Abstract P1-06-02: The effect of race on pathologic complete response rates and overall survival in patients with triple negative breast cancer

Introduction: Despite the recent overall improvement in survival for patients with breast cancer, racial disparities in outcomes persist. While studies have demonstrated that socioeconomic factors and access to treatment play a role, differences in tumor biology may also contribute. Black women are significantly more likely to develop triple negative breast cancer (TNBC), the deadliest of the breast cancer subtypes, with more TNBC patients progressing to incurable, metastatic disease than patients with any other breast cancer subtype. Studies have demonstrated that TNBC patients who achieve a pathologic complete response (pCR), defined as no residual invasive cancer in the breast or lymph nodes after neoadjuvant chemotherapy (NAC), have improved survival. We hypothesize that rates of pCR and overall survival (OS) in patients with TNBC may differ by race/ethnicity, which may account in part for the disparities in outcomes observed. Methods: Adult female patients with stage I-III TNBC diagnosed in 2010-2019 who received NAC followed by surgery were identified from the National Cancer Database (NCDB). Race/ethnicity was defined as Hispanic (H), Non-Hispanic White (NHW), Non-Hispanic Black (NHB), Non-Hispanic Asian (NHA), and Non-Hispanic Other (NHO). pCR was defined as no invasive cancer in either the breast or axilla (ypT0/is,N0) at surgery. Logistic regression was used to estimate the association of race/ethnicity with achievement of pCR after adjustment for covariates. Unadjusted OS was estimated using the Kaplan-Meier method, and the log-rank test was used to compare groups. Cox Proportional Hazards models were used to estimate the association of race/ethnicity and achievement of pCR with OS after adjustment for covariates. Additional interaction and subgroup analyses were also conducted. Results: Of the 40,890 patients identified, 29.8% (n=12,173) demonstrated pCR after NAC. The unadjusted 5-year OS rates for those who achieved pCR were significantly higher compared to patients with no pCR (0.917, 95% CI 0.911-0.923 vs 0.667, 95% CI 0.661-0.673, log-rank p< 0.001). Hispanic patients were more likely to achieve pCR (OR 1.19, 95% CI 1.08-1.31, p=0.001), and NHB patients were less likely to achieve pCR (OR 0.89, 95% CI 0.83-0.95, p=0.001) compared to NHW, even after adjustment. Unadjusted OS was also notably lower for NHB patients compared to every other race group (5-year OS rate: NHB 0.709 vs NHW 0.746 vs NHO 0.771 vs H 0.772 vs NHA 0.816, log-rank p< 0.001); however, this difference did not persist after adjustment for patient and disease factors, including achievement of pCR. Interval from diagnosis to start of chemotherapy (OR 0.95, 95% CI 0.94-0.96, p< 0.001) and duration after chemotherapy start to surgery (OR 1.02, 95% CI 1.02-1.03, p< 0.001) were associated with the odds of achieving pCR. Overall, the effect of achieving pCR on OS did not differ by race/ethnicity (interaction p=0.10). Discussion: Achieving pCR after NAC in patients with TNBC is associated with a significant improvement in OS. Yet, rates of pCR appear to differ based on race/ethnicity, with NHB patients demonstrating significantly lower rates of pCR than NHW patients, which may contribute to the disparities in survival outcomes observed. In addition to addressing socioeconomic factors and access to treatment, further research examining whether biological differences exist based on race that influence response of TNBC to current standard therapies is essential for improving survival outcomes for this disproportionately affected patient population.

Citation Format: Hannah E. Woriax, Samantha M. Thomas, Jennifer K. Plichta, Laura H. Rosenberger, Astrid Botty van de bruele, Akiko Chiba, Gayle DiLalla, Carolyn Menendez, E Shelley Hwang, Maggie L. DiNome. The effect of race on pathologic complete response rates and overall survival in patients with triple negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-06-02.

Pragmatic observations from a post-COVID-19 cardiac evaluation register: prevalence of cardiological alterations from a basic diagnostic sequence and contribution of the clinical hystory

Introduction

The prevalence of cardiological sequelae in patients recovered from COVID-19 varies in different reports. This may be due to the population diversity studied or to the complementary methods on which the diagnosis was based.

Objective

1) To determine the prevalence of “de novo” cardiological alterations (DN) in the population recovered from COVID-19 using a basic cardiological evaluation sequence. 2) To evaluate the contribution of the clinical history (CH) in the detection of DN.

Methods

Patients (pts) with COVID-19, PCR (+) were included. The pts attended an ambulatory consultation office at least 30 days after discharge from COVID-19. The evaluation was performed in a stepwise manner: first Interview: CH, physical examination (PE), and EKG; second Interview: routine laboratory test, C-reactive protein, echocardiogram and cardiac biomarkers. Other complementary studies (Holter, RMI, CCG) were requested according to previous findings. The diagnosis of DN (by PE, EKG or echocardiogram, alone or with the addition of other methods) was defined as the appearance of cardiological alterations in patients with no pre-existing known heart disease or the progression of a known cardiac disease. The prevalence of DN is described. Sensitivity, specificity and predictive value of CH for DN are reported.

Results

A total of 246 pts were evaluated with the first interview (age: 52±13 years; women: 47.8%; caucasian: 60.6%; overweight: 79%; some pathological history: 71.5%; previous heart disease: 15.4%; hospitalization during the acute phase of COVID: 78.8%; mild Covid: 37%, moderate: 39%, severe: 24%; time between discharge and post-COVID evaluation: 68±42 days). DN were detected in 62 pts: rhythm disturbances: 41 (sinus tachycardia: 23 (18 isolated), sinus bradycardia: 3, supraventricular arrhythmia: 6, ventricular arrhythmia: 14); conduction disturbance: 10, ventricular dysfunction: 20 (12 de novo, 8 progression). Specific diagnoses: myocarditis: 6, coronary artery disease: 5, acute mitral insufficiency: 1. In 16 pts (6.5%) DN had clinical relevance. Six of them (2.4%) required hospitalization. In previously healthy pts with mild COVID, only rhythm disorders were detected in 3 pts. Se, Sp and PV of the CH is shown in Table 1. Eighteen Holter monitoring tests (5 +), 9 MRIs (5 +), 4 CCGs (2 +) were performed.

Conclusions

1) Using a basic cardiac diagnostic sequence, at least 30 days after discharge, a quarter of post-COVID patients had “de novo” cardiological findings. However, a small percentage became clinically relevant. The causal relationship of DN with COVID-19 cannot be unequivocally asserted. Previously healthy patients have low prevalence of cardiac findings detected with a basic diagnostic sequence.

2) The data obtained from the clinical history have a low positive predictive value.

Funding Acknowledgement

Type of funding sources: None.

