Monocyte activation and cytokine production in Malawian children presenting with P. falciparum malaria.

Malaria in malaria-naïve adults is associated with an inflammatory response characterized by expression of specific activation markers on innate immune cells. Here, we investigate activation and adhesion marker expression, and cytokine production in monocytes from children presenting with cerebral malaria (CM, n = 36), severe malarial anaemia (SMA, n = 42) or uncomplicated malaria (UM, n = 66), and healthy aparasitemic children (n = 52) in Blantyre, Malawi. In all malaria groups, but particularly in the two severe malaria groups, monocyte expression of CD11b, CD11c, CD18, HLA-DR and CD86, and percentages of TNF-α- and IL-6-producing monocytes were lower than in healthy controls, while expression of CD11a, TLR2 and TLR4 was lower in children with severe malaria compared with controls. These levels mostly normalized during convalescence, but percentages of cytokine-producing monocytes remained suppressed in children with SMA. In all malaria groups, especially the SMA group, a greater proportion of monocytes were loaded with haemozoin than among controls. In a P. falciparum hyperendemic area, monocytes in children with acute symptomatic malaria have reduced expression of adhesion molecules and activation markers and reduced inflammatory cytokine production. This immune suppression could be due to accumulation of haemozoin and/or previous exposure to P. falciparum.

Pharmacokinetics of Antituberculosis Drugs in HIV-Positive and HIV-Negative Adults in Malawi.

Limited data address the impact of HIV coinfection on the pharmacokinetics (PK) of antituberculosis drugs in sub-Saharan Africa. A total of 47 Malawian adults underwent rich pharmacokinetic sampling at 0, 0.5, 1, 2, 3, 4, 6, 8, and 24 h postdose. Of the subjects, 51% were male, their mean age was 34 years, and 65% were HIV-positive with a mean CD4 count of 268 cells/µl. Antituberculosis drugs were administered as fixed-dose combinations (150 mg rifampin, 75 mg isoniazid, 400 mg pyrazinamide, and 275 mg ethambutol) according to recommended weight bands. Plasma drug concentrations were determined by high-performance liquid chromatography (rifampin and pyrazinamide) or liquid chromatography-mass spectrometry (isoniazid and ethambutol). Data were analyzed by noncompartmental methods and analysis of variance of log-transformed summary parameters. The pharmacokinetic parameters were as follows (median [interquartile range]): for rifampin, maximum concentration of drug in plasma (Cmax) of 4.129 µg/ml (2.474 to 5.596 µg/ml), area under the curve from 0 to 24 h (AUC0-∞) of 21.32 µg/ml · h (13.57 to 28.60 µg/ml · h), and half-life of 2.45 h (1.86 to 3.08 h); for isoniazid, Cmax of 3.97 µg/ml (2.979 to 4.544 µg/ml), AUC0-24 of 22.5 (14.75 to 34.59 µg/ml · h), and half-life of 3.93 h (3.18 to 4.73 h); for pyrazinamide, Cmax of 34.21 µg/ml (30.00 to 41.60 µg/ml), AUC0-24 of 386.6 µg/ml · h (320.0 to 463.7 µg/ml · h), and half-life of 6.821 h (5.71 to 8.042 h); and for ethambutol, Cmax of 2.278 µg/ml (1.694 to 3.098 µg/ml), AUC0-24 of 20.41 µg/ml · h (16.18 to 26.27 µg/ml · h), and half-life of 7.507 (6.517 to 8.696 h). The isoniazid PK data analysis suggested that around two-thirds of the participants were slow acetylators. Dose, weight, and weight-adjusted dose were not significant predictors of PK exposure, probably due to weight-banded dosing. In this first pharmacokinetic study of antituberculosis drugs in Malawian adults, measures of pharmacokinetic exposure were comparable with those of other studies for all first-line drugs except for rifampin, for which the Cmax and AUC0-24 values were notably lower. Contrary to some earlier observations, HIV status did not significantly affect the AUC of any of the drugs. Increasing the dose of rifampin might be beneficial in African adults, irrespective of HIV status. Current co-trimoxazole prophylaxis was associated with an increase in the half-life of isoniazid of 41% (P = 0.022). Possible competitive interactions between isoniazid and sulfamethoxazole mediated by the N-acetyltransferase pathway should therefore be explored further.

Adhesion of Plasmodium falciparum-infected erythrocytes to hyaluronic acid in placental malaria.

