Immunological and infectious risk factors for lung cancer in US veterans with HIV: a longitudinal cohort study

BACKGROUND

HIV infection is independently associated with risk of lung cancer, but few data exist for the relation between longitudinal measurements of immune function and lung-cancer risk in people living with HIV.

METHODS

We followed up participants with HIV from the Veterans Aging Cohort Study for a minimum of 3 years between Jan 1, 1998, and Dec 31, 2012, and used cancer registry data to identify incident cases of lung cancer. The index date for each patient was the later of the date HIV care began or Jan 1, 1998. We excluded patients with less than 3 years' follow-up, prevalent diagnoses of lung cancer, or incomplete laboratory data. We used Cox regression models to investigate the relation between different time-updated lagged and cumulative exposures (CD4 cell count, CD8 cell count, CD4/CD8 ratio, HIV RNA, and bacterial pneumonia) and risk of lung cancer. Models were adjusted for age, race or ethnicity, smoking, hepatitis C virus infection, alcohol use disorders, drug use disorders, and history of chronic obstructive pulmonary disease and occupational lung disease.

FINDINGS

We identified 277 cases of incident lung cancer in 21 666 participants with HIV. In separate models for each time-updated 12 month lagged, 24 month simple moving average cumulative exposure, increased risk of lung cancer was associated with low CD4 cell count (p trend=0·001), low CD4/CD8 ratio (p trend=0·0001), high HIV RNA concentration (p=0·004), and more cumulative bacterial pneumonia episodes (12 month lag only; p trend=0·0004). In a mutually adjusted model including these factors, CD4/CD8 ratio and cumulative bacterial pneumonia episodes remained significant (p trends 0·003 and 0·004, respectively).

INTERPRETATION

In our large HIV cohort in the antiretroviral therapy era, we found evidence that dysfunctional immune activation and chronic inflammation contribute to the development of lung cancer in the setting of HIV infection. These findings could be used to target lung-cancer prevention measures to high-risk groups.

FUNDING

US National Institutes of Health.

Does radiotherapy still have a role in unresected biliary tract cancer?

The benefits of radiotherapy for inoperable biliary tract cancer remain unclear due to the lack of randomized data. We evaluated the impact of radiotherapy on survival in elderly patients using the SEER‐Medicare database. Patients in the SEER‐Medicare database with inoperable biliary tract tumors diagnosed between 1998 and 2011 were included. We used multivariate logistic regression to evaluate factors associated with treatment selection, and multivariate Cox regression and propensity score matching to evaluate treatment selection in relation to subsequent survival. Of the 2343 patients included, 451 (19%) received radiotherapy within 4 months of diagnosis. The use of radiotherapy declined over time, and was influenced by receipt of chemotherapy and patient age, race, marital status, poverty status, and tumor stage and type. Median survival was 9.3 (95% CI 8.7–9.7) months among patients who did not receive radiation and 10.0 (95% CI 9.1–11.3) months among those who received radiation, conditional on having survived 4 months. In patients who received chemotherapy (n = 1053), receipt of radiation was associated with improved survival, with an adjusted hazard ratio of 0.82 (95% 0.70–0.97, P = 0.02). In patients who did not receive chemotherapy (n = 1290), receipt of radiation was not associated with improved survival, with an adjusted hazard ratio of 1.09 (95% 0.91–1.30, P = 0.34). Propensity‐scored matched analyses showed similar results. Despite the survival benefit associated with the addition of radiotherapy to chemotherapy, the use of radiation for unresectable biliary tract cancers has declined over time.

Time trends in cancer incidence in persons living with HIV/AIDS in the antiretroviral therapy era: 1997-2012

OBJECTIVE

Utilizing the Veterans Aging Cohort Study, the largest HIV cohort in North America, we conducted one of the few comprehensive comparisons of cancer incidence time trends in HIV-infected (HIV+) versus uninfected persons during the antiretroviral therapy (ART) era.

DESIGN

Prospective cohort study.

METHODS

We followed 44 787 HIV+ and 96 852 demographically matched uninfected persons during 1997-2012. We calculated age-, sex-, and race/ethnicity-standardized incidence rates and incidence rate ratios (IRR, HIV+ versus uninfected) over four calendar periods with incidence rate and IRR period trend P values for cancer groupings and specific cancer types.

RESULTS

We observed 3714 incident cancer diagnoses in HIV+ and 5760 in uninfected persons. The HIV+ all-cancer crude incidence rate increased between 1997-2000 and 2009-2012 (P trend = 0.0019). However, after standardization, we observed highly significant HIV+ incidence rate declines for all cancer (25% decline; P trend <0.0001), AIDS-defining cancers (55% decline; P trend <0.0001), nonAIDS-defining cancers (NADC; 15% decline; P trend = 0.0003), and nonvirus-related NADC (20% decline; P trend <0.0001); significant IRR declines for all cancer (from 2.0 to 1.6; P trend <0.0001), AIDS-defining cancers (from 19 to 5.5; P trend <0.0001), and nonvirus-related NADC (from 1.4 to 1.2; P trend = 0.049); and borderline significant IRR declines for NADC (from 1.6 to 1.4; P trend = 0.078) and virus-related NADC (from 4.9 to 3.5; P trend = 0.071).

