Mitochondrial gene sequence variants in children with severe malaria anaemia with or without lactic acidosis: a case control study.

BACKGROUND: Evolutionary pressure by Plasmodium falciparum malaria is known to have favoured a large number of human gene adaptations, but there is surprisingly little investigation of the effect of malaria on human mitochondrial sequence variation. Plasmodium falciparum infection can cause severe malaria anaemia (SMA) with insufficient tissue oxygenation, lactic acidosis and death. Despite equal degrees of severe anaemia, some individuals develop lactic acidosis while others do not. A case-control study design was used to investigate whether differences in host mitochondrial gene sequences were associated with lactic acidosis in SMA. Full mitochondrial sequences were obtained from 36 subjects with SMA complicated by lactic acidosis and 37 subjects with SMA without lactic acidosis. The two groups were matched for age, sex, and degree of anaemia. RESULTS: Compared with the reference sequence, a median of 60 nucleotide variants per individual (interquartile range 4-91) was found, with an average frequency of 3.97 variants per 1000 nucleotides. The frequency and distribution of non-synonymous DNA variants in genes associated with oxidative phosphorylation were not statistically different between the two groups. Non-synonymous variants predicted to have the most disruptive effect on proteins responsible for oxidative phosphorylation were present at a similar frequency in both groups. CONCLUSIONS: Lactic acidosis in SMA does not appear to be consistently associated with the high prevalence of any mitochondrial gene variant.

Hypertension control and care at Mulago Hospital ambulatory clinic, Kampala-Uganda.

BACKGROUND: Hypertension is as prevalent in many developing countries, as in the developed world and is the leading cause of cardiovascular morbidity and mortality in Africa. The control of hypertension in this resource limited setting is inadequate, a situation that translates into poorer outcomes in form of increasing incidences of stroke, heart failure, kidney failure and therefore early cardiovascular death. METHODS: This was a chart review of all the patients seen during the months of September 2012 to February 2013. We determined the level of blood pressure control, basic investigations documented as well as the choice of hypertensive treatment among patients attending a hypertension clinic in a national referral hospital, Mulago. RESULTS: Of the 741 patients whose charts were reviewed the median age was 60 years, Inter quartile range (IQR) was 51-71. Six hundred forty-two (86.6%) were females. Blood pressure (BP) control defined as BP lowering to at least 140/90 was seen in only 198 (26.7%) patients. Biophysical measurement documentation was very low especially for waist and hip circumference at 0.3%. Majority of patients, 476 (64.2%) had at least one documented investigation for the complications of hypertension. Only 103 (13.9%) had all investigations documented in their charts. The investigations included; complete blood count (CBC), urinalysis, renal function tests (RFTs), Chest X-Ray (CXR), echocardiography (Echo) and electrocardiography (ECG). The commonly documented investigations were RFTs (45.5%), ECG (45.2%) and Echo (44.2%). The commonly prescribed anti hypertensive medications were; Angiotensin receptor blockers (ARBs)/Angiotensin converting enzyme inhibitors (ACEI) (72.74%), calcium channel blockers (72.3%) and thiazide diuretics (68.6%). Majority of patients were receiving three anti hypertensive medications 313 (42.2%), with 149 (43.6%) of these, on an ACEI/ARB, a calcium channel blocker and a thiazide diuretic. CONCLUSION: Blood pressure control is suboptimal in a tertiary clinic setting at Mulago hospital and documentation of investigations is inadequate. ARB/ACEI, Calcium channel blockers and thiazide diuretics were the commonly prescribed anti hypertensive medications. There is a great need to investigate for renal and cardiac complications as well as exploring reasons for inadequate blood pressure control and consider appropriate interventions to avert bad outcomes.

Dysregulation of the haem-haemopexin axis is associated with severe malaria in a case-control study of Ugandan children.

