Dementia in AIDS patients: incidence and risk factors. Multicenter AIDS Cohort Study

We determined incidence and future projections of dementia after AIDS onset in 492 homosexual men with AIDS in the Baltimore/Los Angeles sites of the Multicenter AIDS Cohort Study, 64 of whom developed dementia. We studied various risk factors for dementia, including demographic and clinical features, medical history, markers of immune status before AIDS, and zidovudine use. During the first 2 years after AIDS, HIV dementia developed at an annual rate of 7%. Overall, 15% of the cohort followed through death developed dementia. The median survival after dementia was 6.0 months. Using a proportional hazards model, risk factors for more rapid development of dementia were lower hemoglobin (relative hazard, 0.59 per additional 2 g/dl; p = 0.0005) and body mass index (relative hazard, 0.64 per additional 5 kg/m2; p = 0.05) 1 to 6 months before AIDS, more constitutional symptoms 7 to 12 months before AIDS (relative hazard, 1.68 per additional symptom, p = 0.005), and older age at AIDS onset (relative hazard, 1.60 per decade older; p = 0.009). In a multivariate model, pre-AIDS hemoglobin remained the most significant predictor of dementia. There were no significant risks defined from demographic characteristics, specific AIDS-defining illnesses, zidovudine use before AIDS, or CD4+ lymphocyte count before AIDS. We project that 12 months after the first AIDS diagnosis, 7.1% of survivors will have dementia. The observed association between anemia, low weight, constitutional symptoms, and dementia suggests a role for cytokines inducing both systemic and neurologic disease.

Reservoirs for HIV-1: mechanisms for viral persistence in the presence of antiviral immune responses and antiretroviral therapy

The success of combination antiretroviral therapy for HIV-1 infection has generated interest in mechanisms by which the virus can persist in the body despite the presence of drugs that effectively inhibit key steps in the virus life cycle. It is becoming clear that viral reservoirs established early in the infection not only prevent sterilizing immunity but also represent a major obstacle to curing the infection with the potent antiretroviral drugs currently in use. Mechanisms of viral persistence are best considered in the context of the dynamics of viral replication in vivo. Virus production in infected individuals is largely the result of a dynamic process involving continuous rounds of de novo infection of and replication in activated CD4(+) T cells with rapid turnover of both free virus and virus-producing cells. This process is largely, but not completely, interrupted by effective antiretroviral therapy. After a few months of therapy, plasma virus levels become undetectable in many patients. Analysis of viral decay rates initially suggested that eradication of the infection might be possible. However, there are several potential cellular and anatomical reservoirs for HIV-1 that may contribute to long-term persistence of HIV-1. These include infected cell in the central nervous system and the male urogenital tract. However, the most worrisome reservoir consists of latently infected resting memory CD4(+) T cells carrying integrated HIV-1 DNA. Definitive demonstration of the presence of this form of latency required development of methods for isolating extremely pure populations of resting CD4(+) T cells and for demonstrating that a small fraction of these cells contain integrated HIV-1 DNA that is competent for replication if the cells undergo antigen-driven activation. Most of the latent virus in resting CD4(+) T cells is found in cells of the memory phenotype. The half-life of this latent reservoir is extremely long (44 months). At this rate, eradication of this reservoir would require over 60 years of treatment. Thus, latently infected resting CD4(+) T cells provide a mechanism for life-long persistence of replication-competent forms of HIV-1, rendering unrealistic hopes of virus eradication with current antiretroviral regimens. The extraordinary stability of the reservoir may reflect gradual reseeding by a very low level of ongoing viral replication and/or mechanisms that contribute to the intrinsic stability of the memory T cell compartment. Given the substantial long-term toxicities of current combination therapy regimens, novel approaches to eradicating this latent reservoir are urgently needed.

