Investigation of a possible extended risk haplotype in the IL23R region associated with ankylosing spondylitis.

The IL23R region on chromosome 1 exhibits complex associations with ankylosing spondylitis (AS). We used publicly available epigenomic information and historical genetic association data to identify a putative regulatory element (PRE) in the intergenic region between IL23R and IL12RB2, which includes two single-nucleotide polymorphisms (SNPs) independently associated with AS-rs924080 (P=2 × 10-3) and rs11578380 (P=2 × 10-4). In luciferase reporter assays, this PRE showed silencer activity (P<0.001). Haplotype and conditional analysis of 4230 historical AS cases and 9700 controls revealed a possible AS-associated extended haplotype, including the PRE and risk variants at three SNPs (rs11209026, rs11209032 and rs924080), but excluding the rs11578380 risk variant. However, the rs924080 association was absent after conditioning on the primary association with rs11209032, which, in contrast, was robust to conditioning on all other AS-associated SNPs in this region (P<2 × 10-8). The role of this putative silencer on some IL23R extended haplotypes therefore remains unclear.

Rilpivirine versus efavirenz in HIV-1-infected subjects receiving emtricitabine/tenofovir DF: pooled 96-week data from ECHO and THRIVE Studies.

OBJECTIVES: Week 96 efficacy and safety of the non-nucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine (RPV) was compared to efavirenz (EFV) in subset of 1,096 subjects who received emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) in pooled data from 2 phase 3 studies. METHODS: ECHO and THRIVE are double-blind, double-dummy, randomized, active-controlled, non-inferiority phase 3 studies of RPV versus EFV plus 2 NRTIs in antiretroviral-naïve adult subjects. The primary and secondary endpoints were the proportion of subjects with HIV-1 RNA <50 copies/ mL using an intent-to-treat, time to loss of virologic response (ITT-TLOVR) analysis at weeks 48 and 96, respectively. Safety, tolerability, immunologic response, adherence level, and other measures were also evaluated. RESULTS: At week 48, noninferior efficacy of RPV+FTC/TDF over EFV+FTC/TDF was established, and at week 96 RPV+FTC/TDF remained noninferior (77% overall response rate in both groups). Through week 96, rates of virologic failure were higher in the RPV+FTC/ TDF group, with low and similar rates of virologic failure and resistance mutations occurring during the second year of follow-up. Treatment with RPV+FTC/TDF was associated with a lower rate of discontinuation due to adverse events and grade 2-4 adverse events including dizziness, abnormal dreams/nightmares, rash, and lipid abnormalities. CONCLUSIONS: The pooled ECHO and THRIVE studies demonstrated noninferiority of RPV+FTC/TDF in achieving virologic response with safety and tolerability advantages over EFV+FTC/TDF through 96 weeks. Higher rates of virologic failure in the RPV+FTC/TDF group were balanced with higher rates of discontinuations due to adverse events in the EFV+FTC/TDF group.

Evidence of genetic association between TNFRSF1A encoding the p55 tumour necrosis factor receptor, and ankylosing spondylitis in UK Caucasians.

OBJECTIVES: To replicate the possible genetic association between ankylosing spondylitis (AS) and TNFRSF1A. METHODS: TNFRSF1A was re-sequenced in 48 individuals with AS to identify novel polymorphisms. Nine single nucleotide polymorphisms (SNPs) in TNFRSF1A and 5 SNPs in the neighbouring gene SCNN1A were genotyped in 1604 UK Caucasian individuals with AS and 1019 matched controls. An extended study was implemented using additional genotype data on 8 of these SNPs from 1400 historical controls from the 1958 British Birth Cohort. A meta-analysis of previously published results was also undertaken. RESULTS: One novel variant in intron 6 was identified but no new coding variants. No definite associations were seen in the initial study but in the extended study there were weak associations with rs4149576 (p=0.04) and rs4149577 (p=0.007). In the meta-analysis consistent, somewhat stronger associations were seen with rs4149577 (p=0.002) and rs4149578 (p=0.006). CONCLUSIONS: These studies confirm the weak genetic associations between AS and TNFRSF1A. In view of the previously reported associations of TNFRSF1A with AS, in Caucasians and Chinese, and the biological plausibility of this candidate gene, replication of this finding in well powered studies is clearly indicated.

