A Germline-Targeting Chimpanzee SIV Envelope Glycoprotein Elicits a New Class of V2-Apex Directed Cross-Neutralizing Antibodies

HIV-1 and its SIV precursors share a broadly neutralizing antibody (bNAb) epitope in variable loop 2 (V2) at the envelope glycoprotein (Env) trimer apex. Here, we tested the immunogenicity of germ line-targeting versions of a chimpanzee SIV (SIVcpz) Env in human V2-apex bNAb heavy-chain precursor-expressing knock-in mice and as chimeric simian-chimpanzee immunodeficiency viruses (SCIVs) in rhesus macaques (RMs). Trimer immunization of knock-in mice induced V2-directed NAbs, indicating activation of V2-apex bNAb precursor-expressing mouse B cells. SCIV infection of RMs elicited high-titer viremia, potent autologous tier 2 neutralizing antibodies, and rapid sequence escape in the canonical V2-apex epitope. Six of seven animals also developed low-titer heterologous plasma breadth that mapped to the V2-apex. Antibody cloning from two of these animals identified multiple expanded lineages with long heavy chain third complementarity determining regions that cross-neutralized as many as 7 of 19 primary HIV-1 strains, but with low potency. Negative stain electron microscopy (NSEM) of members of the two most cross-reactive lineages confirmed V2 targeting but identified an angle of approach distinct from prototypical V2-apex bNAbs, with antibody binding either requiring or inducing an occluded-open trimer. Probing with conformation-sensitive, nonneutralizing antibodies revealed that SCIV-expressed, but not wild-type SIVcpz Envs, as well as a subset of primary HIV-1 Envs, preferentially adopted a more open trimeric state. These results reveal the existence of a cryptic V2 epitope that is exposed in occluded-open SIVcpz and HIV-1 Env trimers and elicits cross-neutralizing responses of limited breadth and potency. IMPORTANCE An effective HIV-1 vaccination strategy will need to stimulate rare precursor B cells of multiple bNAb lineages and affinity mature them along desired pathways. Here, we searched for V2-apex germ line-targeting Envs among a large set of diverse primate lentiviruses and identified minimally modified versions of one chimpanzee SIV Env that bound several human V2-apex bNAb precursors and stimulated one of these in a V2-apex bNAb precursor-expressing knock-in mouse. We also generated chimeric simian-chimpanzee immunodeficiency viruses and showed that they elicit low-titer V2-directed heterologous plasma breadth in six of seven infected rhesus macaques. Characterization of this antibody response identified a new class of weakly cross-reactive neutralizing antibodies that target the V2-apex, but only in occluded-open Env trimers. The existence of this cryptic epitope, which in some Env backgrounds is immunodominant, needs to be considered in immunogen design.

Abdominal Inflammatory Myofibroblastic Tumor: Minimal Inflammatory Infiltrate and Diffuse Immunoreactivity for Caldesmon are Potential Diagnostic Pitfalls

Introduction/Objective

Inflammatory myofibroblastic tumor (IMT) is an uncommon spindle cell lesion that can involve various organs and occurs in multiple body sites. While older terminology (i.e. inflammatory pseudotumor) suggested otherwise, recent molecular studies point toward a neoplastic pathogenesis for IMTs. Herein, we report a case of an abdominal IMT and discuss the morphologic and immunohistochemical pitfalls pertaining to this entity.

Methods

A 75-year-old woman presented with complaints of generalized abdominal pain and distention. An abdominal CT scan showed multiple peritoneal masses, the largest of which measured 23 cm. Biopsy revealed compact fascicles of bland spindle cells exhibiting diffuse actin and caldesmon immunoreactivity, consistent with a spindle cell tumor with smooth muscle differentiation. Mitotic activity was low-to-unapparent. Surgical excision was performed. The cut surface of the tumor was tan-white with hemorrhagic foci. Histopathologic examination of the tumor showed elongated spindle cells set in a loose myxoid stroma rich in blood vessels and a mixed inflammatory infiltrate. Deeper sections of the tumor were more cellular, showing a similar morphology to that seen in the original biopsy, which was virtually devoid of inflammatory cells. Immunohistochemistry showed diffuse staining for desmin, caldesmon, smooth muscle actin, and ALK. FISH analysis showed ALK gene rearrangement in 52% of tumor cells, confirming the diagnosis of IMT.