Retroviral RNA identified in the cerebrospinal fluids and brains of individuals with schizophrenia

Schizophrenia is a serious brain disease of uncertain etiology. A role for retroviruses in the etiopathogenesis of some cases of schizophrenia has been postulated on the basis of clinical and epidemiological observations. We found sequences homologous to retroviral pol genes in the cell-free cerebrospinal fluids (CSFs) of 10 of 35 (29%) individuals with recent-onset schizophrenia or schizoaffective disorder. Retroviral sequences also were identified in the CSFs of 1 of 20 individuals with chronic schizophrenia. However, retroviral sequences were not identified in any of the CSFs obtained from 22 individuals with noninflammatory neurological diseases or from 30 individuals without evidence of neurological or psychiatric diseases (chi(2) = 19.25, P < 0.001). The nucleotide sequences identified in the CSFs of the individuals with schizophrenia or schizoaffective disorder were related to those of the human endogenous retroviral (HERV)-W family of endogenous retroviruses and to other retroviruses in the murine leukemia virus genus. Transcription of RNA homologous to members of the HERV-W family of retroviruses also was found to be up-regulated differentially in the frontal cortex regions of brains obtained postmortem from individuals with schizophrenia, as compared with corresponding tissue from individuals without psychiatric diseases. The transcriptional activation of certain retroviral elements within the central nervous system may be associated with the development of schizophrenia in at least some individuals. The further characterization of retroviral elements within the central nervous system of individuals with schizophrenia might lead to improved methods for the diagnosis and management of this disorder.

PML-IRIS in patients with HIV infection: clinical manifestations and treatment with steroids

BACKGROUND

Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection that develops in immunosuppressed patients with HIV infection. Paradoxically, some of these patients may develop PML during combined antiretroviral therapy in the setting of immune reconstitution. We describe the types of PML in relation to immune reconstitution inflammatory syndrome (IRIS) and the effects of steroid use in these patients.

METHODS

We performed a retrospective review of the literature (1998 to 2007) and of all HIV-infected patients diagnosed with PML-IRIS at Johns Hopkins Hospital (2004 to 2007). We recorded information on clinical features, microbiologic and virological analysis, neuroimaging, pathology, treatment, and outcome.

RESULTS

Of 54 patients with PML-IRIS, 36 developed PML and IRIS simultaneously (PML-s-IRIS) and 18 had worsening of preexisting PML (PML-d-IRIS) after the initiation of combined antiretroviral therapy. PML-IRIS developed between 1 week and 26 months after initiation of antiretroviral therapy. PML-d-IRIS patients developed IRIS earlier, had higher lesion loads on MRI of the brain, had shorter durations of survival, and had higher mortality rate compared to PML-s-IRIS patients. Twelve patients received treatment with steroids, of which five died and seven showed good neurologic recovery. Patients who survived had received steroids early after IRIS diagnosis for longer durations and had contrast enhancement on IRIS neuroimaging.

CONCLUSIONS

Immune reconstitution following initiation of combined antiretroviral therapy may lead to activation of an inflammatory response to detectable or latent JC virus infection. Early and prolonged treatment with steroids may be useful in these patients but requires further investigation.

Failure of cytarabine in progressive multifocal leukoencephalopathy associated with human immunodeficiency virus infection. AIDS Clinical Trials Group 243 Team

BACKGROUND

Progressive multifocal leukoencephalopathy affects about 4 percent of patients with the acquired immunodeficiency syndrome (AIDS), and survival after the diagnosis of leukoencephalopathy averages only about three months. There have been anecdotal reports of improvement but no controlled trials of therapy with antiretroviral treatment plus intravenous or intrathecal cytarabine.

METHODS

In this multicenter trial, 57 patients with human immunodeficiency virus (HIV) infection and biopsy-confirmed progressive multifocal leukoencephalopathy were randomly assigned to receive one of three treatments: antiretroviral therapy alone, antiretroviral therapy plus intravenous cytarabine, or antiretroviral therapy plus intrathecal cytarabine. After a lead-in period of 1 to 2 weeks, active treatment was given for 24 weeks. For most patients, antiretroviral therapy consisted of zidovudine plus either didanosine or stavudine.

RESULTS

At the time of the last analysis, 14 patients in each treatment group had died, and there were no significant differences in survival among the three groups (P=0.85 by the log-rank test). The median survival times (11, 8, and 15 weeks, respectively) were similar to those in previous studies. Only seven patients completed the 24 weeks of treatment. Anemia and thrombocytopenia were more frequent in patients who received antiretroviral therapy in combination with intravenous cytarabine than in the other groups.

CONCLUSIONS

Cytarabine administered either intravenously or intrathecally does not improve the prognosis of HIV-infected patients with progressive multifocal leukoencephalopathy who are treated with the antiretroviral agents we used, nor does high-dose antiretroviral therapy alone appear to improve survival over that reported in untreated patients.

