T-cell intrinsic effects of GITR and 4-1BB during viral infection and cancer immunotherapy

GITR [glucocorticoid inducible tumor necrosis factor receptor (TNFR)-related protein] and 4-1BB are costimulatory TNFR family members that are expressed on regulatory and effector T cells as well as on other cells of the immune system. Here we discuss the role of GITR and 4-1BB on T cells during viral infections and in cancer immunotherapy. Systemic treatment with agonistic anti-4-1BB antibody leads to a number of immune system abnormalities, and clinical trials of anti-4-1BB have been terminated. However, other modes of 4-1BB ligation may be less toxic. To date, similar toxicities have not been reported for anti-GITR treatment of mice, although anti-GITR antibodies can exacerbate mouse autoimmune models. Intrinsic effects of GITR and 4-1BB on effector T cells appear to predominate over their effects on other cell types in some models. Despite their similarities in enhancing T-cell survival, 4-1BB and GITR are clearly not redundant, and both pathways are required for maximal CD8(+) T-cell responses and mouse survival following severe respiratory influenza infection. GITR uses TNFR-associated factor (TRAF) 2 and TRAF5, whereas 4-1BB recruits TRAF1 and TRAF2 to mediate survival signaling in T cells. The differential use of signaling adapters combined with their differential expression may explain the non-redundant roles of GITR and 4-1BB in the immune system.

Endogenous 4-1BB ligand plays a critical role in protection from influenza-induced disease

A critical issue during severe respiratory infection is whether it is the virus or the host response that does the most damage. In this study, we show that endogenous 4-1BBL plays a critical role in protecting mice from severe effects of influenza disease. During mild respiratory influenza infection in which virus is rapidly cleared, the inducible costimulatory receptor 4-1BB is only transiently induced on lung T cells and 4-1BB ligand (4-1BBL) is completely dispensable for the initial CD8 T cell response and mouse survival. In contrast, during more severe respiratory influenza infection with prolonged viral load, 4-1BB expression on lung CD8 T cells is sustained, and 4-1BBL-deficient mice show decreased CD8 T cell accumulation in the lungs, decreased viral clearance, impaired lung function, and increased mortality. Transfer of an optimal number of naive Ag-specific T cells before infection protects wild-type but not 4-1BBL-deficient mice from an otherwise lethal dose of influenza virus. Transfer of T cells lacking the proapoptotic molecule Bim extends the lifespan of 4-1BBL-deficient mice by one to three days, suggesting that at least part of the role of 4-1BB/4-1BBL is to prolong effector cell survival long enough to clear virus. Intranasal delivery of 4-1BBL by recombinant adenovirus marginally improves survival of 4-1BBL-deficient mice at low dose, but exacerbates disease at high dose. These findings suggest a rationale for the evolutionary accumulation of inducible costimulatory molecules, thereby allowing the immune system to sustain the expression of molecules such as 4-1BB to a level commensurate with severity of infection.

TNF family ligands define niches for T cell memory

Immunological memory is a critical feature of the adaptive immune system and the underlying principal behind vaccination. The mechanisms that maintain memory T cell survival between the initial and subsequent encounter with antigen remain incompletely defined. Although the cytokines IL-15 and IL-7 are important in memory T cell homeostasis, additional signals by way of TNFR family members are required for maximal maintenance of T cell memory. Here we propose a unifying model in which subsets of TNF family ligands distinguish the competitive niches for maintenance of CD4 versus CD8 T cell memory. Understanding the unique 'memory niches' defined by TNF family ligand expression will provide new insights into the mechanisms of memory T cell maintenance.

A critical role for TNF receptor-associated factor 1 and Bim down-regulation in CD8 memory T cell survival

The mechanisms that allow the maintenance of immunological memory remain incompletely defined. Here we report that tumor necrosis factor receptor (TNFR)-associated factor (TRAF) 1, a protein recruited in response to several costimulatory TNFR family members, is required for maximal CD8 T cell responses to influenza virus in mice. Decreased recovery of CD8 T cells in vivo occurred under conditions where cell division was unimpaired. In vitro, TRAF1-deficient, antigen-activated T cells accumulated higher levels of the proapoptotic BH3-only family member Bim, particularly the most toxic isoform, Bim(S). In the presence of excess IL-15, memory phenotype T cells with similar surface phenotype and comparable levels of Bcl-2 family members could be generated from WT or TRAF1-deficient T cell receptor transgenic OT-I T cells. However, when the memory CD8 T cells were allowed to compete for survival signals in the absence of antigen in vivo, the TRAF1-deficient T cells showed decreased recovery compared with TRAF1-sufficient T cells. This defect in T cell recovery in vivo was alleviated by introduction of siRNA to down-modulate Bim in TRAF1-deficient memory T cells. These studies identify the TRAF1 signaling axis and Bim down-regulation as critical for CD8 memory T cell survival in vivo.

