Depleted circulatory complement-lysis inhibitor (CLI) in childhood cerebral malaria returns to normal with convalescence.

BACKGROUND: Cerebral malaria (CM), is a life-threatening childhood malaria syndrome with high mortality. CM is associated with impaired consciousness and neurological damage. It is not fully understood, as yet, why some children develop CM. Presented here is an observation from longitudinal studies on CM in a paediatric cohort of children from a large, densely-populated and malaria holoendemic, sub-Saharan, West African metropolis. METHODS: Plasma samples were collected from a cohort of children with CM, severe malarial anaemia (SMA), uncomplicated malaria (UM), non-malaria positive healthy community controls (CC), and coma and anemic patients without malaria, as disease controls (DC). Proteomic two-dimensional difference gel electrophoresis (2D-DIGE) and mass spectrometry were used in a discovery cohort to identify plasma proteins that might be discriminatory among these clinical groups. The circulatory levels of identified proteins of interest were quantified by ELISA in a prospective validation cohort. RESULTS: The proteome analysis revealed differential abundance of circulatory complement-lysis inhibitor (CLI), also known as Clusterin (CLU). CLI circulatory level was low at hospital admission in all children presenting with CM and recovered to normal level during convalescence (p < 0.0001). At acute onset, circulatory level of CLI in the CM group significantly discriminates CM from the UM, SMA, DC and CC groups. CONCLUSIONS: The CLI circulatory level is low in all patients in the CM group at admission, but recovers through convalescence. The level of CLI at acute onset may be a specific discriminatory marker of CM. This work suggests that CLI may play a role in the pathophysiology of CM and may be useful in the diagnosis and follow-up of children presenting with CM.

The IL17F and IL17RA Genetic Variants Increase Risk of Cerebral Malaria in Two African Populations.

Cerebral malaria (CM) is a neurological complication of infection with Plasmodium falciparum that is partly caused by cytokine-mediated inflammation. It is not known whether interleukin-17 (IL-17) cytokines, which regulate inflammation, control the development of CM. To evaluate the involvement of IL-17 cytokines in CM, we analyzed 46 common polymorphisms in IL17A, IL17F, and IL17RA (which encodes the common receptor chain of the members of the IL-17 family) in two independent African populations. A case-control study involving 115 Nigerian children with CM and 160 controls from the community (CC) showed that IL17F reference single nucleotide polymorphism (SNP) 6913472 (rs6913472) (P = 0.004; odds ratio [OR] = 3.12), IL17F rs4715291 (P = 0.004; OR = 2.82), IL17RA rs12159217 (P = 0.01; OR = 2.27), and IL17RA rs41396547 (P = 0.026; OR = 3.15) were independently associated with CM. A replication study was performed in 240 nuclear Malian family trios (two parents with one CM child). We replicated the association for 3 SNPs, IL17F rs6913472 (P = 0.03; OR = 1.39), IL17RA rs12159217 (P = 0.01; OR = 1.52), and IL17RA rs41396547 (P = 0.04; OR = 3.50). We also found that one additional SNP, IL17RA rs41433045, in linkage disequilibrium (LD) with rs41396547, was associated with CM in both Nigeria and Mali (P = 0.002; OR = 4.12 in the combined sample). We excluded the possibility that SNPs outside IL17F and IL17RA, in strong LD with the associated SNPs, could account for the observed associations. Furthermore, the results of a functional study indicated that the aggravating GA genotype of IL17F rs6913472 was associated with lower IL-17F concentrations. Our findings show for the first time that IL17F and IL17RA polymorphisms modulate susceptibility to CM and provide evidence that IL-17F protects against CM.

Affinity proteomics reveals elevated muscle proteins in plasma of children with cerebral malaria.

Systemic inflammation and sequestration of parasitized erythrocytes are central processes in the pathophysiology of severe Plasmodium falciparum childhood malaria. However, it is still not understood why some children are more at risks to develop malaria complications than others. To identify human proteins in plasma related to childhood malaria syndromes, multiplex antibody suspension bead arrays were employed. Out of the 1,015 proteins analyzed in plasma from more than 700 children, 41 differed between malaria infected children and community controls, whereas 13 discriminated uncomplicated malaria from severe malaria syndromes. Markers of oxidative stress were found related to severe malaria anemia while markers of endothelial activation, platelet adhesion and muscular damage were identified in relation to children with cerebral malaria. These findings suggest the presence of generalized vascular inflammation, vascular wall modulations, activation of endothelium and unbalanced glucose metabolism in severe malaria. The increased levels of specific muscle proteins in plasma implicate potential muscle damage and microvasculature lesions during the course of cerebral malaria.

