A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Trial of Antisense RNA Inhibition of HIV Replication and Gene Expression

We examined the feasibility of antisense RNA inhibition of human immunodeficiency virus (HIV) replication. In the first experiment, we established CD4+ T-cell lines constitutively expressing various antisense HIV sequences using the retrovirus-mediated gene transfer technique. These cell lines were tested for their ability to withstand HIV de novo infection. In this challenge assay, however, we could not detect any significant difference in the survival rate between these genetically engineered cell lines and control T cells. In the second approach, the effects of antisense sequences on Tat expression were studied by monitoring the activities of reporter enzymes. A functional Tat expression vector and the antisense sequence expression vector were co-introduced into HeLa cells stably transfected with either the HIV-long terminal repeat (LTR) directed chloramphenicol acetyltransferase (CAT) or luciferase. Although the concentration of the antisense RNA was at least 10-fold higher than that of the sense Tat mRNA in cells, these antisense sequences could not inhibit transactivation of HIV-LTR. Regulation of HIV gene expression has proven to be very complicated and Tat transactivation of the HIV-LTR is extraordinarily strong. Consequently, it may be difficult to block HIV replication by the antisense strategy.

Abstract P5-02-01: Regulated intratumoral expression of IL-12 in combination with cytotoxic agents as a strategy for the treatment of metastatic breast cancer

Major obstacles for the development of immunotherapeutics are the ability of tumors to escape the immune system coupled with toxicity associated with systemic administration. To overcome these challenges, we have developed an adenoviral vector, Ad-RTS-IL-12 (AD), administered intratumorally (IT) under control of the RheoSwitch Therapeutic System® (RTS) technology platform. Expression of IL-12 mRNA and IL-12 protein is tightly regulated by the oral administration of a small molecule activator ligand, veledimex (AL).

We have previously demonstrated a concentration-related increase in IL-12 mRNA concomitant with increase in expression of IL-12 protein in HT1080 cells transduced with AD and incubated with AL. Removal of AL from the media resulted in a return to baseline IL-12 expression within 48 hours. Results from the subcutaneous 4T1 syngeneic BALB/c mouse mammary tumor model demonstrated an AL dose-related increase in tumor IL-12 mRNA and IL-12 protein expression with the maximum IL-12 tumor protein level of 280 ng/mg achieved at 150 mg/m2 AL + 1e10 vp AD. In addition, a return to baseline IL-12 mRNA and IL-12 protein expression was observed on cessation of AL.

The effect of AD + AL on tumor growth rate was evaluated in a subcutaneous 4T1 syngeneic BALB/c mouse mammary tumor model. A single intratumoral injection of 1e10 vp AD combined with oral administration of AL (15, 30, 75 or 150 mg/m2) on a Q1Dx5 schedule led to significant AL dose-related tumor growth inhibition with tumor size reduction of 27%, 37%, 57% and 60%, respectively when compared to vehicle on Day 33. Neither AD or AL alone had an effect on tumor growth rate relative to vehicle control. No change in clinical signs or body weight was observed when compared to vehicle alone. Tumor growth inhibition correlated with an increase in tumor IL-12 levels, a decrease in Tregs, and an increase in cytotoxic T cells. Results from a phase 1 study in melanoma have shown dose-related production of IL-12 and clinical activity in injected and non-injected lesions at 100 and 160 mg of AL.

Cytotoxic agents at low doses have been shown to prime the immune system and combination with immunotherapy may augment tumor specific T-cell immune responses resulting in enhanced efficacy. In the 4T1 mouse mammary tumor model Ad-RTS-mIL12 (1e10vp) + AL (30 mg/m2) combined with palifosfamide (40 or 120 mg/m2 QD IP for 3 days) significantly inhibited tumor growth (∼71-90% vs. control) concomitant with increased median survival when compared to the single agents alone. Based on these findings in a multicenter, open-label, randomized, phase 2 study evaluating the safety and efficacy of AD + AL alone or in combination with cytotoxic agents in subjects with recurrent/metastatic breast cancer with accessible tumor(s) is ongoing. This study assesses AD + AL administered as a monotherapy and a combination therapy. In the monotherapy arm, AD is administered IT on Day 1 and AL 140 mg is administered orally on either a Q1Dx7 or QODx14 schedule. In the combination arm, palifosfamide 120 mg/m2 IV Q1Dx3 is be administered with AD + AL QODx14 (28 day cycle). Preliminary data show that AD + AL is safe and well tolerated. Preclinical and clinical data will be presented.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-02-01.

Abstract P4-07-05: Correlation of a Proliferation Index Combined with Progesterone Receptor to Oncotype DX® in Early Stage ER-Positive Breast Cancer

Background: Different gene expression sets have been reported to reproducibly assess the metastatic potential of early stage operable breast tumors. Knowledge of the biology-based components of amalgamated expression scores may provide insight into the relative contributions of the cellular processes involved. We sought to compare a composite metastasis score (cMS) consisting of a previously reported Metastasis Score (MS), that serves essentially as a proliferation index, and the progesterone receptor (PR) with the Oncotype DX® Recurrence Score (RS) in a regional cancer center setting.

Methods: We examined sections from 152 blocks collected in the Blumenthal Cancer Center that had Oncotype DX® scores (a commercially available service performed by Genomic Health Inc. (GHI)). The study protocol was approved by the Institutional Review Board of the Blumenthal Cancer Center. ER and PR were initially scored by IHC; HER2 was determined by FISH. RT-PCR multiplex TaqMan assays of a 14-gene Metastasis Score (Tutt et al. (2008)) and a multiplex assay for ER, PR and HER2 (Iverson et al. (2009)) were carried out. A cMS was generated with MS and PR using previously constructed weighting. Risk classification of cMS was based on a single pre-established cut point; GHI recommended cut points were used for categorized Oncotype DX® risk. Correlations were estimated by Pearson's product-moment correlation coefficient; a goodness-of-fit test was used to determine differences in the categorical proportions.