Reductions in Stress and Depressive Symptoms in Mothers of Substance-Exposed Infants, Participating in a Psychosocial Program

OBJECTIVE

Depression profoundly impairs psychosocial functioning. Depression can have disruptive effects on a person's family, with significant impact on the psychosocial development of the children. Recent research suggests that a mother's depressive symptoms may increase parenting stress and that parenting stress may, in turn, increase depressive symptoms, with a possible negative cycle to this process. Little is known about how these two factors interact in drug-involved mothers. This study examines how the NEW CONNECTIONS intervention (a parental education and support program for drug-involved parents) acts on parental stress and symptoms of depression.

METHODS

The study site was the NEW CONNECTIONS Infant Intervention Program. The Beck Depression Inventory-II (BDI-II) and the Parenting Stress Index (PSI) were administered to drug- and alcohol-involved mothers (N = 120) at baseline and after the intervention (Week 12).

RESULTS

Four of the seven PSI domains of parenting stress showed a significant reduction (Demandingness, Competence, Isolation, and Role Restriction). Changes in four domains were significantly correlated with reductions in depressive symptoms (Competence, Isolation, Attachment, and Role Restriction). There was a significant reduction in depressive symptoms as measured by the BDI-II.

CONCLUSION

Reduction in some aspects of parenting stress is associated with reduction in depressive symptoms in mothers of substance-exposed infants who participated in the NEW CONNECTIONS psychosocial intervention targeting the parent-child relationship.

Treatment of substance abuse during pregnancy and infant outcome

The objective of this study is to analyze the effects of residential substance abuse treatment on pregnancy outcome among gravidas in a gender-specific program. All clients (cases) who entered a residential substance abuse program for pregnant and postpartum women were eligible for inclusion in the study (n=95). Only those who were in treatment at the time of delivery were included in the present analysis (n=57). Two comparison groups were used: (1) substance abusers who received no treatment during pregnancy (positive control group) and (2) pregnant women who were not substance abusers (negative control group). Cases were matched to controls on ethnicity (negative and positive controls) and drug of choice (positive controls only). Medical records were reviewed and abstracted for cases and controls. The primary drug of choice was cocaine for 56% of clients in the study, heroin 15.8%, and alcohol 10.8%. Average length of time in treatment before delivery was 11.7 weeks. The frequency of pregnancy complications allowing treatment and position controls was significantly higher than the negative control group (p<0.0001). The frequency of perinatal infant complications was increased among treatment group infants (p<0.0001). Two infants in the treatment group were positive for a substance of abuse at birth. In the treatment versus positive control group, mean birth weight (BW) was 3227 versus 2800 g (p<0.01), estimated gestational age (EGA) was 38.9 versus 39 weeks, average head circumference (FOC) was 33.8 versus 32.5 cm (p<0.05), and mean birth length (BLT) was 48.7 cm versus 46.9 (p<0.05). No significant differences were found between treatment and negative control groups. Maternal syphilis was increased in frequency in the positive control group compared with the negative control group (p<0.07). Thirty-percent of mothers had sexually transmitted diseases (STDs) for which infants were at risk and treated prophylactically; no infant in the treatment group contracted a vertically transmitted STD. For every 10 weeks in treatment, BW was increased 340 g, EGA 1 week, FOC 0.8 cm, and BLT 1.8 cm. Thus, substance abuse treatment for pregnant women in the program increased fetal growth, which significantly decreased the risk for poor neonatal outcomes. Importantly, maternal and infant perinatal complications in the treatment group were increased in frequency compared with the two control groups. This may possibly have occurred because healthcare providers were not blinded to maternal treatment status.

Fostering a culture of prevention in a residency program through a continuous quality improvement project

This project explored the effect of a multifaceted quality improvement (QI) intervention at a university-based residency program clinic on the documented provision of preventive services. The intervention, based on the Put Prevention Into Practice program and standard QI techniques, consisted of patient self-administered Health Risk Profiles (HRPs) and a monthly educational curriculum for patients, staff, and providers. Documentation of preventive services in patient charts was measured using a repeated cross-sectional sampling design before and after the 1-year intervention period. Documentation of 8 of 19 preventive services under examination increased significantly (P < .05). Measurements of the intervention, including use of the HRPs and the educational curriculum, revealed little association with the observed improvements. Although the intervention was associated with improved documentation of clinical preventive services, specific elements of the intervention were underused. The authors postulate that the QI process fostered a culture change in the clinic that affected prevention activities. Whether the increased documentation of services reflected an increase in the actual provision of services and whether this increase is clinically significant require further study.

