Evolution of the levels of human leukocyte antigen G (HLA-G) in Beninese infant during the first year of life in a malaria endemic area : using latent class analysis

Background: HLA-G, a non-classical HLA class I antigen, is of crucial interest during pregnancy by inhibiting maternal immune response. Its role during infections is discussed, and it has been described that high levels of soluble HLA-G during childhood increase the risk of malaria. To explore more precisely interactions between soluble HLA-G and malaria, latent class analysis was used to test whether distinct sub-populations of children, each with distinctive soluble HLA-G evolutions may suggest the existence of groups presenting variable malaria susceptibility. Method: A study was conducted in Benin from 2010 to 2013 and 165 children were followed from birth to 12 months. Evolution of soluble HLA-G was studied by the latent class method. Results: Three groups of children were identified: one with consistently low levels of soluble HLA-G during follow-up, a second with very high levels and a last intermediate group. In all groups, low birth weight, high number of malaria infections and high exposure to malaria transmission were associated with high level of soluble HLA-G. Placental malaria was not. Presence of soluble HLA-G in cord blood increased the probability of belonging to the highest trajectory. Conclusion: These results, together with previous ones, confirm the important role of HLA-G in the individual susceptibility to malaria. Assaying soluble HLA-G at birth could be a good indicator of newborns more fragile and at risk of infections during childhood

Modulation of immune cells and Th1/Th2 cytokines in insulin-treated type 2 diabetes mellitus.

Background: The role of the immune system in insulin resistance associated with type 2 diabetes has been suggested. Objectives: We assessed the profile of Th1/Th2 cytokines along with the frequencies of immune cells in insulin-treated type 2 diabetic patients (T2DP). Methods: 45 T2D patients and 43 age-matched healthy subjects were selected. Serum concentrations of T-helper type 1 (Th1) and Th2 cytokines and the frequencies of innate and adaptive immunity cells were assessed. Results: T2DP were hyperglycemic and showed high level of insulin, normal levels of triglycerides and total-cholesterol and without any change in HDL-cholesterol.Compared to healthy subjects, T2DP exhibited significant decreased frequencies of neutrophils, without any change in monocytes, eosinophils and natural killer cells. The percentages of total lymphocytes (CD3+) and CD8+-T-cells decreased whereas those of regulatory T-cells increased without any change in CD4+ T-cells in T2DP. Interestingly, the frequencies of effector CD4+-T and B-cells increased in T2DP. Serum concentrations of IL-2, IFN-\u3b3 and IL-4 decreased while IL-10 significantly enhanced in T2DP, suggesting a differentiation of CD4+T helper cells towards IL-10-producing- Teff-cells in these patients. Conclusion: Insulin-treated type 2 diabetes is associated with anti-inflammatory profile consistent with differentiation of CD4+-Th-cells towards IL-10-producing-Teff-cells, concomitant with increased frequencies of Treg and B-cells, and this may probably offer prevention against certain infections or autoimmune/inflammatory diseases

Malnutrition-modulated diabetes mellitus (MMDM): a state of review

Diabetes is a worldwide public health problem and is progressively increasing in Third World countries, particularly in African continent and Southern Asia due to low socio-economic standards. Since malnutrition and undernutrition with cassava consumption and cyanide intoxication have been thought to be the major cause of diabetes in tropical countries, WHO Expert Committee on Diabetes suggested, in its report, that the relationship between Malnutrition-Modulated Diabetes Mellitus (MMDM) and high cassava consumption should be clarified. Be that as it may, many recent studies have failed to establish a link between tropical diabetes and cassava malnutrition. In this paper, we shed light on MMDM in order to reach a consensus on its clinical, physiological and pathogenic features. Keywords: Tropical diabetes, cassava, immune disease, clinical features. International Journal of Biological and Chemical Sciences Vol. 2 (2) 2008: pp. 230-23

Calcium binding proteins immunohistochemistry and identification of neurons in the mammalian pineal gland of the African giant rat: Cricetomys gambianus.

The presence of true neurons in the rodent pineal gland is still a matter of controversy. In this work, by using immunohistochemistry with five antibodies against calcium-binding proteins (calbindin-D28k, calretinin, calmodulin, neurocalcin and S-100 beta) and Cricetomys gambianus, a rodent belonging to Muridae family living in Africa, we were able to illustrate the presence of neurons in the pineal gland. Anti-calbindin-D28k and anti-calretinin labelled neurons belonging to two neural ganglia. One ganglion was localized in the anterior part of the gland near the pineal stalk and the other one in the posterior portion of the organ. Immunoreactive neurons are medium in size (15-20 microns) and have long thick processes running towards the stalk. Calretinin and calbindin-D28k positive neurons stained with different intensities. Thin processes were detected by anti-calretinin whereas thick processes were preferentially calbindin-D28k positive. Neurocalcin labelled a few smaller neurons and many thin processes within the ganglion. Calmodulin could not be detected immunochemically. Within the ganglia many astrocytic processes were S-100 beta positive. The afferent and the efferent pathways of the pineal ganglia remain to be elucidated.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Ploidy level of the cultivated yams (Dioscorea cayenensis/D. rotundata complex) from Benin Republic as determined by chromosome counting and flow cytometry

The ploidy level of ninety Guinea yam (Dioscorea Cayenesis/D. rotundata complex) cultivars identified within Benin were determined by both chromosome counting from root tip cells and flow cytometry. Three different ploidy levels (4x,6x,8x,) were detected among the samples. Eighty cultivars were tetraploid, five were hexaploid, three were octoploidy and two 4x and 8x ploidy levels. Chromosome counts were in agreement with data from flow cytometry that provides an easier assay for ploidy analysis. Flow cytometry was found to be a reliable tool for rapid determination of ploidy level in yam