Potential mechanisms of endogenous retroviral-mediated genomic instability in human cancer.

Malignancy results from a complex combination of genetic and epigenetic changes, the full effects of which are still largely unknown. Here we summarize current knowledge of the origin, retrotranspositional activity, epigenetic state, and transcription of human endogenous retroviruses (HERVs), and then discuss the potential effects of their deregulation in cancer. Evidence suggests that cancer-associated epigenetic changes most likely underlie potential HERV-mediated effects on genome and transcriptome instability and may play a role in malignancy. Despite our currently limited understanding of the importance of HERVs or other transposable elements in cancer development, we believe that the emerging era of high-throughput sequencing of cancer genomes, epigenomes, and transcriptomes will provide unprecedented opportunities to investigate these roles in the future.

Efficient nonviral Sleeping Beauty transposon-based TCR gene transfer to peripheral blood lymphocytes confers antigen-specific antitumor reactivity.

Genetically engineered lymphocytes hold promise for the treatment of genetic disease, viral infections and cancer. However, current methods for genetic transduction of peripheral blood lymphocytes rely on viral vectors, which are hindered by production and safety-related problems. In this study, we demonstrated an efficient novel nonviral platform for gene transfer to lymphocytes. The Sleeping Beauty transposon-mediated approach allowed for long-term stable expression of transgenes at approximately 50% efficiency. Utilizing transposon constructs expressing tumor antigen-specific T-cell receptor genes targeting p53 and MART-1, we demonstrated sustained expression and functional reactivity of transposon-engineered lymphocytes on encountering target antigen presented on tumor cells. We found that transposon- and retroviral-modified lymphocytes had comparable transgene expression and phenotypic function. These results demonstrate the promise of nonviral ex vivo genetic modification of autologous lymphocytes for the treatment of cancer and immunologic disease.

Risk for opportunistic disease and death after reinitiating continuous antiretroviral therapy in patients with HIV previously receiving episodic therapy: a randomized trial.

BACKGROUND: Episodic use of antiretroviral therapy guided by CD4+ cell counts is inferior to continuous antiretroviral therapy. OBJECTIVE: To determine whether reinitiating continuous antiretroviral therapy in patients who received episodic treatment reduces excess risk for opportunistic disease or death. DESIGN: Randomized, controlled trial. SETTING: Sites in 33 countries. PATIENTS: 5472 HIV-infected individuals with CD4(+) cell counts greater than 0.350 x 10(9) cells/L enrolled from January 2002 to January 2006. INTERVENTION: Episodic or continuous antiretroviral therapy initially, followed by continuous therapy in participants previously assigned to episodic treatment. MEASUREMENTS: Opportunistic disease or death was the primary outcome. RESULTS: Eighteen months after the recommendation to reinitiate continuous therapy, mean CD4+ cell counts were 0.152 x 10(9) cells/L (95% CI, 0.136 to 0.167 x 10(9) cells/L) less in participants previously assigned to episodic treatment (P < 0.001). The proportion of follow-up time spent with CD4+ cell counts of 0.500 x 10(9) cells/L or more and HIV RNA levels of 400 copies/mL or less was 29% for participants initially assigned to episodic therapy and 66% for those assigned to continuous therapy. Participants who reinitiated continuous therapy experienced rapid suppression of HIV RNA levels (89.7% with HIV RNA levels < or =400 copies/mL after 6 months), but CD4+ cell counts after 6 months remained 0.140 x 10(9) cells/L below baseline. The hazard ratio (episodic versus continuous treatment) for opportunistic disease or death decreased after the recommendation to reinitiate continuous therapy (from 2.5 [CI, 1.8 to 3.5] to 1.4 [CI, 1.0 to 2.0]; P = 0.033 for difference). The residual excess risk was attributable to failure to reinitiate therapy by some participants and slow recovery of CD4+ cell counts for those who reinitiated therapy. LIMITATION: Follow-up was too short to assess the full effect of switching from episodic to continuous antiretroviral therapy. CONCLUSION: Reinitiating continuous antiretroviral therapy in patients previously assigned to episodic treatment reduced excess risk for opportunistic disease or death, but excess risk remained. Episodic antiretroviral therapy, as used in the SMART study, should be avoided.