Developing and evaluating ambulatory care: problem-based learning cases

Medical educators have raised concerns about the quality of teaching and learning in busy ambulatory care settings. Problem-based learning (PBL), which allows students to learn to diagnose and manage common ambulatory care problems as they discuss patients away from the clinical setting, is one possible solution for addressing these concerns. This article describes a process for developing realistic and well-written PBL cases for an ambulatory care clerkship. The process details specific steps for writing and evaluating cases to ensure they contain relevant learning issues students often encounter in outpatient training sites. Faculty at other institutions can adapt this process to develop and evaluate PBL cases reflecting the common presenting problems and patient issues at their sites.

Patient and physician explanatory models for acute bronchitis

OBJECTIVES

Our goals were to develop explanatory models to better understand how physicians diagnose and treat acute bronchitis; to describe patient expectations and needs when experiencing an episode of acute bronchitis; and to enhance communication between physician and patient.

STUDY DESIGN

We used qualitative, semi-structured, in-depth interviews to generate patient and physician explanatory models.

POPULATION

We had a purposeful, homogeneous sample of 30 family physicians and 30 adult patients.

OUTCOMES MEASURED

Our multidisciplinary team of investigators used an editing style of analysis to develop patient and physician explanatory models based on the following topics: (1) what caused my illness/etiology, (2) what symptoms I had/onset of symptoms, (3) what my sickness did to me/pathophysiology, (4) how severe is my sickness/course of illness, and (5) what kind of treatment should I receive/treatment.

RESULTS

We found that patient and physician models were congruous for symptoms of acute bronchitis and incongruous for etiology and course of illness. Models were congruous for treatment, although for different reasons.

CONCLUSIONS

Patients may have a very vague understanding of the process of infection and the difference between bacteria and viruses. Compounding this confusion is frequent miscommunication from physicians regarding the clinical course of untreated illness. These factors and non-communicated expectations from patients and fear of missing something on the part of physicians contribute to the decision to treat with antibiotics.

Peripartum cocaine use and adverse pregnancy outcome

The objective of the study was to analyze possible adverse effects of peripartum cocaine use on maternal and fetal outcomes. Informed consent was given by 720 (97%) of 740 women who delivered consecutively at a large urban public hospital to test an umbilical cord blood sample for the presence of non-medically administered drugs of abuse and alcohol and to be interviewed for the study. Samples were tested for the presence of a cocaine metabolite (benzoylecgonine-BZE) by radioimmunoassay. The presence of other substances of abuse (alcohol, methamphetamine, opiates) resulted in exclusion from the sample of 143 subjects. Thus, in this cohort analysis, drug-free controls (N = 469) were compared to those positive for cocaine only (N = 108). Peripartum exposure to cocaine only, and no other substances of abuse, was associated with an increased frequency of abruptio placentae (1.9% vs 0% for control, P < 0.004), thick meconium stained amniotic fluid (3.9% vs 0.7% for controls, P < 0.006), premature rupture of membranes (P < 0.02), genitourinary anomalies (OR = 3.6, P < 0.05), abdominal wall defects (OR = 4.4, P < 0.01) and increased frequency of low birth weight (OR = 2.0, P < 0.02). These are important findings because previous studies have been complicated by the confounding effects of other substances of abuse. Am. J. Hum. Biol. 11:598-602, 1999. Copyright 1999 Wiley-Liss, Inc.

Implementing problem-based learning in a family medicine clerkship

BACKGROUND AND OBJECTIVES

Problem-based learning (PBL) has been implemented in the curriculum of many medical schools, but limited information is available about the outcome of this learning technique. The educational intervention presented in this paper implemented a PBL learning component in our third-year family medicine clerkship and measured the outcomes of this curricular change.

METHODS

One third of the curricular time devoted to didactic teaching in our family medicine clerkship was replaced with PBL activities. Simulated cases were developed and presented to students who, with the aid of faculty facilitators, studied the cases, gathered information about the cases, and developed diagnostic and management plans for the cases. The outcome of the intervention was measured by a) comparing students' scores on the National Board of Medical Examiners (NBME) family medicine clerkship examination to scores achieved by students in the year before PBL was introduced and b) students' evaluations of the relevance and success of PBL in the clerkship curriculum.