Low prevalence of neurological and neuropsychological abnormalities in otherwise healthy HIV-1-infected individuals: results from the multicenter AIDS Cohort Study

Accurate description of the prevalence of neurological impairment in healthy individuals who are infected with human immunodeficiency virus type 1 (HIV-1) has relevance for public health policy, for employment issues, and for planning future health needs. Within the Multicenter AIDS Cohort Study, we determined the cross-sectional prevalence of neurological abnormalities in 270 HIV-1 seropositive homosexual and bisexual men in Centers for Disease Control Groups II and III, using a control group of 193 HIV-1 seronegative homosexual men. Utilizing a neurological and neuropsychological screening battery, we found no differences in the prevalence of neuropsychiatric symptoms or in neuropsychological performance. One hundred nineteen subjects with abnormalities on screening tests completed additional neuropsychological testing and had neurological examinations. The majority had normal results and the frequency of neurological abnormalities and impaired neuropsychological performance was not significantly increased among HIV-1 seropositive subjects. Most of the abnormalities could be attributed to causes other than HIV-1. One subject had mild HIV-1-related dementia, yielding a prevalence of 3.7:1,000 (95% confidence interval: 0.19-23.7:1,000). Magnetic resonance imaging demonstrated sulcal prominence and focal areas of high signal intensity in white matter in 63% of HIV-1 seropositive subjects and 48% of uninfected control subjects. Abnormalities in cerebrospinal fluid were noted in 23 (85%) of 27 HIV-1-infected individuals. Our studies indicate that the prevalence of dementia and other HIV-1-related neurological disorders is very low among healthy HIV-1 seropositive homosexual men. The confounding effects of factors such as substance abuse or preexisting medical conditions must be considered in the neurological evaluation of such patients.

HIV-1 infection: no evidence of cognitive decline during the asymptomatic stages. The Multicenter AIDS Cohort Study

Cross-sectional studies have not adequately resolved the question of whether subjects infected with HIV-1 may suffer cognitive decline during the early, asymptomatic stages of the infection. We studied longitudinally 238 asymptomatic healthy HIV-1-infected homosexual/bisexual men (CDC groups 2 and 3) and 170 uninfected controls in the Multicenter AIDS Cohort Study with neuropsychological testing at semiannual intervals. A comparison of change in scores between visits 1 and 4 as well as a multivariate autoregressive analysis revealed no evidence of decline in test performance over time in the HIV-1-infected group compared with the seronegative controls. These findings suggest that a gradual cognitive decline does not occur during the early, asymptomatic stages of HIV infection.

Patterns of cerebral atrophy in HIV-1-infected individuals: results of a quantitative MRI analysis

Cerebral atrophy is a common radiologic manifestation of HIV dementia. To evaluate the relationship between cognitive impairment and cerebral atrophy, adjusting for age and immune status, we used standardized planimetry to measure the ventricle-brain ratio (VBR) and the bifrontal (BFR) and bicaudate (BCR) ratios, three measures of cerebral atrophy. We analyzed cranial MRIs of 23 HIV-1-seronegative controls (SN) and 116 HIV-1-infected individuals. Of the HIV-1-seropositive individuals, 37 had HIV dementia (DM group), 40 had neurologic or neuropsychological abnormalities insufficient for HIV dementia (NP+ group), and 39 were neurologically normal (NML group). We performed comparisons using analysis of covariance with correction for multiple comparisons. Both the VBR, a general measure of overall cerebral atrophy, and the BCR, a measure of atrophy in the region of the caudate nucleus, are significantly associated with dementia. The association is stronger for BCR enlargement than for VBR enlargement, suggesting that selective caudate region atrophy is associated with HIV dementia. These results indicate that overall cerebral atrophy and prominent caudate region atrophy are important radiographic features of HIV dementia.

Diagnosing dementia. Univariate and multivariate analyses of the mental status examination

Investigators have reported poor recognition of dementia by primary physicians. For this reason, mental status examinations were performed on 72 demented and 144 nondemented medical inpatients to assess the sensitivity, specificity, and predictive value of components of this examination in the diagnosis of dementia. Sensitivity of individual level-of-orientation items was low (15.3 to 56.9%), though specificity was high (91.7 to 100%). Sensitivity of several nonorientation items was high (80.6 to 100%), though specificity was low. A multivariate discriminant equation using both orientation and nonorientation items achieved high sensitivity (89.6% test cases, 87.5% validation cases) and specificity (78.1% test cases, 87.5% validation cases). Adding the easily obtained patient characteristic of age to the equation further increased sensitivity (95.8%, 91.3%), while maintaining specificity (82.3%, 85.4%). From these results, it is concluded that the level-of-orientation screening examination used by clinicians to detect dementia is unacceptably insensitive. In contrast, a composite decision rule including nonorientation items achieves high sensitivity with relatively high specificity.

