Human adipose tissue as a reservoir for memory CD4+ T cells and HIV.

OBJECTIVE: The objective of this study is to determine whether adipose tissue functions as a reservoir for HIV-1. DESIGN: We examined memory CD4(+) T cells and HIV DNA in adipose tissue-stromal vascular fraction (AT-SVF) of five patients [four antiretroviral therapy (ART)-treated and one untreated]. To determine whether adipocytes stimulate CD4(+) T cells and regulate HIV production, primary human adipose cells were cocultured with HIV-infected CD4(+) T cells. METHODS: AT-SVF T cells were studied by flow cytometry, and AT-SVF HIV DNA (Gag and Env) was examined by nested PCR and sequence analyses. CD4(+) T-cell activation and HIV production were measured by flow cytometry and ELISA. RESULTS: AT-SVF CD3(+) T cells were activated (>60% CD69(+)) memory CD4(+) and CD8(+) T cells in uninfected and HIV-infected persons, but the AT-SVF CD4(+)/CD8(+) ratio was lower in HIV patients. HIV DNA (Gag and Env) was detected in AT-SVF of all five patients examined by nested PCR, comparably to other tissues [peripheral blood mononuclear cell (PBMC), lymph node or thymus]. In coculture experiments, adipocytes increased CD4(+) T-cell activation and HIV production approximately two to three-fold in synergy with gamma-chain cytokines interleukin (IL)-2, IL7 or IL15. These effects were mitigated by neutralizing antibodies against IL6 and integrin-α1ß1. Adipocytes also enhanced T-cell viability. CONCLUSION: Adipose tissues of ART-treated patients harbour activated memory CD4(+) T cells and HIV DNA. Adipocytes promote CD4(+) T-cell activation and HIV production in concert with intrinsic adipose factors. Adipose tissue may be an important reservoir for HIV.

HIV replication in conjunction with granzyme B production by CCR5+ memory CD4 T cells: Implications for bystander cell and tissue pathologies.

Granzyme B (GrzB) is expressed by activated T cells and mediates cellular apoptosis. GrzB also acts as an extracellular protease involved in tissue degradation. We hypothesized that GrzB production from activated memory CD4 T cells may be associated with HIV pathogenesis. We found that stimulated memory CD4 T cells (via costimulation, cytokines, and TLR ligands) concomitantly produced GrzB and HIV. Both GrzB and HIV expression were mainly restricted to CCR5-expressing memory CD4+CD45RO+ T cells, including Th1 and Th17 subsets. Activated memory CD4 T cells also mediated tissue damage, such as disruption of intestinal epithelial monolayers. In non-human primates, CD4 T cells of rhesus macaques (pathogenic SIV hosts) expressed higher GrzB compared to African green monkeys (non-pathogenic SIV hosts). These results suggest that GrzB from CCR5+ memory CD4 T cells may have a role in cellular and tissue pathologies during HIV infection.

Randomized trial to evaluate nutritional status and absorption of enteral feeding after brain death.

CONTEXT: Catecholamines and inflammatory mediators, with elevated levels after brain death, are associated with reduced function and survival of transplanted organs. Enteral nutrition reduces tissue damage and may benefit organs. OBJECTIVE: To evaluate the effects of immunomodulating enteral nutrition in organ donors. DESIGN: Prospective, randomized, open-label study. SETTING: Intensive care unit. PATIENTS: Thirty-six brain-dead organ donors. INTERVENTIONS: Donors were randomized to receive enteral nutrition containing omega-3 polyunsaturated fatty acid, antioxidants, and glutamine or standard care (fasting). Donors received hormonal replacement therapy of corticosteroid, levothyroxine, dextrose, and insulin. MAIN OUTCOME MEASURES: Gastrointestinal assimilation (measured by 13 carbon-labeled uracil breath analysis), quantity of organs recovered, resting energy expenditure, urine level of urea nitrogen, and serum levels of albumin, prealbumin, interleukin 6, tumor necrosis factor-α, and C-reactive protein were evaluated. RESULTS: Thirteen patients (36%) assimilated 13C-labeled uracil. Resting energy expenditure was significantly higher than predicted between 10 and 14 hours after baseline in 33 donors (P= .007). Other measures were not conclusively different between fed and fasting groups. No adverse events occurred that were related to the enteral feeding. CONCLUSIONS: About 30% of donors metabolized 13C-labeled uracil, although no difference in oxidation rate was found between fasting and fed donors. Corticosteroid administration lowers plasma levels of interleukin 6 and most likely contributes to greater than predicted resting energy expenditure. Thus energy needs may not be met during fasting if hormones are given. Consequences of this possible energy deficit warrant further study.

