Prenatal diagnosis of giant cardiac rhabdomyoma in tuberous sclerosis complex: a new therapeutic option with everolimus.

Tuberous sclerosis complex (TSC) is a genetic disorder characterized by abnormal cell proliferation and tumor growth in a number of organ systems, primarily the brain, kidneys, eyes and heart. Clinical symptoms vary according to the location of the tumor. The most common disorders are seizures, neurodevelopmental disorders, renal failure and arrhythmias. TSC was found to be influenced by inhibitors of the protein kinase mammalian target of rapamycin (mTOR), which regulates abnormal cellular proliferation. mTOR inhibitors have been studied effectively in patients with subependymal giant-cell astrocytomas and renal angiolipomas in the context of TSC. We describe a prenatally diagnosed case of giant rhabdomyoma, due to right ventricular outflow tract obstruction, which presented as a duct-dependent lesion. Postnatal treatment with the mTOR inhibitor everolimus initiated significant regression of the cardiac tumor. This finding suggests that mTOR inhibitor therapy is an option for giant rhabdomyomas that develop in the neonatal period.

No impact of endogenous prothrombotic conditions on the risk of central venous line-related thrombotic events in children: results of the KIDCAT study (KIDs with Catheter Associated Thrombosis).

BACKGROUND AND OBJECTIVE: Central venous lines (CVLs) are the major exogenous risk factor for deep venous thrombosis (DVT) in children. The study objective was to assess whether endogenous prothrombotic conditions contribute to the risk of CVL-related DVT in children. METHODS: This was a cohort study of consecutive children with heart disease requiring CVLs for perioperative care. CVLs were inserted percutaneously in the upper venous system and patients received prophylaxis with continuous unfractionated heparin (50 u kg(-1)  d(-1) ). Blood samples to test for prothrombotic conditions were collected prospectively and assayed in a blinded fashion. Outcome assessment was by screening for DVT by venography, venous ultrasound and echocardiography. RESULTS: The study population consisted of 90 children, median age 2.7 years (0 months-18 years). Prevalence rates of antithrombin deficiency, protein C deficiency, protein S deficiency, heterozygous factor V Leiden, prothrombin G20210A mutation, methylentetrahydrofolate C677TT genotype, hyperhomocysteinemia, lupus anticoagulant, anticardiolipin antibodies and increased levels of lipoprotein (a) were within the range reported for the general population. At least one prothrombotic condition was present in 38% of children and combined abnormalities in 8%. The incidence of DVT was 28% (25/90), and most DVTs were asymptomatic. None of the prothrombotic conditions showed a significant association with DVT. The population attributable risk (i.e. the risk of DVT in the overall population attributable to a specific condition) did not exceed 2.2%. CONCLUSION: Prothrombotic conditions did not have an important impact on the risk of DVT in children with short-term CVLs. The results of the study suggest that screening for prothrombotic conditions is not justified in this setting.

Danon disease: case report and detection of new mutation.

Danon disease is an X-linked disorder resulting from mutations in the lysosome-associated membrane protein-2 (LAMP2) gene. We report a male patient with skeletal myopathy, mental retardation, and massive hypertrophic obstructive cardiomyopathy necessitating heart transplantation. Immunohistochemistry of skeletal muscle and leukocytes, western blot analysis of leukocytes and cardiac muscle, flow cytometry, and DNA sequencing were performed. Muscle biopsy revealed autophagic vacuolar myopathy and lack of immunohistochemically detectable LAMP-2. Diagnosis of Danon disease was confirmed by western blot analysis of myocardial tissue and peripheral blood sample of the patient showing deficiency of LAMP-2 in myocardium and leukocytes. Moreover, absence of LAMP-2 in lymphocytes, monocytes and granulocytes was shown by flow cytometric analysis. Genetic analysis of the LAMP2 gene revealed a novel 1-bp deletion at position 179 (c.179delC) at the 3' end of exon 2, resulting in a frameshift with a premature stop codon.

The prevalence of parasite infestation and house dust mite sensitization in Gabonese schoolchildren.