BACKGROUND: Malaria is associated with haemolysis and the release of plasma haem. Plasma haem can cause endothelial injury and organ dysfunction, and is normally scavenged by haemopexin to limit toxicity. It was hypothesized that dysregulation of the haem-haemopexin pathway contributes to severe and fatal malaria infections. METHODS: Plasma levels of haemin (oxidized haem), haemopexin, haptoglobin, and haemoglobin were quantified in a case-control study of Ugandan children with Plasmodium falciparum malaria. Levels at presentation were compared in children with uncomplicated malaria (UM; n = 29), severe malarial anaemia (SMA; n = 27) or cerebral malaria (CM; n = 31), and evaluated for utility in predicting fatal (n = 19) vs non-fatal (n = 39) outcomes in severe disease. A causal role for haemopexin was assessed in a pre-clinical model of experimental cerebral malaria (ECM), following disruption of mouse haemopexin gene (hpx). Analysis was done using Kruskall Wallis tests, Mann-Whitney tests, log-rank tests for survival, and repeated measures ANOVA. RESULTS: In Ugandan children presenting with P. falciparum malaria, haemin levels were higher and haemopexin levels were lower in SMA and CM compared to children with UM (haemin, p < 0.01; haemopexin, p < 0.0001). Among all cases of severe malaria, elevated levels of haemin and cell-free haemoglobin at presentation were associated with subsequent mortality (p < 0.05). Compared to ECM-resistant BALB/c mice, susceptible C57BL/6 mice had lower circulating levels of haemopexin (p < 0.01), and targeted deletion of the haemopexin gene, hpx, resulted in increased mortality compared to their wild type littermates (p < 0.05). CONCLUSIONS: These data indicate that plasma levels of haemin and haemopexin measured at presentation correlate with malaria severity and levels of haemin and cell-free haemoglobin predict outcome in paediatric severe malaria. Mechanistic studies in the ECM model support a causal role for the haem-haemopexin axis in ECM pathobiology.

Chitinase 3-like 1 is induced by Plasmodium falciparum malaria and predicts outcome of cerebral malaria and severe malarial anaemia in a case-control study of African children.

BACKGROUND: Severe and fatal malaria are associated with dysregulated host inflammatory responses to infection. Chitinase 3-like 1 (CHI3L1) is a secreted glycoprotein implicated in regulating immune responses. Expression and function of CHI3L1 in malaria infection were investigated. METHODS: Plasma levels of CHI3L1 were quantified in a case-control study of Ugandan children presenting with Plasmodium falciparum malaria. CHI3L1 levels were compared in children with uncomplicated malaria (UM; n = 53), severe malarial anaemia (SMA; n = 59) and cerebral malaria (CM; n = 44) using the Kruskall Wallis-test, and evaluated for utility in predicting fatal (n = 23) versus non-fatal (n = 80) outcomes in severe disease using the Mann Whitney U test, receiver operating characteristic curves, and combinatorial analysis. Co-culture of P. falciparum with human peripheral blood mononuclear cells and the Plasmodium berghei ANKA experimental model of cerebral malaria were used to examine the role of CHI3L1 in severe malaria. RESULTS: In children presenting with falciparum malaria, CHI3L1 levels were increased in SMA and CM versus UM (p < 0.001). Among severe malaria cases, CHI3L1 levels at presentation predicted subsequent death (area under receiver operating characteristic curve 0.84 [95% CI 0.76-0.92]) and in combination with other host biomarkers, predicted mortality with high sensitivity (100% [85.7-100]) and specificity (81.3% [71.3-88.3]). Plasmodium falciparum stimulated CHI3L1 production by human peripheral blood mononuclear cells in vitro. CHI3L1 was increased in plasma and brain tissue in experimental cerebral malaria, but targeted Chi3l1 deletion did not alter cytokine production or survival in this model. CONCLUSIONS: These data suggest that plasma CHI3L1 measured at presentation correlates with malaria severity and predicts outcome in paediatric SMA and CM, but do not support a causal role for CHI3L1 in cerebral malaria pathobiology in the model tested.

Severe falciparum malaria associated with massive pulmonary embolism.

Falciparum malaria is known to cause alterations in the coagulation cascade, including disseminated intravascular coagulation. Microthrombotic complications are the best described; however, a number of cases of thrombosis involving larger vessels have been published in the literature. Herein, we describe the case of a woman with malaria associated with massive pulmonary embolism.