CONCLUSION

Improved HIV care resulting in improved immune function most likely contributed to the HIV+ incidence rate and the IRR declines. Further promotion of early and sustained ART, improved ART regimens, reduction of traditional cancer risk factor (e.g. smoking) prevalence, and evidence-based screening could contribute to future cancer incidence declines among HIV+ persons.

Abstract 4308: Multiplicative interaction between HIV infection status and FIB-4 in prediction of hepatocellular carcinoma risk

Purpose: FIB-4 is an established marker of liver fibrosis and cirrhosis, calculated from platelet count, alanine transaminase, aspartate transaminase, and age. We previously found baseline FIB-4 to be strongly associated with hepatocellular carcinoma (HCC) risk among HIV-infected (HIV+) patients in the US; a similar finding was reported among persons who consume alcohol or are chronic hepatitis B virus (HBV) carriers in South Korea. Longitudinal associations between FIB-4 and HCC risk have not yet been explored. We aimed to expand our prior investigation by including uninfected patients, using time-updated FIB-4, and testing for multiplicative interaction between HIV status and FIB-4 in the prediction of HCC risk. We hypothesized that the relationship between FIB-4 and HCC risk would differ by HIV status.

Methods: We tested this hypothesis in the Veterans Aging Cohort Study, an open cohort that enrolls HIV+ veterans when they begin HIV care in the Veterans Health Administration and matches two uninfected patients by age, sex, race/ethnicity, and clinical site. We used proportional hazards regression models with time-varying covariates to calculate hazard ratios (HR) and 95% confidence intervals (CI) for FIB-4, adjusted for HCC risk factors (age, sex, race, hepatitis C virus (HCV) infection, HBV infection, smoking, alcohol, BMI, and diabetes). We used the counting process to create time-updated FIB-4 intervals and examined one-, three-, and five-year lagged FIB-4. We identified incident HCC cases from the VA Central Cancer Registry and determined hepatitis C virus and hepatitis B virus status from laboratory results. We defined low (3.25) as previously established.

Results: Between 2000 and 2012, among 37,158 HIV+ subjects, 202 developed HCC. Among 78,339 uninfected subjects, 207 developed HCC. There was a significant multiplicative interaction between HIV status and one-year lagged FIB-4 (interaction p = 0.0015). High FIB-4 was a stronger predictor of HCC in the uninfected than in HIV+. Among uninfected, the adjusted HR was 6.9 (95% CI: 3.4, 12.5) for intermediate FIB-4 and 40.0 (95% CI: 22.3, 71.8) for high FIB-4 compared to uninfected with low FIB-4. Among HIV+, with the same reference group (uninfected with low FIB-4), the adjusted HR was 2.1 (95% CI: 1.0, 4.4) for low FIB-4, 6.4 (95% CI: 3.5, 11.7) for intermediate FIB-4, and 23.7 (95% CI: 13.1, 42.9) for high FIB-4. There was no interaction between FIB-4 and HCV status (p = 0.92). Results were qualitatively similar using a three- or five-year lag.

Conclusions: Calculated from routine, non-invasive laboratory tests, FIB-4 is a strong, independent HCC risk factor in both HIV+ and uninfected subjects after adjustment for other HCC risk factors. FiB-4 appears to be a stronger risk factor in uninfected than in HIV+.

Citation Format: Lesley S. Park, Janet P. Tate, Vincent Lo Re, Adeel A. Butt, Cynthia Gibert, Matthew Bidwell Goetz, Sheldon T. Brown, Joseph Lim, David Rimland, Jennifer S. Lee, Amy C. Justice, Robert Dubrow. Multiplicative interaction between HIV infection status and FIB-4 in prediction of hepatocellular carcinoma risk. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4308.

Prevalence of non-HIV cancer risk factors in persons living with HIV/AIDS: a meta-analysis

OBJECTIVE

The burden of cancer among persons living with HIV/AIDS (PLWHA) is substantial and increasing. We assessed the prevalence of modifiable cancer risk factors among adult PLWHA in Western high-income countries since 2000.

DESIGN

Meta-analysis.

METHODS

We searched PubMed to identify articles published in 2011-2013 reporting prevalence of smoking, alcohol consumption, overweight/obesity, and infection with human papillomavirus (HPV), hepatitis C virus (HCV) and hepatitis B virus (HBV) among PLWHA. We conducted random effects meta-analyses of prevalence for each risk factor, including estimation of overall, sex-specific, and HIV-transmission-group-specific prevalence. We compared prevalence in PLWHA with published prevalence estimates in US adults.