Circulatory hepcidin is associated with the anti-inflammatory response but not with iron or anemic status in childhood malaria.

Cerebral malaria (CM) and severe malarial anemia (SMA) are the most serious life-threatening clinical syndromes of Plasmodium falciparum infection in childhood. Therefore, it is important to understand the pathology underlying the development of CM and SMA as opposed to uncomplicated malaria (UM). Increased levels of hepcidin have been associated with UM, but its level and role in severe malarial disease remains to be investigated. Plasma and clinical data were obtained as part of a prospective case-control study of severe childhood malaria at the main tertiary hospital of the city of Ibadan, Nigeria. Here, we report that hepcidin levels are lower in children with SMA or CM than in those with milder outcome (UM). While different profiles of pro- and anti-inflammatory cytokines were observed between the malaria syndromes, circulatory hepcidin levels remained associated with the levels of its regulatory cytokine interleukin-6 and of the anti-inflammatory cytokine inerleukin-10, irrespective of iron status, anemic status, and general acute-phase response. We propose a role for hepcidin in anti-inflammatory processes in childhood malaria.

Haemoglobinuria among children with severe malaria attending tertiary care in Ibadan, Nigeria.

BACKGROUND: Haemoglobinuria is one of the manifestations of severe malaria and results from severe intravascular haemolysis. Glucose-6-phosphate dehydrogenase (G6PD) deficiency has been implicated in its aetiology. Haemoglobinuria may be associated with severe anaemia and, less frequently, acute renal failure. METHODS: A prospective case-control study was carried out to determine the incidence of haemoglobinuria as confirmed by dipstick urinalysis, microscopy and spectrophotometric measurement, among children with severe malaria. A total of 251 children presenting at the Children's Emergency Ward with severe malaria were recruited over a period of 21 months. The G6PD status and the outcomes of severe malaria in children with and without haemoglobinuria was studied with respect to renal failure, the recurrence of haemoglobinuria and blood pressure changes over a three-month follow-up period. RESULTS: It was found that the incidence of haemoglobinuria among children with severe malaria is 19.1%. Children <5 years constituted 76.8% of all the study patients. Patients with haemoglobinuria had median age of 52.5 months, which was significantly higher than 35 months in patients without haemoglobinuria (p=0.001). Although, haemaglobinuria was commoner among boys (54.2%) than girls (45.8%), the difference was not statistically significant. There were no significant differences between children with and without haemoglobinuria regarding their nutritional status or parasite densities. Among the clinical features of the study patients, only jaundice was significantly associated with haemoglobinuria (p=0.0001). Renal failure occurred in three out of 48 children with haemoglobinuria and in none of the 203 without. There was not recurrence of haemoglobinuria in the follow-up period. At discharge, blood pressure was elevated in six children (one previously haemoglobinuric), but all returned to normal within the follow-up period. CONCLUSIONS: Haemoglobinuria was a prominent feature of severe malaria and it was significantly associated with jaundice at presentation. Haemoglobinuria was commoner in older children than younger children but not related to sex. G6PD deficiency was not an independent predictor of the occurrence or outcome of haemoglobinuria. Blood pressure was not affected by haemoglobinuria on admission nor during follow-up.

Data-driven malaria prevalence prediction in large densely populated urban holoendemic sub-Saharan West Africa.

Over 200 million malaria cases globally lead to half-million deaths annually. The development of malaria prevalence prediction systems to support malaria care pathways has been hindered by lack of data, a tendency towards universal "monolithic" models (one-size-fits-all-regions) and a focus on long lead time predictions. Current systems do not provide short-term local predictions at an accuracy suitable for deployment in clinical practice. Here we show a data-driven approach that reliably produces one-month-ahead prevalence prediction within a densely populated all-year-round malaria metropolis of over 3.5 million inhabitants situated in Nigeria which has one of the largest global burdens of P. falciparum malaria. We estimate one-month-ahead prevalence in a unique 22-years prospective regional dataset of > 9 × 104 participants attending our healthcare services. Our system agrees with both magnitude and direction of the prediction on validation data achieving MAE ≤ 6 × 10-2, MSE ≤ 7 × 10-3, PCC (median 0.63, IQR 0.3) and with more than 80% of estimates within a (+ 0.1 to - 0.05) error-tolerance range which is clinically relevant for decision-support in our holoendemic setting. Our data-driven approach could facilitate healthcare systems to harness their own data to support local malaria care pathways.