Results: Eighty-nine (59%), 51 (34%), and 12 (8%) of the 152 tumors tested had low, intermediate and high Oncotype DX® Recurrence Scores, respectively. The continuous scores for cMS and RS were correlated (r=0.71). Of the 89 tumors categorized as low risk by RS, 78 (88%) and 11 (12%) were at low and high risk by cMS, respectively; all (12) of the tumors categorized as high risk by RS were high risk by cMS; and of the 51 tumors with intermediate RS, 27 (53%) were categorized as low risk and 24 (47%) as high risk by cMS. Correlations of RT-PCR PR levels with overall RS and cMS scores were 0.70 and 0.71, respectively. The MS had correlations of 0.50 and 0.80 with RS and cMS, respectively. The categorized risk proportions of this patient population differed from those reported by Paik et al. (2004) (p=1.47x10-7). Tumors with HER2 gene amplification by FISH [3/141 (2%)] were under-represented (p=0.016) relative to Paik et al. (2004) [55/715 (8%)]; the proportion of PR negative tumors for Paik et al. [126/668 (19%)] and this study [14/149 (9%)], were also dissimilar (p=0.006).

Conclusions: Despite sharing few genes, the continuous scores for cMS and RS show good correlation. The correlation of PR with these two scores suggests the level of this hormone receptor makes a similar significant contribution to both scores in this patient population. MS was more highly correlated to cMS than RS. Distinguishable features of cMS relative to the amalgamated RS include binary categorization of a continuous score and availability and transparency of discrete and combined scores for the endocrine and proliferation components. Under-representation of HER2- amplified tumors suggests exclusion of this patient group from testing.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-07-05.

Validation of an RT-PCR multi-gene prognostic signature for distant metastasis in node negative (N-), ER positive (ER+) breast cancer patients using FFPE sections

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Background: We sought to validate a previously developed 14-gene prognostic signature and a metastasis score (MS) that predicted distant metastasis in N-, ER+ breast cancer patients in an independent sample set of patients without systemic treatment. The genes consisted primarily of proliferation genes involved in p53 and TNF signaling pathways. Methods: : A cohort of 294 N-, ER+ breast cancer patients from Guy's Hospitals, London, UK without systemic therapy were tested. The cohort had a mean age of 55.5 yrs with 49% > 55 yrs, mean tumor size of 1.93 (max. 3) cm, and a median follow up of 14.3 yrs. The primary endpoint was distant metastasis free survival. RT-PCR was carried out on fixed sections. The MS was calculated. Results: The mean MS (SD) was 0.44 (0.59) with a range of -1.31 to 2.0. Hazard of distant metastasis increased 3.02 fold (95% CI 1.91–4.76, p <0.0001) per unit increase in MS from Cox model. The pre-determined cut point of zero was used to stratify patients into low- and high-risk groups. The 5-yr distant-metastasis-free survival rate (DMFSR) for low- and high-risk groups were 1 and 0.86 (SE 0.024); the 10-yr DMFSR were 0.97 (0.021) and 0.77 (0.030), respectively. Univariate Cox regression analyses indicated that MS (hazard ratio (HR) 5.65, 95% CI 2.05–15.56, p=0.008), tumor size (HR 1.62, p=0.0047) and tumor grade (HR 2.52, p=0.036) were significant but age was not. Multivariate Cox regression indicated that the signature had independent prognostic value with a HR of 4.71 (1.42–15.61, p=0.011) after adjusting for age, tumor size and grade. AUC of MS at 5-and 10-yr were 0.78 (0.71–0.85, p<0.001) and 0.73 (0.66–0.80, p<0.001) with sensitivities of 1 and 0.96 and specificities of 0.31 and 0.31 at zero cut point, respectively. The differential risk between the median MS scores of the lowest and highest deciles was 8-fold. Conclusions: A previously defined RT-PCR prognostic signature for N-, ER+ patients has been confirmed. A metastasis score that quantifies distant metastasis risk, not confounded with treatment effect can complement treatment response predictors. Insight on natural history of tumors is critical for evaluating impact of therapy.

No significant financial relationships to disclose.

Microbial disease in humans: A genomic perspective

The approach of whole-genome shotgun sequencing coupled with the availability of computational algorithms to facilitate the assembly, gene prediction, and functional annotation of entire genomes has sparked a revolution in our understanding of the biology of free-living organisms. More than 40 bacterial genomes have been sequenced to date, of which several are important human pathogens. The capacity to sequence and assemble entire genomes of bacteria, pathogenic protozoans, and fungi in a rapid and cost-effective way has energized every aspect of microbial science. Comparative genome analysis allows us to dissect the evolutionary forces at work and provides insights into adaptations of microbes to their unique ecological niches. Factors that shape host-pathogen interactions and their outcomes include genetic polymorphisms in the microbial pathogen and host, both of which can impact on microbial virulence or host immune responses to infection. The availability of the genome sequence of entire organisms, together with the use of high-throughput sequence-based genomic technologies to define microbial and host physiological states, provides the unparalleled opportunity to better define clinical outcomes in the field of infectious diseases. There is one overarching lesson: completion of the genomic sequence of any species answers many questions, while at the same time it invites totally new questions.

Implications of the human genome for understanding human biology and medicine

Clinical researchers, practicing physicians, patients, and the general public now live in a world in which the 2.9 billion nucleotide codes of the human genome are available as a resource for scientific discovery. Some of the findings from the sequencing of the human genome were expected, confirming knowledge presaged by many decades of research in both human and comparative genetics. Other findings are unexpected in their scientific and philosophical implications. In either case, the availability of the human genome is likely to have significant implications, first for clinical research and then for the practice of medicine. This article provides our reflections on what the new genomic knowledge might mean for the future of medicine and how the new knowledge relates to what we knew in the era before the availability of the genome sequence. In addition, practicing physicians in many communities are traditionally also ambassadors of science, called on to translate arcane data or the complex ramifications of biology into a language understood by the public at large. This article also may be useful for physicians who serve in this capacity in their communities. We address the following issues: the number of protein-coding genes in the human genome and certain classes of noncoding repeat elements in the genome; features of genome evolution, including large-scale duplications; an overview of the predicted protein set to highlight prominent differences between the human genome and other sequenced eukaryotic genomes; and DNA variation in the human genome. In addition, we show how this information lays the foundations for ongoing and future endeavors that will revolutionize biomedical research and our understanding of human health.