Effects of route of inoculation and viral genetic variation on antibody responses to polyomavirus SV40 in Syrian golden hamsters.

Genetic variants of polyomavirus SV40 are powerful agents with which to define viral effects on cells and carcinogenesis pathways. We hypothesized that differences in biologic variation among viral strains affect the process of viral infection and are reflected in antibody responses to the viral nonstructural large T-antigen (TAg) protein but not in neutralizing antibody responses against the inoculated viral particles. We analyzed the production of TAg antibody and neutralizing antibody in Syrian golden hamsters that were inoculated with SV40 viral strains by intracardiac, intravenous, or intraperitoneal routes and remained tumor free. Compared with the intraperitoneal route, intravascular (that is, intravenous, intracardiac) inoculation resulted in increased frequency of responsiveness to TAg but not in higher TAg antibody titers. The intravascular route was superior both for eliciting neutralizing antibody responses and for higher titers of those responses. Viruses with complex regulatory regions induced TAg antibody more often than did viruses with simple regulatory regions after intraperitoneal but not intravascular injections, with no differences in antibody titers. This viral genetic variation had no effect on neutralizing antibody production after intraperitoneal or intravascular inoculations or on neutralizing antibody titers achieved. These findings confirm that SV40 variants differ in their biologic properties. Route of inoculation combined with viral genetic variation significantly influence the development of serum antibodies to SV40 TAg in tumor-free hamsters. Route of inoculation-but not viral genetic variation-is an important factor in production of neutralizing antibody to SV40.

Granzyme B- and Fas ligand-mediated cytotoxic function induced by mitogenic CD28 stimulation of human memory CD4+ T cells.

Some human memory CD4(+) T cells have cytotoxic functions best understood in the context of viral infections; however, their possible role in pathologic processes is understudied. The novel discovery that mitogenic CD28 antibodies induced proliferation and expansion of Tregs offered therapeutic promise for autoimmune disorders. However, the failed TGN1412 trial forced reassessment of this concept. As memory CD4(+) T cells are known to produce toxic molecules, including granzyme B (GrzB) and FasL, we wondered whether mitogenic CD28 was able to induce these cytotoxic molecules. A commercially available mitogenic human CD28 mAb (clone ANC28.1) was used to determine whether mitogenic CD28 induces cytotoxic function from human memory CD4(+) T cells. We found that stimulation of memory CD4(+) T cells by ANC28.1, as well as by conventional costimulation (CD3/CD28 mAb), robustly induced enzymatically active GrzB, along with increased surface expression of FasL. These functional phenotypes were induced in association with increased expression of T cell activation markers CD69 and CD25, and elimination of target cells by ANC28.1-activated memory CD4(+) T cells involved both GrzB and FasL. Additionally, ANC28.1-activated memory CD4(+) T cells caused disruption of epithelial cell monolayer integrity, which was partially mediated by GrzB. These findings reveal functions of memory CD4(+) T cells previously unknown to be induced by mitogenic CD28, and suggest that these pathogenic mechanisms may have been responsible for some of the widespread tissue destruction that occurred in the TGN1412 trial recipients.

Myelosuppression and infectious complications in children with Down syndrome and acute lymphoblastic leukemia.

Children with Down syndrome (DS) bear an increased risk of acute lymphoblastic leukemia (ALL) and treatment complications. We compared blood counts and toxicities in 22 DS and 44 non-DS ALL patients. Patients with DS had deeper, longer neutrophil and monocyte count nadirs; more toxicities (HR 2.0, P = 0.0005); longer hospitalizations (HR 1.4, P < 0.0001); and more frequent microbiologically documented infections (HR 5.7, P = 0.0019), mucositis (HR 29.0, P = 0.0006), and cellulitis (HR 3.0, P = 0.033). Severe neutropenia, monocytopenia, and increased cellulitis in DS-ALL suggest the importance of skin hygiene, vigilance and aggressive treatment of cutaneous infections.