Results

Studies in the literature show that IMTs express smooth muscle markers such as SMA (90%) and desmin (50%). However, immunoreactivity for caldesmon is rarely reported. ALK immunoreactivity is seen in about 35–60% of cases, and when gene rearrangement involving ALK is detected the diagnosis can be confirmed.

Conclusion

Historically, several terms have been used to describe IMTs, including inflammatory pseudotumor and inflammatory pseudosarcomatous fibromyxoid tumor. While the nomenclature consistently implies an inflammatory infiltrate, this tumor could have various morphological patterns with some areas showing very little to absent inflammation, as demonstrated in our case. Hence, making an accurate diagnosis could be challenging on a limited biopsy. Therefore, ALK testing should be included as part of the diagnostic workup of spindle cell neoplasms with smooth muscle differentiation.

Overweight, obesity and high blood pressure in an ethnically diverse sample of adolescents in Britain: the Medical Research Council DASH study

OBJECTIVES

To examine the impact of overweight on mean, high normal and high blood pressure in early adolescence, and how this relates to ethnicity and socio-economic status.

DESIGN

Cross-sectional study with anthropometric and blood pressure measurements.

SETTING

A total of 51 secondary schools in London.

SAMPLE

A total of 6407 subjects, 11-13 years of age, including 1204 White UK, 698 Other Whites, 911 Black Caribbeans, 1065 black Africans, 477 Indians and 611 Pakistanis/Bangladeshis.

MAIN OUTCOME MEASURES

Mean, high normal (gender, age and height-percentile-specific 90-94th percentile) and high (>/=95th percentile) blood pressure.

RESULTS

Based on the International Obesity Task Force age-specific thresholds, 19% of boys and 23% of girls were overweight, and 8% of each were obese. Overweight and obesity were associated with large increases in the prevalence of high normal and high blood pressures compared with those not overweight. The increases in the prevalence of high systolic pressure associated with overweight were as follows: boys, odds ratio 2.50 (95% confidence intervals 1.73-3.60) and girls 3.39 (2.36-4.85). Corresponding figures for obesity were: boys 4.31 (2.82-6.61) and girls 5.68 (3.61-8.95). Compared with their White British peers, obesity was associated with larger effects on blood pressure measures only among Indians, despite more overweight and obesity among black Caribbean girls and overweight among Black African girls. The effect of socio-economic status was inconsistent.

CONCLUSIONS

The tendency to high blood pressure among adult Black African origin populations was not evident at these ages. These results suggest that the rise in obesity in adolescence portends a rise in early onset of cardiovascular disease across ethnic groups, with Indians appearing to be more vulnerable.

Diabetes and ethnic minorities

The global prevalence of diabetes for all age groups is estimated to be 2.8%. Type 2 diabetes accounts for at least 90% of diabetes worldwide. Diabetes incidence, prevalence, and disease progression varies by ethnic group. This review highlights unique aspects of the risk of developing diabetes, its overwhelming vascular complications, and their management mainly using data among South Asians and African-Caribbeans in the UK but also using non-UK data. It is concluded that although the origin of the ethnic differences in incidence need further clarification, many factors should be amenable to prevention and treatment in all ethnic groups worldwide.

Dietary advice for treatment of type 2 diabetes mellitus in adults

BACKGROUND

While initial dietary management immediately after formal diagnosis is an 'accepted' cornerstone of treatment of type 2 diabetes mellitus, a formal and systematic overview of its efficacy and method of delivery is not currently available.

OBJECTIVES

To assess the effect of type and frequency of different types of dietary advice to all adults with type 2 diabetes on weight, measures of diabetic control, morbidity, total mortality and quality of life.

SEARCH STRATEGY

We carried out a comprehensive search of The Cochrane Library (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to October Week 1, 2003), EMBASE (1980 to Week 40, 2003), CINAHL (1982 to October Week 1, 2003), AMED (1985 to October 2003), bibliographies and contacted relevant experts.

SELECTION CRITERIA

All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention in adults with type 2 diabetes mellitus.

DATA COLLECTION AND ANALYSIS

The lead investigator performed all data extraction and quality scoring with duplication being carried out by one of the other six investigators independently with discrepancies resolved by discussion and consensus. Authors were contacted for missing data. For continuous outcomes, endpoint data were preferred to change data.