Infection with Plasmodium falciparum during pregnancy leads to the accumulation of parasite-infected erythrocytes in the placenta, and is associated with excess perinatal mortality, premature delivery and intrauterine growth retardation in the infant, as well as increased maternal mortality and morbidity. P. falciparum can adhere to specific receptors on host cells, an important virulence factor enabling parasites to accumulate in various organs. We report here that most P. falciparum isolates from infected placentae can bind to hyaluronic acid, a newly discovered receptor for parasite adhesion that is present on the placental lining. In laboratory isolates selected for specific high-level adhesion, binding to hyaluronic acid could be inhibited by dodecamer or larger oligosaccharide fragments or polysaccharides, treatment of immobilized receptor with hyaluronidase, or treatment of infected erythrocytes with trypsin. In vitro flow-based assays demonstrated that high levels of adhesion occurred at low wall shear stress, conditions thought to prevail in the placenta. Our findings indicate that adhesion to hyaluronic acid is involved in mediating placental parasite accumulation, thus changing the present understanding of the mechanisms of placental infection, with implications for the development of therapeutic and preventative interventions.

Simple measures are as effective as invasive techniques in the diagnosis of pulmonary tuberculosis in Malawi.

SETTING: Detection of smear-positive pulmonary tuberculosis (PTB) cases is vital for tuberculosis (TB) control. Methods to augment sputum collection are available, but their additional benefit is uncertain in resource-limited settings. OBJECTIVE: To compare the diagnostic yields using five methods to obtain sputum from adults diagnosed with smear-negative PTB in Malawi. DESIGN: Self-expectorated sputum was collected under supervision for microscopy and mycobacterial culture in the study laboratory. Confirmed smear-negative patients provided physiotherapy-assisted sputum and induced sputum, followed the next morning by gastric washing and bronchoalveolar lavage (BAL) samples. RESULTS: A total of 150 patients diagnosed with smear-negative PTB by the hospital service were screened; 39 (26%) were smear-positive from supervised self-expectorated sputum examined in the study laboratory. The remaining 111 confirmed smear-negative patients were enrolled in the study; 89% were human immunodeficiency virus positive. Seven additional smear-positive cases were diagnosed using the augmented sputum collection techniques. No differences were observed in the numbers of cases detected using the different methods. Of the 46 smear-positive cases, 44 (95.6%) could be detected from self-expectorated and physiotherapy-assisted samples. CONCLUSIONS: For countries such as Malawi, the best use of limited resources to detect smear-positive PTB cases would be to improve the quality of self-expectorated sputum collection and microscopy. The additional diagnostic yield using BAL after induced sputum is limited.

The outcome of non-typhoidal salmonella meningitis in Malawian children, 1997-2006.

INTRODUCTION: The clinical course and outcome of non-typhoidal salmonella (NTS) meningitis in Malawian children over a 10-year period (1997-2006) is described. METHODS: Demographic, clinical and laboratory data were collected for all children over 2 months of age admitted with salmonella meningitis to Queen Elizabeth Central Hospital from 1997 to 2006. In the 1st year, salmonellae were susceptible to chloramphenicol, and children received 2 weeks of chloramphenicol treatment. When NTS resistance to chloramphenicol started to appear in 1998, treatment was changed to ceftriaxone. From 2002, the duration of antibiotic therapy was extended to 4-weeks which included 2 weeks of intravenous ceftriaxone and a further 2 weeks of oral ciprofloxacin. RESULTS: The in-hospital case fatality rate (CFR) was 52.3% (48.2% until 2002 and 53.9% after prolonged antibiotic therapy was introduced). Of the survivors, one in 12 (8.3%) became completely well (sequelae-free) in the period 1997-2001 while 18 of 31 survivors (58.1%) made a complete recovery during 2002-2006 (p<0.01). After the 4-week course of antimicrobial therapy was introduced, the number of relapses or recurrences fell from nine in 15 (60%) survivors treated with chloramphenicol or ceftriaxone to three in 35 (8.7%) survivors who received 4 weeks of antibiotics (p<0.0001). CONCLUSION: In Malawi, salmonella meningitis has a CFR of approximately 50%, which has remained constant over many years. Residual morbidity, however, has decreased over 10 years, despite rising numbers of multi-drug-resistant cases of NTS. This improvement might be owing to better treatment and management and/or reduced pathogenicity of the multi-drug-resistant bacteria.

Variation in the ICAM1 gene is not associated with severe malaria phenotypes.

