[Tuberculosis Abscess of the Chest Wall on an Immunocompetent Patient in the Teaching Hospital of Dakar (Senegal)]

Tuberculosis remains a problem of public health, in spite of the numerous significant advances noted in the diagnosis in recent years. The involvement of the thoracic wall is a rare extra lung shape. Its clinical presentation is not specific and a collected thoracic tumefaction is the main clinical demonstration. The diagnosis is improved by the use of non-invasive tools such as the Xpert MTB/Rif® test with a good sensibility on the pus. Medical care is based on medical treatment and sometimes associated with surgical treatment.

[Profiles of IgG responses against CSP, GLURP and LSA-3NR2 in urban malaria (Dakar): relations with haemoglobin levels and parasite densities]

Malaria remains a major health problem in sub- Saharan African countries despite substantial decreases in morbidity and mortality due to sustained control programs. Vaccines candidates were mainly tested in rural endemic setting; however increasing proportion of the population is living in urban area. Evaluation of the qualitative or quantitative immune responses to key targets of anti-Plasmodium immunity requires further investigation in urban area. In a cohort of 144 patients with mild malaria living in Dakar, we analyzed IgG responses against target antigens of P. falciparum: CSP, LSA-3NR2 and GLURP by ELISA. A mean age of 15 yrs (4-65 yrs) was found and patients were separated in 59 adults (<15yrs) and 85 children (≤15 yrs). Parasites densities (0,01-15%) did not differ between the two age groups. In contrast, haemoglobin levels appeared lower in children (4.5-16.6 g/dl) (p<0.01). For the immune results, the most recognized antigens were GLURP and CSP compared to LSA-3NR2. Levels of IgG against these antigens were significantly different between the two age groups and they were positively correlated (rho = 0.32; p<0.001). In addition, levels of IgG anti-GLURP were associated with low parasitemia (≤1%) and absence of anemia (≥11g/dl), particularly in adults (p<0.001). In a multiple regression analysis, no significant relationship was found between parasite densities and IgG responses against all the tested antigens. Our study shows the implication of IgG anti-GLURP in humoral immune response against the parasite. The present work contributes to determine IgG levels that can be used as relevant immunologic biomarkers in urban clinical malaria.

[IgG responses to candidate malaria vaccine antigens in the urban area of Dakar (Senegal): evolution according to age and parasitemia in patients with mild symptoms]

Malaria remains a major problem in African countries despite substantial decreases in morbidity and mortality due to sustained control programs. Studies for the evaluation of qualitative or quantitative Ab responses to key targets of anti-plasmodium immunity were mostly done in rural endemic setting compared to urban area. In a cohort of 200 patients with mild malaria and living in Dakar, we analyze total and subclasses IgG responses to a panel of P. falciparum blood stage antigens: MSP1p19, MSP3, EB200, GST-5 and R23. A mean age of 15 yrs (4 to 56 yrs) and parasitemia between 0.1 to 17% were found. Levels of IgG anti-MSP3 were higher in patients with low parasitemia (≤1%) and appear negatively correlated to parasite densities (Rho =. 0.54; p= 0.021). This correlation is more significant in children (≤ 15 yrs). In addition, an increase of IgG responses against MSP1p19 is highly observed in adults having a parasitemia less than 1%. In those patients, we find that IgG1 subclasses were predominant (p <0.01). Our study shows an association between Ab responses and parasitemia. This association is dependant to IgG anti-MSP3 in children and IgG anti-MSP1p19 in adults living in urban area.

[Specific antibodies to Plasmodium falciparum antigens in immune patients: IV--Cross-sectional analysis of anti-P. falciparum Ab responses in a mesoendemic zone of transmission in Sine-Saloum region]

We report here a comparative study of specific antibody responses to blood stages of P. falciparum in 100 individuals aged from 3 to 76 years, living in the village of Ndiop (an area where parasite transmission is approximately 20 infective bites per year). We have used 2 antigen preparations: crude merozoites and infected erythrocyte ghosts (GRp). High specific antibody responses were found in the villagers' sera, with IgG levels being significantly higher than those directed to the whole P. falciparum schizont Ag preparation; the reverse was found for IgM responses. An imbalanced IgG subclass Ab response was evidenced towards cytophilic IgG1+/gG3+ responses rather than to IgG2+/lgG4+. Mean levels of antibodies increased significantly with age and a strong relationship was evidenced in individual levels of Ab responses towards all the Ag studied. Investigation of the morbidity, recorded as the number of confirmed clinical accesses, underlined a significant inverse relationship only with the levels of IgG to GRp. Taken together, these results proved usefullness of crude P. falciparum Ags for immuno-epidemiological related studies and underlined GRp as a particular target of Ab responses.

Imbalanced distribution of IgM and IgG antibodies against Plasmodium falciparum antigens and merozoite surface protein-1 (MSP1) in pregnancy

In malaria endemic areas, pregnancy is assumed to be associated with a specific reduction in immunity to Plasmodium falciparum malaria. To understand some of the mechanisms which underlie such a poor immunity, we have attempted to examine the frequency and distribution of IgM and IgG antibodies to a crude antigenic extract of parasitized erythrocytes and to the merozoite surface protein-1 (MSP1), in a population of mothers compared to control non-pregnant women, all living in Dakar and suburbs. Specifically, this work describes: (i) the responses of mothers and control women; (ii) the balance between IgM and IgG responses; and (iii) responses to malarial antigen and to MSP1. An unexpected balance between P. falciparum-specific IgM and IgG is shown, associated with a substantial increase in anti-MSP1 IgM, and a decrease in anti-MSP1 IgG in parturients.