Sequence analysis of the human genome: implications for the understanding of nervous system function and disease

The recent publication of the sequence of the human genome will accelerate the discovery of new genetic susceptibility factors for human disease, leading to the development of novel diagnostics and therapeutics. The exhaustive analysis of the human genome sequence will be the focus of the biomedical research community for many years to come. In particular, comparative analysis of the available eukaryotic genome sequences is an important approach to further our understanding of gene structure, function, and evolution. Our initial analysis of the human genome sequence has revealed many interesting features that are relevant to nervous system function, evolution, and disease. We analyzed the prominent features of predicted human proteins involved in neuronal function and prepared a comparative analysis of 146 human genes that have alleles (or mutations) conferring susceptibility for 168 neurologic diseases.

Mutation screening of the TNFRSF11A gene encoding receptor activator of NF kappa B (RANK) in familial and sporadic Paget's disease of bone and osteosarcoma

Paget's disease of bone (PDB) is a common disorder characterized by focal areas of increased and disorganized osteoclastic bone resorption, leading to bone pain, deformity, pathological fracture, and an increased risk of osteosarcoma. Genetic factors play an important role in the pathogenesis of Paget's disease. In some families, the disease has been found to be linked to a susceptibility locus on chromosome 18q21-22, which also contains the gene responsible for familial expansile osteolysis (FEO)--a rare bone dysplasia with many similarities to Paget's disease. Insertion mutations of the TNFRSF11A gene encoding Receptor Activator of NF kappa B (RANK) have recently been found to be responsible for FEO and rare cases of early onset familial Paget's disease. Loss of heterozygosity (LOH) affecting the PDB/FEO critical region has also been described in osteosarcomas suggesting that TNFRSF11A might also be involved in the development of osteosarcoma. In order to investigate the possible role of TNFRSF11A in the pathogenesis of Paget's disease and osteosarcoma, we conducted mutation screening of the TNFRSF11A gene in patients with familial and sporadic Paget's disease as well as DNA extracted from Pagetic bone lesions, an osteosarcoma arising in Pagetic bone and six osteosarcoma cell lines. No specific abnormalities of the TNFRSF11A gene were identified in a Pagetic osteosarcoma, the osteosarcoma cell lines, DNA extracted from Pagetic bone lesions, or DNA extracted from peripheral blood in patients with familial or sporadic Paget's disease including several individuals with early onset Paget's disease. These data indicate that TNFRSF11A mutations contribute neither to the vast majority of cases of sporadic or familial PDB, nor to the development of osteosarcoma.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

Whole genomes: the foundation of new biology and medicine

Our genomic DNA sequence provides a unique glimpse of the provenance and evolution of our species, the migration of peoples, and the causation of disease. Understanding the genome may help resolve previously unanswerable questions, including perhaps which human characteristics are innate or acquired. Such an understanding will make it possible to study how genomic DNA sequence varies among populations and among individuals, including the role of such variation in the pathogenesis of important illnesses and responses to pharmaceuticals. The study of the genome and the associated proteomics of free-living organisms will eventually make it possible to localize and annotate every human gene, as well as the regulatory elements that control the timing, organ-site specificity, extent of gene expression, protein levels, and post-translational modifications. For any given physiological process, we will have a new paradigm for addressing its evolution, development, function, and mechanism.

Sequencing the entire genomes of free-living organisms: the foundation of pharmacology in the new millennium

The power and effectiveness of clinical pharmacology are about to be transformed with a speed that earlier in this decade could not have been foreseen even by the most astute visionaries. In the very near future, we will have at our disposal the reference DNA sequence for the entire human genome, estimated to contain approximately 3.5 billion bp. At the same time, the science of whole genome sequencing is fostering the computational science of bioinformatics needed to develop practical applications for pharmacology and toxicology. Indeed, it is likely that pharmacology, toxicology, bioinformatics, and genomics will merge into a new branch of medical science for studying and developing pharmaceuticals from molecule to bedside.

Pilot study of the immunologic effects of recombinant human growth hormone and recombinant insulin-like growth factor in HIV-infected patients

OBJECTIVE

To study the immunologic effects of recombinant human growth hormone (rhGH), recombinant human insulin-like growth factor type 1 (rhIGF-1), or the combination, in patients with moderately advanced HIV infection.

DESIGN

Randomized but not blinded trial.

SETTING

Government medical research center.

PATIENTS

Twenty-four HIV-infected patients with CD4 cell counts of 100-400 x 10(6)/l who were receiving nucleoside antiretroviral therapy.

INTERVENTIONS

Either rhGH, rhIGF-1, or the combination was administered subcutaneously for 12 weeks.

MAIN OUTCOME MEASURES

Immunologic parameters, including T-cell subsets and assays of in vitro interleukin (IL)-2 production in response to antigens and mitogens, and safety profile.

RESULTS

Plasma IGF-1 levels were low or low-normal prior to treatment and increased with all three therapies. There were no significant changes in CD4 cell counts, RA/RO CD4 cell subsets, natural killer cell function, immunoglobulin levels, or in vitro IL-2 production in response to mitogen or alloantigens. However, there was an upward trend (and for p18IIIB a statistically significant increase) in the in vitro IL-2 production in response to each of five HIV envelope peptides. Potential toxic effects included fatigue, arthralgia, edema, myalgia, and headache. Patients also were noted to have weight gain averaging 4 kg early in the course of treatment.

CONCLUSIONS

These results suggest that treatment with rhGH/rhIGF-1 was reasonably well tolerated and that modest improvement in HIV-specific immune function was attained. Further studies will help clarify the therapeutic potential of rhGH/rhIGF-1 as an immunostimulator in the setting of HIV infection.

Phase II trial with dose titration of paclitaxel for the therapy of human immunodeficiency virus-associated Kaposi's sarcoma

PURPOSE

To investigate the antitumor activity and safety of paclitaxel in patients with advanced human immunodeficiency virus (HIV)-associated Kaposi's sarcoma (KS).

PATIENTS AND METHODS

Twenty-nine patients with advanced HIV-associated KS were enrolled. The patients were overall quite immunosuppressed (median CD4 count, 15 cells/microL). Paclitaxel was initially administered at 135 mg/m2 over 3 hours every 3 weeks without filgrastim support; the dose was increased as tolerated to a maximum of 175 mg/m2. Patients who failed to respond or progressed could then receive filgrastim support or paclitaxel administered over 96 hours.