Outcome of cranial surgery in Nigerian patients with hemoglobinopathies: A retrospective study.

BACKGROUND: Surgical intervention in patients with hemoglobinopathies has been extensively reviewed in the literature, but information on the outcome of cranial surgery in this patient population in sub-Saharan Africa is limited. METHODS: This is a retrospective study of patients with hemoglobinopathies, who underwent brain surgery in our facility. The review covered a 5-year period. We examined patient- and surgery-related variables and described the surgical complications as well as the 60-day mortality. RESULTS: A total of nine procedures (eight under general anesthesia and one under local anesthesia) were performed on seven patients with hemoglobinopathy during the study period. Eight (88.9%) of these were done in female patients and one (11.1%) in a male patient. Six (66.7%) were performed in patients with no previous history of blood transfusion. Hb SC accounted for five (55.6%), Hb SS for three (33.3%), and Hb CC for one (11.1%) procedure, respectively. Three (33.3%) of these procedures were brain tumor-related, three (33.3%) trauma-related, one (11.1%) cosmetic, one (11.1%) vascular, and one for a postoperative complication. Only one (11.1%) procedure was associated with preoperative blood transfusion, whereas there was a need for blood transfusion following five (55.6%) of the procedures. There was a mortality rate of 11.1% (1 case). Other complications were recorded after three (33.3%) of the procedures and none with five (55.6%) of the procedures. CONCLUSION: Neurosurgery is possible and safe in patients with hemoglobin disorders. Adequate preoperative preparation, proper anesthetic techniques, meticulous surgery, and excellent postoperative care can help optimize outcome of surgical intervention in this patient population.

Low plasma haptoglobin is a risk factor for life-threatening childhood severe malarial anemia and not an exclusive consequence of hemolysis.

Severe Malarial Anemia (SMA), a life-threatening childhood Plasmodium falciparum malaria syndrome requiring urgent blood transfusion, exhibits inflammatory and hemolytic pathology. Differentiating between hypo-haptoglobinemia due to hemolysis or that of genetic origin is key to understand SMA pathogenesis. We hypothesized that while malaria-induced hypo-haptoglobinemia should reverse at recovery, that of genetic etiology should not. We carried-out a case-control study of children living under hyper-endemic holoendemic malaria burden in the sub-Saharan metropolis of Ibadan, Nigeria. We show that hypo-haptoglobinemia is a risk factor for childhood SMA and not solely due to intravascular hemolysis from underlying schizogony. In children presenting with SMA, hypo-haptoglobinemia remains through convalescence to recovery suggesting a genetic cause. We identified a haptoglobin gene variant, rs12162087 (g.-1203G > A, frequency = 0.67), to be associated with plasma haptoglobin levels (p = 8.5 × 10-6). The Homo-Var:(AA) is associated with high plasma haptoglobin while the reference Homo-Ref:(GG) is associated with hypo-haptoglobinemia (p = 2.3 × 10-6). The variant is associated with SMA, with the most support for a risk effect for Homo-Ref genotype. Our insights on regulatory haptoglobin genotypes and hypo-haptoglobinemia suggest that haptoglobin screening could be part of risk-assessment algorithms to prevent rapid disease progression towards SMA in regions with no-access to urgent blood transfusion where SMA accounts for high childhood mortality rates.

A Functional IL22 Polymorphism (rs2227473) Is Associated with Predisposition to Childhood Cerebral Malaria.

Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection. This encephalopathy is characterized by coma and is thought to result from mechanical microvessel obstruction and an excessive activation of immune cells leading to pathological inflammation and blood-brain barrier alterations. IL-22 contributes to both chronic inflammatory and infectious diseases, and may have protective or pathogenic effects, depending on the tissue and disease state. We evaluated whether polymorphisms (n = 46) of IL22 and IL22RA2 were associated with CM in children from Nigeria and Mali. Two SNPs of IL22, rs1012356 (P = 0.016, OR = 2.12) and rs2227476 (P = 0.007, OR = 2.08) were independently associated with CM in a sample of 115 Nigerian children with CM and 160 controls. The association with rs2227476 (P = 0.01) was replicated in 240 nuclear families with one affected child from Mali. SNP rs2227473, in linkage disequilibrium with rs2227476, was also associated with CM in the combined cohort for these two populations, (P = 0.004, OR = 1.55). SNP rs2227473 is located within a putative binding site for the aryl hydrocarbon receptor, a master regulator of IL-22 production. Individuals carrying the aggravating T allele of rs2227473 produced significantly more IL-22 than those without this allele. Overall, these findings suggest that IL-22 is involved in the pathogenesis of CM.

Malaria induces anemia through CD8+ T cell-dependent parasite clearance and erythrocyte removal in the spleen.

UNLABELLED: Severe malarial anemia (SMA) in semi-immune individuals eliminates both infected and uninfected erythrocytes and is a frequent fatal complication. It is proportional not to circulating parasitemia but total parasite mass (sequestered) in the organs. Thus, immune responses that clear parasites in organs may trigger changes leading to anemia. Here, we use an outbred-rat model where increasing parasite removal in the spleen escalated uninfected-erythrocyte removal. Splenic parasite clearance was associated with activated CD8(+) T cells, immunodepletion of which prevented parasite clearance. CD8(+) T cell repletion and concomitant reduction of the parasite load was associated with exacerbated (40 to 60%) hemoglobin loss and changes in properties of uninfected erythrocytes. Together, these data suggest that CD8(+) T cell-dependent parasite clearance causes erythrocyte removal in the spleen and thus anemia. In children infected with the human malaria parasite Plasmodium falciparum, elevation of parasite biomass (not the number of circulating parasites) increased the odds ratio for SMA by 3.5-fold (95% confidence intervals [CI95%], 1.8- to 7.5-fold). CD8(+) T cell expansion/activation independently increased the odds ratio by 2.4-fold (CI95%, 1.0- to 5.7-fold). Concomitant increases in both conferred a 7-fold (CI95%, 1.9- to 27.4-fold)-greater risk for SMA. Together, these data suggest that CD8(+)-dependent parasite clearance may predispose individuals to uninfected-erythrocyte loss and SMA, thus informing severe disease diagnosis and strategies for vaccine development. IMPORTANCE: Malaria is a major global health problem. Severe malaria anemia (SMA) is a complex disease associated with partial immunity. Rapid hemoglobin reductions of 20 to 50% are commonly observed and must be rescued by transfusion (which can carry a risk of HIV acquisition). The causes and risk factors of SMA remain poorly understood. Recent studies suggest that SMA is linked to parasite biomass sequestered in organs. This led us to investigate whether immune mechanisms that clear parasites in organs trigger anemia. In rats, erythropoiesis is largely restricted to the bone marrow, and critical aspects of the spleen expected to be important in anemia are similar to those in humans. Therefore, using a rat model, we show that severe anemia is caused through CD8(+) T cell-dependent parasite clearance and erythrocyte removal in the spleen. CD8 activation may also be a new risk factor for SMA in African children.

The choice of arthroplasty for secondary osteoarthritis of the hip joint following avascular necrosis of the femoral head in sicklers.

Secondary osteoarthritis of the hip joint often complicates avascular necrosis of the femoral head in young adults suffering from sickle cell anemia. These patients, particularly in our environment, are usually reluctant to use walking aids like crutches to alleviate the pain since they believe that these devices are temporary measures. They often demand long-term solutions which border on surgery. The surgical procedures carried out in these patients range from osteotomies to arthroplasties. With the advent of various forms of hip implants, osteotomies are not as popular in modern-day orthopedic practice. In this series, we treated five patients with secondary osteoarthritis in six hip joints (bilateral in one patient) using cementless bipolar arthroplasty with good outcome. This implant is available and affordable in Nigeria, and the use of a cementless implant obviates damage to the acetabulum and may make revision surgeries less hazardous both for the surgeon and the patient.

Psychosocial burden of sickle cell disease on caregivers in a Nigerian setting.