Evidence from autopsy and in vitro binding studies suggests that adhesion of erythrocytes infected with Plasmodium falciparum to the human host intercellular adhesion molecule (ICAM)-1 receptor is important in the pathogenesis of severe malaria. Previous association studies between polymorphisms in the ICAM1 gene and susceptibility to severe malarial phenotypes have been inconclusive and often contradictory. We performed genetic association studies with 15 single nucleotide polymorphisms (SNPs) around the ICAM1 locus. All SNPs were screened in a family study of 1071 trios from The Gambia, Malawi and Kenya. Two key non-synonymous SNPs with previously reported associations, rs5491 (K56M or 'ICAM-1(Kilifi)') and rs5498 (K469E), were tested in an additional 708 Gambian trios and a case-control study of 4058 individuals. None of the polymorphisms were associated with severe malaria phenotypes. Pooled results across our studies for ICAM-1(Kilifi) were, in severe malaria, odds ratio (OR) 1.02, 95% confidence interval (CI) 0.96-1.09, P=0.54, and cerebral malaria OR 1.07, CI 0.97-1.17, P=0.17. We assess the available epidemiological, population genetic and functional evidence that links ICAM-1(Kilifi) to severe malaria susceptibility.

Malawians permit research bronchoscopy due to perceived need for healthcare.

OBJECTIVES: Bronchoalveolar lavage obtained at bronchoscopy is useful for research on pulmonary defence mechanisms. Bronchoscopy involves some discomfort and risk to subjects. We audited the process of consent, experienced adverse effects and reasons for participation among research bronchoscopy volunteers. DESIGN: 100 consecutive volunteer research subjects attending for bronchoscopy, repeat bronchoscopy or routine recruitment clinic were interviewed. Information was gathered about volunteer motivation, perception of the consent process and adverse effects of bronchoscopy. Suggestions for improvement were requested. Responses were themed by a second investigator prior to data analysis. RESULTS: 81 bronchoscopy-experienced subjects (total of 263 procedures) and 19 new volunteers were interviewed. 19 subjects (21%) reported adverse symptoms during or after bronchoscopy, but no symptoms were of sufficient severity that they would not repeat the procedure. The frequency of symptoms was not related to gender, the quality of the lavage or the HIV status of the subject. 76 subjects (94%) reported that the information given pre-procedure was useful and adequate but 43 (56%) had further questions mostly relating to their own results. The reasons given for research participation were access to health assessment (75 subjects), access to treatment when ill (61 subjects), desire to participate in research (15 subjects) and remuneration (6 subjects). 7 subjects complained that the remuneration was inadequate. CONCLUSIONS: The main incentive to participation in research bronchoscopy was access to healthcare. Informed consent and procedure technique were adequate but subjects would value more feedback about individual and project results.

Plasmodium falciparum-infected erythrocytes induce tissue factor expression in endothelial cells and support the assembly of multimolecular coagulation complexes.

BACKGROUND: Plasmodium falciparum malaria infects 300-500 million people every year, causing 1-2 million deaths annually. Evidence of a coagulation disorder, activation of endothelial cells (EC) and increase in inflammatory cytokines are often present in malaria. OBJECTIVES: We have asked whether interaction of parasitized red blood cells (pRBC) with EC induces tissue factor (TF) expression in vitro and in vivo. The role of phosphatidylserine-containing pRBC to support the assembly of blood coagulation complexes was also investigated. RESULTS: We demonstrate that mature forms of pRBC induce functional expression of TF by EC in vitro with productive assembly of the extrinsic Xnase complex and initiation of the coagulation cascade. Late-stage pRBC also support the prothrombinase and intrinsic Xnase complex formation in vitro, and may function as activated platelets in the amplification phase of the blood coagulation. Notably, post-mortem brain sections obtained from P. falciparum-infected children who died from cerebral malaria and other causes display a consistent staining for TF in the EC. CONCLUSIONS: These findings place TF expression by endothelium and the amplification of the coagulation cascade by pRBC and/or activated platelets as potentially critical steps in the pathogenesis of malaria. Furthermore, it may allow investigators to test other therapeutic alternatives targeting TF or modulators of EC function in the treatment of malaria and/or its complications.

When is "malaria" malaria? The different burdens of malaria infection, malaria disease, and malaria-like illnesses.