RESULTS

Of 28 assessable patients, 20 had major responses (18 partial responses [PRs], one clinical complete response [CR], and one CR), for a major response rate of 71.4% (95% confidence interval [CI], 51.3% to 86.8%). Each of the five patients with pulmonary KS responded, as did all four assessable patients who had previously received anthracycline therapy for KS. Of six patients who went on to receive a 96-hour infusion of paclitaxel, five had major responses. Neutropenia was the most frequent dose-limiting toxicity; possible novel toxicities included late fevers, late rash, and eosinophilia. Two patients developed an elevated creatinine concentration and one cardiomyopathy.

CONCLUSION

Paclitaxel has substantial activity against advanced HIV-associated KS as a single agent, even in patients with pulmonary involvement or who had previously received anthracyclines. Further research is needed to define the optimal treatment schedule and its role vis-a-vis the other available therapies for this disease.

Effect of combination therapy with zidovudine and didanosine on neuropsychological functioning in patients with symptomatic HIV disease: a comparison of simultaneous and alternating regimens

OBJECTIVE

To evaluate the effects of treatment with alternating and simultaneous regimens of zidovudine and didanosine on neuropsychological function in patients with symptomatic HIV-1 disease, focusing on patients with possible HIV-1-associated central nervous system (CNS) compromise at entry.

DESIGN

Randomized non-blinded clinical trial.

SETTING

Government medical research center.

PATIENTS

Thirty-eight patients with symptomatic HIV-1 disease, of whom 21 had evidence of CNS compromise at entry.

RESULTS

After 12 weeks of therapy, overall significant improvements in memory (P < 0.01) and focused attention (P < 0.001) were seen on both regimens. These gains, however, were largely limited to those patients with HIV-1-associated CNS compromise at entry (P < 0.05). Improvements were also noted in receptive vocabulary, reading, perceptual discrimination and reasoning, divided attention, motor strength, and in mood and affect. Improvements in those latter functions were generally of limited magnitude and were of comparable size for both compromised and non-compromised patients. There was no overall difference between the two drug regimens in the effects on CNS parameters.

CONCLUSIONS

Therapy-related improvements were noted particularly for patients with HIV-1-associated CNS compromise. Neuropsychological functions that have been implicated in AIDS dementia--memory and attention--showed the greatest gains. In contrast to the previously described superiority of the simultaneous regimen with regard to immunologic and virologic parameters, there was no difference between the regimens with regard to CNS measures. This supports the contention that the CNS constitutes a relative independent compartment in terms of HIV disease and treatment.

Phase I/II study of intermittent all-trans-retinoic acid, alone and in combination with interferon alfa-2a, in patients with epidemic Kaposi's sarcoma

PURPOSE

A phase I/II study of oral all-trans-retinoic acid (ATRA; tretinoin), administered every other week alone and then in combination with interferon (IFN) alfa-2a, was undertaken to evaluate the activity, toxicity, and pharmacokinetics of this regimen in patients with human immunodeficiency virus (HIV)-associated Kaposi's sarcoma (KS).

PATIENTS AND METHODS

Thirteen patients with HIV-associated KS, eight of whom had more than 100 CD4 cells/microL, were entered. The protocol initially called for patients to receive 150 mg/m2/d of ATRA every other week. However, this regimen was associated with headaches, and the initial dose of ATRA was reduced to 40 mg/m2/d orally in three divided doses, increasing to a maximum of 100 mg/m2/d. After 12 weeks, IFN alfa-2a could be added.

RESULTS

The principal toxicities from ATRA were headaches (12 patients) and dry skin or lip (seven patients). Of 12 assessable patients, 10 had progressive disease and two had stable disease on ATRA alone. One of eight assessable patients who went on to receive ATRA plus IFN alfa-2a had partial response (PR). There were no overall changes in the serum HIV p24 antigen (Ag) level or CD4 count during treatment with ATRA alone. Peak ATRA levels decreased during the week of continuous ATRA therapy, but rebounded when treatment was resumed after a week without the drug.

CONCLUSION

Intermittent ATRA therapy was reasonably well tolerated and provided a means to circumvent the low plasma exposure found with continuous ATRA therapy. However, we were unable to document antitumor activity in patients with HIV-associated KS.

Treatment of HIV-associated Kaposi's sarcoma with paclitaxel

We investigated whether paclitaxel was active in AIDS-associated Kaposi's sarcoma. We gave 135 mg/m2 intravenously over 3 hours every 21 days. Follow-up is available on the first 20 patients, most of whom had advanced Kaposi's sarcoma and severe immunocompromise. Neutropenia was the most frequent dose-limiting toxic effect; novel toxic effects included late fevers, rash, and eosinophilia. Creatinine increased in 2 patients and 1 patient had cardiomyopathy. There were 13 partial responses (65%, 95% CI 41-85%). All 5 patients with pulmonary involvement responded. Paclitaxel appears to be active against Kaposi's sarcoma as a single agent. Further studies, including a randomised trial, are warranted.

Human immunodeficiency virus type 1 (HIV-1) viremia changes and development of drug-related mutations in patients with symptomatic HIV-1 infection receiving alternating or simultaneous zidovudine and didanosine therapy

The changes in viremia levels and the development of drug-related mutations were examined in 26 patients with symptomatic human immunodeficiency virus type 1 (HIV-1) infection participating in a randomized trial comparing alternating (A) and simultaneous (S) regimens of zidovudine and didanosine therapy. Patients on both arms had significant reduction in serum RNA copies from baseline throughout the 2 years of study. Significant differences between the two arms were demonstrated over the first 2-3 months of therapy. Analyses with nested polymerase chain reaction revealed that the emergence of the didanosine-related position 74 Leu-->Val mutation was significantly blocked in both regimens, while the zidovudine-related mutation at codon 215 was not affected. Determination of the overall durability of the antiviremic effect of the A and S regimens of zidovudine and didanosine and clinical implications of the results require further research.