Regional brain atrophy in HIV-1 infection: association with specific neuropsychological test performance

Quantified magnetic resonance imaging (MRI) was related to neuropsychological (NP) test scores in an asymptomatic HIV-1 seropositive group, a non-demented AIDS/ARC group, a group of subjects with HIV-1 dementia, and a seronegative control group. The MRIs were quantified using three planimetric measures of brain structure: the bicaudate ratio (a measure of caudate region atrophy), the bifrontal ratio (a measure of frontal region atrophy), and the ventricle to brain ratio (a measure of overall cerebral atrophy). Cognitive performance was assessed with standard NP tests. Significant correlations between the MRI ratios and many of the NP tests were observed. Of the tests grooved pegboard, part B of the trail making test, the verbal fluency test, and the digit span forward were associated with MRI abnormalities. The bicaudate ratio was most closely associated with the NP tests. These findings indicate that ventricular enlargement, especially in the region of the caudate, is closely related to poor NP test performance in HIV-1 infection.

Factors associated with incident human immunodeficiency virus-dementia

BACKGROUND

Antecedents to human immunodeficiency virus-dementia (HIV-D) are poorly understood.

OBJECTIVE

To identify risk factors for HIV-D.

METHODS

Subjects who are positive for HIV who have CD4+ counts either below 200/microL or below 300/microL with evidence of cognitive impairment were enrolled in this study. Neurologic, cognitive, functional, and laboratory assessments were done semiannually for up to 30 months. Human immunodeficiency virus-dementia was diagnosed using American Academy of Neurology criteria for probable HIV-1-associated dementia complex.

RESULTS

One hundred forty-six nondemented patients were enrolled, 45 of whom subsequently met criteria for incident HIV-D. In univariate analyses using the Cox proportional hazards regression model, the following variables were significantly associated with time to develop dementia: cognitive: abnormal scores on Timed Gait, Verbal Fluency, Grooved Pegboard, and Digit Symbol tests; attention-memory, psychomotor, and executive function domain scores; and the diagnosis of minor cognitive/motor disorder; neurologic and medical: increased abnormalities on the neurologic examination, extrapyramidal signs, history of HIV-related medical symptoms; functional: higher reported role or physical function difficulties. Depression was also a strong risk factor, along with sex, hematocrit, hemoglobin, and beta2-microglobulin levels. In a multivariate model that used cognitive domain scores, covariates with significant hazard ratios included depression, executive dysfunction, and the presence of minor cognitive/motor disorder.

CONCLUSION

Cognitive deficits, minor cognitive/motor disorder, and depression may be early manifestations of HIV-D.

Prospective evaluation of somatic and autonomic small fibers in selected autonomic neuropathies

BACKGROUND

There are a number of distal and generalized small-fiber neuropathies. The neuropathologic basis is poorly understood as somatic and autonomic C fibers are not usually studied in the same region of the body.

OBJECTIVE

To evaluate prospective somatic and autonomic C-fiber function in 11 healthy control subjects and 38 patients with different clinical patterns of neuropathy.

METHODS

Distal small-fiber neuropathy (DSFN), peripheral neuropathy (PN), diabetic neuropathy (DN), neuropathic postural tachycardia syndrome (POTS), and idiopathic autonomic neuropathy (IAN) were evaluated. Intraepidermal nerve fiber density was used to evaluate distal somatic C fibers. Both quantitative sudomotor axon reflex test and skin norepinephrine content were measured for the biopsy site to assess distal autonomic C-fiber function. Postganglionic sudomotor, adrenergic, and cardiovagal functions were evaluated by autonomic reflex testing and quantified using a Composite Autonomic Severity Scale.

RESULTS

Skin norepinephrine concentration was significantly related to CASS. DN was associated with somatic and autonomic C-fiber impairment with good agreement. POTS was associated with selective distal autonomic deficit. DSFN had combined distal somatic and C-fiber impairment. IAN showed combined and selective distal and generalized autonomic C-fiber impairment. The somatic neuropathies had C-fiber impairment affecting both populations to varying degrees.

CONCLUSION

Although a general agreement exists between the loss of somatic C fibers and autonomic deficits, selective involvement occurs for specific autonomic neuropathies.