MAIN RESULTS

Thirty-six articles reporting a total of eighteen trials following 1467 participants were included. Dietary approaches assessed in this review were low-fat/high-carbohydrate diets, high-fat/low-carbohydrate diets, low-calorie (1000 kcal per day) and very-low-calorie (500 kcal per day) diets and modified fat diets. Two trials compared the American Diabetes Association exchange diet with a standard reduced fat diet and five studies assessed low-fat diets versus moderate fat or low-carbohydrate diets. Two studies assessed the effect of a very-low-calorie diet versus a low-calorie diet. Six studies compared dietary advice with dietary advice plus exercise and three other studies assessed dietary advice versus dietary advice plus behavioural approaches. The studies all measured weight and measures of glycaemic control although not all studies reported these in the articles published. Other outcomes which were measured in these studies included mortality, blood pressure, serum cholesterol (including LDL and HDL cholesterol), serum triglycerides, maximal exercise capacity and compliance. The results suggest that adoption of regular exercise is a good way to promote better glycaemic control in type 2 diabetic patients, however all of these studies were at high risk of bias.

REVIEWERS' CONCLUSIONS

There are no high quality data on the efficacy of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for well-designed studies which examine a range of interventions, at various points during follow-up, although there is a promising study currently underway.

Dietary advice for treatment of type 2 diabetes mellitus in adults

BACKGROUND

While initial dietary management immediately after formal diagnosis is an 'accepted' cornerstone of treatment of type 2 diabetes mellitus, a formal and systematic overview of its efficacy and method of delivery is not currently available.

OBJECTIVES

To assess the effect of type and frequency of different types of dietary advice to all adults with type 2 diabetes on weight, measures of diabetic control, morbidity, total mortality and quality of life.

SEARCH STRATEGY

We carried out a comprehensive search of The Cochrane Library (The Cochrane Library Issue 3, 2003), MEDLINE (1966 to October Week 1, 2003), EMBASE (1980 to Week 40, 2003), CINAHL (1982 to October Week 1, 2003), AMED (1985 to October 2003), bibliographies and contacted relevant experts.

SELECTION CRITERIA

All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention in adults with type 2 diabetes mellitus.

DATA COLLECTION AND ANALYSIS

The lead investigator performed all data extraction and quality scoring with duplication being carried out by one of the other six investigators independently with discrepancies resolved by discussion and consensus. Authors were contacted for missing data. For continuous outcomes, endpoint data were preferred to change data.

MAIN RESULTS

Thirty-six articles reporting a total of eighteen trials following 1467 participants were included. Dietary approaches assessed in this review were low-fat/high-carbohydrate diets, high-fat/low-carbohydrate diets, low-calorie (1000 kcal per day) and very-low-calorie (500 kcal per day) diets and modified fat diets. Two trials compared the American Diabetes Association exchange diet with a standard reduced fat diet and five studies assessed low-fat diets versus moderate fat or low-carbohydrate diets. Two studies assessed the effect of a very-low-calorie diet versus a low-calorie diet. Six studies compared dietary advice with dietary advice plus exercise and three other studies assessed dietary advice versus dietary advice plus behavioural approaches. The studies all measured weight and measures of glycaemic control although not all studies reported these in the articles published. Other outcomes which were measured in these studies included mortality, blood pressure, serum cholesterol (including LDL and HDL cholesterol), serum triglycerides, maximal exercise capacity and compliance. The results suggest that adoption of regular exercise is a good way to promote better glycaemic control in type 2 diabetic patients, however all of these studies were at high risk of bias.

REVIEWERS' CONCLUSIONS

There are no high quality data on the efficacy of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for well-designed studies which examine a range of interventions, at various points during follow-up, although there is a promising study currently underway.

High prevalence of type 2 diabetes in all ethnic groups, including Europeans, in a British inner city: relative poverty, history, inactivity, or 21st century Europe?

OBJECTIVE

To compare the prevalence of type 2 diabetes in white Europeans and individuals of African-Caribbean and Pakistani descent.

RESEARCH DESIGN AND METHODS

Random sampling of population-based registers in inner-city Manchester, Britain's third most impoverished area. A total of 1,318 people (25-79 years of age) were screened (minimum response 67%); 533 individuals without known diabetes underwent 2-h glucose tolerance testing, classified by 1999 World Health Organization criteria.