RESULTS

The meta-analysis included 113 publications. Overall summary prevalence estimates were current smoking, 54% [95% confidence interval (CI) 49-59%] versus 20-23% in US adults; cervical high-risk HPV infection, 46% (95% CI 34-58%) versus 29% in US females; oral high-risk HPV infection, 16% (95% CI 10-23%) versus 4% in US adults; anal high-risk HPV infection (men who have sex with men), 68% (95% CI 57-79%), with no comparison estimate available; chronic HCV infection, 26% (95% CI 21-30%) versus 0.9% in US adults; and HBV infection, 5% (95% CI 4-5%) versus 0.3% in US adults. Overweight/obesity prevalence (53%; 95% CI 46-59%) was below that of US adults (68%). Meta-analysis of alcohol consumption prevalence was impeded by varying assessment methods. Overall, we observed considerable study heterogeneity in prevalence estimates.

CONCLUSION

Prevalence of smoking and oncogenic virus infections continues to be extraordinarily high among PLWHA, indicating a vital need for risk factor reduction efforts.

Predicting Risk of End-Stage Liver Disease in Antiretroviral-Treated Human Immunodeficiency Virus/Hepatitis C Virus-Coinfected Patients

Background.  End-stage liver disease (ESLD) is an important cause of morbidity among human immunodeficiency virus (HIV)/hepatitis C virus (HCV)-coinfected patients. Quantifying the risk of this outcome over time could help determine which coinfected patients should be targeted for risk factor modification and HCV treatment. We evaluated demographic, clinical, and laboratory variables to predict risk of ESLD in HIV/HCV-coinfected patients receiving antiretroviral therapy (ART). Methods.  We conducted a retrospective cohort study among 6016 HIV/HCV-coinfected patients who received ART within the Veterans Health Administration between 1997 and 2010. The main outcome was incident ESLD, defined by hepatic decompensation, hepatocellular carcinoma, or liver-related death. Cox regression was used to develop prognostic models based on baseline demographic, clinical, and laboratory variables, including FIB-4 and aspartate aminotransferase-to-platelet ratio index, previously validated markers of hepatic fibrosis. Model performance was assessed by discrimination and decision curve analysis. Results.  Among 6016 HIV/HCV patients, 532 (8.8%) developed ESLD over a median of 6.6 years. A model comprising FIB-4 and race had modest discrimination for ESLD (c-statistic, 0.73) and higher net benefit than alternative strategies of treating no or all coinfected patients at relevant risk thresholds. For FIB-4 >3.25, ESLD risk ranged from 7.9% at 1 year to 26.0% at 5 years among non-blacks and from 2.4% at 1 year to 14.0% at 5 years among blacks. Conclusions.  Race and FIB-4 provided important predictive information on ESLD risk among HIV/HCV patients. Estimating risk of ESLD using these variables could help direct HCV treatment decisions among HIV/HCV-coinfected patients.

Comparison of risk and age at diagnosis of myocardial infarction, end-stage renal disease, and non-AIDS-defining cancer in HIV-infected versus uninfected adults

BACKGROUND

Although it has been shown that human immunodeficiency virus (HIV)-infected adults are at greater risk for aging-associated events, it remains unclear as to whether these events happen at similar, or younger ages, in HIV-infected compared with uninfected adults. The objective of this study was to compare the median age at, and risk of, incident diagnosis of 3 age-associated diseases in HIV-infected and demographically similar uninfected adults.

METHODS

The study was nested in the clinical prospective Veterans Aging Cohort Study of HIV-infected and demographically matched uninfected veterans, from 1 April 2003 to 31 December 2010. The outcomes were validated diagnoses of myocardial infarction (MI), end-stage renal disease (ESRD), and non-AIDS-defining cancer (NADC). Differences in mean age at, and risk of, diagnosis by HIV status were estimated using multivariate linear regression models and Cox proportional hazards models, respectively.

RESULTS

A total of 98 687 (31% HIV-infected and 69% uninfected) adults contributed >450 000 person-years and 689 MI, 1135 ESRD, and 4179 NADC incident diagnoses. Mean age at MI (adjusted mean difference, -0.11; 95% confidence interval [CI], -.59 to .37 years) and NADC (adjusted mean difference, -0.10 [95% CI, -.30 to .10] years) did not differ by HIV status. HIV-infected adults were diagnosed with ESRD at an average age of 5.5 months younger than uninfected adults (adjusted mean difference, -0.46 [95% CI, -.86 to -.07] years). HIV-infected adults had a greater risk of all 3 outcomes compared with uninfected adults after accounting for important confounders.

CONCLUSIONS

HIV-infected adults had a higher risk of these age-associated events, but they occurred at similar ages than those without HIV.