Functional roles for C5a and C5aR but not C5L2 in the pathogenesis of human and experimental cerebral malaria.

The host immune response plays an important role in the onset and progression of cerebral malaria (CM). The complement system is an essential component of the innate immune response to malaria, and its activation generates the anaphylatoxin C5a. To test the hypothesis that C5a signaling contributes to the pathogenesis of CM, we investigated a causal role for the C5a receptors C5aR and C5L2 in a mouse model of experimental CM (ECM) induced by Plasmodium berghei ANKA infection, and using a case-control design, we examined levels of C5a in plasma samples from Ugandan children presenting with CM or uncomplicated malaria (UM). In the ECM model, C5aR(-/-) mice displayed significantly improved survival compared to their wild-type (WT) counterparts (P = 0.004), whereas C5L2(-/-) mice showed no difference in survival from WT mice. Improved survival in C5aR(-/-) mice was associated with reduced levels of the proinflammatory cytokines tumor necrosis factor (TNF) and gamma interferon (IFN-γ) and the chemokine, monocyte chemoattractant protein 1 (MCP-1) (CCL2). Furthermore, endothelial integrity was enhanced, as demonstrated by increased levels of angiopoietin-1, decreased levels of angiopoietin-2 and soluble ICAM-1, and decreased Evans blue extravasation into brain parenchyma. In the case-control study, the median levels of C5a at presentation were significantly higher in children with CM versus those in children with UM (43.7 versus 22.4 ng/ml; P < 0.001). These findings demonstrate that C5a is dysregulated in human CM and contributes to the pathogenesis of ECM via C5aR-dependent inflammation and endothelial dysfunction.

Benzathine penicillin adherence for secondary prophylaxis among patients affected with rheumatic heart disease attending Mulago Hospital.

INTRODUCTION: Rheumatic heart disease (RHD) frequently occurs following recurrent episodes of acute rheumatic fever (ARF). Benzathine penicillin (benzapen) is the most effective method for secondary prophylaxis against ARF whose efficacy largely depends on adherence to treatment. Various factors determine adherence to therapy but there are no data regarding current use of benzapen in patients with RHD attending Mulago Hospital. The study aims were (1) to determine the levels of adherence with benzapen prophylaxis among rheumatic heart disease patients in Mulago Hospital, and (2) establish the patient factors associated with adherence and, (3) establish the reasons for missing monthly benzathine penicillin injections. METHODS: This was a longitudinal observational study carried out in Mulago Hospital cardiac clinics over a period of 10 months; 95 consecutive patients who satisfied the inclusion criteria were recruited over a period of four months and followed up for six months. Data on demographic characteristics and disease status were collected by means of a standardised questionnaire and a card to document the injections of benzapen received. RESULTS: Most participants were female 75 (78.9%). The age range was five to 55 years, with a mean of 28.1 years (SD 12.2) and median of 28 years. The highest education level was primary school for most patients (44, 46.3%) with eight (8.4%) of the patients being illiterate. Most were either NYHA stage II (39, 41.1%) or III (32, 33.7%). Benzathine penicillin adherence: 44 (54%) adhered to the monthly benzapen prophylaxis, with adherence rates ≥ 80%; 38 (46%) patients were classified as non-adherent to the monthly benzapen, with rates less than 80%. The mean adherence level was 70.12% (SD 29.25) and the median level was 83.30%, with a range of 0-100%; 27 (33%) patients had extremely poor adherence levels of ≤ 60%. Factors associated with adherence: higher education status, residing near health facility favoured high adherence, while painful injection was a major reason among poor performers. CONCLUSION: The level of non-adherence was significantly high (46%). Residence in a town/city and having at least a secondary level of education was associated with better adherence, while the painful nature of the benzapen injections and lack of transport money to travel to the health centre were the main reasons for non-adherence among RHD patients in Mulago.

Cardiovascular complications in newly diagnosed rheumatic heart disease patients at Mulago Hospital, Uganda.