Disparities in Genetic Testing for Heritable Solid-Tumor Malignancies

Genetic testing offers providers a potentially life saving tool for identifying and intervening in high-risk individuals. However, disparities in receipt of genetic testing have been consistently demonstrated and undoubtedly have significant implications for the populations not receiving the standard of care. If correctly used, there is the potential for genetic testing to play a role in decreasing health disparities among individuals of different races and ethnicities. However, if genetic testing continues to revolutionize cancer care while being disproportionately distributed, it also has the potential to widen the existing mortality gap between various racial and ethnic populations.

Do Histopathology and Clinical Outcomes of Breast Atypia Vary by Race/Ethnicity?

BACKGROUND

The clinical behavior of breast cancer varies by racial and ethnic makeup (REM), but the impact of REM on the clinical outcomes of breast atypia remains understudied. We examined the impact of REM on risk of underlying or subsequent carcinoma following a diagnosis of breast atypia.

METHODS

In this retrospective, single-institution chart review, adult women diagnosed with breast atypia (atypical ductal hyperplasia, atypical lobular hyperplasia, or lobular carcinoma in situ) were stratified by REM. Regression modeling was used to estimate risk of underlying or subsequent carcinoma.

RESULTS

We identified 539 patients with breast atypia, including 15 Hispanic (2.8%), 127 non-Hispanic black (23.6%), and 397 non-Hispanic white women (73.7%). Diagnoses included 75.1% atypical ductal hyperplasia (n = 405), 4.6% atypical lobular hyperplasia (n = 25), and 20.2% lobular carcinoma in situ (n = 109). Rates for each type of atypia did not vary by REM (P = 0.33). Of those with atypia on needle biopsy, the rate of underlying carcinoma at excision was 17.3%. After adjustment, REM was not associated with greater risk for carcinoma at excision (P = 0.41). Of those with atypia alone on surgical excision, the rate of a subsequent carcinoma diagnosis was 15.4% (median follow-up 49 mo). REM was not associated with a long-term risk for carcinoma (P = 0.37) or differences in time to subsequent carcinoma (log-rank P = 0.52). Chemoprevention uptake rates were low (10.6%), especially among Hispanic (0%) and non-Hispanic black (3.8%) patients (P = 0.01).

CONCLUSIONS

Among patients with atypia, REM does not appear to influence type of histologic atypia, risk for carcinoma, or clinical outcome, despite differences in chemoprevention rates.

Synthesis and biological evaluation against Leishmania donovani of novel hybrid molecules containing indazole-based 2-pyrone scaffolds

A series of novel indazole-pyrone hybrids were synthesized by a one pot reaction between N-alkyl-6(5)-nitroindazoles and 2-pyrone (4-hydroxy-6-methyl-2H-pyran-2-one) using indium or stannous chloride as the reducing system in the presence of acetic acid in tetrahydrofuran. The hybrid molecules were obtained in good to excellent yields (72-92%) and characterized by NMR and single crystal X-ray diffraction. Nineteen compounds were tested in vitro against both Leishmania donovani (MHOM/ET/67/HU3, also called LV9) axenic and intramacrophage amastigotes. Among all, five compounds showed anti-leishmanial activity against intracellular L. donovani with an IC₅₀ in the range of 2.25 to 62.56 μM. 3-(1-(3-Chloro-2-ethyl-2H-indazol-6-ylamino)ethylidene)-6-methyl-3H-pyran-2,4-dione 6f was found to be the most active compound for axenic amastigotes and intramacrophage amastigotes of L. donovani with IC₅₀ values of 2.48 ± 1.02 μM and 2.25 ± 1.89 μM, respectively. However, the cytotoxicity of the most promising compound justifies further pharmacomodulations.

Omega-3 versus isoflavones in the control of vasomotor symptoms in postmenopausal women

Determine the efficacy and tolerability of omega-3 fatty acids versus soybean isoflavones in reducing the vasomotor symptoms (VMSs) frequency in postmenopausal women. A randomized, prospective, two-arm study was performed in healthy postmenopausal women aged 45-65. The two arms were: two capsules/day of omega-3 (425 mg of omega-3/capsule) administered orally (n = 38) and two tablets/day of soybean isoflavones (54.4 mg of isoflavones/tablet) (n = 30), over 16 weeks. The mean baseline frequency of moderate and severe VMSs per week in the omega-3 group was 24.56 and 23.90, respectively, and 19.65 and 19.51 in the isoflavone group. After 4 months, the reduction in moderate and severe hot flashes with omega-3 was significant (p < .001), whereas in the case of isoflavones, there was a significant difference in severe (p = .02) hot flashes after 4 months, but not in moderate hot flashes (p = .077). Omega-3 did not demonstrate significant efficacy differences versus isoflavones over time. The use of omega-3 has a beneficial effect on hot flash reduction after 4 months of treatment. This is comparable to the benefits found with soybean isoflavones after 3-4 weeks and after 4 months in severe hot flash women, but higher than those found with soybean isoflavones in moderate symptom women.

Transmission of Staphylococcus aureus between mothers and infants in an African setting

Staphylococcus aureus colonization is a risk factor for invasive disease. There is a need to understand S. aureus colonization in infancy as the burden of S. aureus infections in infants is high. We aimed to investigate the transmission of S. aureus between mothers and their newborns during the first year after delivery in an African setting. In a longitudinal cohort study, colonization of Gabonese mother-infant pairs was assessed at delivery and after 1, 9 and 12 months. Swabs were taken from mothers (nares, mammillae) and infants (nares and throat). Isolates were characterized and risk factors for colonization were assessed using a standardized questionnaire. We recruited 311 mothers and 318 infants including seven sets of twins. Maternal and infant colonization rates declined synchronously following a peak after 1 month at 40% (mothers) and 42% (infants). Maternal colonization was a risk factor for S. aureus carriage in infants. Based on spa typing, direct mother-to-infant transmission was evident in 5.6%. Of all methicillin-resistant isolates (n = 9), 44.4% were related to the USA300 clone; 56.7% (n = 261) of all S. aureus carried Panton-Valentine leukocidin encoding genes. Direct mother-to-infant transmission was rare and cannot explain the increase of carriage in infants within the first month. A transmission from external sources is likely and challenges the S. aureus infection control in newborns and infants in an African setting. The detection of USA300-related MRSA fuels the concern about the spread of this clone in Central Africa.

Malaria during pregnancy

Each year approximately 50 million women living in malaria endemic areas become pregnant and are at risk of the adverse health impact of malaria. Approximately half of them live in sub-Saharan Africa and most of them in areas of intense falciparum transmission. The increased susceptibility to malaria of pregnant women has long been recognized. Although some progress has been accomplished in recent years, resulting in the identification of intermittent preventive treatment (IPTp) and insecticide treated nets (ITNs) as key strategies to control malaria in pregnancy in Africa, much work needs to be done to control malaria effectively in this high at risk group. There are still many gaps in knowledge that need to be addressed: from the biological mechanism(s) that explains the increased susceptibility during pregnancy, the most effective control measures in different transmission areas and the best drugs for case management.