BACKGROUND: Allergic diseases seem less prevalent in communities in less developed parts of the world, where parasite infections are highly prevalent. Altogether not much is known about the association between chronic infections with tissue and blood-dwelling parasites and atopy. METHODS: In an area in Gabon endemic for blood and tissue parasites, 520 schoolchildren were parasitologically examined and skin prick-tested for a set of common environmental aeroallergens. Levels of allergen-specific IgE and polyclonal IgE were measured. RESULTS: In schoolchildren schistosome and filarial infections increased with age, whereas malaria was more prevalent in younger children. In contrast to allergen sensitization that increased with age, skin test reactivity tended to decline. The number of children with mite-specific IgE antibodies (47%) by far exceeded the number responding to skin prick testing (11%). Mite sensitization was found to be the highest in children infected with schistosomes and/or filariae whereas skin test reactivity was lowest. The multiple logistic regression showed that the risk of a positive skin test was 8-fold higher with increasing levels of mite-specific IgE but was reduced by 72% when infected with blood stage helminths. CONCLUSIONS: Chronic blood and tissue parasite infections that are often capable of modulating immune responses in the host are negatively associated with skin test reactivity in a sensitized population.

Effect of antipyretic drugs in children with malaria.

A comparison of different antipyretics in children with malaria showed a small effect of naproxen, but not of metamizol, on the reduction of fever peaks. Antipyretic treatment had no effect on fever clearance and therefore should be used cautiously in the treatment of malaria.

Promoter variants of the human mannose-binding lectin gene show different binding.

Mannose-binding lectin (MBL) levels in the plasma of humans are highly variable. The level is influenced by gene mutations in exon1 and the promoter. Here we describe the distribution of three point mutations linked with a deletion in the MBL gene promoter in populations of Central Africa, Thailand, and Papua New Guinea. Among African children we find 20% with the wild-type allele, 53% are heterozygous, and 27% are homozygous for the mutation. In Thailand we find 65% with the wild-type allele, 33% are heterozygous, and 2% are homozygous for the variant. In Papua New Guinea the polymorphism is not found. The occurrence of the mutation was associated with MBL levels in the plasma (P = 0.043). Oligonucleotides derived from the variant promoter regions bind proteins differently according to their DNA sequence. The binding of proteins can be influenced by induction with interleukin-6.

Low interleukin-12 activity in severe Plasmodium falciparum malaria.

We compared interleukin-12 (IL-12) and other cytokine activities during and after an acute clinical episode in a matched-pair case-control study of young African children who presented with either mild or severe Plasmodium falciparum malaria. The acute-phase, pretreatment plasma IL-12 and alpha interferon (IFN-alpha) levels, as well as the acute-phase mitogen-stimulated whole-blood production capacity of IL-12, were significantly lower in children with severe rather than mild malaria. IL-12 levels, in addition, showed strong inverse correlations both with parasitemia and with the numbers of circulating malaria pigment-containing neutrophils. Acute-phase plasma tumor necrosis factor (TNF) and IL-10 levels were significantly higher in those with severe malaria, and the concentrations of both of these cytokines were positively correlated both with parasitemia and with the numbers of pigment-containing phagocytes in the blood. Children with severe anemia had the highest levels of TNF in plasma. In all the children, the levels in plasma and production capacities of all cytokines normalized when they were healthy and parasite free. The results indicate that severe but not mild P. falciparum malaria in young, nonimmune African children is characterized by down-regulated IL-12 activity, contrasting markedly with the up-regulation of both TNF and IL-10 in the same children. A combination of disturbed phagocyte functions resulting from hemozoin consumption, along with reduced IFN-gamma responses, may contribute to these differential effects.

Malarial anaemia in African children associated with high oxygen-radical production.

Reactive oxygen intermediates are thought to be involved in both the illness and parasite destruction during malaria. We measured innately increased reactive oxygen intermediate production in Gabonese children with severe malaria and anaemia.

Antibody responses to Plasmodium falciparum: evolution according to the severity of a prior clinical episode and association with subsequent reinfection.

We measured sporozoite- and total parasite antigen-specific IgG and IgM antibodies before and after treatment in matched groups of Gabonese children who presented with either mild or severe Plasmodium falciparum malaria. We investigated the influence of various parameters on these antibody responses, including clinical presentation, age, and post-treatment reinfection profiles. IgG but not IgM responses were strongly influenced by both clinical and parasitological status. IgG responses to the repeat region of the circumsporozoite protein, which were low at admission, particularly so in those with severe anemia, increased after treatment but showed no association with either age or reinfection profiles. Total parasite antigen-specific IgG responses were strongly influenced by parasitological status, and also differed significantly when segregated according to clinical status at admission, age, and reinfection histories. Most notably, anti-parasite IgG responses measured when children were parasite-free were higher and a good indicator of recent reinfections in those who presented with mild rather than with severe malaria. The profile of responses in the latter group suggests some immune system dysfunction, which may reflect the induction of tolerance to parasite antigens.