Th2-immune polarizing and anti-inflammatory properties of insulin are not effective in type 2 diabetic pregnancy

Background. The implication of the immune system in the physiopathology of pregnancy complicated by diabetes has been reported. Here, we investigated the effects of insulin treatment on the frequencies of immune cell subpopulations as well as T cell-derived cytokines in type 2 diabetic (T2D) pregnancy compared to gestational diabetes mellitus (GDM).Methods. Fifteen (15) women with GDM, twenty (20) insulin-treated T2D pregnant women, and twenty-five (25) pregnant controls were selected. Immune cell subpopulation frequencies were determined in blood using flow cytometry. The proliferative capacity of T cells was performed, and serum and cell culture supernatant cytokine levels were also quantified.Results. The frequencies of total CD3+ and CD4+ T cells and nonclassical monocytes significantly increased in insulin-treated T2D pregnant women compared to pregnant controls. The proportions of CD4+ T cells as well as B cells were significantly higher in women with GDM than in pregnant controls. GDM was associated with high frequencies of total CD3+ and CD4+ T cells and B cell expansion, suggesting a concomitant activation of cellular and humoral immunity. Concomitantly, Th1/Th2 ratio, determined as IFN-gamma/IL-4, was shifted towards Th1 phenotype in women with GDM and insulin-treated T2D pregnant women. Besides, isolated T cells elicited similar proliferative capacity in the three groups of women. Insulin-treated T2D pregnant women and women with GDM exhibited a low serum IL-10 level, without any change in the number of Treg cells.Conclusion. Our study showed that, despite insulin treatment, pregnant women with T2D displayed a proinflammatory status consistent with high proportions of CD3+ and CD4+ T cells, upregulation of Th1 cytokines, and low IL-10 production, suggesting a reduced immune-suppressive activity of regulatory T cells. However, GDM, although associated with proinflammatory status, has shown increased humoral immunity consistent with high proportion of CD19+ B cells. Thus, the lack of response to insulin in diabetes during pregnancy and clinical implications of these immunological parameters deserves further investigations

High plasma levels of HLA-G are associated with low birth weight and with an increased risk of malaria in infancy

Background: The immunosuppressive properties of HLA-G protein can create a tolerogenic environment that may allow Plasmodium falciparum to avoid host immune responses. There are known associations between high levels of circulating soluble HLA-G (sHLA-G) and either parasite or viral infections and it has been suggested that the induction of sHLA-G expression could be a mechanism via which infectious agents subvert host immune defence. The study presented here is the first to investigate the possible association between sHLA-G and malaria or malaria related risk factors in Benin. Methods: A parasitological and clinical follow-up of 165 mothers and their newborns from delivery through to one year of age was conducted in the Tori Bossito area of southern Benin. Plasma levels of sHLA-G were determined by ELISA in maternal peripheral and cord blood and again in infants' peripheral blood at 3, 6, 9 and 12 months of age. The associations between the levels of sHLA-G and malaria risk factors were investigated through multivariate mixed models. Results: Strong correlations were observed between the maternal and cord plasma concentrations of sHLA-G. In multivariate analyses, high cord plasma levels of sHLA-G were independently associated with (i) low birth weight and (ii) an increased risk of P. falciparum infection in infancy. Conclusion: These results show for the first time the possible involvement of sHLA-G in generating immune tolerance during pregnancy-associated malaria. Soluble HLA-G may represent a useful marker of susceptibility to malaria in infants and be associated with the higher susceptibility to infection observed for LBW children

Experimental huts trial of the efficacy of pyrethroids/piperonyl butoxide (PBO) net treatments for controlling multi-resistant populations of Anopheles funestus s.s. in Kpomè, Southern Benin

Open Access Journal; Published online: 13 June 2018Background: Insecticides resistance in Anopheles mosquitoes limits Long-Lasting Insecticidal Nets (LLIN) used for malaria control in Africa, especially Benin. This study aimed to evaluate the bio-efficacy of current LLINs in an area where An. funestus s.l. and An. gambiae have developed multi-resistance to insecticides, and to assess in experimental huts the performance of a mixed combination of pyrethroids and piperonyl butoxide (PBO) treated nets on these resistant mosquitoes. Methods: The study was conducted at Kpomè, Southern Benin. The bio-efficacy of LLINs against An. funestus and An. gambiae was assessed using the World Health Organization (WHO) cone and tunnel tests. A released/recapture experiment following WHO procedures was conducted to compare the efficacy of conventional LLINs treated with pyrethroids only and LLINs with combinations of pyrethroids and PBO. Prior to huts trials, we confirmed the level of insecticide and PBO residues in tested nets using high performance liquid chromatography (HPLC). Results: Conventional LLINs (Type 2 and Type 4) have the lowest effect against local multi-resistant An. funestus s.s. and An. coluzzii populations from Kpomè. Conversely, when LLINs containing mixtures of pyrethroids and PBO (Type 1 and Type 3) were introduced in trial huts, we recorded a greater effect against the two mosquito populations (P < 0.0001). Tunnel test with An. funestus s.s. revealed mortalities of over 80% with this new generation of LLINs (Type 1 and Type 3),while conventional LLINs produced 65.53 ± 8.33% mortalities for Type 2 and 71.25 ±7.92% mortalities for Type 4. Similarly, mortalities ranging from 77 to 87% were recorded with the local populations of An. coluzzii. Conclusion: This study suggests the reduced efficacy of conventional LLINs (Pyrethroids alone) currently distributed in Benin communities where Anopheles populations have developed multi-insecticide resistance. The new generation nets (pyrethroids+PBO) proved to be more effective on multi-resistant populations of mosquitoes