Cancer Incidence in HIV-Infected Versus Uninfected Veterans: Comparison of Cancer Registry and ICD-9 Code Diagnoses

BACKGROUND

Given the growing interest in the cancer burden in persons living with HIV/AIDS, we examined the validity of data sources for cancer diagnoses (cancer registry versus International Classification of Diseases, Ninth Revision [ICD-9 codes]) and compared the association between HIV status and cancer risk using each data source in the Veterans Aging Cohort Study (VACS), a prospective cohort of HIV-infected and uninfected veterans from 1996 to 2008.

METHODS

We reviewed charts to confirm potential incident cancers at four VACS sites. In the entire cohort, we calculated cancer-type-specific age-, sex-, race/ethnicity-, and calendar-period-standardized incidence rates and incidence rate ratios (IRR) (HIV-infected versus uninfected). We calculated standardized incidence ratios (SIR) to compare VACS and Surveillance, Epidemiology, and End Results rates.

RESULTS

Compared to chart review, both Veterans Affairs Central Cancer Registry (VACCR) and ICD-9 diagnoses had approximately 90% sensitivity; however, VACCR had higher positive predictive value (96% versus 63%). There were 6,010 VACCR and 13,386 ICD-9 incident cancers among 116,072 veterans. Although ICD-9 rates tended to be double VACCR rates, most IRRs were in the same direction and of similar magnitude, regardless of data source. Using either source, all cancers combined, most viral-infection-related cancers, lung cancer, melanoma, and leukemia had significantly elevated IRRs. Using ICD-9, eight additional IRRs were significantly elevated, most likely due to false positive diagnoses. Most ICD-9 SIRs were significantly elevated and all were higher than the corresponding VACCR SIR.

CONCLUSIONS

ICD-9 may be used with caution for estimating IRRs, but should be avoided when estimating incidence or SIRs. Elevated cancer risk based on VACCR diagnoses among HIV-infected veterans was consistent with other studies.

Time trends in glioblastoma multiforme survival: the role of temozolomide

BACKGROUND

In 2005, maximum safe surgical resection, followed by radiotherapy with concomitant temozolomide (TMZ), followed by adjuvant TMZ became the standard of care for glioblastoma (GBM). Furthermore, a modest, but meaningful, population-based survival improvement for GBM patients occurred in the US between 1999 (when TMZ was first introduced) and 2008. We hypothesized that TMZ usage explained this GBM survival improvement.

METHODS

We used national Veterans Health Administration (VHA) databases to construct a cohort of GBM patients, with detailed treatment information, diagnosed 1997-2008 (n = 1645). We compared survival across 3 periods of diagnosis (1997-2000, 2001-2004, and 2005-2008) using Kaplan-Meier curves. We used proportional hazards models to calculate period hazard rate ratios (HRs) and 95% confidence intervals (CIs), adjusted for demographic, clinical, and treatment covariates.

RESULTS

Survival increased over calendar time (stratified log-rank P < .0001). After adjusting for age and Charlson comorbidity score, for cases diagnosed in 2005-2008 versus 1997-2000, the HR was 0.72 (95% CI, 0.64-0.82; p-trend < .0001). Sequentially adding non-TMZ treatment variables (ie, surgery, radiotherapy, non-TMZ chemotherapy) to the model did not change this result. However, adding TMZ to the model containing age, Charlson comorbidity score, and all non-TMZ treatments eliminated the period effect entirely (HR = 1.01; 95% CI, 0.86-1.19; p-trend = 0.84).

CONCLUSIONS

The observed survival improvement among GBM patients diagnosed in the VHA system between 1997 and 2008 was completely explained by TMZ. Similar studies in other populations are warranted to test the generalizability of our finding to other patient cohorts and health care settings.

HIV as an independent risk factor for incident lung cancer

BACKGROUND

It is unclear whether the elevated rate of lung cancer among HIV-infected persons is due to biological effects of HIV, surveillance bias, or excess smoking. We compared the incidence of lung cancer between HIV-infected and demographically similar HIV-uninfected patients, accounting for smoking and stage of lung cancer at diagnosis.

DESIGN

Data from the Veterans Aging Cohort Study Virtual Cohort were linked to data from the Veterans Affairs Central Cancer Registry, resulting in an analytic cohort of 37,294 HIV-infected patients and 75,750 uninfected patients.

METHODS

We calculated incidence rates of pathologically confirmed lung cancer by dividing numbers of cases by numbers of person-years at risk. We used Poisson regression to determine incidence rate ratios (IRRs), adjusting for age, sex, race/ethnicity, smoking prevalence, previous bacterial pneumonia, and chronic obstructive pulmonary disease.

RESULTS

The incidence rate of lung cancer in HIV-infected patients was 204 cases per 100,000 person-years [95% confidence interval (CI) 167-249] and among uninfected patients was 119 cases per 100,000 person-years (95% CI 110-129). The IRR of lung cancer associated with HIV infection remained significant after multivariable adjustment (IRR 1.7; 95% CI 1.5-1.9). Lung cancer stage at presentation did not differ between HIV-infected and uninfected patients.