In Nigeria, with a high prevalence of sickle cell disease (SCD), families bear most of the burden of care for patients with this chronically disabling illness, because there are no national social welfare provisions. To assess the severity of indices of psychosocial burden among relatives of 24 SCD patients in crisis, in comparison with relatives of 57 SCD patients in stable condition. Cross-sectional study, using a burden instrument and Goldberg's General Health Questionnaire. Objective burden indices were significantly higher for SCD in crisis. The financial burden of SCD in crisis was significantly higher than the burden of disruption of family routines. 57.9% of all caregivers experienced little or no difficulty coping with SCD. Relatives with higher educational and occupational attainments (compared with those with lower attainments) experienced significantly lesser financial burden, disruption of family routines, and psychological distress. Compared with a similar study of cancer patients, relatives of patients in SCD crisis perceived similar financial, family routine burdens and psychological distress scores. Compared with US and UK reports, our caregivers were predominantly married and reflected the national range of socioeconomic groups. Global rating of burden was significantly predicted by disruption of family routines and higher age of caregivers. The psychosocial burden of SCD can be significantly reduced by controlling the frequency and duration of crises, as well as providing adequate information and socioeconomic support to families. Hematology staff should be sensitive to the psychosocial dimensions of SCD.

Haemoglobin F levels in healthy Nigerian adults.

Sickle Cell disease is a major genetic disorder in tropical Africa; its severity is often ameliorated by the presence of high levels of HbF, which is genetically determined. HbF was assessed in healthy Nigeria adults using the two minutes alkali denaturation method of Betke. The subjects studied included twenty-six males and twenty-four females all with HbA this was compared with twenty heterozygotes (HbAS). The mean HbF of the entire subject studied was 2.5 +/- 1.7% (range 0.4-12.8%). The mean value for Individuals with HbA genotype was 2.7 +/- 3.4% (range 0.4-12.8%). While the AS subject had a mean of 2.4 +/- 2.2% (range 0.7-8.4%). Twenty-two percent of the population studied had value greater than 3%. The high Level of HbF among healthy adults is believed to be genetic and related to the high prevalence of sickle cell disease in this sub-region. The association between HbF and high Persistence of fetal haemoglobin (HPFH) and the thalassaemias are discussed.

Severe childhood malaria syndromes defined by plasma proteome profiles.

BACKGROUND: Cerebral malaria (CM) and severe malarial anemia (SMA) are the most serious life-threatening clinical syndromes of Plasmodium falciparum infection in childhood. Therefore it is important to understand the pathology underlying the development of CM and SMA, as opposed to uncomplicated malaria (UM). Different host responses to infection are likely to be reflected in plasma proteome-patterns that associate with clinical status and therefore provide indicators of the pathogenesis of these syndromes. METHODS AND FINDINGS: Plasma and comprehensive clinical data for discovery and validation cohorts were obtained as part of a prospective case-control study of severe childhood malaria at the main tertiary hospital of the city of Ibadan, an urban and densely populated holoendemic malaria area in Nigeria. A total of 946 children participated in this study. Plasma was subjected to high-throughput proteomic profiling. Statistical pattern-recognition methods were used to find proteome-patterns that defined disease groups. Plasma proteome-patterns accurately distinguished children with CM and with SMA from those with UM, and from healthy or severely ill malaria-negative children. CONCLUSIONS: We report that an accurate definition of the major childhood malaria syndromes can be achieved using plasma proteome-patterns. Our proteomic data can be exploited to understand the pathogenesis of the different childhood severe malaria syndromes.

Hearing impairment in persons with the hemoglobin SC genotype.