Rate of decline of ferritin in patients with hemophagocytic lymphohistiocytosis as a prognostic variable for mortality.

Hemophagocytic lymphohistiocytosis (HLH) is difficult to diagnose and treat. Highly elevated ferritin is strongly associated with HLH and levels may provide a prognostic marker. A comprehensive review of ferritin data from our patients during treatment was analyzed with respect to mortality. A patient was 17 times more likely to die when percent ferritin decrease was less than 50% as compared to a 96% or greater decrease as indicated with multivariate logistic modeling. Higher maximum ferritin levels in the first 3 weeks also contributed to the odds of death (OR = 5.6; 90% CI = 1.2-24.9). Regular ferritin measurements may be useful predicting outcomes in HLH patients.

Lymphotropism of Merkel cell polyomavirus infection, Nova Scotia, Canada.

To test the hypothesis that Merkel cell polyomavirus (MCPyV) can infect cells of the lymphoid system, we analyzed 353 specimens, including 152 non-Hodgkin lymphomas, 44 Hodgkin lymphomas, 110 benign lymph nodes, 27 lymph nodes with metastasis, and 20 extranodal tissue samples. MCPyV DNA was detected by quantitative PCR in 13 (6.6%) of 196 lymphomas, including 5 (20.8%) of 24 chronic lymphocytic leukemia specimens, and in 11 (10%) of 110 benign lymph nodes, including 8 (13.1%) of 61 samples of reactive hyperplasia and 3 (10.3%) of 29 normal lymph nodes. Other samples were MCPyV negative. Sequence analysis of 9 virus-positive samples confirmed the identity of MCPyV; 3 viral strains were represented. Immunohistochemical testing showed that 1 T-cell lymphoma expressed MCPyV T-antigen. These findings suggest that the lymphoid system plays a role in MCPyV infection and may be a site for MCPyV persistence.

Efficacy of a motivational behavioral intervention to promote chlamydia and gonorrhea screening in young women: a randomized controlled trial.

BACKGROUND: Seeking screening and treatment for chlamydia (CT) and gonorrhea (GC) by young women is critical to reduction of asymptomatic cervicitis and its complications. OBJECTIVES: To evaluate the efficacy of a client-centered motivational behavioral intervention (MBI), to promote seeking of sexually tranmitted infection (STI) checkups by young women. METHODS: Three hundred seventy-six of 770 eligible sexually active, nonpregnant, English-speaking women (mean age 18.5 years) were recruited from an urban reproductive health clinic and randomized to two groups: intervention plus standard care (MBI) or standard care alone (SC). MBI (two sessions plus booster) was based on the Transtheoretical Model of Change and employed motivational interviewing. Outcome measures monitored for 12 months included: client-initiated clinic visits for STI checkups in response to seven high-risk sexual behaviors by self-report (primary), consistent condom use, number of CT and GC episodes, and movement along the stages of change obtained at baseline and 6- and 12-month follow-up assessments (secondary). Analyses included chi-square, logistic regression, and generalized estimating equations. RESULTS: At baseline, more than 70% endorsed the action stage of change for seeking STI checkups for three of seven high-risk sexual behaviors. No significant differences were noted between the two groups for the primary or secondary outcomes. Across groups, having multiple partners and being pregnant or thinking one might be pregnant were associated with STI checkups. CONCLUSIONS: This is the first known client-centered clinical trial to promote STI screening. Risk-taking and health-seeking behaviors are complex and interrelated with STI and pregnancy concerns. The intervention may have an effect if it is targeted to women in a less medically connected community-based sample.

Variable frequency of polyomavirus SV40 and herpesvirus EBV in lymphomas from two different urban population groups in Houston, TX.