Five-year follow-up of a phase I study of didanosine in patients with advanced human immunodeficiency virus infection

Starting in 1988, 72 patients with advanced human immunodeficiency virus (HIV) infection were enrolled in a phase I study of didanosine at the National Cancer Institute. Beginning in 1992, patients with decreases in CD4 cell counts could switch to a combination of zidovudine and didanosine. The estimated median survival for all patients was 28 months (95% confidence interval, 23-46). However, for patients whose entry CD4 cell counts were 100-300/mm3, the estimated 4-year survival was 80%. Baseline CD4 and CD8 cell counts, hemoglobin, lymphocytes, sedimentation rates, diagnosis of AIDS, and fever were significant predictors of overall survival. Principal toxicities were pancreatitis and peripheral neuropathy; no new toxicities were seen with extended didanosine treatment that had not been observed in shorter-term studies. This 5-year follow-up shows that didanosine can be tolerated for > 4 years in some patients with advanced HIV infection and may have particular long-term utility in patients with moderately advanced immunosuppression.

Molecular foundations of cancer: new targets for intervention

Conceptual and practical advances in molecular medicine are changing our understanding of cancer pathogenesis. In time this should provide the opportunity to alter the natural history of many cancers.

Interleukin-10 suppresses human immunodeficiency virus-1 replication in vitro in cells of the monocyte/macrophage lineage

The cytokine interleukin-10 (IL-10) has been implicated in the pathogenesis of a number of disease states, including Epstein-Barr virus and human immunodeficiency virus (HIV-1) infections. In the acquired immunodeficiency syndrome (AIDS), it has been suggested that IL-10 may have a deleterious effect by suppressing cell-mediated immunity. However, there are few data on its direct effects on HIV-1 replication. In the present study, we have found that recombinant human IL-10 (rhIL-10), present during days 0 through 2, potently inhibits HIV production in elutriated monocyte/macrophage (M/M) cultures with a 50% inhibitory concentration (IC50) of approximately 0.03 U/mL. This effect did not appear to be caused by toxicity to M/M because there was no change in cell viability, ability to phagocytose latex beads, or protein synthesis as measured by [3H]-leucine incorporation, at doses of rhIL-10 that inhibit viral replication. In addition, lipopolysaccharide-induced production of IL-1 beta, IL-6, or tumor necrosis factor-alpha was not affected at these doses, nor were human mononuclear cell proliferative responses to phytohemagglutinin, OKT3 antibody, or tetanus toxoid. HIV-1 replication was similarly decreased by rhIL-10 in the monocytoid line U937 without signs of cellular toxicity. However, these effects required much higher concentrations of rhIL-10, and viral production was only partially suppressed. rhIL-10 also slightly inhibited HIV-induced cytopathicity in ATH-8, a tetanus toxoid-specific, retrovirally immortalized T-cell line, but had no effect on HIV replication in the H9 and MOLT-4 T cell lines. Thus, rhIL-10 appears to inhibit HIV replication predominantly in cells of the M/M lineage. This effect may serve to reduce viral production in patients with AIDS. However, additional studies will be needed to more precisely define its physiologic role in this disease.

Oncology and hematology

Net overexpression or derangements of PTK-encoding oncogenes and ras serve as critical driving forces in the evolution of many epithelial and lymphohematopoietic cancers. The ability to impede signal transduction through ras-based pathways could provide a powerful molecular target for therapy and prevention of a broad spectrum of malignant neoplasms.

Administration of pentosan polysulfate to patients with human immunodeficiency virus-associated Kaposi's sarcoma

BACKGROUND

Neovascularization induced by basic fibroblast growth factor (basic FGF) or FGF-like cytokines is thought to play a substantial role in the pathogenesis of human immunodeficiency virus (HIV)-associated Kaposi's sarcoma. Pentosan polysulfate has been shown to inhibit basic FGF and FGF-like dependent tumor growth both in vitro and in vivo. Moreover, it has been found to inhibit the growth of Kaposi's sarcoma-derived spindle cells in vitro. These observations suggested that pentosan polysulfate might be worth exploring as a potential agent for the treatment of Kaposi's sarcoma.

PURPOSE

The purpose of this phase 1 clinical trial was to determine the maximum tolerated dose of pentosan polysulfate in patients with HIV-associated Kaposi's sarcoma and whether or not this compound had activity against this neoplasm.

METHODS

Sixteen HIV-seropositive patients with Kaposi's sarcoma received pentosan polysulfate via continuous venous infusion for 3-6 weeks and then received a subcutaneous dose three times per week. Three different doses of pentosan polysulfate were administered: 2 mg/kg per day by infusion followed by 2 mg/kg per dose given subcutaneously (six patients), 3 mg/kg per day by infusion followed by 3 mg/kg per dose given subcutaneously (five patients), and 4 mg/kg per day by infusion followed by 4 mg/kg per dose given subcutaneously (five patients). Five of the 16 patients in the study also received injections of 1 mg of pentosan polysulfate into two different lesions two times a week for 3 weeks, followed by intralesional therapy once weekly. After receiving pentosan polysulfate for 6 weeks, patients were administered 100 mg zidovudine (AZT) orally every 4 hours in conjunction with pentosan polysulfate.

RESULTS

The maximally tolerated dose of pentosan polysulfate given by continuous venous infusion was found to be 3 mg/kg per day. No patient had an objective clinical antitumor response to either systemic or intralesional pentosan polysulfate administration; however, three patients had stable Kaposi's sarcoma for 3-27 weeks. No statistically significant effect on CD4 cells or serum HIV p24 antigen was noted during pentosan polysulfate administration. Dose-limiting toxic effects were characterized by anticoagulation and thrombocytopenia and were reversible.

CONCLUSION

Pentosan polysulfate was well tolerated in this patient population. However, no objective tumor response or evidence of anti-HIV activity was noted; therefore, no claim of activity can be made in this trial.

IMPLICATION

Continued investigation into the use of angiogenesis inhibitors with improved activity and toxicity profiles or different mechanisms of action is warranted.