BACKGROUND: Complications of rheumatic heart disease are associated with severe morbidity and mortality in developing countries where the disease prevalence remains high. Due to lack of screening services, many patients present late, with severe valve disease. In Uganda, the disease and its complications are still not well studied. OBJECTIVE: To profile and describe cardiovascular complications in newly diagnosed rheumatic heart disease patients attending the Mulago National Referral Hospital in Uganda. METHODS: This was a cross-sectional study where consecutive, newly diagnosed rheumatic heart disease patients were assessed and followed up for complications, such as heart failure, pulmonary hypertension, atrial fibrillation, recurrence of acute rheumatic fever, and stroke. RESULTS: A total of 309 (115 males and 196 females) definite rheumatic heart disease patients aged 15-60 years were enrolled in the study and analysed. Complications occurred in 49% (152/309) of the newly diagnosed rheumatic heart disease cases, with heart failure (46.9%) the most common complication, followed by pulmonary arterial hypertension (32.7%), atrial fibrillation (13.9%), recurrence of acute rheumatic fever (11.4%), infective endocarditis (4.5%) and stroke (1.3%). Atrial fibrillation and acute rheumatic fever were the most common complications associated with heart failure. CONCLUSION: In this study we found that about 50% of newly diagnosed rheumatic heart disease patients in Uganda presented with complications. Heart failure and pulmonary arterial hypertension were the most commonly observed complications.

Presenting features of newly diagnosed rheumatic heart disease patients in Mulago Hospital: a pilot study.

INTRODUCTION: Rheumatic heart disease (RHD) continues to cause gross distortions of the heart and the associated complications of heart failure and thromboembolic phenomena in this age of numerous high-efficacy drugs and therapeutic interventions. Due to the lack of contemporary local data, there is no national strategy for the control and eradication of the disease in Uganda. This study aimed to describe the presenting clinical features of newly diagnosed patients with RHD, with particular reference to the frequency of serious complications (atrial fibrillation, systemic embolism, heart failure and pulmonary hypertension) in the study group. METHODS: One hundred and thirty consecutive patients who satisfied the inclusion criteria were recruited over a period of eight months from June 2011 to January 2012 at the Mulago Hospital, Uganda. Data on demographic characteristics, disease severity and presence of complications were collected by means of a standardised questionnaire. RESULTS: Seventy-one per cent of the patients were female with a median age of 33 years. The peak age of the study group was 20 to 39 years, with the commonest presenting symptoms being palpitations, fatigue, chest pain and dyspnoea. The majority of the patients presented with moderate-to-severe valvular disease. Pure mitral regurgitation was the commonest valvular disease (40.2%), followed by mitral regurgitation plus aortic regurgitation (29%). Mitral regurgitation plus aortic regurgitation plus mitral stenosis was found in 11% of patients. There was only one case involving the tricuspid valve. The pulmonary valves were not affected in all patients; 45.9% of patients presented in severe heart failure in NYHA class III/IV, 53.3% had pulmonary hypertension, 13.9% had atrial fibrillation and 8.2% had infective endocarditis. All patients presented with dilated atria (> 49 mm). CONCLUSION: A significant proportion of RHD patients present to hospital with severe disease associated with severe complications of advanced heart failure, pulmonary hypertension, infective endocarditis and atrial fibrillation. There is a need to improve awareness of the disease among the population, and clinical suspicion in primary health workers, so that early referral to specialist management can be done before severe damage to the heart ensues.

Systemic release of high mobility group box 1 (HMGB1) protein is associated with severe and fatal Plasmodium falciparum malaria.