BACKGROUND: Studies have reported differing frequencies of detection of polyomavirus simian virus 40 (SV40) in association with human lymphomas. OBJECTIVE: We addressed the hypothesis that SV40 positivity in lymphomas can vary among sampled populations. STUDY DESIGN: Archival paraffin-embedded lymphoma specimens (n=171) from patients at two urban hospitals in Houston, TX, USA, were analyzed following a cross-sectional study design. Extracted DNAs were characterized by quantitative polymerase chain reaction for the cellular RNase P gene and for SV40 and herpesvirus Epstein-Barr virus (EBV) sequences. RESULTS: Patient characteristics of the two study populations differed significantly whereas the classification of tumor types studied did not. SV40 DNA was detected more frequently in lymphomas from the public hospital population (10/44, 23%) than in lymphomas from the veterans' hospital (VAMC) (4/127, 3%; P<0.0001). EBV detection in lymphomas also differed between the two groups (17/44, 39% vs. 23/127, 18%; P=0.01). SV40 positivity was associated with a younger age category of VAMC lymphoma patients (P=0.02). Expression of T-antigen was detected by immunohistochemistry in half of lymphomas that contained SV40 DNA. Variation was observed in the quality and quantity of DNA recovered from paraffin-embedded specimens, but there was no difference in recoveries of DNA from samples from the two hospitals. CONCLUSIONS: This study demonstrated that, in a direct comparison, the prevalence of SV40 DNA in lymphomas can differ significantly between groups with different demographic distributions.

Radiographic abnormalities in Rothmund-Thomson syndrome and genotype-phenotype correlation with RECQL4 mutation status.

OBJECTIVE: The purpose of this study was to summarize the radiographic skeletal findings in patients with Rothmund-Thomson syndrome (RTS) and to determine whether there is an association between the presence of skeletal abnormalities and the mutational status of the RECQL4 gene. SUBJECTS AND METHODS: Twenty-eight subjects with RTS underwent skeletal surveys and RECQL4 DNA mutation testing. Radiographs were reviewed by two radiologists. RECQL4 mutation testing by DNA sequencing of the gene was performed by a diagnostic laboratory. Genotype-phenotype analysis by Fisher's exact test was performed to investigate whether there was a correlation between mutation status and skeletal abnormalities. RESULTS: Twenty-one (75%) of the subjects had at least one significant skeletal abnormality, the more common being abnormal metaphyseal trabeculation, brachymesophalangy, thumb aplasia or hypoplasia, osteopenia, dislocation of the radial head, radial aplasia or hypoplasia, and patellar ossification defects. Three subjects had a history of destructive bone lesion (osteosarcoma). Genotype-phenotype analysis showed a significant correlation between RECQL4 mutational status and the presence of skeletal abnormalities (p < 0.0001). CONCLUSION: Skeletal abnormalities are frequent in persons with RTS. Many of these abnormalities are not clinically apparent but are detectable on radiographs. The presence of skeletal abnormalities correlates with RECQL4 mutation status, which has been found to correlate with risk of osteosarcoma. Skeletal surveys aid in both diagnosis and management of RTS.

Highly elevated ferritin levels and the diagnosis of hemophagocytic lymphohistiocytosis.

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a potentially lethal condition characterized by a pathologic inflammation. The diagnostic criteria for HLH include fever, splenomegaly, cytopenias, hypertriglyceridemia, hypofibrinogenemia, abnormal natural killer cell (NK cell) functional assay, elevated soluble IL-2Ralpha level, and elevated ferritin level (>500 microg/L). Institution of timely therapy in these critically ill patients may be delayed by difficulties establishing the diagnosis. NK cell functional assay and soluble IL-2Ralpha level may require send-out to a specialized lab. However, ferritin level is available on a same-day basis at most institutions. In this study, we examined the utility of quantitative ferritin levels in diagnosing HLH. PROCEDURE: All patients with ferritin values >500 microg/L obtained at Texas Children's Hospital between January 10, 2003 and January 10, 2005 were identified. Patient charts were reviewed for ferritin levels and hospital course. RESULTS: During the study interval, 330 patients had ferritin levels >500 microg/L. Ten of the 330 patients were diagnosed with HLH. A ferritin level over 10,000 microg/L was 90% sensitive and 96% specific for HLH. Another diagnostic category with significantly elevated ferritin level was illness of unknown cause (n = 10), and only two of these patients were fully evaluated for HLH. CONCLUSIONS: Ferritin levels above 10,000 microg/L appear to be specific and sensitive for HLH. In patients without a significant medical history and a new onset of febrile illness with highly elevated ferritin levels, the diagnosis of HLH should be evaluated.