The incidence of clinical malaria detected by active case detection in children in Ifakara, southern Tanzania

Between July 2000 and June 2001, we used weekly active case detection (ACD) of clinical malaria episodes in 618 children aged < 5 years to describe the epidemiology of malaria in Ifakara, southern Tanzania. Plasmodium falciparum-positive blood slides prepared from children with axillary temperature 37.5 degrees C were used to define clinical malaria and a rolling cross-sectional survey documented the prevalences of parasitaemia and anaemia. A random subsample of children was visited daily for 1 month at the end of the study to assess the effect of more frequent visits on estimated incidence rates. Only 50 (8%) children had 1 or more episodes of clinical malaria during the year, an overall incidence of 0.275 episodes/100 child-weeks-at-risk, with no age dependence. The maximum parasite prevalence of 25% was reached in children aged 4 years. The incidence of illness was significantly lower in children visited daily than in those visited weekly, suggesting a marked effect of frequent visits on estimated incidence rates. We conclude that the age pattern of malaria detected through ACD is a more robust epidemiological indicator than absolute incidence rate estimates and that, in contrast to the surrounding area, Ifakara town is subject to only moderate perennial malaria transmission.

Malaria during pregnancy: a priority area of malaria research and control

More than 2000 million people live in areas where malaria transmission occurs and are therefore at risk of being infected. It follows that 1000 million people are exposed to the risks of malaria when pregnant. Although the special features of malaria during pregnancy have been recognized for nearly a century(1), it is only recently that it is being considered as a priority for malaria research and control, as discussed here by Clara Menendez.

TSH stimulates leptin secretion by a direct effect on adipocytes

Leptin is a circulating hormone secreted by adipose tIssue which acts as a signal to the central nervous system where it regulates energy homeostasis and neuroendocrine processes. Although leptin modulates the secretion of several pituitary hormones, no information is available regarding a direct action of pituitary products on leptin release. However, it has been pointed out that leptin and TSH have a coordinated pulsatility in plasma. In order to test a direct action of TSH on in vitro leptin secretion, a systematic study of organ cultures of human omental adipose tIssue was performed in samples obtained at surgery from 34 patients of both sexes during elective abdominal surgery. TSH powerfully stimulated leptin secretion by human adipose tIssue in vitro. In contrast, prolactin, ACTH, FSH and LH were devoid of action. These results suggest that leptin and the thyroid axis maintain a complex and dual relationship and open the possibility that plasmatic changes in TSH may contribute to the regulation of leptin pulses.

Sexuality in the climacteric years

Menopause is a time of anatomic, physiological and psychological changes that often influence in the sexuality of aging female. Being sexual functioning an important aspect of health and well-being, doctors should have an holistic approach reassuring about the possibility of treating the various symptoms. The central nervous system is an important target for sex steroid hormone; estrogen, progestagens and androgens are able to modulate several brain functions, and receptors for gonadal steroids have been identified in several brain areas. Because there is no test that physicians can make to assess sexual function, taking a sexual history is probably the most important aspect in the diagnostic and treatment of sexual problems. Hormonal transition with decreasing levels of estrogen and testosterone produces clinical effects, so women need to make adjustments for this period of life. Testosterone is an important component of female sexuality, and alterations in its circulating levels play an important role in psychological and sexual changes that occur after menopause. This is the reason why the research in identifying women who have a decrease androgen active should be aimed. Treatment may include education about sexuality and medical management of symptoms or problems interfering with sexual activity. Also treatment implications and the diverse aspects that may influence on sexuality in the climacteric years are discussed.

Inter-observer variation in the assessment of clinical signs in sick Tanzanian children

We assessed the inter-observer agreement in identification of a range of 24 clinical signs associated with disease presentation in 327 children aged < 5 years admitted to hospital in January-June 1999 in Ifakara, southern Tanzania. Children with diagnoses of malaria, pneumonia, diarrhoea, anaemia and malnutrition were examined independently by 2 clinical officers. Findings were recorded on a standard proforma. The Kappa-statistic was used to assess inter-observer agreement for each sign. Physical signs were more likely to be agreed upon by clinicians if they involved inspection than if they involved auscultation. The signs included in the Integrated Management of Childhood Illness (IMCI) algorithm were found to be largely appropriate (Kappa-scores > 0.41) although there was only fair agreement (Kappa-score 0.21-0.40) in the detection of neck stiffness and chest indrawing and slight agreement in the detection of dehydration (Kappa-score 0.199). All objective neurological signs were less reliably assessed in infants than in older children. The difficulties surrounding the diagnosis of impaired consciousness in young children should increase vigilance in the diagnosis and management of neurological complications of illnesses in infancy.

Effect of malaria on soluble transferrin receptor levels in Tanzanian infants

The diagnosis of iron deficiency anemia in malaria endemic areas is complicated by the influence of the infection on the laboratory tests conventionally used to assess iron status. Determination of soluble transferrin receptor (sTfR) levels has been shown to be a sensitive indicator of iron deficiency in adults and is not affected by a range of infectious and inflammatory conditions. The utility of sTfR levels in the diagnosis of iron deficiency in malaria endemic areas remains unresolved. Three hundred and fourteen infants in a rural area of southern Tanzania living under conditions of intense and perennial malaria transmission were studied to determine the utility of sTfR plasma levels in the assessment of iron deficiency anemia. Independent of the presence of anemia, malaria parasitemia was associated with a significant increase in sTfR plasma levels that were even higher than those found in iron deficiency anemia. We conclude that the measurement of sTfR levels does not have a role in the diagnosis of iron deficiency anemia in young children exposed to malaria infection.

Retinoic acid and vitamin D(3) powerfully inhibit in vitro leptin secretion by human adipose tissue

Leptin, the product of the ob gene, is secreted into the circulation by white adipose tissue; its major role being to participate in the regulation of energy homeostasis. Plasma leptin levels are mainly determined by the relative adiposity of the subject; however, the great dispersion of values for any given body mass index and the noteworthy gender-based differences indicate that other factors are operating. Steroid hormones actively participate in the regulation of leptin secretion; however, non-steroid nuclear hormones have either not been studied or have provided contradictory results. In order to understand the role of hormones of the non-steroid superfamily such as 3,5,3'-tri-iodothyronine (T(3)), vitamin D(3) and retinoic acid (RA) in the control of leptin secretion, in the present work doses of 10(-9), 10(-8) and 10(-7) M of these compounds have been studied on in vitro leptin secretion. The organ culture was performed with omental adipose tissue samples from healthy donors (n=28). T(3) was devoid of effect at any dose studied, while an inhibition of leptin secretion was observed with 9-cis-RA (slight) and all-trans-RA (potent). Interestingly, vitamin D(3) exerted a powerfully inhibitory role at the doses studied, and its action was synergistic with all-trans-RA. In conclusion, in vitro leptin secretion by human adipose tissue is negatively controlled by either RA or vitamin D(3). The clinical significance of leptin regulation by this superfamily of nuclear receptors remains to be ascertained.