Association of the ICAM-1Kilifi mutation with protection against severe malaria in Lambaréné, Gabon.

The intercellular adhesion molecule-1 (ICAM-1) is thought to be a receptor that mediates binding of Plasmodium falciparum-infected erythrocytes. Especially in vital organs, the binding of parasitized cells to the endothelium via ICAM-1 may lead to severe disease and death. Recently, a mutation in the coding region of ICAM-1, termed ICAM-1Kilifi, was described, causing a change from Lys to Met in the loop that interacts with rhinoviruses, lymphocytes, and parasitized red blood cells. Surprisingly, this mutation was shown to increase susceptibility of Kenyan children to severe malaria in one study. When we compared the distribution of ICAM-1Kilifi in two groups of Gabonese children enrolled in a case-control, matched-pair study who presented with either mild or severe malaria, we found that 55% of the patients with mild malaria were carriers whereas only 39% of those with severe malaria were carriers. The difference in the distribution of ICAM-1Kilifi homozygous pairs between the groups, as well as the distribution of ICAM-1Kilifi carriers, was statistically highly significant (P = 0.027 and P = 0.012, by the McNemar test). In a group of healthy school children from the same region, a distribution of 52% ICAM-1Kilifi carriers to 48% wild-type individuals was found. In a survey for the ICAM-1Kilifi in other malaria-endemic regions, this allele was also found in Nigeria and Papua New Guinea, but not in Thailand.

High oxygen radical production is associated with fast parasite clearance in children with Plasmodium falciparum malaria.

It has been hypothesized that reactive oxygen intermediates (ROI) released by leukocytes play a major role in the immune response to many infectious agents. In the present study, the parasitologic and clinical courses of 75 Gabonese children with Plasmodium falciparum malaria were compared with the ability of their granulocytes to produce oxygen radicals. The luminol-dependent chemiluminescence in granulocyte suspensions for the children was measured without stimulation and after stimulation with phorbol-12-myristate-13-acetate, N-formyl-methionyl-leucyl-phenylalanine, or tumor necrosis factor. A significant association was found between fast parasite clearance time and high oxygen radical generation in both the unstimulated and stimulated granulocyte preparations. No correlation was found between fever clearance time and ROI generation. These findings suggest that ROI play a pivotal role in the immune response as a first line of defense against P. falciparum malaria.

Interferon-gamma responses are associated with resistance to reinfection with Plasmodium falciparum in young African children.

The contribution of T cell-mediated responses was studied with regard to resistance to reinfection in groups of Gabonese children participating in a prospective study of severe and mild malaria due to infection with Plasmodium falciparum. In those admitted with mild malaria, but not in those with severe malaria, production of IFN-gamma by peripheral blood mononuclear cells (PBMC) in response to either liver-stage or merozoite antigen peptides was associated with significantly delayed first reinfections and with significantly lower rates of reinfection. Proliferative or tumor necrosis factor responses to the same peptides showed no such associations. Production of interferon-gamma by PBMC in response to sporozoite and merozoite antigen peptides was observed in a higher proportion of those presenting with mild malaria. Differences in the Th1/Th2 cytokine balance may be linked to the ability to control parasite multiplication in these young children, helping to explain the marked differences observed in both susceptibility to infection as well as in clinical presentation.

HLA class II factors associated with Plasmodium falciparum merozoite surface antigen allele families.

In Plasmodium falciparum malaria, certain human leukocyte antigens (HLA) and the parasite's merozoite surface antigens 1 and 2 (MSA-1, MSA-2) have been shown to influence the course of the infection. This report is on associations of distinct HLA factors with the occurrence of particular MSA families in a group of patients with either severe or mild P. falciparum malaria in Gabon. Different distributions of HLA-DPB1 alleles were found in the 2 groups. DR *04 alleles were observed more frequently among patients with severe malaria. Several alleles of different loci were associated with distinct MSA allele families. In addition, carriers of the amino acid methionine at position 11 of the DPA1 allele were more often infected by MSA-1 K1 parasites and less frequently by MSA-1 RO33 parasites. Furthermore, associations of HLA factors with polyclonal infections were found.