CD8 apoptosis may be a predictor of T cell number normalization after immune reconstitution in HIV.

BACKGROUND: As part of the Houston Vanguard study, a subset of 10 patients randomized to receive IL-2 therapy were compared to 4 patients randomized to not receive IL-2, for markers of T cell activation and death during the first three cycles of IL-2. All patients were treated with combination antiretroviral therapy (ART) and were virally suppressed. The purpose of the study was to examine the role of CD8(+) T cell death in responses to ART and IL-2 therapy. METHODS: Lymphocytes were examined at Day 0, 5 and 30 days during three cycles of IL-2 therapy. CD25, CD38, HLA-DR expression and annexin (cell death) were examined on CD4 and CD8 subpopulations. Follow up studies examined CD4 levels and CD4:CD8 reconstitution after 6 years using both univariant and multivariate analyses. RESULTS: Human lymphocytes responded to IL-2 therapy by upregulation of CD25 on CD4(+) T cells, leading to an increase in CD4 cell counts. CD8(+) T cells did not increase CD25 expression, but upregulated activation antigens (CD38 and DR) and had increased death. At baseline, 7 of the 14 patients had high CD8+ T cell apoptosis (mean 17.0% +/- 6.0). We did an exploratory analysis of immune status after six years, and found that baseline CD8+ T cell apoptosis was correlated with CD4 cell count gain beginning two years post enrollment. Patients with low levels of CD8(+) T cell apoptosis at baseline (mean 2.2% +/- 2.1) had significantly higher CD4 cell counts and more normalized CD4:CD8 ratios than patients with high CD8(+) T cell apoptosis (mean CD4 cell counts 1,209 +/- 164 vs 754 +/- 320 cells/mm(3); CD4:CD8 ratios 1.55 vs. 0.70, respectively). CONCLUSION: We postulate that CD8(+) T cell apoptosis may reflect inherent activation status, which continues in some patients even though viral replication is suppressed which influences the ability of CD4(+) T cells to rebound. Levels of CD8(+) T cell apoptosis may therefore be an independent predictor of immune status, which should be shown in a prospective study.

Clinicopathologic features of osteosarcoma in patients with Rothmund-Thomson syndrome.

PURPOSE: Patients with Rothmund-Thomson syndrome (RTS) and RECQL4 gene mutations have an increased risk of developing osteosarcoma (OS). Because RTS is considered a genomic instability syndrome, patients may experience increased toxicity with chemotherapy. The purpose of this study was to summarize the clinical features and response to therapy of OS in patients with RTS. The results of this analysis will help to define treatment guidelines for this complex and rare condition. PATIENTS AND METHODS: An international cohort of patients with RTS and OS was enrolled in an institutional review board-approved study at Baylor College of Medicine (Houston, TX). Medical records were reviewed, and the following information was extracted: clinical features, treatment, pathologic findings, and clinical outcome. RESULTS: The median age at diagnosis of OS for the 12 patients was 10 years. The most common primary tumor sites were the long bones (femur, tibia); the most frequent histologic subtype was conventional OS. Histologic response to chemotherapy and outcome were similar to other published large series of sporadic OS. Eight patients are alive and disease free; four died as a result of cancer. Five patients required chemotherapy dose modifications, most commonly due to mucositis from doxorubicin. CONCLUSION: Our results indicate that patients with RTS and OS are younger, but that their clinical behavior is similar to patients with sporadic OS. Our report suggests that these patients should initially be treated with conventional doses of chemotherapy as prescribed by current protocols; however, cautious and careful clinical observation is warranted to monitor for enhanced doxorubicin sensitivity in patients with RTS.

A phase II trial using thalidomide for Langerhans cell histiocytosis.