Development of optimal bicistronic lentiviral vectors facilitates high-level TCR gene expression and robust tumor cell recognition.

In human gene therapy applications, lentiviral vectors may have advantages over gamma-retroviral vectors in several areas, including the ability to transduce nondividing cells, resistance to gene silencing and a potentially safer integration site profile. However, unlike gamma-retroviral vectors it has been problematic to drive the expression of multiple genes efficiently and coordinately with approaches such as internal ribosome entry sites or dual promoters. Using different 2A peptides, lentiviral vectors expressing two-gene T-cell receptors directed against the melanoma differentiation antigens gp100 and MART-1 were constructed. We demonstrated that addition of amino-acid spacer sequences (GSG or SGSG) before the 2A sequence is a prerequisite for efficient synthesis of biologically active T-cell receptors and that addition of a furin cleavage site followed by a V5 peptide tag yielded optimal T-cell receptor gene expression. Furthermore, we determined that the furin cleavage site was recognized in lymphocytes and accounted for removal of residual 2A peptides at the post-translational level with an efficiency of 20-30%, which could not be increased by addition of multiple furin cleavage sites. The novel bicistronic lentiviral vector developed herein afforded robust anti-melanoma activities to engineered peripheral blood lymphocytes, including cytokine secretion, cell proliferation and lytic activity. Such optimal vectors may have immediate applications in cancer gene therapy.

CD4+ count-guided interruption of antiretroviral treatment.

BACKGROUND: Despite declines in morbidity and mortality with the use of combination antiretroviral therapy, its effectiveness is limited by adverse events, problems with adherence, and resistance of the human immunodeficiency virus (HIV). METHODS: We randomly assigned persons infected with HIV who had a CD4+ cell count of more than 350 per cubic millimeter to the continuous use of antiretroviral therapy (the viral suppression group) or the episodic use of antiretroviral therapy (the drug conservation group). Episodic use involved the deferral of therapy until the CD4+ count decreased to less than 250 per cubic millimeter and then the use of therapy until the CD4+ count increased to more than 350 per cubic millimeter. The primary end point was the development of an opportunistic disease or death from any cause. An important secondary end point was major cardiovascular, renal, or hepatic disease. RESULTS: A total of 5472 participants (2720 assigned to drug conservation and 2752 to viral suppression) were followed for an average of 16 months before the protocol was modified for the drug conservation group. At baseline, the median and nadir CD4+ counts were 597 per cubic millimeter and 250 per cubic millimeter, respectively, and 71.7% of participants had plasma HIV RNA levels of 400 copies or less per milliliter. Opportunistic disease or death from any cause occurred in 120 participants (3.3 events per 100 person-years) in the drug conservation group and 47 participants (1.3 per 100 person-years) in the viral suppression group (hazard ratio for the drug conservation group vs. the viral suppression group, 2.6; 95% confidence interval [CI], 1.9 to 3.7; P<0.001). Hazard ratios for death from any cause and for major cardiovascular, renal, and hepatic disease were 1.8 (95% CI, 1.2 to 2.9; P=0.007) and 1.7 (95% CI, 1.1 to 2.5; P=0.009), respectively. Adjustment for the latest CD4+ count and HIV RNA level (as time-updated covariates) reduced the hazard ratio for the primary end point from 2.6 to 1.5 (95% CI, 1.0 to 2.1). CONCLUSIONS: Episodic antiretroviral therapy guided by the CD4+ count, as used in our study, significantly increased the risk of opportunistic disease or death from any cause, as compared with continuous antiretroviral therapy, largely as a consequence of lowering the CD4+ cell count and increasing the viral load. Episodic antiretroviral therapy does not reduce the risk of adverse events that have been associated with antiretroviral therapy. (ClinicalTrials.gov number, NCT00027352 [ClinicalTrials.gov].).

The second-look operation improves survival in suboptimally debulked stage III ovarian cancer patients.