The role of red blood cell polymorphisms in resistance and susceptibility to malaria.

In regions highly endemic for Plasmodium falciparum malaria, red cell polymorphisms that confer resistance to severe disease are widespread. Sickle cell trait, alpha-thalassemia, glucose-6-phosphate dehydrogenase deficiency, and blood groups were determined in 100 children from Gabon with severe malaria who were matched with 100 children with mild malaria and followed up for evaluation of reinfections. The sickle cell trait was significantly associated with mild malaria and blood group A with severe malaria. During follow-up, the original severe cases had significantly higher rates of reinfection than the original mild cases, with higher parasitemia and lower hematocrit values. Incidence rates did not differ in the context of erythrocyte polymorphisms, but patients with sickle cell trait presented with markedly lower levels of parasitemia than those without. Thus, the severity of malaria is partly determined by the presence of blood group A and the sickle cell trait. The different presentation of reinfections in severe versus mild cases probably reflects different susceptibility to malaria.

No influence of socioeconomic factors on severe malarial anaemia, hyperparasitaemia or reinfection.

Malaria is responsible for nearly 500 million clinical cases per year, only a small proportion of whom will become severely ill. Socioeconomic risk factors may play a role in the development of severe malaria in African children and in their susceptibility to reinfection. In Gabon, 100 children suffering from severe malaria, defined as hyperparasitaemia and/or severe anaemia, were matched for sex, age and provenance to 100 children with mild malaria. Socioeconomic factors were assessed using a standard questionnaire and compared between the 2 groups. The children were followed-up and the time to first reinfection was recorded. No significant influence of socioeconomic factors could be detected on the severity of disease or the time to first reinfection. Socioeconomic factors are not major determinants of severe malarial anaemia and hyperparasitaemia in children in Gabon.

Merozoite surface antigen 1 and 2 genotypes and rosetting of Plasmodium falciparum in severe and mild malaria in Lambaréné, Gabon.

We present a case-control study to investigate the distribution of Plasmodium falciparum genotypes in patients with severe and mild malaria. We compared clinical and parasitological data with the parasites' genotype and rosetting. The study group consisted of 100 children suffering severe malaria, defined as severe anaemia and hyperparasitaemia. These children were matched by age, sex and provenance with 100 children with mild malaria. For characterization of the parasites we used the polymerase chain reaction to determine merozoite surface antigen (MSA) 1 and 2 genotypes and the phenomenon of rosette formation. We found a significant association between rosette formation and disease severity, and a significant association of severe anaemia with the presence of the MSA-1 allele K1. Infections with 2 genotypes in the severely affected group were significantly associated with severe anaemia and the presence of MSA-1 allele K1. Comparison with the findings of other groups led to the conclusion that the occurrence of P. falciparum genotypes seems to differ geographically.

Randomised placebo-controlled study of atovaquone plus proguanil for malaria prophylaxis in children.

BACKGROUND: The combination of atovaquone and proguanil is highly effective and safe for the treatment of Plasmodium falciparum malaria. We aimed in this randomised, double-blind, placebo-controlled study to assess the efficacy and safety of this combination for malaria prophylaxis. METHODS: 320 children who lived in a hyperendemic area for P falciparum malaria were stratified by weight and randomly assigned atovaquone plus proguanil or placebo once daily for 12 weeks. All children received initial curative treatment with atovaquone and proguanil before the start of chemosuppression. We recorded adverse events daily and collected thick blood smears once a week. The primary endpoint was a positive blood smear. FINDINGS: 25 of 140 children in the placebo group and none of the 125 children in the atovaquone plus proguanil group had positive smears during chemosuppression (p<0.001). Adverse events during the chemosuppression phase did not differ between the groups. INTERPRETATION: The combination of atovaquone plus proguanil is a highly effective and well-tolerated chemosuppressive antimalarial in children. This drug combination could replace current regimens.