Intermittent treatment for malaria and anaemia control at time of routine vaccinations in Tanzanian infants: a randomised, placebo-controlled trial

BACKGROUND

Clinical malaria and severe anaemia are major causes of paediatric hospital admission and death in many malaria-endemic settings. In the absence of an effective and affordable vaccine, control programmes continue to rely on case management while attempting the large-scale deployment of insecticide-treated nets. We did a randomised, placebo-controlled trial to assess the efficacy and safety of intermittent sulphadoxine-pyrimethamine treatment on the rate of malaria and severe anaemia in infants in a rural area of Tanzania.

METHODS

We randomly assigned 701 children living in Ifakara, southern Tanzania, sulphadoxine-pyrimethamine or placebo at 2, 3, and 9 months of age. All children received iron supplementation between 2 and 6 months of age. The intervention was given alongside routine vaccinations delivered through WHO's Expanded Program on Immunisation (EPI). The primary outcome measures were first or only episode of clinical malaria, and severe anaemia in the period from recruitment to 1 year of age. Morbidity monitoring through a hospital-based passive case-detection system was complemented by cross-sectional surveys at 12 and 18 months of age. Results were expressed in terms of protective efficacy (100 [1-hazard ratio]%) and analysis was by intention to treat.

FINDINGS

40 children dropped out (16 died, 11 migrated, 12 parents withdrew consent, and one for other reasons). Intermittent sulphadoxine-pyrimethamine treatment was well tolerated and no drug-attributable adverse events were recorded. During the first year of life, the rate of clinical malaria (events per person-year at risk) was 0.15 in the sulphadoxine-pyrimethamine group versus 0.36 in the placebo group (protective efficacy 59% [95% CI 41-72]), and the rate of severe anaemia was 0.06 in the sulphadoxine-pyrimethamine group versus 0.11 in the placebo group (50% [8-73]). Serological responses to EPI vaccines were not affected by the intervention.

INTERPRETATION

This new approach to malaria control reduced the rate of clinical malaria and severe anaemia by delivering an available and affordable drug through the existing EPI system. Data are urgently needed to assess the potential cost-effectiveness of intermittent treatment in areas with different patterns of malaria endemicity.

Placental malaria is associated with cell-mediated inflammatory responses with selective absence of natural killer cells

Immunosuppression, particularly of cell-mediated responses, has classically been thought to play a major role in the increased susceptibility to malaria observed in pregnant women. An immunohistochemical characterization of the inflammatory infiltrate in a group of 41 placentas from women living in a Plasmodium falciparum-hyperendemic area in Tanzania revealed a marked increase in the number of monocytes and macrophages and cytotoxic T cells in the intervillous space of placentas with active malaria infection, compared with noninfected placentas, placentas from women with past infection, and a control group of placentas from Spain. This increase was associated with the severity of the infection. High numbers of monocytes and macrophages were associated with low birth weight. We also detected a complete absence of NK cells in the intervillous space in all placentas. This apparently physiological absence of NK cells may contribute to hindering the clearance of the parasite. These results indicate that placental malaria does not appear to be associated with cell-mediated immunosuppression. The role of the absence of NK cells in increased susceptibility to malaria needs to be further elucidated.

The burden of malaria in pregnancy in malaria-endemic areas

Pregnant women in malarious areas may experience a variety of adverse consequences from malaria infection including maternal anemia, placental accumulation of parasites, low birth weight (LBW) from prematurity and intrauterine growth retardation (IUGR), fetal parasite exposure and congenital infection, and infant mortality (IM) linked to preterm-LBW and IUGR-LBW. We reviewed studies between 1985 and 2000 and summarized the malaria population attributable risk (PAR) that accounts for both the prevalence of the risk factors in the population and the magnitude of the associated risk for anemia, LBW, and IM. Consequences from anemia and human immunodeficiency virus infection in these studies were also considered. Population attributable risks were substantial: malaria was associated with anemia (PAR range = 3-15%), LBW (8-14%), preterm-LBW (8-36%), IUGR-LBW (13-70%), and IM (3-8%). Human immunodeficiency virus was associated with anemia (PAR range = 12-14%), LBW (11-38%), and direct transmission in 20-40% of newborns, with direct mortality consequences. Maternal anemia was associated with LBW (PAR range = 7-18%), and fetal anemia was associated with increased IM (PAR not available). We estimate that each year 75,000 to 200,000 infant deaths are associated with malaria infection in pregnancy. The failure to apply known effective antimalarial interventions through antenatal programs continues to contribute substantially to infant deaths globally.

Malaria-related anaemia

Malaria infection in humans by Plasmodium species is associated with a reduction in haemoglobin levels, frequently leading to anaemia. Plasmodium falciparum causes the most severe and profound anaemia, with a significant risk of death. This cannot be explained simply by the direct destruction of parasitized red blood cells at the time of release of merozoites, a process shared by all these species. In this review, Clara Menendez, Alan Fleming and Pedro Alonso focus on recent advances in our knowledge of the pathophysiology, epidemiology, management and prevention of anaemia from falciparum malaria.

The in vitro secretion of human leptin is gender-dependent but independent of the body mass index of the donors

OBJECTIVE

Leptin is an adipocyte-secreted hormone acting as a signal to the central nervous system, where it regulates energy homeostasis and neuroendocrine processes. Leptin plasma levels are mainly regulated by the percentage of body fat, but are also controlled by several metabolic and nutritional variables. Data regarding leptin secretion suggest that it is gender regulated, and higher levels are present in women than men; however, the biological basis for this sex-related difference is unknown. To clarify those points, a systematic study with tissue cultures from human omental adipose tissue was performed.

DESIGN AND METHODS

Surgically obtained samples from 137 patients (68 women, 69 men) were evaluated. The assay was standardized in periods of 24 h ending at 96 h. Each adipose tissue sample from a single donor was incubated in triplicate and leptin results expressed as the mean of the integrated secretion into the medium (nanograms of leptin/g tissue per time).

RESULTS

Tissue adipose cultures showed a steady leptin secretion throughout the 96 h studied, with the peak of secretory activity reached at 48 h; afterwards, the in vitro secretion reached a plateau state. Spontaneous leptin secretion in the 24 h and 48 h period, as well as the area under the curve analyzed in the 0-48 h period, showed a gender-based difference that was significantly (P<0. 05) higher in women than in men. When data of spontaneous leptin secretion were correlated with the body mass index (BMI) of the donors, no correlation was found. This suggests that in vivo leptin levels are dependent on the total amount of fat of the individual, but independent of the leptin secretory rate by the adipose tissue of the donor.