Neuronal density in the superior frontal and temporal gyri does not correlate with the degree of human immunodeficiency virus-associated dementia

Human immune deficiency virus (HIV) disease may be associated, neuropathologically, with significant neuronal loss and clinically with a severe dementia. However, the significance of neuronal loss in the development of dementia has not been established. In this study we have undertaken a stereological determination of the neuronal numerical density and neuronal volumes in post mortem tissue from the superior frontal and superior temporal gyri in 32 patients who died of acquired immune deficiency syndrome (AIDS). All were prospectively clinically characterized, with dementia identified or excluded, and antiretroviral medication documented. This study combines morphometric techniques with prospective clinical assessment of dementia. As previously demonstrated, all patients dying with AIDS showed neuronal loss, but this was not related to the presence of HIV-associated dementia.

A Comparison of Five Brief Screening Tools for HIV-Associated Neurocognitive Disorders in the USA and South Africa

Screening for HIV-associated neurocognitive disorders (HAND) is important to improve clinical outcomes. We compared the diagnostic sensitivity and specificity of the mini-mental state examination, International HIV dementia scale (IHDS), Montreal cognitive assessment, Simioni symptom questionnaire and cognitive assessment tool-rapid version (CAT-rapid) to a gold standard neuropsychological battery. Antiretroviral-experienced participants from Cape Town, South Africa, and Baltimore, USA, were recruited. The sensitivity and specificity of the five tools, as well as those of the combined IHDS and CAT-rapid, were established using 2 × 2 contingency tables and ROC analysis. More than a third (65165) had symptomatic HAND. In detecting HIV-D, the CAT-Rapid had good sensitivity (94 %) and weak specificity (52 %) (cut-point ≤10), while the IHDS showed fair sensitivity (68 %) and good specificity (86 %) (cut-point ≤10). The combined IHDS and CAT-rapid showed excellent sensitivity and specificity for HIV-D at a cut-off score of ≤16 (out of 20; 89 and 82 %). No tool was adequate in screening for any HAND. The combination IHDS and CAT-rapid tool appears to be a good screener for HIV-D but is only fairly sensitive and poorly specific in screening for any HAND. Screening for milder forms of HAND continues to be a clinical challenge.

Metacognition in HIV-1 seropositive asymptomatic individuals: self-ratings versus objective neuropsychological performance. Multicenter AIDS Cohort Study (MACS)

This study examined the relationship between actual and self-reported neuropsychological deficits, depression, and HIV-1 serostatus. The subjects, who consisted of 479 individuals, 256 who were HIV seronegative (SN) and 233 who were HIV-1 seropositive though still asymptomatic (ASP), were administered a standardized neuropsychological screening battery consisting of measures of attention, motor speed, psychomotor speed, verbal memory, verbal fluency, and depression. To assess subjects' subjective sense of their cognitive status, the Cognitive Failures Questionnaire (CFQ), a 25-item self-report questionnaire, was also administered. The results of MANOVA failed to reveal group differences between the SN and ASP groups on the measures of neuropsychological function. Similarly, the ASP and SN groups did not differ on the number or severity of reported cognitive failures. However, a positive correlation was found between CFQ scores and level of depression. These results do not support the hypothesis that ASP individuals are aware of cognitive decline prior to detection using standard neuropsychologic screening instruments. The data do suggest that the presence of depressed mood, independent of serostatus or actual neuropsychological impairment, is associated with increased cognitive complaints.

Intravenous administration of an AAV-2 vector for the expression of factor IX in mice and a dog model of hemophilia B

Previous experiments have demonstrated the stable expression of factor IX (FIX) protein in mice and canine models of hemophilia B following portal vein gene transfer with a recombinant adeno-associated virus (rAAV) vector encoding FIX. Here, we present the results of studies that further optimized the rAAV vector transgene cassette used to express FIX and explored the use of the less-invasive intravenous (i.v.) route of vector administration for the treatment of hemophilia B. First, a liver-specific promoter was evaluated in conjunction with cis-acting regulatory elements in mice. Constructs that included both the beta-globin intron and the woodchuck hepatitis virus post-transcriptional regulatory element resulted in the highest level of FIX expression in vivo. Using this optimized vector, we demonstrate that i.v. injection was feasible for hepatic gene transfer in mice, achieving 70-80% of portal vein expression levels of FIX. In further studies using the Chapel Hill strain of hemophilia B dogs, we demonstrate for the first time FIX expression and partial correction of the bleeding disorder following i.v. administration of an AAV vector.