A pilot study of sequential therapy with zidovudine plus acyclovir, dideoxyinosine, and dideoxycytidine in patients with severe human immunodeficiency virus infection

A pilot study was initiated to explore a sequential combination antiretroviral regimen in 21 patients with AIDS or advanced human immunodeficiency virus (HIV) infection, who had received little or no prior anti-HIV therapy. The mean entry CD4 cell count was 184/mm3. Patients received 3-week cycles consisting of zidovudine plus acyclovir, dideoxyinosine, and dideoxycytidine for 1 week each. Overall, the regimen was well tolerated for up to 3 years. The principal toxicities were anemia, nausea, and vomiting; 1 patient developed retinal lesions. The mean CD4 cell count reached a peak of 64 cells/mm3 above baseline at week 8 (P = .005 compared to baseline) and remained above baseline for > 40 weeks. Patients also gained weight and had decreases in serum HIV p24 antigen. Eight patients developed opportunistic infections or tumors. Only 4 patients died during 3 years of follow-up. This regimen appears to be generally tolerable and to have anti-HIV activity. Additional studies will be needed, however, to learn how to best combine the available agents in patients with HIV infection.

Effect of a recombinant CD4-IgG on in vitro T helper cell function: data from a phase I/II study of patients with AIDS

Ten patients with AIDS were enrolled in a phase I/II protocol of recombinant CD4-IgG (rCD4-IgG) treatment. Patients' peripheral blood leukocytes (PBL) were tested before, during, and after therapy with rCD4-IgG for T helper (TH) cell function assessed by antigen- and mitogen-stimulated proliferation and interleukin-2 production in response to influenza A virus, allogeneic PBL (alloantigens), and phytohemagglutinin. Although clinical benefit was not evident, rCD4-IgG treatment was associated with rapid and potent improved TH cell function for two of three stimuli tested in 90% of the patients. These data are complemented by an in vitro experimental model that demonstrates the opposing immunologic effects of rgp120 and rCD4-IgG on TH cell function of PBL from uninfected individuals. Thus, restoration of TH cell function by rCD4-IgG in the absence of increased CD4 cell counts could be due to removal of an immunosuppressive factor, possibly gp120. These findings suggest that rCD4-IgG can induce partial restoration of immune function in AIDS patients, even in the absence of apparent short-term clinical benefit.

Challenges in the therapy of HIV infection

Drugs that inhibit HIV replication have been shown to have clinical utility in patients with HIV infection. However, the immunological improvement induced by available anti-HIV therapies in patients with AIDS is incomplete and transient. Explanations for this may include immunological barriers to complete reconstitution, low therapeutic indices of the available drugs, and the development of viral resistance. An understanding of these processes may provide important leads for the development of improved therapy for AIDS.

Parameters affecting the development of non-Hodgkin's lymphoma in patients with severe human immunodeficiency virus infection receiving antiretroviral therapy

PURPOSE

To investigate the occurrence of non-Hodgkin's lymphoma (NHL) in human immunodeficiency virus (HIV)-infected patients receiving long-term antiretroviral therapy and factors associated with the development of these lymphomas.

PATIENTS AND METHODS

The charts of 55 patients with advanced HIV infection receiving zidovudine (formerly known as azidothymidine [AZT])-based therapy and 61 patients receiving dideoxyinosine (ddI) were examined for the occurrence of NHL. Stored samples from the AZT-based treatment cohort were examined retrospectively for parameters predictive of the subsequent development of lymphoma.

RESULTS

Eight of 55 patients receiving AZT-based therapy developed NHL, yielding an estimated probability of 12% (95% confidence interval [CI], 4.7% to 27.1%) after 24 months, and 29.2% (95% CI, 15.2% to 48.7%) after 36 months. Four of 61 patients receiving ddI developed NHL, yielding a 6.2% (95% CI, 2.1% to 17%) estimated probability after 24 months, and 9.5% (95% CI, 3.6% to 22.8%) after 36 months. The difference between these cohorts was not significant (two-tailed P [P2] = .13). Patients with less than 50 CD4 cells/microL developed NHL at a significantly higher rate (P2 = .0085). This was particularly true for patients who presented with primary CNS lymphoma (PCNSL). For patients receiving AZT-based therapy, pretreatment serum interleukin-6 (IL-6) levels were somewhat higher in those who subsequently developed NHL than in those who did not (P2 = .048).

CONCLUSION

HIV-infected patients with profound immunodeficiency, especially those with less than 50 CD4 cells/microL, are at substantial risk of developing NHL and particularly PCNSL. Additional studies are needed to define the role of other factors such as IL-6 in the pathogenesis of these opportunistic tumors.

Challenges in the therapy of HIV infection

Drugs that inhibit human immunodeficiency virus (HIV) replication have been shown to have clinical utility in patients with HIV infection. However, the immunological improvement induced by available anti-HIV therapies in patients with acquired immune deficiency syndrome (AIDS) is incomplete and transient. Explanations for this may include immunological barriers to complete reconstitution, low therapeutic indices of the available drugs, and the development of viral resistance. An understanding of these processes, as discussed here by Robert Yarchoan and colleagues, may provide important leads for the development of improved therapy for AIDS.

Differential phosphorylation of azidothymidine, dideoxycytidine, and dideoxyinosine in resting and activated peripheral blood mononuclear cells

The antiviral activity of azidothymidine (AZT), dideoxycytidine (ddC), and dideoxyinosine (ddI) against HIV-1 was comparatively evaluated in PHA-stimulated PBM. The mean drug concentration which yielded 50% p24 Gag negative cultures were substantially different: 0.06, 0.2, and 6 microM for AZT, ddC, and ddI, respectively. We found that AZT was preferentially phosphorylated to its triphosphate (TP) form in PHA-PBM rather than unstimulated, resting PBM (R-PBM), producing 10- to 17-fold higher ratios of AZTTP/dTTP in PHA-PBM than in R-PBM. The phosphorylation of ddC and ddI to their TP forms was, however, much less efficient in PHA-PBM, resulting in approximately 5-fold and approximately 15-fold lower ratios of ddCTP/dCTP and ddATP/dATP, respectively, in PHA-PBM than in R-PBM. The comparative order of PHA-induced increase in cellular enzyme activities examined was: thymidine kinase > uridine kinase > deoxycytidine kinase > adenosine kinase > 5'-nucleotidase. We conclude that AZT, ddC, and ddI exert disproportionate antiviral effects depending on the activation state of the target cells, i.e., ddI and ddC exert antiviral activity more favorably in resting cells than in activated cells, while AZT preferentially protects activated cells against HIV infection. Considering that HIV-1 proviral DNA synthesis in resting lymphocytes is reportedly initiated at levels comparable with those of activated lymphocytes, the current data should have practical relevance in the design of anti-HIV chemotherapy, particularly combination chemotherapy.