In a single-institution retrospective cohort study, 230 patients were treated for stage III primary ovarian cancer and 175 became eligible for second-look operations by virtue of a complete clinical response after primary surgical cytoreduction and platinum-based combination chemotherapy. Of these, 109 underwent a second-look operation. Optimal primary cytoreduction was defined as residual disease < or =1 cm. Median follow-up was 68.3 months. Five-year survival for all the 230 stage III ovarian cancers was 43.4%. Among all eligible patients (n = 175), there was no survival difference (P = 0.67) in those having second look (57.3%, 5-year survival) versus no second look (48.7%). In those patients with optimal primary cytoreduction (n = 118), there was no survival advantage to second look (69% versus 61%, P = 0.7). However, in those with suboptimal primary cytoreduction (n = 47), 5-year survival was 36% in those having second look versus only 13% in those refusing second look (P < 0.05). Multivariate analysis identified second-look surgery as the only significant independent prognostic variable affecting survival (RR = 0.321, P < 0.04). Patients with suboptimal debulking at primary surgery for stage III ovarian cancer appear to achieve a survival benefit from second-look surgical procedures, presumably from the early identification and treatment of residual disease.

Long-term treatment with subcutaneous T-20, a fusion inhibitor, in HIV-infected patients: patient satisfaction and impact on activities of daily living.

T-20 is a novel antiretroviral agent that inhibits the fusion of human immunodeficiency virus (HIV) with target cell membranes. It is delivered by self-administered, twice-daily, subcutaneous injections. The impact of this mode of administration on patients' ability to conduct normal activities of daily living (ADL) and comply with a T-20 treatment regimen was assessed as part of a 48-week, phase 2 trial (T20-205). Patients' opinions on the impact of T-20 on ADL, ease of use of T-20, and choice to continue with T-20 were assessed by two questionnaires completed at baseline and week 48 (or study withdrawal). ADL were measured using a Likert-type scale based on established instruments with questions added to assess HIV-specific issues. Seventy previously treated patients received T-20 in combination with an average of five oral antiretroviral agents. Relative to other HIV/AIDS drugs, T-20 had little impact on ADL, with the majority of patients (54%-96%) agreeing (somewhat or strongly) that subcutaneous injections had not limited ADL. Patients found the injections relatively easy to perform with more than 47% of patients stating that each aspect of the injections (ease of injection, storage, reconstitution, and disposal of sharps) were very easy or easy. If medically indicated, 98% of patients stated that they would choose to continue with T-20. The most common reasons for this were the perceived effectiveness of T-20 and lack of side effects. In conclusion, the need to deliver T-20 via twice-daily subcutaneous injections was not considered an important barrier by HIV-positive patients seeking improvement or stabilization of their condition.

The coxsackievirus and adenovirus receptor is a transmembrane component of the tight junction.

The coxsackievirus and adenovirus receptor (CAR) mediates viral attachment and infection, but its physiologic functions have not been described. In nonpolarized cells, CAR localized to homotypic intercellular contacts, mediated homotypic cell aggregation, and recruited the tight junction protein ZO-1 to sites of cell-cell contact. In polarized epithelial cells, CAR and ZO-1 colocalized to tight junctions and could be coprecipitated from cell lysates. CAR expression led to reduced passage of macromolecules and ions across cell monolayers, and soluble CAR inhibited the formation of functional tight junctions. Virus entry into polarized epithelium required disruption of tight junctions. These results indicate that CAR is a component of the tight junction and of the functional barrier to paracellular solute movement. Sequestration of CAR in tight junctions may limit virus infection across epithelial surfaces.

Antibody engineering for targeted therapy of cancer: recombinant Fv-immunotoxins.

Recombinant Fv-immunotoxins are a new class of biologic anticancer agents composed of a recombinant antibody fragment linked to a very potent bacterial toxin. These potent molecules are designed to specifically bind and kill cancer cells that express a specific target antigen on their cell surface. Recombinant Fv-immunotoxins are an excellent example for the concept of rational drug design. They combine the progress in understanding cancer biology, -the recent knowledge on the mechanisms of malignant transformation and the special properties of cancer cells, -with the enormous developments in recombinant DNA technology and antibody engineering. Recombinant Fv immunotoxins were developed for solid tumors and hematological malignancies and have been characterized intensively for their biological activity in vitro and in vivo in animal models. The excellent in vitro and in vivo activities of recombinant Fv-immunotoxins have lead to their pre-clinical development and to the initiation of clinical trial protocols. Recent trials have demonstrated potent clinical efficacy in patients with malignant diseases that are refractory to traditional modalities of cancer treatment. It is thus suggested that this strategy can be developed into a separate modality of cancer treatment with the basic rationale of specifically targeting cancer cells on the basis of their unique surface markers combined with potent effective biological toxic agents that directly kill the cancer cell. Efforts are now being made to improve the current molecules and to develop new agents with better clinical efficacy. In this review, we will describe the rationale in designing Fv-immunotoxins and will review current progress made in using these agents for cancer treatment.