PIP: The efficacy and safety of combined atovaquone and proquanil as a chemosuppressive antimalarial were investigated in a randomized placebo-control study of 315 schoolchildren 4-16 years of age from Lambarene, Gabon--an area where Plasmodium falciparum malaria is endemic and parasites are highly resistant to chloroquine. The children were categorized on the basis of weight (11-20, 21-30, 31-40, and 41 kg and over). At baseline, 115 children (37%) had a positive blood smear for malaria. In the initial phase of the study, all 315 children received the combined treatment. After 3 days of curative treatment, P. falciparum and P. malariae were still detected in 5 and 11 children, respectively. After 1 week of curative treatment, all children with these parasites had negative blood smears. Of the 265 children who completed the initial curative phase, 125 were assigned the combined treatment (dose adjusted for weight) and 140 received a placebo. During a total of 28 person-years of observation in the atovaquone and proquanil group, protective efficacy was 100%. In the 28 person-years of observation accumulated among untreated controls, positive blood smears were detected in 25 children; parasites began to emerge 4 weeks after the initial curative phase. During the 4-week follow-up period, during which time neither group received treatment, positive blood smears were found in 12 controls and 3 cases (emerging only in the last 4 observation days). Although gastrointestinal symptoms were reported, the rate did not differ significantly between cases and controls. These findings suggest that the combination of atovaquone and proquanil could replace current antimalarial regimens if donated supplies were available.

Operations on the thoracic aorta and hypothermic circulatory arrest: is aprotinin safe?

INTRODUCTION: The safety of aprotinin, especially when used with profound hypothermic circulatory arrest, is still a matter of intense debate despite its presumed salutary effects on blood loss. Many investigators have reported toxic renal effects of high-dose aprotinin in such patients, but no prospective, randomized study has been conducted. To assess the potential detrimental effect of aprotinin on renal function and its putative reduction of blood loss, 50 patients undergoing thoracic aortic operations with the use of profound hypothermic circulatory arrest were randomly assigned to receive either low-dose aprotinin (1 x 10(6) kallikrein activation units) or placebo. METHODS: The specific renal tubular markers beta-2-microglobulin and beta-N-acetyl-D-glucosaminidase, as well as serum creatinine and blood urea nitrogen, creatinine clearance, sodium excretion, and potassium excretion, were measured to evaluate renal function preoperatively, immediately after the procedure, and 24 hours and 48 hours later. RESULTS: No statistically significant difference was found in any measured renal parameter between the two groups (analysis of variance). Renal dysfunction, defined as an elevation of serum creatinine early postoperatively (> or = 1.5 times the preoperative value), occurred in two patients who received aprotinin and in one patient in the control group. Temporary dialysis (hemodialysis or continuous venovenous hemofiltration) was needed in two patients in the aprotinin group versus one in the control group. Furthermore, patients treated with aprotinin had significantly less total postoperative blood loss (718 +/- 340 ml vs 920 +/- 387 ml, p = 0.04). The aprotinin recipients also had a significantly lower transfusion requirement (p < 0.05). CONCLUSION: This controlled trial of low-dose aprotinin in patients undergoing thoracic aortic operations using profound hypothermic circulatory arrest demonstrated no detectable deleterious effects on renal function; moreover, the use of aprotinin was associated with significantly lower need for transfusion.

Parasite antigen-specific interleukin-10 and antibody reponses predict accelerated parasite clearance in Plasmodium falciparum malaria.

Using strict inclusion criteria, we conducted a hospital-based, case-control study in which 100 Gabonese children with severe Plasmodium falciparum malaria were matched for age, gender and provenance with 100 children presenting with mild malaria. Parasite antigen-specific cellular and humoral immunological responses were measured and compared with post-treatment parasite clearance times in each group. Significantly faster parasite clearance times were associated with in vitro production of IL-10 by acute-phase peripheral blood mononuclear cells (PBMC) in response to both liver and asexual stage parasite antigens, but not with proliferative, IFN-gamma, or TNF responses to the same antigens. In addition, in those children with mild malaria, higher levels of acute-phase antibody responses to liver stage antigen-1 (LSA-1) were associated with faster parasite clearance times, and were correlated with the presence of IL-10 responses to the same antigen. No such associations were found for IL-10 or antibody responses to a range of asexual blood stage antigens. Those with severe malaria had significantly lower levels of anti-LSA-1 antibodies compared to their counterparts with mild malaria. In conclusion, the results of this study suggest that parasite antigen-specific IL-10-mediated antibody responses may play a role in the control of asexual stage parasite multiplication in P. falciparum malaria.