Anomalous accumulation and decay of 2',3'-dideoxyadenosine-5'-triphosphate in human T-cell cultures exposed to the anti-HIV drug 2',3'-dideoxyinosine

The rates of accumulation and decay of 2',3'-dideoxyadenosine-5'-triphosphate (ddATP) have been examined after incubation with the anti-human immunodeficiency virus (HIV) agents 2',3'-dideoxyinosine (ddIno) and 2',3'-dideoxyadenosine (ddAdo) in human T-cell systems frequently used for assay of anti-HIV agents (MOLT-4 and CEM). Formation of ddATP from ddIno or ddAdo was rapid and concentration-dependent, with no saturation of phosphorylation being observed up to extremely high levels (1 mM) of drug. Rates of removal of ddATP from MOLT-4 cells were slow (t1/2 = 25-40 hr) and appeared to be monophasic. These unusually long half-times for ddATP utilization are not a general property of purine dideoxypurine nucleosides: when the corresponding guanine analog (2',3'-dideoxyguanosine) was examined under the same conditions, the t1/2 of ddGTP removal was only 3-5 hr. Similar results were observed with the human T-cell line CCRF-CEM. Coadministration with ddIno of inosine monophosphate dehydrogenase inhibitors, such as ribavirin and tiazofurin, yielded higher levels of ddATP in MOLT-4 and CEM cells, but did not influence the slow removal of ddATP from T-cells. The long half-time for disappearance of ddATP from cells may permit the maintenance of pharmacologically effective levels of ddATP within cells with relatively infrequent administration of the parent drug (ddIno or ddAdo).

The pathogenesis of AIDS lymphomas: a foundation for addressing the challenges of therapy and prevention

The association between AIDS and a spectrum of malignancies relates to chronic, profound defects in both cellular and humoral mechanisms of immune surveillance. Ironically, as AIDS patients live longer in response to increasingly effective antiretroviral therapies, the incidence of AIDS-related malignancies will continue to rise. The emergence of non-Hodgkin's lymphomas (NHL) as a major sequela of HIV infection bears a striking relationship to depletion of CD4 lymphocytes, particularly below 50/mm3. The ability to interfere early in the course of active HIV infection with additional mechanisms that may promulgate transformed cell hyperproliferation and clonal expansion--growth factors, HIV itself or other viruses (Epstein-Barr, in particular), aberrant oncogene or tumor suppressor genes expression, factors that induce genetic instability or DNA damage or alter host or viral genome repair--might decrease the occurrence or prolong the time to development of AIDS-related malignancies. The development of antiretroviral strategies that confer long-term suppression of HIV activity and relative preservation of immune function are essential to the ultimate prevention of malignancies that arise as a consequence of HIV-induced immunosuppression.

Trends in program project grant funding at the National Cancer Institute

In summary, analysis of the P01 program indicates that differences exist in scores and funding requirements between purely basic and translational P01s; P01 funding has been stable and the P01 policies consistent; growth in average costs for P01s has lagged compared to R01s; P01 grantees have a higher success rate than R01 grantees; priority score compression reduces the P01 payline without reducing the number of grants funded; exception funding in P01s expands the number of grants awarded and helps to meet the scientific program needs of the NCI; almost all R01 and P01 applications in the first quartile are funded; comparably ranked R01s and P01s are funded at equivalent percentages of recommended funding levels; the percentage of approved funds awarded declines as scores for R01s and P01s become less favorable. Because the resources available are finite, the NCI carefully considers the competing demands for RPG funds. On balance, however, the P01 program is still in good health. In combination with the other methods we use to make RPG awards, the P01 program is a vital component of our research grant program. Faced with budget realities, however, some difficult decisions have to be made. The NCI is open to suggestions on how to distribute research funds to best promote cancer research throughout the country. The NCI is particularly interested in hearing researchers' perceptions of problems so that, whenever it is appropriate, we can modify our course. There are important questions to consider for the future. Should there be greater or lesser use of RFAs in allocating resources for P01 grants? What algorithm optimally distributes resources among R01s, P01s, and other funding instruments in the RPGs? Should exceptions be used more or less heavily in the P01 funding process? Should other grant programs outside the RPG budget, such as the P50 SPORE program, be used to relieve pressures on the P01 budget? Should the number of projects within P01s be limited? How can peer review groups be given opportunities to provide priority scores that better reflect distinguishable differences in highly meritorious P01s? Should P01 scores be normalized? How could the R01 percentile concept be applied to P01s? How can the results from standing study sections be synchronized with results from ad hoc review groups? What changes in peer review procedures would promote equitable score distributions and budget recommendations across years? How can the NCI provide stability for established P01s without impinging on the ability of new P01s to enter the system?(ABSTRACT TRUNCATED AT 400 WORDS)

Changes in drug sensitivity of human immunodeficiency virus type 1 during therapy with azidothymidine, dideoxycytidine, and dideoxyinosine: an in vitro comparative study

Human immunodeficiency virus type 1 (HIV-1) strains were isolated from nine patients before and after prolonged therapy with either an alternating regimen of 3'-azido-3'-deoxythymidine (AZT) and 2',3'-dideoxycytidine (ddC) (AZT/ddC) or 2',3'-dideoxyinosine (ddI) alone. All strains obtained from four patients who received AZT/ddC for up to 41 mo were highly insensitive to AZT in vitro. Only one strain obtained after AZT/ddC therapy showed reduced susceptibility to ddC in addition to AZT and had previously unreported amino acid substitutions in the viral polymerase-encoding pol region, whereas three other strains had one or more of the five previously reported AZT-related mutations. In five HIV-1 strains from patients who received ddI for up to 29 mo, no appreciable decrease in sensitivity to ddI was detected. Two strains isolated after ddI therapy had no significant amino acid mutations, although three strains had a mutation reportedly associated with ddI administration. These data suggest that HIV-1 develops reduced susceptibility to AZT more readily than to ddC and ddI and/or that the reduced susceptibility to ddC and ddI is modest in degree. Moreover, the present data suggest that an alternating regimen of AZT and ddC does not block the emergence of AZT-insensitive variants. It should be noted, however, that the current results do not provide a basis for concluding that AZT/ddC or ddI is inferior, equivalent, or superior to AZT as therapy of AIDS.