BACKGROUND: Severe falciparum malaria (SM) pathogenesis has been attributed, in part, to deleterious systemic host inflammatory responses to infection. High mobility group box 1 (HMGB1) protein is an important mediator of inflammation implicated in sepsis pathophysiology. METHODS: Plasma levels of HMGB1 were quantified in a cohort of febrile Ugandan children with Plasmodium falciparum infection, enrolled in a prospective observational case-controlled study, using a commercial enzyme-linked immunosorbent assay. The utility of HMGB1 to distinguish severe malaria (SM; n = 70) from uncomplicated malaria (UM; n = 33) patients and fatal (n = 21) versus non-fatal (n = 82) malaria, at presentation, was examined. Receiver operating characteristic curve analysis was used to assess the prognostic accuracy of HMGB1. The ability of P. falciparum-parasitized erythrocytes to induce HMGB1 from peripheral blood mononuclear cells was assessed in vitro. The effect of an anti-HMGB1 neutralizing antibody on disease outcome was assessed in the experimental Plasmodium berghei ANKA rodent parasite model of SM. Mortality and parasitaemia was assessed daily and compared to isotype antibody-treated controls. RESULTS: Elevated plasma HMGB1 levels at presentation were significantly associated with SM and a subsequent fatal outcome in paediatric patients with P. falciparum infection. In vitro, parasitized erythrocytes induced HMGB1 release from human peripheral blood mononuclear cells. Antibody-mediated neutralization of HMGB1 in the experimental murine model of severe malaria failed to reduce mortality. CONCLUSION: These data suggest that elevated HMGB1 is an informative prognostic marker of disease severity in human SM, but do not support HMGB1 as a viable target for therapeutic intervention in experimental murine SM.

Inter-relationships of cardinal features and outcomes of symptomatic pediatric Plasmodium falciparum MALARIA in 1,933 children in Kampala, Uganda.

Malaria remains a challenging diagnosis with variable clinical presentation and a wide spectrum of disease severity. Using a structured case report form, we prospectively assessed 1,933 children at Mulago Hospital in Kampala, Uganda with acute Plasmodium falciparum malaria. Children with uncomplicated malaria significantly differed from those with severe disease for 17 features. Among 855 children with severe disease, the case-fatality rate increased as the number of severity features increased. Logistic regression identified five factors independently associated with death: cerebral malaria, hypoxia, severe thrombocytopenia, leukocytosis, and lactic acidosis. Cluster analysis identified two groups: one combining anemia, splenomegaly, and leukocytosis; and a second group centered on death, severe thrombocytopenia, and lactic acidosis, which included cerebral malaria, hypoxia, hypoglycemia, and hyper-parasitemia. Our report updates previous clinical descriptions of severe malaria, quantifies significant clinical and laboratory inter-relationships, and will assist clinicians treating malaria and those planning or assessing future research (NCT00707200) (www.clinicaltrials.gov).

Cytoadherence in paediatric malaria: ABO blood group, CD36, and ICAM1 expression and severe Plasmodium falciparum infection.

As a leading cause of childhood mortality worldwide, selection pressure by Plasmodium falciparum continues to shape the human genome. Severe disturbances within the microcirculation result from the adhesion of infected erythrocytes to host receptors on monocytes, platelets, and endothelium. In this prospective study, we compared expression of all major host cytoadhesion receptors among Ugandan children presenting with uncomplicated malaria (n = 1078) versus children with severe malaria (n = 855), including cerebral malaria (n = 174), severe anaemia (n = 522), and lactic acidosis (n = 154). We report a significant survival advantage attributed to blood group O and increased monocyte expression of CD36 and ICAM1 (CD54). The high case fatality rate syndromes of cerebral malaria and lactic acidosis were associated with high platelet CD36 expression and thrombocytopenia, and severe malaria anaemia was characterized by low ICAM1 expression. In a logistic regression model of disease severity, odds ratios for the mitigating effects of blood group O, CD36, and ICAM1 phenotypes were greater than that of sickle haemoglobin. Host genetic adaptations to Plasmodium falciparum suggest new potential malaria treatment strategies.

S1P is associated with protection in human and experimental cerebral malaria.