The hemoglobin (Hb) SC genotype is seen in persons who have inherited the gene for hemoglobin S from one parent and the gene for hemoglobin C from the other. Some people with this genotype develop Hb SC disease, a variant of sickle cell disease. Hb SC disease, a compound heterozygous condition, is the most common of the hemoglobinopathies and the least severe, although it is still serious. One of the documented complications of the presence of the Hb SC genotype is sensorineural hearing loss (SNHL). We conducted a prospective case-control study of 43 subjects, aged 15 to 65 years, who had the Hb SC genotype to determine the incidence of SNHL and to determine if the hearing loss in these subjects was correlated with sex or age. Our control group was made up of 100 generally healthy, sex- and age-matched subjects with the normal Hb AA genotype. SNHL was defined as a loss of more than 25 dB HL at two or more frequencies in the same ear or at one or more frequencies in both ears. We found that SNHL was present in 12 of the 43 subjects (27.9%) in the Hb SC group (17 of 86 ears [19.8%]) and in 17 of the 100 subjects (17.0%) in the Hb AA group (21 of 200 ears [10.5%]; the difference between the two groups was not statistically significant (chi(2) = 1.589; p = 0.105). We found that in the Hb SC group, SNHL was more common among females than males (38.5 vs. 11.8%), although the difference was not quite significant statistically (chi(2) = 2.435; p = 0.056); in the Hb AA group, the incidence was fairly equal-15.4 and 18.8%, respectively (chi(2) = 0.033; p = 0.427). Therefore, we conclude that the hearing loss in the subjects of this study was not correlated with the presence of the Hb SC genotype in either sex. In terms of age, SNHL was significantly more common in subjects aged 41 to 65 years than in those aged 15 to 40 years in both genotype groups. In the Hb SC group, SNHL was present in 4 of the 33 younger subjects (12.1%) and in 8 of the 10 older subjects (80.0%) (chi(2) = 14.354; p < 0.001). In the Hb AA group, the corresponding figures were 7 of 85 (8.2%) and 10 of 15 (66.7%) (chi(2) = 26.840; p < 0.001). Therefore, we conclude that the hearing loss in the subjects of this study was a function of age and was not associated with the presence of the Hb SC genotype.

Plasma fibrinogen levels in Nigerian homozygous (Hb SS) sickle cell patients.

The plasma fibrinogen levels in 50 Nigerian sickle cell disease (Hb SS) patients in steady state and 50 healthy age and sex-matched (Hb AA) control subjects were determined for the purpose of assessing their baseline values. The fibrinogen levels were assessed using two methods, the clot weight and Clauss, on all the samples for the purpose of comparison. It was observed in this study that the Hb SS patients had significantly higher fibrinogen levels than the healthy Hb AA control subjects, both by the clot weight method (p < 0.001) and the Clauss (p < 0.005). The mean fibrinogen levels (4.1 +/- 2.1 g/L) of the Hb SS patients as determined by the clot weight method, were significantly higher than the values (2.2 +/- 0.3 g/L) obtained by the Clauss method. The mean values for the two methods were 2.8 +/- 0.9 and 2.0 +/- 0.08 g/L, respectively, among the control individuals with a statistically significant difference (p < 0.005). Estimation of the plasma fibrinogen levels in sickle cell disease patients might be a useful indicator of hyper coagulability, while early diagnosis may help to prevent vaso-occlusive crises in these patients.

Plasma levels of some blood coagulation parameters in Nigerian homozygous sickle cell patients (HbSS) in steady state.

The plasma levels of some blood coagulation parameters; prothrombin time, (PT), partial thromboplastin time with kaolin (PTTK), thrombin clotting time, (TCT), fibrinogen and factor X assay were determined in 50 Nigerian homozygous (HbSS) patients and 50 HbAA healthy individuals for the purpose of assessing their baseline values and susceptibility of patients with sickle cell disease (SCD) to hyper coagulability. Standard procedures were used for all variables. The mean age of the study participants was 21.7 +/- 5.0 years. The mean PT of 13.7 +/- 1.4 s in HbSS patients was found to be significantly longer than the mean PT value of 12.9 +/- 1.0 in HbAA control subjects (p < 0.001). The mean PTTK values of 46.0 +/- 9.6 s in HbSS patients was also found to be significantly higher than the 41.0 +/- 3.7 s recorded among the control subjects (p < 0.001). The mean TCT of 6.4 +/- 0.8 s in HbSS patients was however found to be significantly lower than the mean value of 10.6 +/- 0.8 s obtained in the control group. Fibrinogen level (4.1 +/- 2.1 g/l) in HbSS patients and 2.8 +/- 0.9 g/l in HbAA controls was also found to be significantly different (p < 0.001). Factor X level in the sickle cell patients, (64.6 +/- 14.9%) was equally found to be significantly lower than that of the apparently healthy HbAA control individuals (95.2 +/- 7.2%) (p < 0.001).