CONCLUSION

In our cohort of demographically similar HIV-infected and uninfected patients, HIV infection was an independent risk factor for lung cancer after controlling for potential confounders including smoking. The similar stage distribution between the two groups indicated that surveillance bias was an unlikely explanation for this finding.

FIB-4 index is associated with hepatocellular carcinoma risk in HIV-infected patients

BACKGROUND

Chronic inflammation caused by hepatitis B virus infection, hepatitis C virus infection, and/or heavy alcohol use can lead to fibrosis, cirrhosis, and eventually hepatocellular carcinoma (HCC). FIB-4 is an index score calculated from platelet count, alanine transaminase, aspartate transaminase, and age that predicts fibrosis and cirrhosis. We hypothesized that high FIB-4 would be associated with development of HCC in HIV-infected persons, who are at high risk due to high prevalence of viral hepatitis and alcohol consumption, and possibly due to HIV infection itself.

METHODS

Using proportional hazards models, we tested this hypothesis among 22,980 HIV-infected men from the Veterans Aging Cohort Study. We identified incident HCC cases from the Veterans Affairs Central Cancer Registry.

RESULTS

During follow-up, there were 112 incident HCC diagnoses. The age- and race/ethnic group-adjusted HR was 4.2 [95% confidence interval (CI), 2.4-7.4] for intermediate FIB-4 and 13.0 (95% CI, 7.2-23.4) for high FIB-4, compared with low FIB-4. After further adjustment for enrollment year, CD4 count, HIV-1 RNA level, antiretroviral therapy use, hepatitis B and C virus infection, alcohol abuse/dependency, and diabetes, FIB-4 remained a strong, significant, independent risk factor for HCC. The multivariate-adjusted HR was 3.6 (95% CI, 2.1-6.4) for intermediate FIB-4 and 9.6 (95% CI, 5.2-17.4) for high FIB-4.

CONCLUSIONS

Calculated from routine, noninvasive laboratory tests, FIB-4 is a strong, independent HCC risk factor in HIV-infected patients.

IMPACT

FIB-4 might prove valuable as an easily measured index to identify those at highest risk for HCC, even prior to development of clinical cirrhosis.

Rehospitalization among elderly patients with thyroid cancer after thyroidectomy are prevalent and costly

BACKGROUND

Thyroid cancer increases in incidence and aggressiveness with age. The elderly are the fastest growing segment of the U.S. population. Reducing rates of rehospitalization would lower cost and improve quality of care. This is the first study to report population-level information characterizing rehospitalization after thyroidectomy among the elderly.

METHODS

The Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked database was used to identify patients older than aged 65 years with thyroid cancer who underwent thyroidectomy from 1997-2002. Patient and hospital characteristics were studied to predict the risk of rehospitalization. Outcomes were 30-day unplanned rehospitalization rate, cost, and length of stay (LOS) of readmission.

RESULTS

Of 2,127 patients identified, 69% were women, 84% had differentiated thyroid cancer, and 52% underwent total thyroidectomy. Mean age was 74 years. A total of 171 patients (8%) underwent 30-day unplanned rehospitalization. Rehospitalization was associated with increased comorbidity, advanced stage, number of lymph nodes examined, increased LOS of index admission, and small hospital size (all P < 0.05). Patients with a complication during index hospital stay were more likely to be readmitted (P < 0.001), whereas patients who saw an outpatient medical provider after index discharge returned less frequently (P < 0.001). Forty-seven percent of readmissions were for endocrine-related causes. Mean LOS and cost of rehospitalization were 3.5 days and $5,921, respectively. Unplanned rehospitalization was associated with death at 1 year compared with nonrehospitalized patients (18% vs. 6%; P < 0.001).

DISCUSSION

Rehospitalization among Medicare beneficiaries with thyroid cancer after thyroidectomy is prevalent and costly. Further study of predictors could identify high-risk patients for whom enhanced preoperative triage, improved discharge planning, and increased outpatient support might prove cost-effective.

Effects of active HCV replication on neurologic status in HIV RNA virally suppressed patients

BACKGROUND

Hepatitis C virus (HCV) is a frequent copathogen with HIV. Both viruses appear to replicate in the brain and both are implicated in neurocognitive and peripheral neuropathy syndromes. Interaction of the viruses is likely to be complicated and better understanding of the contributions of each virus will be necessary to make evidence-based therapeutic decisions.

METHODS

This study was designed to determine if active HCV infection, identified by quantitative HCV RNA determination, is associated with increased neurocognitive deficits or excess development of distal sensory peripheral neuropathy in HIV coinfected patients with stable HIV viral suppression. The AIDS Clinical Trials Group Longitudinal Linked Randomized Trials (ALLRT) study was the source of subjects with known HIV treatment status, neurocognitive and neuropathy evaluations, and HCV status. Subjects were selected based on HCV antibody status (249 positive; 310 negative).