CONCLUSIONS

Leptin secretion from omental adipose tissue in vitro is: (i) significantly higher in samples from women than in samples from men; and (ii) not correlated with the BMI, showing that in vitro leptin secretion is not related to the adiposity of the donor.

Humoral immune responses during a malaria vaccine trial in Tanzanian infants

The development of a malaria vaccine is a priority for improved and sustained malaria control. Optimal use of a vaccine in Africa will only be achieved if it can be delivered through the Expanded Programme of Immunization (EPI). We have completed a trial of the peptide vaccine SPf66 in Tanzanian infants, given alongside the EPI vaccines. This paper describes the humoral responses to SPf66 and the EPI vaccines. A total of 1207 infants were recruited into a two-arm, double-blind, individually randomized placebo-controlled trial of SPf66. The objectives of the trial were to determine the safety, immunogenicity and efficacy of SPf66 and to assess interactions with EPI vaccines when three doses of SPf66 were delivered alongside the EPI vaccines. Cross-sectional surveys were carried out to asses seroconversion rates to the EPI vaccines and the antibody response to SPf66 (NANP)50 and Plasmodium falciparum lysates. Seroconversion rates to EPI vaccines were high and no statistically significant differences in prevalence or titres were found between SPf66 and placebo recipients. IgG antibodies against SPf66 (NANP)50 and whole P. falciparum lysate were present in high titres in mothers of recruited children at the time of birth. Vaccination with SPf66 stimulated a good anti-SPf66 IgG response which declined to preimmunization levels by 2 years of age and which was not associated with protection against clinical malaria. The vaccine induced no IgG antibodies against (NANP)50 or P. falciparum lysates. SPf66 stimulated a humoral immune response when given to very young infants and did not interfere with seroconversion to EPI vaccines. The response to SPf66 was qualitatively different from that seen in older children, in whom SPf66 has been shown to be moderately efficacious. This difference raises concerns about the difficulties of immunizing very young infants who need to be targeted by antimalarial vaccination programs.

The association between atopy and asthma in a semirural area of Tanzania (East Africa)

BACKGROUND

Atopy is consistently associated with asthma, except in a study in Africa. We assessed the association between atopy and asthma in women from a semirural area of Tanzania (East Africa).

METHODS

All pregnant women delivering at the district hospital during a 1-year period were recruited (n = 658, 60.6% of those selected). Asthma was investigated by a standard questionnaire and atopy by specific IgE (immunoglobulin E) antibodies to Dermatophagoides pteronyssinus (Der p 1) and cockroach.

RESULTS

The prevalence of wheezing chest was 10.7%; of asthma, 3.5%. Levels of specific IgE of >0.35 kU/l (73%) and high levels of total IgE (62% higher than 1000 kU/l) were highly prevalent. Specific IgE antibody levels in sera were not associated with asthma (3.8% of women with negative specific IgE to any antigen had asthma in comparison to 4.0% of women with positive specific IgE; odds ratio [OR] = 1.06, 0.35-3.22). Total IgE was not different between women with asthma and women without asthma (P=0.36).

CONCLUSIONS

In tropical regions, the association between allergy and asthma is complex, and specific IgE reactivity to environmental allergens may not be related to asthma.

Transient Horner's syndrome in a trauma patient with thoracic epidural analgesia: a case report

Homer's syndrome, which classically presents as ipsilateral ptosis, meiosis, and facial anhydrosis, may present as a consequence of thoracic epidural analgesia. Pain that limits the patient's ability to maintain adequate pulmonary mechanics may optimally be treated with a thoracic epidural. The importance of recognition of a Horner's syndrome in such a patient is critical in preventing unnecessary anxiety for the patient and potentially embarking on an unnecessary diagnostic workup. The following is a case presentation of a patient who sustained multiple rib fractures in an automobile accident. The patient presented with a Horner's syndrome after a thoracic epidural infusion had begun. This article highlights the importance of early recognition of this benign, transient syndrome and discusses the pathways and potential mechanism of this process.

Transient Horner's Syndrome in a Trauma Patient with Thoracic Epidural Analgesia: A Case Report

Horner's syndrome, which classically presents as ipsilateral ptosis, meiosis, and facial anhydrosis, may present as a consequence of thoracic epidural analgesia. Pain that limits the patient's ability to maintain adequate pulmonary mechanics may optimally be treated with a thoracic epidural. The importance of recognition of a Horner's syndrome in such a patient is critical in preventing unnecessary anxiety for the patient and potentially embarking on an unnecessary diagnostic workup. The following is a case presentation of a patient who sustained multiple rib fractures in an automobile accident. The patient presented with a Horner's syndrome after a thoracic epidural infusion had begun. This article highlights the importance of early recognition of this benign, transient syndrome and discusses the pathways and potential mechanism of this process.

The impact of placental malaria on gestational age and birth weight

Maternal malaria is associated with reduced birth weight, which is thought to be effected through placental insufficiency, which leads to intrauterine growth retardation (IUGR). The impact of malaria on preterm delivery is unclear. The effects of placental malaria-related changes on birth weight and gestational age were studied in 1177 mothers (and their newborns) from Tanzania. Evidence of malaria infection was found in 75.5% of placental samples. Only massive mononuclear intervillous inflammatory infiltration (MMI) was associated with increased risk of low birth weight (odds ratio ¿OR, 4.0). Maternal parasitized red blood cells and perivillous fibrin deposition both were associated independently with increased risk of premature delivery (OR, 3.2; OR, 2.1, respectively). MMI is an important mechanism in the pathogenesis of IUGR in malaria-infected placentas. This study also shows that placental malaria causes prematurity even in high-transmission areas. The impact of maternal malaria on infant mortality may be greater than was thought previously.

Placental pathology in malaria: a histological, immunohistochemical, and quantitative study

To characterize the histological changes in malarial placentas and their relationship with parity and maternal and cord parasitemias, we conducted a histological study on 1,179 placentas from Ifakara, Tanzania, an area with intense and perennial malaria transmission. Immunohistochemical and quantitative studies for CD45, fibrin, and villous area were performed in 60 cases. Four hundred fifteen placentas (35.2%) showed parasites (active infections); in 303 of them, parasites co-existed with pigment covered by fibrin (chronic infections), and in 112 only parasites were detected (acute infections). Four hundred seventy-five cases (40.3%) showed hemozoin deposition without parasites (past infections). Of women with parasitized placentas, 46.3% did not show parasites in the peripheral blood. Basal membrane thickening (P = .002), fibrinoid necrosis (P = .004), and prominence of syncytial knots (P = .031) were associated with active malarial infection. No quantitative differences for perivillous fibrin deposition or villous area were found. The most significant association with active malarial infection was intervillous infiltration by mononuclear inflammatory cells (P < .001). Chronic infections were associated with the most severe changes, particularly intervillous mononuclear inflammation (OR, 28.7; 95% CI = 16.0 to 51.5, P< .001). Past infections showed only minimal differences with noninfected placentas. Primiparas showed chronic infections more frequently than multiparas (52% v 15%, P < .001). They also showed significantly higher placental parasitemias and intervillous inflammatory infiltrate. In conclusion, placental histology is more sensitive than peripheral blood examination in detecting malarial infection during pregnancy. Most malarial infections recover during pregnancy, leaving few residual changes in the placenta. Intervillous inflammation is the most frequent finding associated with malaria and is especially severe in primiparas, suggesting that mechanisms other than immunosuppression are responsible for the high susceptibility in this group.