Clinical trials in HIV-associated cognitive impairment: cognitive and functional outcomes

Cognitive and functional outcomes are of primary interest in the design of efficacy trials in HIV-associated cognitive impairment. In a longitudinal cohort study, weak associations were found between measures of cognitive performance and commonly used measures of daily functioning (mostly self-report measures) in HIV-infected individuals. Modifications of current functional scales or new functional instruments are needed to assess the clinical relevance of cognitive changes in clinical trials of HIV-associated cognitive impairment.

Generation of a transcription map at the HSD17B locus centromeric to BRCA1 at 17q21

A detailed transcription map of the 320-kb region containing the HSD17B locus on chromosome 17 was generated. Thirty unique cDNA fragments, retrieved following the hybridization of immobilized YACs to primary pools of cDNAs prepared from RNA of mammary gland, ovary, placenta, and the Caco-2 cell line, were aligned into 10 transcription units by physical mapping and hybridization to RNAs of a series of tissues. The cDNAs were then further characterized by sequencing and used to screen mammary gland cDNA libraries. Fragments corresponding to the broadly expressed gamma-tubulin and Ki antigen genes were identified. A full-length cDNA clone encoding a 117-amino-acid protein homologous to the rat ribosomal protein L34 was isolated. Portions of genes with restricted patterns of expression were also obtained, including the previously characterized HSD17B1. One new gene, for which a full-length cDNA was isolated, was found to have an interesting tissue-specific pattern of expression with abundant mRNA in both the colon and the testis and in the mammary carcinoma cell line BT-474. This contrasted with the barely detectable level observed in several tissues including normal mammary gland. Of the five additional transcription units identified, one showed no similarity, two showed identity to human expressed sequences, and two displayed similarity to genes of animal species by amino acid alignment. These latter cDNA clones include potential homologues of a rat nuclear tyrosine phosphatase and of a factor of Drosophila that is known to be involved in the negative regulation of transcription of segment identity genes.

HIV-1 reverse transcriptase sequence in plasma and cerebrospinal fluid of patients with AIDS dementia complex treated with Abacavir

OBJECTIVE

To assess HIV-1 RNA levels and the relationship between HIV-1 reverse transcriptase (RT) genotype from plasma and cerebrospinal fluid (CSF) during treatment with abacavir (Ziagen, ABC) or placebo in combination with stable background therapy (SBG) in subjects with AIDS dementia complex (ADC) (study CNA3001).

DESIGN

One-hundred and five HIV-1 infected adults with ADC were randomized to receive either ABC (600 mg twice daily) or ABC-matched placebo (twice daily) in addition to SBG for 12 weeks.

METHODS

Plasma and CSF were collected for population sequencing at baseline and week 12 (CSF optional). Sequences were analyzed for mutations associated with resistance to nucleoside reverse transcriptase inhibitors (NRTI).

RESULTS

Sixty out of sixty-seven subjects with baseline plasma HIV-RT sequence data harbored virus with > or = 1 NRTI-associated mutations; 50 out of 67 had the M184V mutation. At week 12, more subjects in the ABC group had plasma HIV-1 RNA < or = 400 copies/ml than the SBG group (46% versus 13%, P = 0.002). Non-response to ABC was associated with multiple baseline zidovudine (ZDV)/stavudine (d4T)-associated mutations. Baseline RT mutation patterns differed in 14 out of 21 (67%) paired samples from plasma and CSF. Four subjects experienced > 1 log10 copies/ml reductions in CSF HIV-1 RNA, two in the absence of reductions in plasma HIV-1 RNA and two with undetectable plasma HIV-1 RNA at baseline.

CONCLUSIONS

Substantial decreases in plasma and CSF HIV-1 RNA following addition of ABC were not precluded by baseline HIV-1 NRTI-associated mutations, including the M184V mutation, but non-responders commonly harbored multiple ZDV/d4T-associated mutations. HIV-1 RNA responses and RT genotype appear to be discordant between CSF and plasma in some subjects.