In this review we discuss the different meanings of the term 'malaria' and urge writers and readers to distinguish accurately between them. The distinction is important in clinical practice, clinical trials, epidemiology, and the evaluation of control programs. Both over- and underdiagnosis of malaria as the cause of a disease episode are inevitable; overdiagnosis is common in high-transmission areas and underdiagnosis is common in areas with little or no transmission. Parasite density thresholds, attributable fractions, and clinical algorithms have played important but only partial roles in strengthening diagnosis. Methods by which malaria infection could be confidently identified as the cause, rather than an irrelevant accompaniment, of an illness, are important targets for research. One such 'signature' is a distinctive retinopathy that occurs in severe malaria and not in clinically similar diseases. Other indicators of a malarial etiology of clinical disease are needed to strengthen clinical and scientific approaches to the control of malaria.

Practical HPLC methods for the quantitative determination of common antimalarials in Africa.

This article describes high-performance liquid chromatographic assays for the quantification of sulfadoxine (SDX), pyrimethamine (PYM), chloroquine (CQ), amodiaquine (AQ) and desethylamodiaquine (AQM) from whole blood. All four assays were set up and validated in Malawi using a common high-performance liquid chromatography platform and column and involved the use of simple mobile phase and extraction reagents. Calibration curves were linear (r(2)>0.95) in the ranges 5-100microg/ml, 50-1000, 150-1500, 100-1000 and 100-1000ng/ml for SDX, PYM, CQ, AQ and AQM, respectively. Intra-assay and inter-assay coefficients of variation were <15% at 3 points spanning the concentration range and <20% at the lower limit of quantification. The assays were specific with no interference from the other antimalarials described in this report. All four assays use liquid-liquid extraction, reversed-phase chromatography and UV detection and require between 50 and 200microl of blood. Because the assays share common instruments and reagents, they are cost-efficient and could be used to optimise antimalarial drug therapies in other resource poor settings.

Changes in optic nerve head blood flow in children with cerebral malaria and acute papilloedema.

OBJECTIVE: To investigate capillary blood flow in the optic nerve head (ONH) of children with cerebral malaria. METHODS: Malawian children with cerebral malaria admitted to a paediatric research ward were examined by direct and indirect ophthalmoscopy. ONH blood flow was measured using laser Doppler flowmetry (LDF) in suitable patients. Mean blood volume and velocity were obtained from 30 to 60 s recordings from the temporal ONH and used to calculate blood flow. These were compared with admission variables, funduscopic findings and disease outcomes. RESULTS: 45 children with cerebral malaria had LDF recordings; 6 subsequently died and 5 survivors had neurological sequelae. 12 (27%) had papilloedema. The mean microvascular blood volume was higher in patients with papilloedema (3.28 v 2.54 arbitrary units, p = 0.002). The blood velocity correlated directly with haematocrit (r = 0.46, p = 0.001) and inversely with blood glucose (r = -0.49, p = 0.001). CONCLUSION: The increase in ONH microvascular blood volume in papilloedema measured by LDF is consistent with current theories of pathogenesis of papilloedema. LDF has potential as a tool to distinguish papilloedema from pseudopapilloedematous disc swellings. The relationship between blood velocity and haematocrit may relate to levels of sequestration in cerebral malaria.

Efficacy of rectal artesunate compared with parenteral quinine in initial treatment of moderately severe malaria in African children and adults: a randomised study.

BACKGROUND: Many patients with malaria of increasing severity cannot take medicines orally, and delay in injectable treatment can be fatal. We aimed to assess the reliability of absorption, antimalarial efficacy, and tolerability of a single rectal dose of artesunate in the initial management of moderately severe falciparum malaria. METHODS: 109 children and 35 adults were randomly assigned to rectal artesunate (single dose of about 10 mg/kg) or parenteral quinine treatment (10 mg/kg at 0, 4, and 12 h). The primary endpoint was the proportion of patients with peripheral asexual parasitaemia of less than 60% of that at baseline after 12 h. Secondary endpoints were clinical response and concentrations of drug in plasma. Analysis was by intention-to-treat. FINDINGS: All artesunate-treated patients had pharmacodynamic or pharmacokinetic evidence of adequate drug absorption. 80 (92%) of 87 artesunate-treated children had a 12 h parasite density lower than 60% of baseline, compared with three of 22 (14%) receiving quinine (relative risk 0.09 [95% CI 0.04-0.19]; p<0.0001). In adults, parasitaemia at 12 h was lower than 60% of baseline in 26 (96%) of 27 receiving artesunate, compared with three (38%) of eight receiving quinine (relative risk 0.06 [0.01-0.44]; p=0.0009). These differences were greater at 24 h. Clinical response was equivalent with rectal artesunate and parenteral quinine. INTERPRETATION: A single rectal dose of artesunate is associated with rapid reduction in parasite density in adults and children with moderately severe malaria, within the initial 24 h of treatment. This option is useful for initiation of treatment in patients unable to take oral medication, particularly where parenteral treatment is unavailable.