Cerebral malaria (CM) is associated with excessive inflammatory responses and endothelial activation. Sphingosine 1-phosphate (S1P) is a signaling sphingolipid implicated in regulating vascular integrity, inflammation and T-cell migration. We hypothesized that altered S1P signaling during malaria contributes to endothelial activation and inflammation, and show that plasma S1P levels were decreased in Ugandan children with CM compared with children with uncomplicated malaria. Using the Plasmodium berghei ANKA (PbA) model of experimental CM (ECM), we demonstrate that humanized S1P lyase (hS1PL)(-/-) mice with reduced S1P lyase activity (resulting in increased bio-available S1P) had improved survival compared with wild-type littermates. Prophylactic and therapeutic treatment of infected mice with compounds that modulate the S1P pathway and are in human trials for other conditions (FTY720 or LX2931) significantly improved survival in ECM. FTY720 treatment improved vascular integrity as indicated by reduced levels of soluble intercellular adhesion molecule (sICAM), increased angiopoietin 1 (Ang1) (regulator of endothelial quiescence) levels, and decreased Evans blue dye leakage into brain parenchyma. Furthermore, treatment with FTY720 decreased IFNγ levels in plasma as well as CD4(+) and CD8(+) T-cell infiltration into the brain. Finally, when administered during infection in combination with artesunate, FTY720 treatment resulted in increased survival to ECM. These findings implicate dysregulation of the S1P pathway in the pathogenesis of human and murine CM and suggest a novel therapeutic strategy to improve clinical outcome in severe malaria.

Combinations of host biomarkers predict mortality among Ugandan children with severe malaria: a retrospective case-control study.

BACKGROUND: Severe malaria is a leading cause of childhood mortality in Africa. However, at presentation, it is difficult to predict which children with severe malaria are at greatest risk of death. Dysregulated host inflammatory responses and endothelial activation play central roles in severe malaria pathogenesis. We hypothesized that biomarkers of these processes would accurately predict outcome among children with severe malaria. METHODOLOGY/FINDINGS: Plasma was obtained from children with uncomplicated malaria (n = 53), cerebral malaria (n = 44) and severe malarial anemia (n = 59) at time of presentation to hospital in Kampala, Uganda. Levels of angiopoietin-2, von Willebrand Factor (vWF), vWF propeptide, soluble P-selectin, soluble intercellular adhesion molecule-1 (ICAM-1), soluble endoglin, soluble FMS-like tyrosine kinase-1 (Flt-1), soluble Tie-2, C-reactive protein, procalcitonin, 10 kDa interferon gamma-induced protein (IP-10), and soluble triggering receptor expressed on myeloid cells-1 (TREM-1) were determined by ELISA. Receiver operating characteristic (ROC) curve analysis was used to assess predictive accuracy of individual biomarkers. Six biomarkers (angiopoietin-2, soluble ICAM-1, soluble Flt-1, procalcitonin, IP-10, soluble TREM-1) discriminated well between children who survived severe malaria infection and those who subsequently died (area under ROC curve>0.7). Combinational approaches were applied in an attempt to improve accuracy. A biomarker score was developed based on dichotomization and summation of the six biomarkers, resulting in 95.7% (95% CI: 78.1-99.9) sensitivity and 88.8% (79.7-94.7) specificity for predicting death. Similar predictive accuracy was achieved with models comprised of 3 biomarkers. Classification tree analysis generated a 3-marker model with 100% sensitivity and 92.5% specificity (cross-validated misclassification rate: 15.4%, standard error 4.9%). CONCLUSIONS: We identified novel host biomarkers of pediatric severe and fatal malaria (soluble TREM-1 and soluble Flt-1) and generated simple biomarker combinations that accurately predicted death in an African pediatric population. While requiring validation in further studies, these results suggest the utility of combinatorial biomarker strategies as prognostic tests for severe malaria.

Ultrasound findings in Plasmodium falciparum malaria: a pilot study.