RESULTS

HCV RNA viral loads were detectable in 172 participants with controlled HIV infection and available neurologic evaluations in the ALLRT. These participants were compared with 345 participants with undetectable HCV viral load and the same inclusion criteria from the same cohort. Neurocognitive performance measured by Trail-Making A or B and digit symbol testing was not dissimilar between the 2 groups. In addition, there was no significant association between active HCV replication and distal sensory neuropathy.

CONCLUSION

Clinically significant neurocognitive dysfunction and peripheral neuropathy were not exacerbated by active hepatitis C virus infection in the setting of optimally treated HIV infection.

Interleukin 15 and its receptor

Interleukin 15 (IL-15) is a member of the four-helix bundle cytokine family that shares many in vitro biological activities with IL-2. Previous work demonstrated that IL-15 utilizes the beta and gamma chains of the IL-2 receptor (IL-2R), and that these are essential for IL-15-mediated signal transduction. However, several lines of evidence indicated the existence of an additional, IL-15-specific receptor component. An IL-15 binding chain was identified on a murine T cell clone, and direct expression cloning was used to isolate the corresponding cDNA. The predicted structure of this protein shows sequence similarity to the IL-2R alpha chain. Transfection of this cDNA into a murine, IL-3-dependent myeloid cell line, 32D-01, conferred IL-15 binding and, together with transfection of the IL-2R beta chain, rendered the cells responsive to IL-15 stimulation. This experiment confirmed that the IL-15 binding chain is part of the IL-15 receptor, and it is designated as the IL-15R alpha subunit. The expression pattern of the IL-15R alpha mRNA is distinct from that of IL-2R alpha mRNA. Recombinant expression of a soluble form of IL-15R alpha demonstrated that it is a potent inhibitor of IL-15 biological activity.

Impact of recent welfare and immigration reforms on use of Medicaid for prenatal care by immigrants in California

This study investigates the impact of the recent welfare and immigration changes on the use of Medicaid by low-income pregnant immigrant women in California. The study presents findings from interviews with government officials, safety-net prenatal care providers, and immigrant advocates who serve low-income pregnant Asian and Latina immigrants at the national, state, or local levels. These informants spoke of policy actions that affect immigrants' abilities to use Medicaid for coverage of prenatal care. These actions include (1) the sharing of information between the California Department of Health Services and the federal Immigration and Naturalization Service, (2) the slow and confusing implementation of the reforms, and (3) the intimidating Medicaid eligibility process. The findings demonstrate how the policies changed the immigrant women's relationship with safety-net prenatal care providers, and sparked intense actions on the part of their advocates to sustain the women's access to perinatal care.

Morphology and metabolism of Ba-alginate-encapsulated hepatocytes with galactosylated chitosan and poly(vinyl alcohol) as extracellular matrices

Lactobionic acid, bearing a beta-galactose group, was coupled with chitosan to provide synthetic extracellular matrices together with poly(vinyl alcohol) (PVA). The hepatocytes encapsulated in Ba-alginate capsules with galactosylated chitosan (GC) and PVA as extracellular matrices showed aggregation morphologies as the incubation time increased. Ba-alginate-encapsulated hepatocytes with GC exhibited a higher metabolic function in albumin secretion compared to those entrapped in Ba-alginate beads and monolayer-cultured on a collagen-immobilized polystyrene dish. The ammonia removal ability of monolayer-cultured hepatocytes decreased with increasing culture time and disappeared completely after three days. In contrast, the ammonia removal ability of encapsulated and entrapped hepatocytes increased with increasing incubation time in the first seven and five days, respectively. Thereafter, the entrapped hepatocytes lost ammonia removal ability quickly while the encapsulated hepatocytes kept a relatively high ammonia removal ability up to 13 days. The trace amount of GC in the core matrices enabled encapsulated cells to enhance their ammonia removal and albumin secretion ability. The results obtained with 3-(3,4-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) also showed that the capsules incorporated with GC can provide a better microenvironment for cell aggregation along with nutrition and metabolite transfer. Due to the nature of the liquid core, the encapsulated hepatocytes showed very good mobility. This facilitated cell-cell interaction and cell-matrix interaction.

Autosomal telomere exchange results in the rapid amplification and dispersion of Csf2ra genes in wild-derived mice

Common laboratory strains such as C57BL/6J carry a single Csf2ra gene that maps to the distal end of Chromosome (Chr) 19. Here we report that several species of wild mice contain multiple Csf2ra genes. Using interspecific backcross mapping and in situ hybridization, we demonstrate that one of these species, Mus spretus, carries four Csf2ra genes dispersed among the distal tips of Chrs 4, 10, 13, and 19. Our data further suggest that these additional Csf2ra genes are not generated by retrotransposition, but rather by nonhomologous subtelomeric exchanges that could be mediated in part by ribosomal genes located at the subtelomeric regions of Chrs 4, 13, and 19. Although we do not know whether these additional Csf2ra genes are functionally active, our studies suggest that subtelomeric exchange provides a potent means for rapid gene amplification in the mouse.