RESULTS

Students' NBME clerkship examination scores increased from a mean of 66 the year before PBL began to 73 after PBL was implemented. More than 80% of students reported that PBL was a good way to learn family medicine, and 85% reported that the PBL technique provided sufficient information to formulate learning issues.

CONCLUSIONS

PBL can be introduced into a third-year family medicine clerkship curriculum with general acceptance by students. Students rated the technique highly, and their examination scores improved.

Verifying the curriculum of a family medicine clerkship

The learning experience during a medical school clinical rotation is largely shaped by students' patient encounters. This paper reports on how a log system for recording these encounters can be used for course planning and evaluation. Over the past 5 years, 960 third-year students completed log forms based on their clinical encounters during a required 4-week family medicine clerkship at UT Southwestern. These forms were then optically scanned and the information entered into a computerized database. Log form data revealed that the most common medical problems encountered by students in their ambulatory settings were similar to those reported in the general family practice literature. There was a great deal of consistency in the types of encounters from year to year. The data also showed some differences among clerkship sites in terms of patient demographics and the most frequently reported diagnoses. Information generated from student log forms has been used by the clerkship faculty to determine required readings, prioritize didactic topics and other teaching, adjust curriculum content, prepare support materials and develop examinations. Given the utility of the information obtained and the ease of use of optical mark encounter sheets, we recommend this system for other clerkships.

Treatment of acute bronchitis in adults. A national survey of family physicians

BACKGROUND

The purpose of this study was to determine how family physicians in the United States treat acute bronchitis in an otherwise healthy adult.

METHODS

A 33-item questionnaire on the diagnosis and treatment of acute bronchitis was mailed to a random sample of 500 physicians who are members of the American Board of Family Practice.

RESULTS

Thirty-two of the 500 sampled physicians could not be located by mail; 265 of those who received the questionnaire responded. The response rate was 57% (265/468). Sixty-three percent of responding physicians indicated that antibiotics are their first choice of treatment for the otherwise healthy, nonsmoking adult with acute bronchitis. The decision to use antibiotics as the first choice of treatment did not vary by physician's sex, age, years in practice, practice location, practice type, or percentage of HMO patients. Only 6% of responding physicians reported using beta 2 agonist bronchodilators as their first choice of treatment. Physicians in this study stated that they prescribe an antibiotic 75% of the time in treating nonsmoking patients with acute bronchitis (first choice or otherwise). If the patient is a smoker, physicians reported that they prescribe antibiotics 90% of the time (F = 110.25; df = 1; P > .0001). Physicians reported that for patients who smoke it takes longer for coughs to totally resolve and longer for them to return to a normal activity level than for nonsmokers.

CONCLUSIONS

Family physicians report that antibiotics are their most common treatment for acute bronchitis in the otherwise healthy adult. Previous clinical trials have shown only marginal improvement in symptoms when patients with this condition are treated with an antibiotic. With antibiotic resistance emerging as a major global health problem, it is essential that other methods of treatment be evaluated.

Diagnosis of acute bronchitis in adults: a national survey of family physicians

BACKGROUND

The purpose of this study was to determine how family physicians in the United States diagnose acute bronchitis in otherwise healthy adults.

METHODS

A 33-item questionnaire on the diagnosis and treatment of acute bronchitis was mailed to a random sample of 500 physicians who are members of the American Board of Family Practice.

RESULTS

Two hundred sixty-five physicians responded. Of those who did not respond, 32 could not be located. Of those who did respond, 10 were either retired or were practicing in another specialty. The net response rate was 56% (255/458). Responding physicians stated that character of cough and sputum production are the most important items used in diagnosing acute bronchitis. Fifty-eight percent indicated that the cough should be productive, and 60% stated that the sputum should be purulent. Seventy-two percent of respondents did not feel that wheezing or rhonchi need to be present. Younger physicians and those who selected antibiotics as their first treatment choice were more likely to define acute bronchitis as the presence of a productive cough with purulent sputum (P < .05). Physicians from an academic setting were more likely to define acute bronchitis as a productive cough (P < .05). Thirty-six percent of physicians from practices serving populations with > or = 60% managed care patients included wheezing or rhonchi in the definition of acute bronchitis, compared with 26% of all others (P < .05).

CONCLUSIONS

Variations in the diagnosis of acute bronchitis in otherwise healthy adults can be attributed to physician age, treatment choice, and practice setting. A significant number of family physicians did not require a productive cough as part of the diagnostic criteria for acute bronchitis. This finding needs to be considered in studies evaluating treatment. Additional qualitative studies are necessary to identify other factors involved in diagnosing acute bronchitis.

