as assessed by responses to staphylococcal enterotoxin B and cytomegalovirus antigens ( P < 0.05). In the setting of lymphopenia, combined vaccine therapy and adoptive T-cell transfer fosters the development of enhanced memory T-cell responses.

Relapse remains a major cause of treatment failure after autotransplantation (auto-PBSCT) for Hodgkin's disease (HD). The administration of non-crossresistant therapies during the post-transplant period may delay or prevent relapse. We prospectively studied the role of consolidation chemotherapy (CC) after auto-PBSCT in 37 patients with relapsed or refractory HD. Patients received high-dose gemcitabine-BCNU-melphalan and auto-PBSCT followed by involved-field radiation and up to four cycles of the DCEP-G regimen, which consisted of dexamethasone, cyclophosphamide, etoposide, cisplatin, gemcitabine given at 3 and 9 months post transplant alternating with a second regimen (DPP) of dexamethasone, cisplatin, paclitaxel at 6 and 12 months post transplant. The probabilities of event-free survival (EFS) and overall survival (OS) at 2.5 years were 59% (95% CI=42-76%) and 86% (95% CI=71-99%), respectively. In all, 17 patients received 54 courses of CC and 15 were surviving event free (2.5 years, EFS=87%). There were no treatment-related deaths during or after the CC phase. Post-transplant CC is feasible and well tolerated. The impact of this approach on EFS should be evaluated in a larger, randomized study.

Four patients with chronic myelogenous leukemia (CML) that was refractory to interferon alpha (two patients) or imatinib mesylate (two patients), and who lacked donors for allogeneic stem cell transplantation, received autotransplants followed by infusions of ex vivo costimulated autologous T cells. At day +30 (about 14 days after T-cell infusion), the mean CD4+ cell count was 481 cells/ μ l (range 270–834) and the mean CD8+ count was 516 cells/ μ l (range 173–1261). One patient had a relative lymphocytosis at 3.5 months after T-cell infusion, with CD4 and CD8 levels of 750 and 1985 cells/ μ l, respectively. All the four patients had complete cytogenetic remissions early after transplantation, three of whom also became PCR negative for the bcr/abl fusion mRNA. One patient, who had experienced progressive CML while on interferon alpha therapy, became PCR− post transplant, and remained in a molecular CR at 3.0 years of follow-up. All the four patients survived at 6, 9, 40, and 44 months post transplant; the patient who remained PCR+ had a cytogenetic and hematologic relapse of CML, but entered a molecular remission on imatinib. Autotransplantation followed by costimulated autologous T cells is feasible for patients with chronic phase CML, who lack allogeneic donors and can be associated with molecular remissions.

Relapse remains a major cause of treatment failure after autotransplantation (auto-PBSCT) for Hodgkin's disease (HD). The administration of non-crossresistant therapies during the post-transplant period may delay or prevent relapse. We prospectively studied the role of consolidation chemotherapy (CC) after auto-PBSCT in 37 patients with relapsed or refractory HD. Patients received high-dose gemcitabine–BCNU–melphalan and auto-PBSCT followed by involved-field radiation and up to four cycles of the DCEP-G regimen, which consisted of dexamethasone, cyclophosphamide, etoposide, cisplatin, gemcitabine given at 3 and 9 months post transplant alternating with a second regimen (DPP) of dexamethasone, cisplatin, paclitaxel at 6 and 12 months post transplant. The probabilities of event-free survival (EFS) and overall survival (OS) at 2.5 years were 59% (95% CI=42–76%) and 86% (95% CI=71–99%), respectively. In all, 17 patients received 54 courses of CC and 15 were surviving event free (2.5 years, EFS=87%). There were no treatment-related deaths during or after the CC phase. Post-transplant CC is feasible and well tolerated. The impact of this approach on EFS should be evaluated in a larger, randomized study.

The persistence of symptoms in Lyme disease patients following antibiotic therapy, and their causes, continue to be a matter of intense controversy. The studies presented here explore antibiotic efficacy using nonhuman primates. Rhesus macaques were infected with B. burgdorferi and a portion received aggressive antibiotic therapy 4-6 months later. Multiple methods were utilized for detection of residual organisms, including the feeding of lab-reared ticks on monkeys (xenodiagnosis), culture, immunofluorescence and PCR. Antibody responses to the B. burgdorferi-specific C6 diagnostic peptide were measured longitudinally and declined in all treated animals. B. burgdorferi antigen, DNA and RNA were detected in the tissues of treated animals. Finally, small numbers of intact spirochetes were recovered by xenodiagnosis from treated monkeys. These results demonstrate that B. burgdorferi can withstand antibiotic treatment, administered post-dissemination, in a primate host. Though B. burgdorferi is not known to possess resistance mechanisms and is susceptible to the standard antibiotics (doxycycline, ceftriaxone) in vitro, it appears to become tolerant post-dissemination in the primate host. This finding raises important questions about the pathogenicity of antibiotic-tolerant persisters and whether or not they can contribute to symptoms post-treatment.

[This corrects the article on p. e29914 in vol. 7.].

Invariable region (IR)6, an immunodominant conserved region of VlsE, the antigenic variation protein of Borrelia burgdorferi is currently used for the serologic diagnosis of Lyme disease in humans and canines. A longitudinal assessment of anti-IR6 antibody levels in B. burgdorferi–infected rhesus monkeys revealed that this level diminished sharply after antibiotic treatment (within 25 weeks). In contrast, antibody levels to P39 and to whole-cell antigen extracts of B. burgdorferi either remained unchanged or diminished less. A longitudinal analysis in dogs yielded similar results. In humans, the anti-IR6 antibody titer diminished by a factor of ⩾4 in successfully treated patients and by a factor of <4 in treatment-resistant patients. This result suggests that the quantification of anti-IR6 antibody titer as a function of time should be investigated further as a test to assess response to Lyme disease therapy or to determine whether a B. burgdorferi infection has been eliminated

Background. Tuberculosis (TB) leads to the death of 1.7 million people annually. The failure of the bacille Calmette-Guérin vaccine, synergy between AIDS and TB, and the emergence of drug resistance have worsened this situation. It is imperative to delineate the mechanisms employed by Mycobacterium tuberculosis to successfully infect and persist in mammalian lungs. Methods. Nonhuman primates (NHPs) are arguably the best animal system to model critical aspects of human TB. We studied genes essential for growth and survival of M. tuberculosis in the lungs of NHPs experimentally exposed to aerosols of an M. tuberculosis transposon mutant library. Results. Mutants in 108 M. tuberculosis genes (33.13% of all genes tested) were attenuated for in vivo growth. Comparable studies have reported the attenuation of only ∼6% of mutants in mice. The M. tuberculosis mutants attenuated for in vivo survival in primates were involved in the transport of various biomolecules, including lipid virulence factors; biosynthesis of cell-wall arabinan and peptidoglycan; DNA repair; sterol metabolism; and mammalian cell entry. Conclusions. Our study highlights the various virulence mechanisms employed by M. tuberculosis to overcome the hostile environment encountered during infection of primates. Prophylactic approaches aimed against bacterial factors that respond to such in vivo stressors have the potential to prevent infection at an early stage, thus likely reducing the extent of transmission of M. tuberculosis,