Critical role for CD8 in binding of MHC tetramers to TCR: CD8 antibodies block specific binding of human tumor-specific MHC-peptide tetramers to TCR.

There are conflicting opinions about the role that the T cell coreceptors CD4 and CD8 play in TCR binding and activation. Recent evidence from transgenic mouse models suggests that CD8 plays a critical role in TCR binding and activation by peptide-MHC complex multimers (tetramers). Here we show with a human CTL clone specific for a tumor-associated MHC-peptide complex that the binding of tetramers to the TCR on these cells is completely blocked by anti-human CD8 Abs. Moreover, the staining of CTLs with specific MHC-peptide tetramers simultaneously with anti-CD8 Abs was completely blocked with three different anti-CD8 Abs. This blockage was mediated by anti-CD8 Abs but not anti-CD3 Abs and was dose dependent. The blocking effect of the anti-CD8 Abs was attributable to directly inhibiting tetramer binding and was not attributable to Ab-mediated TCR-CD8 internalization and down-regulation. Our results have important implications in TCR binding to MHC-peptide tetramers. MHC-peptide tetramers are widely used today in combination with anti-CD8 Abs for the phenotypic analysis of T cell populations and in the study of T cell responses under various pathological conditions such as infectious diseases and cancer. Our results indicate that also in the human system CD8 plays a critical role in the interaction of MHC-peptide multimers with TCR.

Multiple regions within the coxsackievirus and adenovirus receptor cytoplasmic domain are required for basolateral sorting.

The coxsackievirus and adenovirus receptor (CAR) mediates attachment and infection by coxsackie B viruses and many adenoviruses. In human airway epithelia, as well as in transfected Madin-Darby canine kidney cells, CAR is expressed exclusively on the basolateral surface. Variants of CAR that lack the cytoplasmic domain or are attached to the cell membrane by a glycosylphosphatidylinositol anchor are expressed on both the apical and basolateral surfaces. We have examined the localization of CAR variants with progressive truncations of the cytoplasmic domain, as well as with mutations that ablate a potential PDZ (PSD95/dlg/ZO-1) interaction motif and a putative tyrosine-based sorting signal. In addition, we have examined the targeting of two murine CAR isoforms, with different C-terminal sequences. The results suggest that multiple regions within the CAR cytoplasmic domain contain information that is necessary for basolateral targeting.

Use of genotypic resistance testing to guide hiv therapy: clinical impact and cost-effectiveness.

BACKGROUND: Genotypic sequencing for drug-resistant strains of HIV can guide the choice of antiretroviral therapy. OBJECTIVE: To assess the cost-effectiveness of genotypic resistance testing for patients acquiring drug resistance through failed treatment (secondary resistance) and those infected with resistant virus (primary resistance). DESIGN: Cost-effectiveness analysis with an HIV simulation model incorporating CD4 cell count and HIV RNA level as predictors of disease progression. DATA SOURCES: Published randomized trials and data from the Multicenter AIDS Cohort Study, the national AIDS Cost and Services Utilization Survey, the Red Book, and an institutional cost-accounting system. TARGET POPULATION: HIV-infected patients in the United States with baseline CD4 counts of 0.250 x 10(9) cells/L. TIME HORIZON: Lifetime. PERSPECTIVE: Societal. INTERVENTIONS: Genotypic resistance testing and clinical judgment, compared with clinical judgment alone, in two contexts: after initial treatment failure (secondary resistance testing) and before initiation of antiretroviral therapy (primary resistance testing). OUTCOME MEASURES: Life expectancy, quality-adjusted life expectancy, and cost-effectiveness in dollars per quality-adjusted life-year (QALY) gained. RESULTS OF BASE-CASE ANALYSIS: Secondary resistance testing increased life expectancy by 3 months, at a cost of $17 900 per QALY gained. The cost-effectiveness of primary resistance testing was $22 300 per QALY gained with a 20% prevalence of primary resistance but increased to $69 000 per QALY gained with 4% prevalence. RESULTS OF SENSITIVITY ANALYSIS: The cost-effectiveness ratio for secondary resistance testing remained under $25 000 per QALY gained, even when effectiveness and cost of testing and antiretroviral therapy, quality-of-life weights, and discount rate were varied. CONCLUSIONS: Genotypic antiretroviral resistance testing following antiretroviral failure is cost-effective. Primary resistance testing also seems to be reasonably cost-effective and will become more so as the prevalence of primary resistance increases.