The reliability and validity of the subjective peripheral neuropathy screen

Painful sensory neuropathy (PSN) is the most common neurological disorder associated with HIV infection and affects up to 30% of HIV-positive individuals. PSN may develop as a consequence of HIV infection or from the toxic effect of the antiretrovirals. Although several tools have been developed to screen for PSN, their validity and reliability has yet to be established among HIV-positive patients. The Subjective Peripheral Neuropathy Screen (SPNS) is a brief self-report tool that is currently being administered in the AIDS Clinical Trials Group. The objective of this study was to establish the psychometric properties of the SPNS screening tool for the correct identification of PSN in HIV-positive individuals. Specifically the goals were to determine the reliability, the validity, and the diagnostic efficiency of the SPNS in the detection of PSN. Data were abstracted on subjects enrolled in an ongoing natural history cohort. The SPNS was administered to a convenience sample of 39 HIV-positive individuals with PSN and 44 HIV-positive controls. Results showed the SPNS to be internally consistent (Cronbach's alpha = .86). SPNS score differences assessed by t-test were significantly different for individual symptoms of parasthesias, numbness, and pain of the lower extremities, and for severity measures (the Clinical Severity Grade, and the Average Severity Score) between the HIV-positive groups (p < .05). Using Spearman's rank, significant correlations were demonstrated between the neurological exam and the Clinical Severity Grade and the Average Severity Score, the neurological exam and vibratory quantitative sensory testing (QST) only, and the severity measures and vibratory QST only. Sensitivity and specificity analysis demonstrated that numbness of the lower extremities was the symptom with the highest efficiency for correctly classifying PSN. Thus, internal consistency, construct validity, and criterion related validity were confirmed with the SPNS for the correct classification of PSN in HIV-positive individuals.

Neurocognitive impairment in HIV-infected individuals with previous syphilis

Cognitive impairment is common in HIV-infected individuals, as is syphilis. Treponema pallidum, the bacterium that causes syphilis, invades the central nervous system early in disease. We hypothesized that HIV-infected patients with a history of syphilis or neurosyphilis would have more cognitive impairment than HIV-infected individuals without these infections. Eighty-two of 1574 enrollees in CHARTER, a prospective, observational study, had reactive serum rapid plasma reagin (RPR) tests. They were matched to 84 controls with non-reactive RPR by age, gender, ethnicity and HIV risk factor. Participants underwent comprehensive neuropsychological (NP) evaluations. RPR results were confirmed and serum fluorescent treponemal antibody absorption (FTA-ABS) test reactivity determined at a central laboratory. Sera from 101 of 166 participants were FTA-ABS reactive, indicating past or current syphilis. Among the 136 individuals without confounding conditions, compared with patients who had never had syphilis, those with prior syphilis had a greater number of impaired NP test domains (1.90 SD [1.77] versus 1.25 [1.52], P = 0.03), a higher global deficit score (0.47 [0.46] versus 0.31 [0.33], P = 0.03), and more were impaired in the NP learning domain (36 [42.9%] of 84 versus 13 [25.0%] of 52, P = 0.04). These effects of prior syphilis remained after controlling for education and premorbid intelligence.

Improved Adenoviral Vector for Vascular Gene Therapy

Abstract —First-generation, E1-deleted adenoviral vectors (ΔE1-AV) can transduce the vascular endothelium with high efficiency, but their use is limited by the resulting acute endothelial injury and the long-term development of intimal hyperplasia. To reduce the impact of viral proteins on the gene-modified cells, a second-generation adenoviral vector with an additional pair of deletions in the E4 region was developed. To determine whether this ΔE1/ΔE4-AV vector would be useful for vascular gene transfer, we directly compared the efficiency of gene transfer to uninjured rabbit carotid arteries using either an ΔE1/ΔE4-AV or an ΔE1-AV vector encoding β-galactosidase. Both vectors efficiently transduced vascular endothelium; however, the ΔE1/ΔE4-AV vector gene–modified vessels showed higher β-galactosidase expression 10 days after gene transfer. Importantly, the ΔE1/ΔE4-AV vector produced substantially less endothelial cell activation, less inflammation, and reduced neointimal hyperplasia compared with the ΔE1-AV vector–treated vessels. The ΔE1-AV vector–transduced vessels also demonstrated significantly impaired endothelium-dependent relaxation whereas the ΔE1/ΔE4-AV vector did not impact vasomotor function, even at doses of virus in 5-fold excess of the amount required for >90% transduction of the endothelium. We conclude that the ΔE1/ΔE4-AV vector is superior to the ΔE1-AV vector for vascular gene therapy because of the prolonged transgene expression, reduced vascular inflammation, reduced intimal hyperplasia, and maintenance of normal vasomotor function.