Plasma HIV burden in Malawian children co-infected with rotavirus.

Fifty-eight HIV-infected children with acute rotavirus diarrhea were tested for plasma HIV RNA. There was no difference between acute and convalescent mean viral loads, and little change in CD4 cell counts. Compared with the 16 children who died within 4 weeks, 31 survivors had slightly lower viral loads at presentation and significantly higher CD4 cell counts. Low CD4 cell counts, but not HIV-1-RNA concentrations, were predictive of Death. Local, enteric rotavirus infection did not appear to affect blood HIV viral load or CD4 cell counts in this small group of children.

The effect of Plasmodium falciparum malaria on HIV-1 RNA blood plasma concentration.

OBJECTIVES: This study was undertaken to determine the relative effect of malaria infection on HIV concentration in blood plasma, and prospectively to monitor viral concentrations after antimalarial therapy. DESIGN: A prospective, double cohort study was designed to compare the blood HIV-1 RNA concentrations of HIV-positive individuals with and without acute malaria illness. Subjects were followed for 4 weeks after successful malaria therapy, or for 4 weeks from enrollment (controls). METHODS: Malawian adults with symptomatic Plasmodium falciparum parasitemia (malaria group) and asymptomatic, aparasitemic blood donors (control group) were tested for HIV-1 antibodies to identify appropriate study groups. The malaria group received antimalarial chemotherapy only and were followed with sequential blood films. In both groups, blood plasma HIV-1 RNA viral concentrations were determined at enrollment and again at 1, 2 and 4 weeks. RESULTS: Forty-seven malaria patients and 42 blood donors were enrolled. At enrollment blood plasma HIV-1 RNA concentrations were approximately sevenfold higher in patients with malaria than in blood donors (medians 15.1 x 10(4) and 2.24 x 10(4) copies/ml, respectively, P = 0.0001). No significant changes in median HIV-1 concentrations occurred in the 21 blood donors followed to week 4 (P = 0.68). In the 27 subjects successfully treated for malaria who were followed to week 4, a reduction in plasma HIV-1 RNA was observed from a median of 19.1 x 10(4) RNA copies/ml at enrollment, to 12.0 x 10(4) copies/ml at week 4, (P = 0.02). Plasma HIV-1 concentrations remained higher in malaria patients than controls (median 12.0 x 10(4) compared with 4.17 x 10(4) copies/ml, P = 0.086). CONCLUSIONS: HIV-1 blood viral burden is higher in patients with P. falciparum malaria than in controls and this viral burden can, in some patients, be partly reduced with antimalarial therapy.

Bacteremia in febrile Malawian children: clinical and microbiologic features.

BACKGROUND: There are no published data for the incidence or etiology of childhood bacteremia in Malawi. We describe the clinical and microbiologic features of children admitted to hospital from whom blood cultures yielded bacterial pathogens. METHODS: Any neonate or child admitted to the pediatric wards of the Queen Elizabeth Central Hospital had a blood culture taken in the event of fever without obvious clinical explanation. Clinical and microbiologic data were prospectively collected for children with a significant positive culture. RESULTS: Between September, 1996, and August, 1997, we processed 2,123 cultures. Of these, 365 (17.2%) grew a pathogen. Non-typhi salmonellae (NTS) and enteric Gram-negative bacilli constituted 67.4% of isolates, and Streptococcus pneumoniae constituted 16.4%. More than two-thirds of NTS episodes coincided with the peak malaria transmission season (January to June); 67% of bacteremic children were malnourished, 28% severely so. Patients with NTS bacteremia were significantly more likely to have coincident malaria and to have splenomegaly and anemia than children with other infecting organisms. The overall mortality was 38% but varied considerably according to age and nutritional status. Prior antibiotic use, coincident malaria or meningitis did not adversely affect outcome. In vitro resistance to the commonly available antibiotics ampicillin and trimethoprim-sulfamethoxazole was found in 76 and 71% of NTS isolates. Screening tests for penicillin resistance suggested a rate of 21% among pneumococci. CONCLUSIONS: Bacteremia is common in hospitalized Malawian children and has a high mortality. There are high rates of resistance to some of the commonly used antibacterial agents.

Detection of group C rotavirus in children with acute gastroenteritis in Blantyre, Malawi.