The cost effectiveness of combination antiretroviral therapy for HIV disease.

BACKGROUND: Combination antiretroviral therapy with a combination of three or more drugs has become the standard of care for patients with human immunodeficiency virus (HIV) infection in the United States. We estimated the clinical benefits and cost effectiveness of three-drug antiretroviral regimens. METHODS: We developed a mathematical simulation model of HIV disease, using the CD4 cell count and HIV RNA level as predictors of the progression of disease. Outcome measures included life expectancy, life expectancy adjusted for the quality of life, lifetime direct medical costs, and cost effectiveness in dollars per quality-adjusted year of life gained. Clinical data were derived from major clinical trials, including the AIDS Clinical Trials Group 320 Study. Data on costs were based on the national AIDS Cost and Services Utilization Survey, with drug costs obtained from the Red Book. RESULTS: For patients similar to those in the AIDS Clinical Trials Group 320 Study (mean CD4 cell count, 87 per cubic millimeter), life expectancy adjusted for the quality of life increased from 1.53 to 2.91 years, and per-person lifetime costs increased from $45,460 to $77,300 with three-drug therapy as compared with no therapy. The incremental cost per quality-adjusted year of life gained, as compared with no therapy, was $23,000. On the basis of additional data from other major studies, the cost-effectiveness ratio for three-drug therapy ranged from $13,000 to $23,000 per quality-adjusted year of life gained. The initial CD4 cell count and drug costs were the most important determinants of costs, clinical benefits, and cost effectiveness. CONCLUSIONS: Treatment of HIV infection with a combination of three antiretroviral drugs is a cost-effective use of resources.

Drug-resistant Drosophila indicate glutamate-gated chloride channels are targets for the antiparasitics nodulisporic acid and ivermectin.

The fruit fly Drosophila melanogaster was used to examine the mode of action of the novel insecticide and acaricide nodulisporic acid. Flies resistant to nodulisporic acid were selected by stepwise increasing the dose of drug in the culture media. The resistant strain, glc(1), is at least 20-fold resistant to nodulisporic acid and 3-fold cross-resistant to the parasiticide ivermectin, and exhibited decreased brood size, decreased locomotion, and bang sensitivity. Binding assays using glc(1) head membranes showed a marked decrease in the affinity for nodulisporic acid and ivermectin. A combination of genetics and sequencing identified a proline to serine mutation (P299S) in the gene coding for the glutamate-gated chloride channel subunit DmGluClalpha. To examine the effect of this mutation on the biophysical properties of DmGluClalpha channels, it was introduced into a recombinant DmGluClalpha, and RNA encoding wild-type and mutant subunits was injected into Xenopus oocytes. Nodulisporic acid directly activated wild-type and mutant DmGluClalpha channels. However, mutant channels were approximately 10-fold less sensitive to activation by nodulisporic acid, as well as ivermectin and the endogenous ligand glutamate, providing direct evidence that nodulisporic acid and ivermectin act on DmGluClalpha channels.

Recombinant human single-chain MHC-peptide complexes made from E. coli By in vitro refolding: functional single-chain MHC-peptide complexes and tetramers with tumor associated antigens.