The central nervous system and HRT

In postmenopausal women, both the aging process and the hypoestrogenism due to the loss of ovarian function seem to be related to the progressive impairment of cognitive functions and to a higher risk of developing Alzheimer's disease (AD). This paper reviews the potentially beneficial effects of hormonal replacement therapy (HRT) on cognition and on the risk of developing AD. Articles relevant to the topic were selected by reviewing MEDLINE data and references of previous published reviews on this subject. Epidemiological studies on the effects of HRT on cognitive functioning have yielded disparate results, perhaps because of varying methodology and designs. However, the available data suggest that the use of HRT could be associated with a lower risk for AD. This conclusion should be interpreted with caution, since most of the studies were case-control studies, and thus subjected to several sources of bias. Further well-designed and conducted clinical trials and longitudinal studies would be required to clarify the effects of estrogens on cognition and AD.

African children with malaria in an area of intense Plasmodium falciparum transmission: features on admission to the hospital and risk factors for death

Malaria remains the most important parasitic cause of mortality in humans. Its presentation is thought to vary according to the intensity of Plasmodium falciparum transmission. However, detailed descriptions of presenting features and risk factors for death are only available from moderate transmission settings. Such descriptions help to improve case management and identify priority research areas. Standardized systematic procedures were used to collect clinical and laboratory data on 6,624 children admitted to hospital over a 1-year period in an intensely malarious part of Tanzania. Frequencies of signs and symptoms were calculated and their association with a fatal outcome was assessed using multivariate logistic regression. There were 72 deaths among 2,432 malaria cases (case fatality rate [CFR] = 3.0%); 44% of the cases and 54% of the deaths were in individuals less than 1 year of age. There was no association between level of parasitemia and CFR. Increased risk of dying was independently found in all children with hypoglycemia (odds ratio [OR] = 6.7, 95% confidence interval [CI] = 3.9-11.7), in children 1-7 months of age with tachypnea (OR = 8.8, 95% CI = 2.6-30.5) and dehydration (OR = 5.0, 95% CI = 1.9-14.2), and in children 8 months to 4 years of age with chest indrawing (OR = 4.7, 95% CI = 2.0-11.2) and inability to localize a painful stimulus (OR = 6.9, 95% CI = 2.9-16.5). Children in the bottom quartile of weight-for-age were more likely to die (OR = 2.1, 95% CI = 1.3-3.5). Eight percent of the malaria cases had severe anemia (packed cell volume < 15%) but 24% received a blood transfusion. The epidemiology of malaria disease may be more complex than previously thought. Improved case management in a wide variety of health facilities may result from adequate identification and treatment of dehydration and hypoglycemia. Transfusion-requiring anemia is a major problem and sustainable, effective preventive measures are urgently needed.

Prevalence and mother-to-infant transmission of hepatitis viruses B, C, and E in Southern Tanzania

Hepatitis B and C markers were tested in 980 pregnant women, in the infants born to infected mothers, and in a random sample of 42 and 50, respectively, children born to uninfected mothers in Tanzania. Sixty-two women (6.3%) were positive for HBsAg and 15 (24%) were HBeAg-seropositive. Anti-HCV was detected in 49 women (5%), 15 (31%) of whom had detectable viremia. HCV RNA serum levels were low and only genotype 4 was identified. Sixty-six women (6.7%) were positive for anti-HIV, six of whom were coinfected with HBV and one with HCV. Anti-HEV was negative in the 180 women tested. At 8 months of age, HBsAg was detected in 8% and 2% of children born to HBV-infected and noninfected mothers, respectively (P = 0.2). Corresponding figures at 18 months of age were 31% and 21% (P = 0.3). When tested at 2 months of age, HCV RNA was not detected in any of the 43 children born to anti-HCV-positive mothers nor in any of 50 children born to anti-HCV-negative mothers. At 18 months, only one child, born to an anti-HCV-positive mother, had detectable HCV RNA. None of the infants born to women with HIV coinfection were infected with hepatitis viruses. This study suggests that exposure to HEV does not occur in southern Tanzania. The prevalence of current HBV infection in pregnant women from rural Tanzania is lower than in other sub-Saharan areas. In early childhood, HBV infection appears to occur by horizontal rather than maternofilial mechanisms of transmission. The prevalence of HCV infection is similar to that in other African countries. The results of this study show for the first time in Africa that mother-to-infant transmission does not play a significant role in the acquisition of HCV infection.

Evaluation of the SPf66 vaccine for malaria control when delivered through the EPI scheme in Tanzania

BACKGROUND

Malaria control programmes need to protect young children, who bear the brunt of malaria disease and death in Africa. The development of a vaccine is a priority if improved and sustained malaria control is to be achieved. The best use of a vaccine in Africa will be achieved if it can be delivered through the expanded programme of immunization (EPI). We conducted a trial designed to evaluate the efficacy of SPf66 vaccine for malaria control when delivered through the EPI scheme in Tanzania.

METHODS

The study was a two-arm, double blind, individually randomized placebo controlled trial involving 1207 infants. The primary objective of the trial was to estimate the efficacy of three doses of SPf66 given at 1, 2 and 7 months of age in preventing clinical episodes of malaria. These were documented through a health facility-based passive case detection system.

RESULTS

Among 1207 randomized children, overall compliance for third dose was 91%. SPf66 was safe, immunogenic and did not interfere with the humoral immune responses to EPI vaccines. There were 294 children among SPf66 recipients and 288 among placebo recipients with at least one malaria episode, yielding a vaccine efficacy estimate of 2% (95% CI: -16, 16; P = 0.84).

CONCLUSION

This has been the first trial of a malaria vaccine among very young infants. It provides information on the safety of peptide vaccines administered at this early age as well as their capacity to induce immune responses without negatively interacting with EPI vaccines. Given the modest protection previously documented in older age groups and the lack of efficacy in younger infants, this vaccine in its current alum-based formulation does not appear to have a role in malaria control in sub-Saharan Africa. The lack of efficacy found in this trial also raises concerns about potential difficulties of inducing protective immune responses against malaria through immunization in infants.