The challenge of cancer research

The challenge of cancer research can be summarized by simple statistics. In 1992, more than 1.1 million Americans are expected to develop cancer, and roughly 520,000 are expected to die from cancer. The National Cancer Institute's (NCI's) mission is to eradicate the death and suffering from cancer, to cure cancer once it starts and ultimately to prevent cancer. To this end, initiatives that promote continued development of sophisticated molecular technologies and clinical application of those technologies to the prevention, diagnosis and treatment of cancer are of surpassingly high priority. Epidemiological studies tell us that at least 30-50% of cancer is directly related to smoking, diet and environmental factors. Treatment studies indicate that significant gains in survival are possible and have already been achieved in some cancers, with promise from new drugs and other modalities (including genetic engineering) for still other cancers. Prevention strategies such as smoking reduction, diet, environmental measures, chemoprevention and vaccine development have the potential to achieve a substantial reduction in cancer mortality. This reduction, realized over two decades, would result in at least 100,000 lives saved per year in this country, and a large number can be saved just by applying what we already know.

A pilot study of 2',3'-dideoxyinosine for the treatment of chronic hepatitis B

The nucleoside analog 2',3'-dideoxyinosine, currently being used to treat patients infected with the human immunodeficiency virus, has been shown to inhibit viral replication in certain cell culture systems of hepatitis B virus and the duck model of chronic hepatitis B infection. We studied the effect of dideoxyinosine on viral replication in patients with chronic hepatitis B. In the initial dose-finding phase, patients received sequential 2-wk courses of dideoxyinosine in escalating doses of 3, 6 and 9 mg/kg/day. In the second, long-term treatment phase, patients received dideoxyinosine at a dose of 9 mg/kg/day for 12 wk. Dideoxyinosine was given orally in three divided doses. The effects of dideoxyinosine on hepatitis B were assessed by serial measurements of ALT, hepatitis B virus DNA and DNA polymerase activity in serum. Six patients completed the dose-finding phase, and five patients continued into the long-term treatment phase. No significant differences were seen in serum aminotransferases, hepatitis B virus DNA levels or DNA polymerase activity at any time during treatment when compared with pretreatment levels. All patients remained positive for HBeAg during treatment and during 6 mo of follow-up. Thus at the doses tested, dideoxyinosine had no appreciable effect on viral replication in patients with chronic hepatitis B.

Effects of bone marrow stimulatory cytokines on human immunodeficiency virus replication and the antiviral activity of dideoxynucleosides in cultures of monocyte/macrophages

Cells of the monocyte lineage are important targets for the replication of human immunodeficiency virus (HIV). Our group and others have previously shown that granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates HIV replication in monocyte/macrophages, but that it also enhances the anti-HIV activity of 2',3'-dideoxy-3'-azidothymidine (AZT). In the present study, we have explored the effects of other bone marrow stimulatory cytokines on the replication of HIV and on the anti-HIV activity of certain dideoxynucleosides in human peripheral blood monocyte/macrophages (M/M). Like GM-CSF, macrophage CSF (M-CSF) enhanced HIV replication in M/M. In contrast, granulocyte CSF (G-CSF) and erythropoietin (Epo) had no such effects. The anti-HIV activity of zidovudine (AZT) was increased in M/M exposed to GM-CSF. In contrast, the anti-HIV activity of AZT was unchanged in M/M exposed to M-CSF, and the activities of 2',3'-dideoxycytidine (ddC) and 2',3'-dideoxyinosine (ddl) were unchanged or slightly diminished in M/M stimulated with GM-CSF or M-CSF. These differential activities of AZT and ddC were paralleled by differential effects of the cytokines on the anabolism of these drugs to their active 5'-triphosphate moieties. GM-CSF increased the levels of AZT-5'-triphosphate (at least in part through an increase in thymidine kinase activity) and overall induced an increase in the ratio of AZT-5'-triphosphate/thymidine-5'-triphosphate. In contrast, M-CSF-induced increases in AZT-5'-triphosphate were roughly matched by increases in thymidine-5'-triphosphate. Also, GM-CSF- or M-CSF-induced increases in the levels of ddC-5'-triphosphate were associated with parallel increases in the levels of deoxycytidine-5'-triphosphate (the physiologic nucleoside that competes at the level of reverse transcriptase), so that there was relatively little net change in the ddC-5'-triphosphate/deoxycytidine-5'-triphosphate ratio. Thus, bone marrow stimulatory cytokines may have a variety of effects on HIV replication and on the activity and metabolism of dideoxynucleosides in M/M.

Plasma HIV-1 viremia in HIV-1 infected individuals assessed by polymerase chain reaction

We established a method to estimate the amounts of HIV-1 particles in plasma from patients with HIV-1 infection by using polymerase chain reaction (PCR) following reverse transcription (RT) of viral RNA (RNA-PCR) and assessed the potential usefulness of this approach to monitor the changes of viral load in patients with AIDS or AIDS-related complex (ARC) receiving 2',3'-dideoxyinosine (ddI). Plasma samples were obtained from 77 patients with HIV-1 infection (49 AIDS/ARC and 28 asymptomatic seropositives). Following ultracentrifugation of plasma, RNA was extracted from the pelleted virus and subjected to RT and PCR. The number of HIV-1 virus particles in each sample was determined using known amounts of HIV-1 DNA as reference control for PCR. The current plasma RNA-PCR technique quantitatively detected HIV-1 particles in plasma from 76 of 77 (98.7%) HIV-1-infected individuals examined. The numbers of HIV-1 particles in plasma from patients with AIDS or ARC were markedly higher than those in plasma from asymptomatic seropositive individuals (p less than 0.0001). Higher levels of plasma HIV-1 particle numbers were detected in individuals with lower CD4+ T cell counts. Patients (n = 10) who received oral ddI at doses greater than or equal to 6.4 mg/kg/day for 8 to 14 weeks had a profound decrease in plasma HIV-1 particle numbers (p = 0.0051). Patients (n = 7) receiving ddI for 45 to 71 weeks also had a decrease (p = 0.018). It should be noted, however, that more research is required to evaluate the usefulness of this technique in assessing the disease status and monitoring the activity of antiretroviral therapy.