BACKGROUND: Few new drugs for treatment of Langerhans cell histiocytosis (LCH) have been studied. Tumor necrosis factor-alpha (TNF-alpha) is a prime therapeutic target since it appears to be present in elevated amounts in LCH lesions. Thalidomide inhibits TNF-alpha production by affecting the gene promoter as well as other anti-cytokine effects. PROCEDURES: A Phase II trial of thalidomide for treatment of LCH patients who had failed primary and at least one secondary regimen was conducted. Sixteen patients were enrolled: nine males and seven females ranging in age from 19 months to 45 years. Six patients were high risk (HR) because of spleen, liver, lung, or bone marrow involvement. The low risk (LR) patients included six with bone/skin LCH, one with multiple bone, one with skin/bone/pituitary, one with skin/bone/brain, and one with skin only disease involvement. Fifteen patients remained on treatment from 3 weeks to over 1 year. RESULTS: Among the LR patients there were four complete responses, three partial responses, and two with no response to thalidomide. No HR patient responded to thalidomide and all died of pulmonary, liver, or bone marrow failure. Thalidomide may have played a role in the pulmonary failure. Other toxicities that required stopping therapy included neutropenia, peripheral neuropathy, and fatigue. CONCLUSIONS: Thalidomide is an effective therapy for some LR patients with LCH, but showed no significant responses in HR patients. Dose-limiting toxicities may reduce its efficacy in LR patients. Additional trials with improved anti-TNF therapies would appear warranted.

Neural tube defects: knowledge and preconceptional prevention practices in minority young women.

OBJECTIVE: To assess 1) knowledge of neural tube defect (NTD) prevention by folic acid, 2) frequency of intake of multivitamins and folate- and folic acid-fortified food, and 3) factors associated with knowledge and prevention practices among sexually active minority adolescent and young adult women. METHODS: Young minority women were enrolled in a folic acid program at 3 urban Houston, Texas, reproductive health clinics and assessed for NTD knowledge and preventive practices. A 3-month supply of multivitamins was also dispensed at enrollment. A 3-month program follow-up survey of a randomly selected sample at 2 sites was conducted. RESULTS: Of 387 women (mean age: 18 +/- 1.9 years), 72% were black and 28% were Hispanic. At enrollment, clinics were a major source of information of NTD prevention (44%); 52% had heard of folic acid, 45% had heard of NTDs, and 50% had heard of birth defects prevention by multivitamins. Significantly more Hispanic than black young women had heard of NTDs (59% vs 39%). Pregnancy history, regular birth control use, and education level for age were independently associated with knowledge. In young women with low education level for age, regular birth control use was significantly associated with knowledge. At enrollment, daily multivitamin intake was very low (9%) and folate-rich foods were consumed in inadequate amounts. Adequate folate diet was not associated with knowledge. The program follow-up survey indicated that 88% to 92% had knowledge of NTDs and folic acid, and 67% reported taking a daily multivitamin. CONCLUSIONS: Publicly funded clinics may be the only source of information on NTD prevention for many minority young women. Preliminary evidence suggests that a promotion program improves knowledge, and dispensing of multivitamins increases multivitamin use. However, clinicians in such programs need to reinforce daily adherence to multivitamins in young women.

Simian virus 40 in human cancers.

BACKGROUND: Many studies have reported the presence of simian virus 40 (SV40) deoxyribonucleic acid (DNA) or protein in human brain tumors and bone cancers, malignant mesothelioma, and non-Hodgkin's lymphoma. However, the small samples and lack of control groups in some reports have made it difficult to assess their reliability. METHODS: Studies were included in this analysis if they met the following criteria: original studies of patients with primary brain tumors and bone cancers, malignant mesothelioma, or non-Hodgkin's lymphoma; the investigation of SV40 was performed on primary cancer specimens; the analysis included a control group; and the same technique was used for cases and controls. Included reports were published from 1975 to 2002. RESULTS: Thirteen studies fulfilled the criteria for the investigation of primary brain cancers (661 tumors and 482 control samples). Specimens from patients with brain tumors were almost four times more likely to have evidence of SV40 infection than were those from controls (odds ratio [OR] = 3.9; 95% confidence interval [CI]: 2.6 to 5.8). The association was even stronger for mesothelioma (OR = 17; 95% CI: 10 to 28; based on 15 studies with 528 mesothelioma samples and 468 control samples) and for bone cancer (OR = 25; 95% CI: 6.8 to 88; based on four studies with 303 cancers and 121 control samples). SV40 DNA was also more frequent in samples from patients with non-Hodgkin's lymphoma (OR = 5.4; 95% CI: 3.1 to 9.3; based on three studies with 301 cases and 578 control samples) than from controls. CONCLUSION: These results establish that SV40 is associated significantly with brain tumors, bone cancers, malignant mesothelioma, and non-Hodgkin's lymphoma. Studies are needed to assess current prevalence of SV40 infections.