Soluble recombinant MHC-peptide complexes are valuable tools for molecular characterization of immune responses as well as for other functional and structural studies. In this study, soluble recombinant single-chain human MHC (scMHC)-peptide complexes were generated by in vitro refolding of inclusion bodies from bacterially expressed engineered HLA-A2 in the presence of tumor-associated or viral peptides. The scMHC molecule was composed of beta2-microglobulin connected to the first three domains of the HLA-A2 heavy chain through a 15-amino acid flexible linker. Highly purified scMHC-peptide complexes were obtained in high yield using several peptides derived from the melanoma antigens gp100 and MART-1 or a viral peptide derived from HTLV-1. The scMHC complexes were characterized in detail and were found to be correctly folded and able to specifically bind HLA-A2-restricted peptides. We also generated scMHC-peptide tetramers, which were biologically functional; they induced a peptide-specific CTL clone to be activated and secrete IFN-gamma, and were able to stain specifically CTL lines. Such recombinant soluble scMHC-peptide complexes and tetramers should prove of great value for characterization of immune responses involving CTL, for visualization of antigen-specific immune responses, for in vitro primary CTL induction, and for peptide binding assays and structural studies.

Retroviral rebound syndrome after cessation of suppressive antiretroviral therapy in three patients with chronic HIV infection.

BACKGROUND: Although viral rebound follows cessation of suppressive antiretroviral therapy in chronic HIV infection, a viremic clinical syndrome has not been described. OBJECTIVE: To describe a retroviral syndrome associated with cessation of effective antiretroviral therapy in chronic HIV infection. DESIGN: Case reports. SETTING: Outpatient HIV specialty clinics in Seattle, Washington, and Boston, Massachusetts. PATIENTS: Three patients with chronic HIV infection who discontinued suppressive antiretroviral therapy. MEASUREMENTS: Clinical course, plasma HIV RNA levels, and CD4 cell counts before, during, and after cessation of antiretroviral therapy. RESULTS: Within 6 weeks after stopping antiretroviral therapy, each patient experienced a clinical illness that resembled a primary HIV syndrome. This coincided with a marked increase in HIV RNA level and, in two of three patients, a decrease in CD4 cell count. After antiretroviral therapy was restarted, each patient's symptoms rapidly resolved in association with resuppression of HIV RNA and increase in CD4 cell count or percentage. CONCLUSION: A retroviral rebound syndrome similar to that seen in primary HIV syndrome can occur in patients with chronic HIV infection after cessation of suppressive antiretroviral therapy.

Founder BRCA 1 and 2 mutations among a consecutive series of Ashkenazi Jewish ovarian cancer patients.

OBJECTIVE: The purpose of this study was to describe the incidence of the three Ashkenazi Jewish founder genetic BRCA 1 and 2 mutations among an unselected, consecutive group of Ashkenazi Jewish ovarian cancer patients. MATERIALS AND METHODS: From 7/30/96 to 4/12/99, 92 Ashkenazi Jewish patients with histologically confirmed epithelial ovarian cancer had surgery. All of these patients had DNA extracted from 5-microm sections of their paraffin-embedded surgical specimen tissue blocks using the Qiagen QIAamp tissue extraction kit. A multiplex (triplex) polymerase chain reaction was performed to amplify fragments for the 185delAG, 5382insC, and 6174delT mutations. The products were hybridized with normal and mutant probes for each of the three mutations. All clinical data were collected retrospectively and statistical significance was evaluated using the chi(2) test or a two-tailed Fisher's exact test, depending on the sample size. RESULTS: There were 23 patients positive for one of the three founder BRCA mutations. Fourteen patients were positive for the 185delAG mutation, 2 patients were positive for the 5382insC mutation, and 7 patients were positive for the 6174 delT mutation (61, 9, and 30%, respectively). This represented a 25% incidence (95% CI: 16-34%) of one of the three founder BRCA mutations among our 92 Ashkenazi Jewish ovarian cancer patients. None of the patients was positive for more than one mutation. There was no statistically significant difference in parity, histology, grade, or stage between the BRCA founder mutation positive and negative patients. The difference between the percentage of mutation carriers among patients with one affected first-degree relative (13/22 or 59%) compared to those without at least one affected first-degree relative (10/70 or 14%) was highly significant (P = 0.001). CONCLUSIONS: Ashkenazi Jewish ovarian cancer patients represent a group with a high likelihood of being carriers of BRCA 1 and 2 genetic mutations, regardless of family history. As a result, all ovarian cancer patients who are of Ashkenazi Jewish descent should be counseled regarding BRCA 1 and 2 genetic screening, as well as the potential implications of these results for the patient as well as her relatives in terms of prognosis, screening, chemoprevention, and consideration of prophylactic surgical procedures.