RESULTS

More than 60% of individuals reported household annual income < pound10,000 ($15,000) per year. Energetic physical activity was rare and obesity was common. Age-standardized (35-79 years) prevalence (mean 95% CI) of known and newly detected diabetes was 20% (17-24%) in Europeans, 22% (18-26%) in African-Caribbeans, and 33% (25-41%) in Pakistanis. Minimum prevalence (assuming all individuals not tested were normoglycemic) was 11% (8-14%), 19% (15-23%), and 32% (24-40%), respectively. Marked changes in prevalence represent only small shifts in glucose distributions. Regression models showed that greater waist girth, lower height, and older age were independently related to plasma glucose levels, as was physical activity. Substituting BMI and waist-to-hip ratio revealed their powerful contribution.

CONCLUSIONS

A surprisingly high prevalence of diabetes, despite expected increases with new lower criteria, was found in Europeans, as previously established in Caribbeans and Pakistanis. Lower height eliminated ethnic differences in regression models. History and relative poverty, which cosegregate with obesity and physical inactivity, are likely contributors. Whatever the causes, the implications for health services are alarming, although substantial preventive opportunities through small reversals of glucose distributions are the challenge.

Habitual diet in four populations of African origin: a descriptive paper on nutrient intakes in rural and urban Cameroon, Jamaica and Caribbean migrants in Britain

BACKGROUND

The prevalence of chronic diseases is increasing in West Africa, the Caribbean and its migrants to Britain. This trend may be due to the transition in the habitual diet, with increasing (saturated) fat and decreasing fruit and vegetable intakes, both within and between countries.

OBJECTIVE

We have tested this hypothesis by comparing habitual diet in four African-origin populations with a similar genetic background at different stages in this transition.

DESIGN

The study populations included subjects from rural Cameroon urban Cameroon Jamaica and African-Caribbeans in Manchester, UK all aged 25-74 years. Habitual diet was assessed by a food-frequency questionnaire, specifically developed for each country separately.

RESULTS

Total energy intake was greatest in rural Cameroon and lowest in Manchester for all age/sex groups. A tendency towards the same pattern was seen for carbohydrates, protein and total fat intake. Saturated and polyunsaturated fat intake and alcohol intake were highest in rural Cameroon, and lowest in Jamaica, with the intakes in the UK lower than those in urban Cameroon. The percentage of energy from total fat was higher in rural and urban Cameroon than in Jamaica and the UK for all age/sex groups. The opposite was seen for percentage of energy from carbohydrate intake, the intake being highest in Jamaica and lowest in rural Cameroon. The percentage of energy from protein increased gradually from rural Cameroon to the UK.

CONCLUSIONS

These results do not support our hypothesis that carbohydrate intake increased, while (saturated) fat intake decreased, from rural Cameroon to the UK.

Quantifying the association between habitual energy expenditure and blood pressure

BACKGROUND

Previous studies have demonstrated an association between physical inactivity and hypertension, but the methods used to assess activity have been subjective and imprecise. Recently methods have become available allowing measurement of energy expenditure in free-living populations. Our aim was to employ these methods to assess the independent association between energy expenditure, cardio-respiratory fitness and blood pressure.

METHODS

In a cross-sectional study of 775 people (45-70 years) participating in a continuing population-based cohort study, energy expenditure was assessed by 4 days of heart rate monitoring with individual calibration of the relationship between heart rate and energy expenditure, a method validated against doubly-labelled water and whole body calorimetry. Cardio-respiratory fitness was assessed in a sub-maximal test. To adjust for measurement error in the assessment of usual energy expenditure and fitness, 190 subjects repeated both tests on three further occasions at 4-monthly intervals.

RESULTS

A highly significant linear trend in blood pressure was found across quintiles of the physical activity level, the ratio of total energy expenditure to basal metabolic rate. The differences in the mean systolic/diastolic blood pressure between the top and bottom quintile was 6.3/4.4 mmHg in men and 10.7/5.9 mmHg in women. These effects were independent of obesity and cardio-respiratory fitness. Correction for measurement error suggests that the true underlying relationship between usual energy expenditure and blood pressure is stronger still.

CONCLUSIONS

These findings are compatible with a strong association between usual energy expenditure and blood pressure and support public health strategies aimed at increasing overall energy expenditure.