Safety in infants of SPf66, a synthetic malaria vaccine, delivered alongside the EPI

The most likely mechanism to deliver a malaria vaccine in African countries is through the Expanded Program of Immunization (EPI). So far only SPf66, a multistage synthetic peptide, has shown any evidence of protection in Phase III field trials. In Tanzania, SPf66 reduced the risk of clinical malaria by 31% in children aged 1-5 years. In order to progress in the critical path of vaccine development and testing towards the implementation of a new vaccine in malaria control programs, we carried out a randomized double-blind placebo controlled efficacy trial of SPf66 when given alongside the EPI scheme. Monitoring of safety and reactogenicity during this trial included detailed clinical and laboratory assessments on 98 infants and assessment of adverse effects within 1 h of vaccination for all 1207 children vaccinated. Surveillance systems monitored attendances as outpatients, admissions to hospital and fatal events in the community. No serious adverse effects were detected more frequently amongst SPf66 recipients compared to placebo. This first assessment in very young infants of a synthetic vaccine provides evidence of a good safety profile.

Dihydrotestosterone, stanozolol, androstenedione and dehydroepiandrosterone sulphate inhibit leptin secretion in female but not in male samples of omental adipose tissue in vitro: lack of effect of testosterone

Leptin, the product of the Ob gene, is a polypeptide hormone expressed in adipocytes which acts as a signalling factor from the adipose tissue to the central nervous system, regulating food intake and energy expenditure. It has been reported that circulating leptin levels are higher in women than in men, even after correction for body fat. This gender-based difference may be conditioned by differences in the levels of androgenic hormones. To explore this possibility, a systematic in vitro study with organ cultures from human omental adipose tissue, either stimulated or not with androgens (1 microM), was undertaken in samples obtained from surgery on 44 non-obese donors (21 women and 23 men). The assay was standardized in periods of 24 h, ending at 96 h, with no apparent tissue damage. Leptin results are expressed as the mean+/-s.e.m. of the integrated secretion into the medium, expressed as ng leptin/g tissue per 48 h. Spontaneous leptin secretion in samples from female donors (4149+/-301) was significantly higher (P<0.01) than that from male donors (2456+/-428). Testosterone did not exert any significant effect on in vitro leptin secretion in either gender (4856+/-366 in women, 3322+/-505 in men). Coincubation of adipose tissue with dihydrotestosterone (DHT) induced a significant (P<0.05) leptin decrease in samples taken from women (3119+/-322) but not in those taken from men (2042+/-430). Stanozolol, a non-aromatizable androgen, decreased (P<0.05) leptin secretion in female samples (2809+/-383) but not in male (1553+/-671). Dehydroepiandrosterone sulphate (DHEA-S) induced a significant (P<0.01) leptin decrease in female samples (2996+/-473), with no modifications in samples derived from males (1596+/-528). Exposure to androstenedione also resulted in a significant reduction (P<0.01) of leptin secretion in samples taken from women (2231+/-264), with no effect on male adipose tissue (1605+/-544). In conclusion, DHT, stanozolol, DHEA-S and androstenedione induced a significant inhibition of in vitro leptin secretion in samples from female donors, without affecting the secretion in samples from men. Testosterone was devoid of activity in either gender.

Presence of acetyl coenzyme A (CoA) carboxylase and propionyl-CoA carboxylase in autotrophic Crenarchaeota and indication for operation of a 3-hydroxypropionate cycle in autotrophic carbon fixation

The pathway of autotrophic CO2 fixation was studied in the phototrophic bacterium Chloroflexus aurantiacus and in the aerobic thermoacidophilic archaeon Metallosphaera sedula. In both organisms, none of the key enzymes of the reductive pentose phosphate cycle, the reductive citric acid cycle, and the reductive acetyl coenzyme A (acetyl-CoA) pathway were detectable. However, cells contained the biotin-dependent acetyl-CoA carboxylase and propionyl-CoA carboxylase as well as phosphoenolpyruvate carboxylase. The specific enzyme activities of the carboxylases were high enough to explain the autotrophic growth rate via the 3-hydroxypropionate cycle. Extracts catalyzed the CO2-, MgATP-, and NADPH-dependent conversion of acetyl-CoA to 3-hydroxypropionate via malonyl-CoA and the conversion of this intermediate to succinate via propionyl-CoA. The labelled intermediates were detected in vitro with either 14CO2 or [14C]acetyl-CoA as precursor. These reactions are part of the 3-hydroxypropionate cycle, the autotrophic pathway proposed for C. aurantiacus. The investigation was extended to the autotrophic archaea Sulfolobus metallicus and Acidianus infernus, which showed acetyl-CoA and propionyl-CoA carboxylase activities in extracts of autotrophically grown cells. Acetyl-CoA carboxylase activity is unexpected in archaea since they do not contain fatty acids in their membranes. These aerobic archaea, as well as C. aurantiacus, were screened for biotin-containing proteins by the avidin-peroxidase test. They contained large amounts of a small biotin-carrying protein, which is most likely part of the acetyl-CoA and propionyl-CoA carboxylases. Other archaea reported to use one of the other known autotrophic pathways lacked such small biotin-containing proteins. These findings suggest that the aerobic autotrophic archaea M. sedula, S. metallicus, and A. infernus use a yet-to-be-defined 3-hydroxypropionate cycle for their autotrophic growth. Acetyl-CoA carboxylase and propionyl-CoA carboxylase are proposed to be the main CO2 fixation enzymes, and phosphoenolpyruvate carboxylase may have an anaplerotic function. The results also provide further support for the occurrence of the 3-hydroxypropionate cycle in C. aurantiacus.

Effect of iron supplementation and malaria prophylaxis in infants on Plasmodium falciparum genotypes and multiplicity of infection

During a randomized placebo-controlled trial of chemoprophylaxis against Plasmodium falciparum malaria and iron supplementation, in infants living under conditions of intense transmission, all samples of P. falciparum obtained from children aged 5 and 8 months were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis for the msp2 locus. One hundred and six blood samples were analysed for the number of concurrent infections (multiplicity), and the allelic family of each msp2 genotype was determined. Mean multiplicity of infection was, overall, 2.76 infections/child, and it was significantly reduced in infants receiving chemoprophylaxis. This finding might help to explain the rebound effect in morbidity observed after prophylaxis was ended. Iron supplementation did not affect multiplicity of infection. In infants receiving placebo only, or placebo and iron supplementation, a significant positive association was observed between the number of infections and parasite densities (Spearman's p = 0.25, P-0.047). This association was lost in the group receiving chemoprophylaxis alone, or in combination with iron. This study showed a significant association of FC27-like msp2 alleles with prospective risk of clinical malaria in children (relative risk = 1.487, P = 0.013). Such an association was also found for the present risk of clinical malaria in infants receiving prophylaxis (odds ratio = 3.84, P = 0.026), which might imply that chemoprophylaxis may impair the development of premunition.