Comparative cellular catabolism and retention of astatine-, bismuth-, and lead-radiolabeled internalizing monoclonal antibody

Monoclonal antibodies (mAbs) labeled with alpha-emitting radionuclides such as (211)At, (212)Bi, (213)Bi, and (212)Pb (which decays by beta-emission to its alpha-emitting daughter, (212)Bi) are being evaluated for their potential applications for cancer therapy. The fate of these radionuclides after cells are targeted with mAbs is important in terms of dosimetry and tumor detection.

METHODS

In this study, we attached various radionuclides that result in alpha-emissions to T101, a rapidly internalizing anti-CD5 mAb. We then evaluated the catabolism and cellular retention and compared them with those of (125)I- and (111)In-labeled T101. T101 was labeled with (211)At, (125)I, (205,6)Bi, (111)In, and (203)Pb. CD5 antigen-positive cells, peripheral blood mononuclear cells (PBMNC), and MOLT-4 leukemia cells were used. The labeled T101 was incubated with the cells for 1 h at 4 degrees C for surface labeling. Unbound activity was removed and 1 mL medium added. The cells were then incubated at 37 degrees C for 0, 1, 2, 4, 8, and 24 h. The activity on the cell surface that internalized and the activity on the cell surface remaining in the supernatant were determined. The protein in the supernatant was further precipitated by methanol for determining protein-bound and non-protein-bound radioactivity. Sites of internal cellular localization of radioactivity were determined by Percoll gradient centrifugation.

RESULTS

All radiolabeled antibodies bound to the cells were internalized rapidly. After internalization, (205,6)Bi, (203)Pb, and (111)In radiolabels were retained in the cell, with little decrease of cell-associated radioactivity. However, (211)At and (125)I were released from cells rapidly ((211)At < (125)I) and most of the radioactivity in the supernatant was in a non-protein-bound form. Intracellular distribution of radioactivity revealed a transit of the radiolabel from the cell surface to the lysosome. The catabolism patterns of MOLT-4 cells and PBMNC were similar.

CONCLUSION

(211)At catabolism and release from cells were somewhat similar to that of (125)I, whereas (205,6)Bi and (203)Pb showed prolonged cell retention similar to that of (111)In. These catabolism differences may be important in the selection of alpha-radionuclides for radioimmunotherapy.

Improvement of water treatment performance by using polyamine flocculants

In this study, polyamine flocculants were synthesized and applied to Nak-dong river raw water in Korea to examine their efficiency in reducing turbidity, total organic carbon (TOC) and UV254. Synthesized polyamines were effective as flocculants for water treatment and the addition of organic polymer caused a reduction of 50-80% of the consumption of polyaluminium chloride (PAC). The effects of polyamine on the removal of turbidity, TOC and UV254 were investigated via both jar and pilot tests. The adsorption and separation mechanisms for the removal of turbidity and TOC by using the polymer flocculants were also observed.

Soluble cellular adhesion molecules in proliferative vitreoretinopathy and proliferative diabetic retinopathy

PURPOSE

To measure vitreous levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cellular adhesion molecule-1 (sVCAM-1) in the eyes of patients with retinal detachment (RD) due to proliferative diabetic retinopathy (PDR) or proliferative vitreoretinopathy (PVR) and to determine whether the levels of these mediators correlated with clinical parameters of disease.

METHODS

Undiluted vitreous specimens were collected from 50 eyes of 48 patients undergoing vitrectomy for traction RD due to PDR (21 specimens) and recurrent RD due to PVR (19 specimens). Control vitreous specimens were obtained from patients undergoing macular hole repair (10 specimens). The levels of sICAM-1 and sVCAM-1 were measured in each sample by specific enzyme-linked immunoadsorbent assays.

RESULTS

Vitreous levels of sICAM-1 were significantly increased in vitreous specimens from both PVR (median +/- SD; 12.0 +/- 76.3 ng/ml; P < 0.01) and PDR (8.4 +/- 24.0 ng/ml; P < 0.01) when compared to vitreous from eyes with macular holes (0. 3 +/- 4.2 ng/ml). Vitreous levels of sVCAM-1 were significantly increased in both PVR (36.5 +/- 255.2 ng/ml; P < 0.001) and PDR (26. 2 +/- 93.5 ng/ml; P < 0.01) when compared to control vitreous (17.7 +/- 7.8 ng/ml). The vitreous levels of sICAM-1 were higher in cases of PDR which developed recurrent proliferative disease (P < 0.01) and recurrent RD (P = 0.01), whereas the levels of sICAM-1 in PVR and sVCAM-1 in PDR and PVR did not significantly correlate with these clinical parameters.