OBJECTIVE: To investigate whether hand-carried ultrasound technology may be valuable in the assessment of children with acute malaria. Every year, approximately 800,000 children under the age of 5 yrs die of complications of Plasmodium falciparum malaria infection. The advent of hand-carried ultrasound technology has made diagnostic ultrasonography possible in underresourced settings. DESIGN: We performed a pilot observational study collecting clinical data and performing ultrasound examinations on children diagnosed with P. falciparum malaria infection. The targeted ultrasound examination included measurement of optic nerve sheath diameter, color transcranial Doppler insonation of the cerebral vasculature, cardiac ultrasound, and abdominal ultrasound. SETTING: Pediatric acute care unit of Mulago Hospital in Kampala, Uganda. PATIENTS: Thirty-three hospitalized children between the ages of 6 months and 12 yrs with documented acute P. falciparum infection. INTERVENTION: Targeted bedside ultrasound examination. MEASUREMENTS AND MAIN RESULTS: Increased optic nerve sheath diameter was observed in one third of all patients with malaria and in 100% of the patients diagnosed with cerebral malaria. Although higher-than-normal cerebral blood flow velocities were demonstrated in three (25%) of 12 patients with severe anemia, most patients demonstrated a normal cerebral blood flow velocity, suggesting a blunted response to anemia. We did not find evidence of pulmonary hypertension by cardiac ultrasound, and cardiac function did not seem depressed, even among patients with severe anemia and lactic acidosis. Finally, spleen size as determined by palpation significantly overestimated the true incidence of splenomegaly as measured by ultrasound (48% and 24%, respectively). CONCLUSIONS: A targeted ultrasound examination focusing on optic nerve sheath diameter, color transcranial Doppler, cardiac ultrasound, and spleen size may prove useful for patient classification, risk stratification, research studies, and treatment monitoring in pediatric malaria. More studies should be done.

Combined measurement of soluble and cellular ICAM-1 among children with Plasmodium falciparum malaria in Uganda.

BACKGROUND: Intercellular adhesion molecule-1 (ICAM-1) is a cytoadhesion molecule implicated in the pathogenesis of Plasmodium falciparum malaria. Elevated levels of soluble ICAM-1 (sICAM-1) have previously been reported with increased malaria disease severity. However, studies have not yet examined both sICAM-1 concentrations and monocyte ICAM-1 expression in the same cohort of patients. To better understand the relationship of soluble and cellular ICAM-1 measurements in malaria, both monocyte ICAM-1 expression and sICAM-1 concentration were measured in children with P. falciparum infection exhibiting a spectrum of clinical severity. METHODS: Samples were analysed from 160 children, aged 0.5 to 10.8 years, with documented P. falciparum malaria in Kampala, Uganda. The patients belonged to one of three pre-study defined groups: uncomplicated malaria (UM), severe non-fatal malaria (SM-s), and fatal malaria (SM-f). Subset analysis was done on those with cerebral malaria (CM) or severe malaria anaemia (SMA). Monocyte ICAM-1 was measured by flow cytometry. sICAM-1 was measured by enzyme immunoassay. RESULTS: Both sICAM-1 and monocyte cell-surface ICAM-1 followed a log-normal distribution. Median sICAM-1 concentrations increased with greater severity-of-illness: 279 ng/mL (UM), 462 ng/mL (SM-s), and 586 ng/mL (SM-f), p < 0.0001. sICAM-1 levels were not statistically different among children with CM compared to SMA. Monocyte ICAM-1 expression was significantly higher in cases of UM compared with SM-s or SM-f (p < 0.001) and was higher among the subset of patients with CM compared with SMA, p < 0.0014. The combination of sICAM-1 and cellular ICAM-1 identified distinct categories of patients (UM with low sICAM-1 and higher monocyte ICAM-1, CM with both sICAM-1 and monocyte ICAM-1 high, and SMA with sICAM-1 high but monocyte ICAM-1 low). CONCLUSION: In this cohort of children with P. falciparum malaria, sICAM-1 levels were associated with severity-of-illness. Patients with UM had higher monocyte ICAM-1 expression consistent with a role for monocyte ICAM-1 in immune clearance during non-severe malaria. Among the subsets of patients with either SMA or CM, monocyte ICAM-1 levels were higher in CM, consistent with the role of ICAM-1 as a marker of cytoadhesion. Categories of disease in pediatric malaria may exhibit specific combinations of soluble and cellular ICAM-1 expression.