Stroke risk from multiple risk factors combined with hypertension: a primary care based case-control study in a defined population of northwest England

PURPOSE

To examine how hypertension interacts with other known risk factors in affecting the risk of stroke in a primary care based setting.

METHODS

Cases were patients with first-ever stroke identified from the community-based stroke register in 1994-95 in northwest England. Two controls per case were randomly selected from the same primary care site and matched by age and sex. Information on predefined risk factors was extracted from medical records.

RESULTS

267 cases and 534 controls were included. Adjusted odds ratio (OR) for stroke from hypertension was 2.6 (95% confidence interval: 1.7-3.9). In hypertensives who were current smokers, risk of stroke was increased 6 fold as compared to non-smokers without hypertension. Hypertensives who had a preexisting history of myocardial infarction or obesity or diabetes had 3 fold higher risks of stroke. Subjects with hypertension and with a history of transient ischemic attack or atrial fibrillation had > or = 8 fold excess risk of stroke. Among them, the risk was greater in those with poorly controlled or untreated hypertension and in those with well or moderately controlled as compared to subjects without both risk factors. There appeared to be a steady increase in risk of stroke according to the number of risk factors present, particularly in hypertensive subjects.

CONCLUSIONS

Stroke risks in hypertensives associated with combinations of other risk factors appeared to follow an additive model. Subjects with multiple risk factors should be targeted in order to reduce the overall risk for stroke.

Nutrient intake trends among African-Caribbeans in Britain: a migrant population and its second generation

OBJECTIVE

To explore British African-Caribbean (AfC) nutrient intake by migration status (place of birth), diet (traditional Caribbean or more European) and age and relate this ecologically to coronary heart disease (CHD) mortality rates.

DESIGN

Cross-sectional.

SETTING

Inner-city Manchester, UK.

SUBJECTS

Two hundred and fifty-five adults of AfC origin aged 25-79 years, randomly sampled from population registers.

RESULTS

Caribbean-born people (mean age 56, and mean time in Britain 30 years) had significantly lower per cent energy from total and saturated fat than younger British-born AfC people (mean age 29 years) (31.3% vs. 35%, difference in total fat 3.7%, 95%CI 2-5%; in saturated fat 10.9% vs. 12.6%, difference 1.7%, 95%CI 1-2.5%). The Caribbean-born group also ate more fruit (+84g/day-1, 95%CI 36-132g/day-1) and green vegetables (+26 g/day-1, 95%CI 3-49 g/day-1). Men following a traditional diet (> or = 5 days week-1) similarly had a lower per cent energy from fat, at 30.4%, than less traditional eaters, at 33.1% (difference 2.7%, 95%CI 0.7-4.8%). African-Caribbean women, at relatively greater CHD risk than AfC men, had higher body mass indices (BMIs) than AfC men. Compared with national data, AfC subjects consumed some 7% and 5% less energy from total fat and saturated fat, respectively, with over 9% more from carbohydrate. However, there was marked convergence towards the national average in the youngest AfC groups aged 25-34 years, whatever their place of birth.

CONCLUSIONS

Caribbean birthplace has an independent effect on total fat intake and percentage of energy from fat. Together with higher fruit and vegetable intake, these results are consistent with the dietary fat/antioxidant/CHD hypothesis.

The Trp64Arg mutation of the beta3-adrenergic receptor is associated with hyperglycemia and current body mass index in Jamaican women

The Trp64Arg mutation of the beta3-adrenergic receptor (beta3-AR) has been linked to earlier onset of non-insulin-dependent diabetes mellitus (NIDDM), insulin resistance, abdominal obesity, and an increased capacity to gain weight in some European and Japanese populations. We studied the prevalence of the mutation and its association with NIDDM and obesity in our population, in which both rates are high, especially in women. The frequency of the homozygous mutation was 1.53%, and of the Arg allele, 10.5%. Rates were similar in men and women. Significantly higher body mass index (BMI), weight, hip circumference, and fasting and postchallenge 2-hour blood glucose concentrations were associated with the presence of the Arg allele in women but not in men. The association with weight and hip measurements and with hyperglycemia was present only in women aged less than 55 years. In multivariate analysis, the mutation was associated with the BMI and sex in a model that also included age. The variation in fasting and 2-hour blood glucose levels was predicted by beta3-AR, gender, age, and BMI. These results suggest that the presence of the mutation contributes to obesity and hyperglycemia in our female population.