CONCLUSIONS

Soluble forms of ICAM-1 and VCAM-1 are increased in the vitreous cavity of patients with RD due to PDR or PVR, reflecting the inflammatory nature of these conditions and suggesting a possible role for these mediators in the pathogenesis of proliferative retinal disease. The vitreous levels of these sCAMs at the time of surgery may serve as a marker of inflammation, but their specific levels do not predict the likelihood of recurrent proliferation or surgical anatomic success in most cases of PVR and PDR.

Molecular characterization of the human interleukin (IL)-17 receptor

Human interleukin 17 (hIL-17) is a T-cell derived cytokine that exhibits 63% amino acid sequence identity to mouse IL-17 (mIL-17) and 57% identity to a viral protein encoded by the herpesvirus saimiri (HSV) gene 13 (HVS13). The IL-17 family of proteins binds to a unique mouse receptor (mIL-17R). Using nucleic acid hybridization techniques, a cDNA encoding a human homologue of the mIL-17R (hIL-17R) was isolated from a human T cell library. The predicted amino acid sequence of the hIL-17R is 69% identical to the mIL-17R, shares no homology with previously identified cytokine receptor families, and exhibits a broad tissue distribution. The hIL-17R gene was localized to chromosome 22. Monoclonal antibodies (mAbs) generated against the hIL-17R were able to block the IL-17-induced production of cytokine from human foreskin fibroblast (HFF) cells. Binding studies suggest that recombinant hIL-17 binds to the hIL-17R with low affinity.

Dual oncostatin M (OSM) receptors. Cloning and characterization of an alternative signaling subunit conferring OSM-specific receptor activation

Oncostatin M (OSM) is a cytokine whose structural and functional features are similar to other members of the interleukin (IL)-6 family of cytokines (IL-6, IL-11, leukemia inhibitory factor (LIF), granulocyte colonystimulating factor, ciliary neurotrophic factor, and cardiotrophin-1), many of which utilize gp130 as a common receptor subunit. A biologically active OSM receptor has been previously described that consists of a heterodimer of leukemia inhibitory factor receptor (LIFR) and gp130. This LIFR.gp130 complex is also a functional receptor for LIF. We have cloned and characterized an alternative subunit (OSMRbeta) for an OSM receptor complex (a heterodimer of gp130 and OSMRbeta) that is activated by OSM but not by LIF. The signaling capability of specific receptor subunit combinations was analyzed by independent assays measuring cell proliferation or induction of acute phase protein synthesis. Our results demonstrate that both LIF and OSM cause tyrosine phosphorylation and activation of the gp130.LIFR combination, but the gp130.OSMRbeta complex is activated by OSM only. OSM-induced cellular responses, initiated through low affinity binding to gp130, are mediated by two heterodimeric receptor complexes that utilize alternative signal transducing subunits that confer different cytokine specificities to the receptor complex.

Cell-cell adhesion mediated by binding of membrane-anchored ligand LERK-2 to the EPH-related receptor human embryonal kinase 2 promotes tyrosine kinase activity

Human embryonal kinase 2 (HEK2) is a protein-tyrosine kinase that is a member of the EPH family of receptors. Transcripts for HEK2 have a wide tissue distribution. Recently, a still growing family of ligands, which we have named LERKs, for ligands of the eph-related kinases, has been isolated. In order to analyze functional effects between the LERKs and the HEK2 receptor, we expressed HEK2 cDNA in an interleukin-3-dependent progenitor cell line 32D that grows as single cells in culture. Within the group of LERKs, LERK-2 and -5 were shown to bind to HEK2. Membrane-bound and soluble forms of LERK-2 were demonstrated to signal through HEK2 as judged by receptor phosphorylation. Coincubation of HEK2 and LERK-2 expressing cells induced cell-cell adhesion and formation of cell aggregates. This interaction could be inhibited by preincubation of HEK2 expressing cells with soluble LERK-2. Coexpression of HEK2 and LERK-2 in 32D cells showed reduced kinase activity and autophosphorylation of HEK2 compared with the juxtacrine stimulation, which seems to be due to a reduced sensitivity of the receptor.

Characterization of interleukin-15 (IL-15) and the IL-15 receptor complex

IL-15 interacts with a heterotrimeric receptor that consists of the beta and gamma subunits of the IL-2 receptor (IL-2R) as well as a specific, high-affinity IL-15-binding subunit, which is designated IL-15R alpha. Since both the beta and the gamma subunits of the IL-2R are required for signaling by either IL-2 or IL-15, it is not surprising that these cytokines share many activities in vitro. However, the differential expression of these cytokines and the alpha chains of their receptors within various tissues and cell types suggests that IL-2 and IL-15 may perform at least partially distinct physiological functions. The production of IL-15 by macrophages, and possibly other cell types, in response to environmental stimuli and infectious agents suggests that IL-15 may play a role in protective immune responses, allograft rejection, and the pathogenesis of autoimmune diseases.