[Osteomyelitis of the mandible and dysosteosclerosis]. / Dysostéosclérose et ostéite chronique de la mandibule.

Dysosteosclerosis is a rare genetic disorder with a poor prognosis. It is an osteochondrodysplasia similar to osteopetrosis but it is typically characterized by platyspondyly and expanded metaphyses. It shows complications such as compression of cranial nerves, especially the optic nerve, hematologic complications, fractures following mild injury, abnormal dentition, neurological and psychological deterioration, in addition to osteomyelitis of the mandible. We report a new case of dysosteosclerosis complicated by osteomyelitis of the lower maxilla.

[Subcutaneous emphysema, pneumomediastinum, pneumopericardium, pneumorachis, and pneumoretroperitoneum revealing an unknown foreign body aspiration]. / Emphysème sous-cutané massif, pneumomédiastin, pneumopéricarde, pneumorachis et pneumorétropéritoine révélant une inhalation méconnue d'un corps étranger.

Subcutaneous emphysema develops from the spread of air essentially from the mediastinum into the subcutaneous tissue causing progressive distension and infiltration. Diagnostic and therapeutic delay expose the patient to massive air effusion and risk of compression of cervical and mediastinal structures. The initial mechanism is a breach in the tracheobronchial tree with air diffusion into the interstitial space and along the perivascular spaces toward the mediastinum, and then spread and dissection in the subcutaneous tissue. A tracheobronchial foreign body is a very rare cause of emphysema and is often localized. An association with a combination of epidural emphysema, pneumopericardium, or pneumoretroperitoneum is exceptional. Here, we present a unique case associating massive subcutaneous emphysema, pneumomediastinum, pneumopericardium, pneumorrhachis, and pneumoretroperitoneum in a 3.5-year-old child complicating an unrecognized aspirated foreign body. The extraction of the foreign body resulted in gradual regression of the symptoms and the disappearance of these emphysematous locations.

[Neonatal group A streptococcal meningitis and portal vein thrombosis: a casual association?]. / Méningite néonatale à streptocoque A et thrombose porte : une association fortuite ?

Invasive group A streptococcal infections are potentially serious. The occurrence in the neonatal period and meningeal location are two unusual situations. The complications reported in the literature vary; we add the risk of thromboembolic events. We report the case of a newborn, admitted to our department at 22 days of life for late neonatal group A streptococcal meningitis and diffuse cerebral infarction lesions. Ultrasound and abdominal CT scan objectified the presence of portal vein thrombosis and cavernoma. Echocardiography, electrocardiogram, as well as coagulation and thrombophilia tests were normal. Progression was marked by the installation of cerebral atrophy and ventricular dilation without the appearance of signs of portal hypertension over 18 months. We therefore concluded in neonatal group A streptococcal meningitis complicated by multiple thrombosis that can be explained by the invasive properties and hypercoagulability characterizing group A beta-hemolytic streptococcus. However, the characteristics of the fetal circulation may explain the possibility of paradoxical cerebral embolism from portal thrombosis.

Susceptibility to experimental cerebral malaria induced by Plasmodium berghei ANKA in inbred mouse strains recently derived from wild stock.

The neurological syndrome caused by Plasmodium berghei ANKA in rodents partially mimics the human disease. Several rodent models of cerebral malaria (CM) exist for the study of the mechanisms that cause the disease. However, since common laboratory mouse strains have limited gene pools, the role of their phenotypic variations causing CM is restricted. This constitutes an obstacle for efficient genetic analysis relating to the pathogenesis of malaria. Most common laboratory mouse strains are susceptible to CM, and the same major histocompatibility complex (MHC) haplotype may exhibit different levels of susceptibility. We analyzed the influence of the MHC haplotype on overcoming CM by using MHC congenic mice with C57BL/10 and C3H backgrounds. No correlation was found between MHC molecules and the development of CM. New wild-derived mouse strains with wide genetic polymorphisms were then used to find new models of resistance to CM. Six of the twelve strains tested were resistant to CM. For two of them, F(1) progeny and backcrosses performed with the reference strain C57BL/6 showed a high level of heterogeneity in the number and characteristics of the genetic factors associated with resistance to CM.

Cerebral malaria and immunogenetics.