A community based stroke register in a high risk area for stroke in north west England

STUDY OBJECTIVE

To develop a community based stroke register to assess the magnitude of the problem of stroke in an entire health district in a high risk area for stroke.

DESIGN

Community based stroke register from general practice data.

SETTING

East Lancashire Health Authority with a 1995 population of 534,287.

PATIENTS

The stroke register was developed and maintained for one calendar year in East Lancashire between 1 July 1994 and 30 June 1995. Efforts were made to include all patients who had a stroke during this period from participating general practices, using several sources of referral.

MAIN RESULTS

Of the district's 118 general practices, 93 (79%) participated fully, covering a population of 405,272. A total of 932 strokes, including 642 first ever cases, were cross checked and confirmed, with only 50% from any single source, mainly the practices. The total stroke incidence rate was 1.60 per 1000 per year, adjusted for the England and Wales 1991 census population. The rate increased considerably with age from 0.88/1000 for ages 50-54 to 20.56/1000 for ages 85-89 years. From 50-74 years, the age specific incidence was higher in men, but overall it was higher in women (1.87; 95% confidence interval 1.67, 2.04 per 1000) than in men (1.31; 1.15, 1.47 per 1000), and slightly lower than in Oxford a decade earlier. The rate also varied in different localities, with higher rates in the central towns of Hyndburn (2.05/ 1000), Blackburn (1.63/1000), and Burnley (1.80/1000) and lowest values in rural areas (1.18/1000 in Pendle). Case fatality from stroke at 28 days was 34% and the hospital admission rate was high at 70%.

CONCLUSIONS

The multiple source registration method is required for a stroke register. Stroke incidence in this area was still high and there was considerable variation across the district. Case fatality rates were similar to those in previous studies.

A common mutation in the lipoprotein lipase gene promoter, -93T/G, is associated with lower plasma triglyceride levels and increased promoter activity in vitro

Single-strand conformational polymorphism analysis of the lipoprotein lipase promoter identified a T-->G transition at position -93. The frequency in healthy white men was 3.4% (n = 1575). There was an 83% allelic association between -93T-->G and Asp9-->Asn (D9N); all N9 mutations occurred on a -93G allele, but not all -93G mutations occurred on an N9 allele. It was thus possible to assess the effect on plasma triglyceride (Tg) levels of the rare -93G mutation in the presence of the wild-type D9. Carriers of the -93G, with genotype TG/DD, had significantly lower Tg levels than TT/DD individuals (1.36 versus 1.78 mmol/L, P = .01); carriers of both mutations (TG/DN) had the highest Tg levels (1.93 mmol/L). When the group was stratified above and below the sample mean for body mass index (BMI), carriers of the -93G on a D9 allele (TG/DD) were "protected" against the Tg-raising effect of obesity, as assessed by BMI. In Afro-Caribbeans (n = 91), the carrier frequency of -93G was 18-fold higher (63%), with weaker (17%) allelic association between -93G and N9. In vitro, the -93G promoter had 24% higher activity than the -93T in a rat smooth muscle cell line and 18% higher activity in a human adrenal cell line. A protein identified by band-shift assays bound to the -93G but not to the -93T allele, which may explain the lower Tg levels in -93G carriers.

Case-control study of stroke and the quality of hypertension control in north west England

OBJECTIVE

To examine the risk of stroke in relation to quality of hypertension control in routine general practice across an entire health district.

DESIGN

Population based matched case-control study.

SETTING

East Lancashire Health District with a participating population of 388,821 aged < or = 80.

SUBJECTS

Cases were patients under 80 with their first stroke identified from a population based stroke register between 1 July 1994 and 30 June 1995. For each case two controls matched with the case for age and sex were selected from the same practice register. Hypertension was defined as systolic blood pressure > or = 160 mm Hg or diastolic blood pressure > or = 95 mm Hg, or both, on at least two occasions within any three month period or any history of treatment with antihypertensive drugs.

MAIN OUTCOME MEASURES

Prevalence of hypertension and quality of control of hypertension assessed by using the mean blood pressure recorded before stroke) and odds ratios of stroke (derived from conditional logistic regression).