Among 606 children who were treated for acute gastroenteritis at the Queen Elizabeth Central Hospital in Blantyre, Malawi, Group C rotavirus (Gp C RV) was detected by enzyme-linked immunosorbent assay in fecal specimens from 16 (3.9%) of 408 inpatients and in 4 (2.0%) of 198 outpatients. Thirteen (65%) children excreting Gp C RV were coinfected with Group A rotavirus.

Association between measures of vitamin A and the ocular fundus findings in cerebral malaria.

OBJECTIVE: To investigate the relationship between serum vitamin A levels and conjunctival impression cytology and retinal whitening present in Malawian children with cerebral malaria. METHODS: Standard retinal examination and conjunctival impression cytology were performed at hospital admission on 101 consecutively admitted children with cerebral malaria. Blood samples were drawn from 56 children at 24 hours, frozen at -20 degrees C, and transported for assessment of vitamin A levels by high-performance liquid chromatography. Associations among fundus findings and vitamin A measurements were sought. RESULTS: The whitening of the retina that we have previously described in children with cerebral malaria was found to be associated with a mean+/-SD serum vitamin A level of 0.29+/-0.1 micromol/L, compared with a mean vitamin A level of 0.41+/-0.2 micromol/L in children without retinal whitening. Children with retinal whitening were 2.77 (95% CI, 1.06-7.3) times more likely to have abnormal conjunctival impression cytology results than those without whitening. No child had any clinical or ophthalmologic evidence of chronic vitamin A deficiency. CONCLUSIONS: The retinal whitening described in children with cerebral malaria is associated with low serum vitamin A levels and with abnormal conjunctival impression cytology results and may be due to acute vitamin A deficiency at the tissue level.

Clinical-histopathological correlation of the abnormal retinal vessels in cerebral malaria.

BACKGROUND: Clinically abnormal retinal vessels unique to cerebral malaria have previously been shown to be associated with a poor outcome in African children. There have been no studies of the histopathological correlates of these vessels. DESIGN: This is a descriptive study of the clinical-histopathological correlates of the retinal vessels of 11 children who died with cerebral malaria. RESULTS: The retinal vessels in children with cerebral malaria contained many parasitized red blood cells; these cells tended to cluster at the periphery of vessels or, in the case of capillaries, to fill the vessel. Those with late-stage parasites had markedly reduced amounts of hemoglobin. The pattern of dehemoglobinization corresponds to the pattern of clinically abnormal vessels. CONCLUSIONS: The sequestration of late-stage parasitized red blood cells with reduced amounts of hemoglobin accounts for the unique white and pale orange retinal vessels seen in cerebral malaria. Clinical examination of these "marked" vessels offers a method to monitor a basic pathophysiological process of cerebral malaria in vivo. Arch Ophthalmol. 2000;118:924-928

Cerebral malaria in children: clinical implications of cytoadherence.

In endemic areas, most of the people who die from falciparum malaria are young children. Death is commonly preceded by coma (cerebral malaria). The possible role of cytoadherence in this clinical picture is considered.

Increased serum phospholipase A2 activity in Malawian children with falciparum malaria.

Some clinical manifestations of severe malaria resemble those of sepsis and there may be mediators of the host response that are common to both sepsis and malaria. Phospholipase A2 (PLA2), a proinflammatory enzyme whose expression is induced by tumor necrosis factor (TNF), has been implicated in the pathogenesis of complications of the sepsis syndrome. We examined levels of circulating PLA2 in Plasmodium falciparum malaria and studied the association of PLA2 with disease severity. Plasma PLA2 and TNF were measured in 75 Malawian children with P. falciparum malaria. The mean (SD) plasma PLA2 activity in children with acute malaria was 53,804 (37,256) units/ml as compared with 424 (349) units/ml in 34 healthy controls (P < 0.00001). The mean PLA2 activity in 45 convalescent patients was 2,546 (7,372) units/ml (P < 0.00001). In 48 patients with pretreatment PLA2 activity less than 60,000 units/ml, mortality was 8.3%, while in 27 patients with pretreatment PLA2 levels greater than 60,000 units/ml, mortality was 33.3% (P = 0.008). There were significant correlations between PLA2 and TNF (r = 0.471, P < 0.01), density of parasitemia (r = 0.443, P < 0.0001) and a decrease in hematocrit (r = 0.352, P < 0.005). These data show that P. falciparum malaria is associated with a markedly increased circulating PLA2, especially in patients with severe disease, as manifested by high parasite burden, anemia, coma, and death.