Infection, oxford general practice series 40

edited by L. Southgate, C. Lockie, S. Heard and M. Wood, Oxford University Press, 1997. pound27.50 (476 pages) ISBN 0 919 262092 4.

Massive chronic intervillositis of the placenta associated with malaria infection

Massive chronic intervillositis (MCI) is an infrequently recognized placental lesion thought to be of immunologic origin that has been associated with poor fetal outcome. It is characterized by a prominent inflammatory infiltrate in the intervillous space, composed mainly of monocytes and macrophages that can simulate a maternal malignant disorder involving the placenta. The villi are characteristically spared. We report 74 cases of placental malarial infection with morphologic features of MCI. In all cases, the massive inflammatory infiltrate was limited to the intervillous space, which appeared largely obliterated. Increased fibrin deposition and prominent syncytial knots were frequent associated findings. Inflammatory cells were CD45 and CD68 positive, consistent with a monocyte-macrophage population. Some polymorphonuclear leukocytes and scattered T and B lymphocytes were also present. Villi were not inflamed. Malarial pigment was present in all cases, and parasitized maternal erythrocytes were evident in 73 of 74 patients. The histologic pattern of MCI was observed in 17.6% of placentas with malarial parasites. Malarial MCI affected predominantly primigravida women (77%) and was associated with a reduced birth weight, which in 39 (53%) of the infants was less than 2500 g, and a low gestational age. None of the infants with placentas with MCI died in the early neonatal period. Morphologic changes of MCI are seen in a significant percentage of placentas with malarial infection, especially in primigravida women, and are associated with a low birth weight. Malarial infection should therefore be considered in the differential diagnosis of massive intervillous infiltrates.

Randomised placebo-controlled trial of iron supplementation and malaria chemoprophylaxis for prevention of severe anaemia and malaria in Tanzanian infants

BACKGROUND

Malaria and anaemia, especially that due to iron deficiency, are two leading causes of morbidity worldwide. Little is known about the relative contribution of Plasmodium falciparum infection and iron deficiency to the aetiology of anaemia in malaria-endemic areas. We undertook a randomised comparison of different strategies for control of anaemia and malaria in infants, including an assessment of the effect of iron supplementation on malaria susceptibility.

METHODS

832 infants born at one hospital in a malaria-hyperendemic area of Tanzania between January and October, 1995, were randomly assigned to group DI, receiving daily oral iron (2 mg/kg daily) plus weekly Deltaprim (3.125 mg pyrimethamine plus 25 mg dapsone); group IP, receiving iron plus weekly placebo; group DP, receiving daily placebo plus weekly Deltaprim; or group PP. supplementation was given from 8 to 24 weeks of age, and the weekly chemoprophylaxis from 8 to 48 weeks. The frequency of severe anaemia (packed-cell volume < 25%) and malaria episodes was assessed through a combination of passive case detection and cross-sectional surveys.

FINDINGS

The groups that received iron supplementation had a lower frequency of severe anaemia than those that did not receive iron (0.62 vs 0.87 cases per person-year; protective efficacy 28.8% [95% CI 6.3-45.8). Iron supplementation had no effect on the frequency of malaria (0.87 vs 1.00 cases per person-year; protective efficacy 12.8% [-12.8 to 32.5]). The groups that received malaria prophylaxis had lower frequencies of both severe anaemia (0.45 vs 1.04 episodes per person-year; protective efficacy 57.3% [43.0-67.9]) and malaria (0.53 vs 1.34 episodes per person-year; protective efficacy 60.5% [48.2-69.9]) than the groups that did not receive prophylaxis. After the end of the intervention period, children who had received malaria chemoprophylaxis had higher rates of severe anaemia and malaria than non-chemoprophylaxis groups (relative risks 2.2 [1.3-3.7] and 1.8 [1.3-2.6]).

INTERPRETATION

Malaria chemoprophylaxis during the first year of life was effective in prevention of malaria and anaemia but apparently impaired the development of natural immunity. Iron supplementation was effective in preventing severe anaemia without increasing susceptibility to malaria. Our findings support iron supplementation of infants to prevent iron-deficiency anaemia, even in malaria-endemic areas.

A comparative study of the efficacies of chloroquine and a pyrimethamine-dapsone combination in clearing Plasmodium falciparum parasitaemia in school children in Tanzania

A randomized study on the in vivo efficacies of chloroquine and a pyrimethamine-dapsone combination (Maloprim) in clearing P. falciparum parasitaemia was carried out in 77 asymptomatic semi-immune schoolchildren in the Kilombero District of Tanzania. Children were randomized to receive either chloroquine at a dose of 25 mg/kg over three days, or Maloprim (6.25 mg pyrimethamine + 50 mg dapsone for children under 10 years, and 12.5 mg pyrimethamine + 100 mg dapsone for children 10 or more years old) as a single dose. Children were followed-up for malaria parasitaemia at days 2, 7 and 14 after screening, randomization and treatment. The slide positivity rate was lower in the Maloprim group at all cross-sectional surveys (23 vs 37% at day 2; 9 vs 20% at day 7; 21 vs 32% at day 14) but none of these differences reached statistical significance. No cases in the Maloprim group showed RII resistance, whereas in the chloroquine group, 2 cases showed RII resistance and a further 2 cases RIII resistance (6%). No major side-effects were reported. The combination of pyrimethamine-dapsone appears to be a better choice than chloroquine as a chemoprophylactic regimen for malaria in this area. Although they need to be confirmed in a larger study, these results may be of interest to the policy-makers as well as researchers.

Plasmodium falciparum malaria in the first year of life in an area of intense and perennial transmission

A longitudinal study of Plasmodium falciparum malaria in infants in Idete village, south-eastern Tanzania, was conducted over a period of 14 months in order to determine the incidence of P. falciparum infection and clinical malaria in the first year of life. Of 1356 blood slides from cross-sectional surveys, 52.1% were positive for asexual stages of P. falciparum. There were marked increases in P. falciparum prevalence, parasite densities, overall fever incidence and the incidence of malaria fevers with age for the first 6 months of life. The average attack rate, estimated from a reversible catalytic model, was 0.029 per day with a slight increase with age but there was no initial period of protection against infection in neonates. Estimated average duration of infections was 64 days, with infections in older infants lasting much longer than those contracted during the first 2 months of life. These results support the hypotheses that the main effect of passively transferred maternal immunity to malaria is in the control of asexual stage parasites, and that the level of clinical immunity depends upon the extent of recent exposure to parasites. Infants as young as 4 months of age are at high risk of clinical attacks. Intervention programmes against malaria in areas of the highest transmission should therefore be designed to include this group.