RESULTS

Records of 267 cases and 534 controls were examined; 61% and 42% of these subjects respectively were hypertensive. Compared with non-hypertensive subjects hypertensive patients receiving treatment whose average pre-event systolic blood pressure was controlled to < 140 mm Hg had an adjusted odds ratio for stroke of 1.3 (95% confidence interval 0.6 to 2.7). Those fairly well controlled (140-149 mm Hg), moderately controlled (150-159 mm Hg), or poorly controlled (> or = 160 mm Hg) or untreated had progressively raised odds ratios of 1.6, 2.2, 3.2, and 3.5 respectively. Results for diastolic pressure were similar; both were independent of initial pressures before treatment. Around 21% of strokes were thus attributable to inadequate control with treatment, or 46 first events yearly per 100,000 population aged 40-79.

CONCLUSIONS

Risk of stroke was clearly related to quality of control of blood pressure with treatment. In routine practice consistent control of blood pressure to below 150/90 mm Hg seems to be required for optimal stroke prevention.

Genetic analysis of TAP2 in systemic lupus erythematosus patients from two ethnic groups

The aim of this study was to determine whether the TAP2 (Transporter associated with Antigen Processing 2) locus is involved in susceptibility to systemic lupus erythematosus (SLE). We adopted the interethnic approach to overcome problems in the analysis resulting from linkage disequilibrium. The TAP2 gene polymorphisms of the codons corresponding to amino acid positions 379, 565 and 665 were investigated by amplification refractory mutation system polymerase chain reaction (ARMS-PCR) in 186 patients (151 white Europeans, 35 Afrocaribbeans) and 183 controls (79 white Europeans, 104 Afrocaribbeans). In the European SLE patients, the frequency of the TAP2 type V-A-TA was marginally lower compared with the control group (31% vs 42%), with negative linkage disequilibrium between this TAP2 type and DR3 probably accounting for the difference. For the European SLE patients, we confirmed a significant association of DR3 with disease status [odds ratio = 4.16, 95% confidence interval (CI), 2.08-8.39] and in the patients with DR3 there was a significantly high frequency of the TAP2 type V-A-T-. In the Afrocaribbean SLE patients, any associations of disease status with TAP2 phenotype were the inverse of those in the European patients. Thus, in these patients the frequency of V-A-TA was higher than in controls (46% vs 26%, OR = 2.4, 95% CI 1.01-5.74), while the frequency of V-A-T- was lower (26% vs 40%, not significant). Despite possible sampling error, the lack of a difference in TAP2 status between cases and controls within ethnic groups and, if anything, an inverse association across ethnic groups, makes it unlikely that the TAP2 polymorphism studied here is of primary relevance to SLE susceptibility.

Dendritic cells infected in vitro with human T cell leukaemia/lymphoma virus type-1 (HTLV-1); enhanced lymphocytic proliferation and tropical spastic paraparesis

Evidence supporting a role of the dendritic cell (DC) in stimulating autologous T cell activity in tropical spastic paraparesis (TSP) was sought by studies of cells taken from healthy volunteers and exposed to HTLV-1 in vitro. DC were co-cultured with an HTLV-1-producing cell line (MT-2) at 1:1 or 10:1 ratios. These DC stimulated high levels of proliferation in autologous T cells. This was similar to that seen in an autologous mixed leucocyte reaction (AMLR) using cells from TSP patients. The requirement for both DC and virus was confirmed, since neither DC co-cultured with uninfected MT-2 cells nor addition of infected MT-2 cells directly to T cells caused significant stimulation. DC exposed to the highest dose of HTLV-1 (1:1) for 24 h before addition of T cells caused strong stimulation that increased after 8 h but almost disappeared by 72 h. In situ hybridization showed that approximately 25% of DC became infected in cultured cells after preincubation for 24 h, and over 50% were infected with a 72-h preincubation. We suggest that infection of DC by HTLV-1 may be an initial step in altering the immune system in seronegative patients, and that persistent T cell stimulation in those with genetic susceptibility may underlie the production of neurological disease.