Risk of chromosomal abnormalities, with emphasis on live-born offspring of young mothers

In a large public urban hospital obstetrics service with > 123,000 deliveries in a 10-year period (1980-89), the frequencies (0.12%) of any type of chromosomal abnormality and of trisomy syndromes were analyzed for maternal age-related risk, by logistic regression. Focusing on very young gravidas, we found that in the study period there were 9,332 births (7.5% of all deliveries) to mothers < or = 16 years old. Estimated risks of chromosomal abnormalities among offspring associated with very young maternal age (9-16 years) were similar to those age-associated risks of mothers 20-29 years old. Risks of chromosomal abnormalities increase with advancing maternal age and are independent of ethnicity.

Computerized performance support systems: applications in a family practice clerkship

This article describes a computerized performance support system, the Clerkship Learning Expert and Resource Consultant (CLERC), developed to improve the quality and consistency of learning available to medical students in a third-year family practice clerkship. CLERC is an integrated computer system with an interactive knowledge base, software applications, literature search capabilities, and clinical diagnostic software programs. Medical students enrolled in a third-year family practice clerkship use CLERC to access up-to-date clinical information and to complete clerkship assignments.

Reliability of birth certificate reporting of congenital anomalies

Birth certificates comprise an important source of data on the prevalence of genetic conditions and for monitoring possible teratogens in the population. Investigators have found wide variability (12 to 100%) in the accuracy of reporting. In a large public hospital, of those congenital anomalies detected at birth, only 5.4% were recorded on the birth certificate. This is one of the lowest rates ever reported. An underreporting correction factor may be applied if congenital anomalies are distributed randomly with respect to reporting status, and the rate of reporting is sufficient to comprise a valid sample for estimating a correction factor (that is, 20% or more reported). In this study, factors such as numbers or types of anomalies, race, infant birthweight, or estimated gestational age did not significantly influence the rate of birth certificate reporting. Thus, our data satisfied the first but not the second criterion for derivation of a correction factor. In conducting epidemiologic studies, birth certificate data should be used with: (1) great caution; (2) a system of validation with the medical record to estimate the degree of underreporting and to derive a correction factor; and (3) a priori knowledge that underreporting of congenital anomalies on this document is highly prevalent.

Is hyperthermia teratogenic in the human?

Maternal hyperthermia during embryogenesis has been postulated to cause a variety of major congenital anomalies in exposed offspring. Although the literature regarding human exposures is not conclusive, studies using animal models support the contention that major structural anomalies may be produced. In the present study, pregnancy outcome of a cohort of women who reported having a temperature of 101 degrees F or higher for 24 hours or more during the first trimester was compared to a control group of women (matched on last menstrual period, parity, and age) who denied having a fever. A statistically significant increased frequency of a specific type of congenital anomaly, abdominal wall defects, was found in offspring whose mothers had sustained high temperatures during embryogenesis. Although an increased risk of this type of congenital anomaly is not consistent with previous epidemiologic studies, similar defects of this organ system have been reported in offspring of pregnant nonhuman primates (monkeys) and rodents (guinea pigs) who experienced hyperthermia during pregnancy.

HIV prevalence in pregnant intravenous drug users in Dallas, Texas

Information available regarding the prevalence of human immunodeficiency virus (HIV) in pregnant women indicates that the primary risk factor for infection is intravenous drug use. At Parkland Memorial Hospital in Dallas, Texas, approximately 4.7% of pregnant women reported using intravenous drugs. The estimated prevalence of HIV infection among pregnant intravenous drug users at this hospital was 3.3%. This is similar to the HIV infection rates reported for nonpregnant parenteral drug-using populations in other areas of the southwestern United States, suggesting that there may be a lower rate of endemic infection in this region of the country.

Brain growth among fetuses exposed to cocaine in utero: asymmetrical growth retardation

Fetal growth retardation may be associated with maternal cocaine use during pregnancy. The pattern of fetal growth retardation was analyzed in infants born to 80 women who used cocaine, but not alcohol, during pregnancy, and in two comparison groups: 100 infants born to mothers who used neither alcohol nor cocaine during pregnancy and 67 infants whose mothers used alcohol but not cocaine during pregnancy. There were statistically significant differences in head size between the unexposed and cocaine-exposed infants (P less than .001). Notably, head circumference was reduced proportionately more than birth weight in cocaine-exposed infants, a pattern similar to that observed in alcohol-exposed infants. Alcohol- and cocaine-exposed infants were not statistically different in head circumference. We conclude that brain growth of cocaine-exposed infants is similar to that reported for alcohol-exposed infants, and that cocaine-exposed infants may be characterized as having asymmetrical growth retardation.