Cerebral malaria depends largely on the capacity of Plasmodium falciparum infected red blood cells to adhere to the endothelia of microvessels, leading to their occlusion. The most important players include receptors expressed on the surface of the endothelial cell and known to interact with the parasite, cytokines modulating the expression of these adhesion molecules and nitric oxide (NO). Platelets, monocytes and lymphocytes have the ability to adhere to these endothelial receptors and to one another, leading to a more complex situation and an increase in the degree of vessel occlusion. The polymorphism of all these molecules, implicated either in adhesion, in modulation of this adhesion or activation of the expression of diverse endothelial mediators should be an important field of study. Polymorphism of five of these molecules has been explored so far: ICAM-1, TNF-alpha, IL-1-beta, inducible NOS and complement receptor-1 (CR-1). To these studies can be added those concerning mannose binding protein (MBP), a protein playing a role in innate immunity, and the class-I antigen HLA-B53. To date, the only clear cut result concerns TNF-alpha. With the other polymorphisms, either no association is found (IL-1RA, CR-1, MBP), or the results are geographically heterogeneous (ICAM-1, HLA-B53), or contradictory (iNOS2). Most often, the candidate gene approach has been followed, as part of case control studies. One of the main problems in this approach is the difficulty of establishing the control cohort. This difficulty disappears in family studies, which include their own controls. So far, the only results based on complex segregation analysis have been focused on parasite multiplication and not on cerebral malaria.

[Immunogenetics and cerebral malaria]. / Immunogénétique et paludisme cérébral.

Since the identification, in 1954, of the first gene associated with resistance to Plasmodium falciparum, several genes, some of them being implicated in the regulation of the immune response, have been described as possible influences on cerebral pathology. This pathology depends primarily on the capacity of infected red blood cells to adhere to the endothelia of micro-vessels, leading to their occlusion. The major players of cerebral malaria potentially include: receptors expressed on the surface of the endothelial cell and known to interact with infected red blood cells, cytokines modulating the expression of these adhesion molecules, nitric oxide (NO) and Fc epsilon RII/CD23. Cells other than infected red blood cells, such as platelets, monocytes and lymphocytes, have the ability to adhere to these endothelial receptors and to one another, via different ligands, leading to a more complex situation and an increase in the degree of vessel occlusion. The polymorphism of all these molecules, implicated either in adhesion, in modulation of this adhesion or activation of the expression of diverse endothelial mediators should be an important field of study. Polymorphism of five of these molecules has been explored so far: ICAM-1, TNF-alpha, IL-1 beta, iNOS2 (inducible NOS) and CR-1 (complement receptor-1). To these studies, can be added those concerning mannose binding protein (MBP), a protein playing a role in innate immunity, and the class-I antigen HLA-B53. To date the only clear-cut result concerns TNF-alpha. With the other polymorphisms, either no association is found (IL-1RA, CR-1, MBP), or results are geographically heterogeneous (ICAM-1, HLA-B53), or contradictory (iNOS2). Most often, the approach followed has been the candidate gene approach, as part of case control studies. One of the main problems in this approach is the difficulty of establishing the control cohort. This difficulty disappears in family studies, which include their own controls. So far, the only results based on complex segregation analysis have been focused on parasite multiplication and not on cerebral malaria.

T cell response in malaria pathogenesis: selective increase in T cells carrying the TCR V(beta)8 during experimental cerebral malaria.

To characterize the T cells involved in the pathogenesis of cerebral malaria (CM) induced by infection with Plasmodium berghei ANKA clone 1.49L (PbA 1.49L), the occurrence of the disease was assessed in mice lacking T cells of either the alphabeta or gammadelta lineage (TCRalphabeta(-/-) or TCRgammadelta(-/-)). TCRgammadelta(-/-) mice were susceptible to CM, whereas all TCRalphabeta(-/-) mice were resistant, suggesting that T cells of the alphabeta lineage are important in the genesis of CM. The repertoire of TCR V(beta) segment gene expression was examined by flow cytometry in B10.D2 mice, a strain highly susceptible to CM induced by infection with PbA 1.49L. In these mice, CM was associated with an increase of T cells bearing the V(beta)8.1, 2 segments in the peripheral blood lymphocytes. Most V(beta)8.1, 2(+) T cells from peripheral blood lymphocytes of the mice that developed CM belonged to the CD8 subset, and exhibited the CD69(+), CD44(high) and CD62L(low) phenotype surface markers. The link between the increase in V(beta)8.1, 2(+) T cells and the neuropathological consequences of PbA infection was strengthened by the observation that the occurrence of CM was significantly reduced in mice treated with KJ16 antibodies against the V(beta)8.1 and V(beta)8.2 chains, and in mice rendered deficient in V(beta)8.1(+) T cells by a mouse mammary tumor virus superantigen.

Cloned lines of Plasmodium berghei ANKA differ in their abilities to induce experimental cerebral malaria.

Infection with Plasmodium berghei ANKA is usually lethal. The parasite causes in some mouse strains a neurovascular syndrome, experimental cerebral malaria (ECM), involving immunopathological reactions. The effects on the development of ECM of the mouse genetic background have been clearly demonstrated, but nothing is known about the effects of the clonal diversity of the parasite. We showed that various cloned lines derived from a polyclonal line of P. berghei ANKA caused ECM but that the extent of ECM induction was dependent on the amount of inoculum. Subtle differences in ECM characteristics (survival time and hypothermia) were also observed. We also confirmed, using the 1.49L cloned line, that the mouse genetic background strongly affects ECM.