The thrifty genotype and non-insulin dependent diabetes

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Dendritic cells in HIV-1 and HTLV-1 infection

Individuals with HIV-1 infection show two major immunological effects--the early persistent stimulation of immune responses (e.g. of CD8 cells and antibody production) and later catastrophic immunodeficiency. Peripheral blood dendritic cells (DC) become infected with HIV-1 and infected cells can stimulate responses to virus. By contrast infected DC show a reduced capacity to stimulate either primary or secondary responses to other antigens. We have proposed that the block, particularly in primary responses, may be instrumental in the development of immunodeficiency. In HTLV-1 infected patients with tropical spastic paraparesis (TSP) a major feature of disease is 'spontaneous' T cell proliferation thought to underlie development of inflammatory neurological disease. We have now shown that some DC in addition to T cells are infected in TSP and that DC stimulate the persistent T cell activity. Here we demonstrate this using cells from an informative family where the daughter was normal, the father an HTLV-1 seronegative carrier and the mother had TSP. DC from all individuals stimulated normal allogeneic T cells in a mixed leukocyte reaction (MLR) and T cells responded well to normal allogeneic DC. T cells from the daughter showed little stimulation with autologous DC, those from the father showed significant but low stimulation, and T cells from the TSP patient gave a response to autologous DC which exceeded that to allogeneic DC. Taken together, the studies of DC and both HIV-1 and HTLV-1 indicate that infection of DC may play a central role in development of T cell abnormalities in human retrovirus-induced diseases.

Antibody-dependent cell-mediated cytotoxicity: comparison between HTLV-I and HIV-1 assays

This study confirms the presence of detectable antibody-dependent cell-mediated cytotoxicity (ADCC) towards both HTLV-I- and HIV-1-infected cell lines, mediated by normal donor peripheral blood mononuclear cells and either by antibody from adult T-cell lymphoma and tropical spastic paraparesis patients (HTLV-I) or by antibody from sera of patients with persistent generalized lymphadenopathy, AIDS-related complex, AIDS and asymptomatic patients seropositive for HIV-1 infection. A comparison of ADCC towards these two retroviruses, under carefully controlled laboratory conditions, indicates major differences between the capacity of HTLV-I-seropositive sera and HIV-1-seropositive sera to mediate ADCC. In all cases, HIV sera showed low-titre ADCC, in contrast to the high titre (greater than 1:800,000) ADCC mediated by HTLV-I-positive sera. Both sets of sera showed the prozone phenomenon, and heat inactivation may abolish ADCC towards HIV-1-infected cells. Quantitation of surface antigen expression on HTLV-I- and HIV-1-infected cell lines indicated the presence of easily detectable amounts of virus-specific antigen. We conclude that, in contrast to some previous reports, ADCC mediated by HIV-1-specific immunoglobulin G (IgG) antibody is rather weak and of low titre when compared with HTLV-I ADCC. This is true for all cell lines and HIV-1 virus isolate combinations tested.

HTLV-1 infection in tropical spastic paraparesis: lymphocyte culture and serologic response

All 17 patients with tropical spastic paraparesis (TSP) in a series seen in the United Kingdom have antibodies to the human T cell leukemia virus type 1 (HTLV-1). Cultured peripheral blood lymphocytes from these patients formed multinucleated giant cells and reacted with sera and monoclonal antibodies to HTLV-1 in a manner identical to adult T cell leukemia-lymphoma (ATLL) patient lymphocytes. Western blot analysis failed to reveal any marked difference in the antigens recognized by sera from TSP and ATLL patients. The sera from TSP patients, their asymptomatic relatives and ATLL patients were titrated using the following assays: enzyme-linked immunosorbent assays (ELISA), particle agglutination, antibody-dependent cell-mediated cytotoxicity, and pseudotype neutralization. There were significantly stronger serologic responses in the TSP patients than in their relatives or ATLL patients. High antibody titers in the presence of replicating virus often reflect the antigen load; however, these data are also consistent with the suggestion that neurologic damage in TSP may be immunologically mediated.

Antibody to human T-lymphotropic virus type 1 in West-Indian-born UK residents with spastic paraparesis

Of 13 West-Indian-born UK residents with spastic paraparesis of unknown cause, 11 were tested for serum antibody to human T-cell lymphotropic virus type 1 and all were positive. Their magnetic resonance imaging scans were normal or showed only minor abnormalities in the brain, and the spinal cord was normal in the 5 investigated. Of 48 patients with multiple sclerosis, mainly caucasian, none had antibody to HTLV-1 in the blood.