Association between osteosarcoma and deleterious mutations in the RECQL4 gene in Rothmund-Thomson syndrome.

BACKGROUND: Rothmund-Thomson syndrome (RTS) is an autosomal recessive disorder associated with an increased predisposition to osteosarcoma. Children with RTS typically present with a characteristic skin rash (poikiloderma), small stature, and skeletal dysplasias. Mutations in the RECQL4 gene, which encodes a RecQ DNA helicase, have been reported in a few RTS patients. We examined whether a predisposition to developing osteosarcoma among an international cohort of RTS patients was associated with a distinctive pattern of mutations in the RECQL4 gene. METHODS: We obtained clinical information about and biologic samples from 33 RTS patients (age range = 1-30 years). Eleven patients were diagnosed with osteosarcoma. All 21 exons and 13 short introns of the RECQL4 gene were sequenced from the genomic DNA of all subjects. Kaplan-Meier survival analysis was used to estimate the incidence of osteosarcoma among patients with and without mutations predicted to produce a truncated RECQL4 protein. RESULTS: Twenty-three RTS patients, including all 11 osteosarcoma patients, carried at least one of 19 truncating mutations in their RECQL4 genes. The incidence of osteosarcoma was 0.00 per year in truncating mutation-negative patients (100 person-years of observation) and 0.05 per year in truncating mutation-positive patients (230 person-years of observation) (P =.037; two-sided log-rank test). CONCLUSIONS: Mutations predicted to result in the loss of RECQL4 protein function occurred in approximately two-thirds of RTS patients and are associated with risk of osteosarcoma. Molecular diagnosis has the potential to identify those children with RTS who are at high risk of this cancer.

Conventional epidemiology and the link between SV40 and human cancers.

Simian virus 40 (SV40) is known to cause tumourigenesis. The main types of tumour induced by SV40 in laboratory animals mirror the human cancers that have been found to contain SV40 DNA or the viral oncoprotein. Increasing amounts of data support the notion that SV40 may be an aetiological factor in the development of human cancers. Retrospective birth cohort studies have been used in attempts to refute the alleged causal link between SV40 and human cancers. However, these observational studies are affected by several important confounding factors, which mean that firm conclusions cannot be drawn. In this essay, we consider the unique features of SV40 infection in humans and examine the limitations of conventional studies that seek to disprove the aetiological link with human cancer.

Polyomavirus JCV excretion and genotype analysis in HIV-infected patients receiving highly active antiretroviral therapy.

OBJECTIVE: To assess the frequency of shedding of polyomavirus JC virus (JCV) genotypes in urine of HIV-infected patients receiving highly active antiretroviral therapy (HAART). METHODS: Single samples of urine and blood were collected prospectively from 70 adult HIV-infected patients and 68 uninfected volunteers. Inclusion criteria for HIV-infected patients included an HIV RNA viral load < 1000 copies, CD4 cell count of 200-700 x 106 cells/l, and stable HAART regimen. PCR assays and sequence analysis were carried out using JCV-specific primers against different regions of the virus genome. RESULTS: JCV excretion in urine was more common in HIV-positive patients but not significantly different from that of the HIV-negative group [22/70 (31%) versus 13/68 (19%); P = 0.09]. HIV-positive patients lost the age-related pattern of JCV shedding (P = 0.13) displayed by uninfected subjects (P = 0.01). Among HIV-infected patients significant differences in JCV shedding were related to CD4 cell counts (P = 0.03). Sequence analysis of the JCV regulatory region from both HIV-infected patients and uninfected volunteers revealed all to be JCV archetypal strains. JCV genotypes 1 (36%) and 4 (36%) were the most common among HIV-infected patients, whereas type 2 (77%) was the most frequently detected among HIV-uninfected volunteers. CONCLUSION: These results suggest that JCV shedding is enhanced by modest depressions in immune function during HIV infection. JCV shedding occurred in younger HIV-positive persons than in the healthy controls. As the common types of JCV excreted varied among ethnic groups, JCV genotypes associated with progressive multifocal leukoencephalopathy may reflect demographics of those infected patient populations.