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15. Low rate of mother-to-child transmission of HIV-1 after nevirapine intervention in a pilot public health program in Yaounde, Cameroon

Author

Ayouba, Ahidjo, Tene, Gilbert, Cunin, Patrick, Foupouapouognigni, Yacouba, Menu, Elisabeth, Kfutwah, Anfumbom, Thonnon, Jocelyn, Scarlatti, Gabriella, Monny-Lobe, Marcel, Eteki, Nicole, Kouanfack, Charles, Tardy, Michele, Leke, Robert, Nkam, Maurice, Nlend, Anne E., Barre-Sinoussi, Francoise, Martin, Paul M.V., and Nerrienet, Eric

Subjects
Yaounde, Cameroon -- Health aspects, HIV infection -- Research, HIV infection -- Care and treatment, Nevirapine -- Research, Maternal-fetal exchange -- Research, Health
Published
2003

18. Haematological reference intervals for healthy adults in Bamenda, Cameroon

Author

Fondoh, Victor N., primary, Fondoh, Richard M., additional, Awasom, Charles N., additional, Edith, Pefoule L., additional, Ntungwen, Winlove A., additional, Roland, Bong, additional, Enow-Tanjong, Rebeca, additional, Njukeng, Patrick, additional, Shang, Judith, additional, Egbengu, Egbe P., additional, Maruta, Talkmore, additional, Etheline, Akazong, additional, Leke, Robert, additional, Leo, Ayuk, additional, and Nsame, Denis, additional

Published
2020
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21. Acceptability of intrapartum HIV counselling and testing in Cameroon

Author

Tebeu Pierre M, Nana Philip N, Fomulu Nelson, Mbopi-Keou Francois X, Mbu Enow R, Kongnyuy Eugene J, Tonye Rebecca N, and Leke Robert JI

Subjects
Gynecology and obstetrics, RG1-991
Abstract

Abstract Background To assess the acceptability of intrapartum HIV testing and determine the prevalence of HIV among labouring women with unknown HIV status in Cameroon. Method The study was conducted in four hospitals (two referral and two districts hospitals) in Cameroon. Labouring women with unknown HIV status were counselled and those who accepted were tested for HIV. Results A total of 2413 women were counselled and 2130 (88.3%) accepted to be tested for HIV. Of the 2130 women tested, 214 (10.1%) were HIV positive. Acceptability of HIV testing during labour was negatively associated with maternal age, parity and number of antenatal visits, but positively associated with level of education. HIV sero-status was positively associated with maternal age, parity, number of antenatal visits and level education. Conclusion Acceptability of intrapartum HIV testing is high and the prevalence of HIV is also high among women with unknown HIV sero-status in Cameroon. We recommend an opt-out approach (where women are informed that HIV testing will be routine during labour if HIV status is unknown but each person may decline to be tested) for Cameroon and countries with similar social profiles.

Published
2009
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22. Gynaecological morbidity among HIV positive pregnant women in Cameroon

Author

Nana Philip N, Tonye Rebecca N, Mbopi-Keou FX, Kongnyuy Eugene J, Mbu Enow R, and Leke Robert JI

Subjects
Gynecology and obstetrics, RG1-991
Abstract

Abstract Objective To compare the prevalence of gynaecological conditions among HIV infected and non-infected pregnant women. Methods Two thousand and eight (2008) pregnant women were screened for HIV, lower genital tract infections and lower genital tract neoplasia at booking antenatal visit. Results About 10% (198/2008) were HIV positive. All lower genital tract infections except candidiasis were more prevalent among HIV positive compared to HIV negative women: vaginal candidiasis (36.9% vs 35.4%; p = 0.678), Trichomoniasis (21.2% vs 10.6%; p < 0.001), gonorrhoea (10.1% vs 2.5%; p < 0.001), bacterial vaginosis (21.2% vs 15.2%; p = 0.026), syphilis (35.9% vs 10.6%; p < 0.001), and Chlamydia trachomatis (38.4% vs 7.1%; p < 0.001). Similarly, HIV positive women more likely to have preinvasive cervical lesions: low-grade squamous intraepithelial lesion (SIL) (18.2% vs 4.4%; p < 0.001) and high-grade squamous intraepithelial lesion (12.1% vs 1.5%; p < 0.001). Conclusion We conclude that (i) sexually transmitted infections (STIs) are common in both HIV positive and HIV negative pregnant women in Cameroon, and (ii) STIs and preinvasive cervical lesions are more prevalent in HIV-infected pregnant women compared to their non-infected compatriots. We recommend routine screening and treatment of STIs during antenatal care in Cameroon and other countries with similar social profiles.

Published
2008
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25. Influence of intermittent preventive treatment on antibodies to VAR2CSA in pregnant Cameroonian women

Author

Babakhanyan, Anna, Tutterrow, Yeung L, Bobbili, Naveen, Salanti, Ali, Wey, Andrew, Fogako, Josephine, Leke, Robert J, Leke, Rose G F, Taylor, Diane Wallace, Babakhanyan, Anna, Tutterrow, Yeung L, Bobbili, Naveen, Salanti, Ali, Wey, Andrew, Fogako, Josephine, Leke, Robert J, Leke, Rose G F, and Taylor, Diane Wallace

Abstract

Intermittent preventive treatment (IPT) and insecticide-treated bed nets are the standard of care for preventing malaria in pregnant women. Since these preventive measures reduce exposure to malaria, their influence on the antibody (Ab) response to the parasite antigen VAR2CSA was evaluated in pregnant Cameroonian women exposed to holoendemic malaria. Ab levels to full-length VAR2CSA (FV2), variants of the six Duffy binding like (DBL) domains, and proportion of high avidity Ab to FV2 were measured longitudinally in 92 women before and 147 women after IPT. As predicted, reduced exposure interfered with acquisition of Ab in primigravidae, with 71% primigravidae being seronegative to FV2 at delivery. Use of IPT for > 13 weeks by multigravidae resulted in 26% of women being seronegative at delivery and a significant reduction in Ab levels to FV2, DBL5, DBL6, proportion of high avidity Ab to FV2, and number of variants recognized. Thus, in women using IPT important immune responses were not acquired by primigravidae and reduced in a portion of multigravidae, especially women with one to two previous pregnancies. Longitudinal data from individual multigravidae on IPT suggest that lower Ab levels most likely resulted from lack of boosting of the VAR2CSA response and not from a short-lived Ab response.

Published
2016

28. Comparison of the specificity of antibodies to VAR2CSA in Cameroonian multigravidae with and without placental malaria:a retrospective case-control study

Author

Babakhanyan, Anna, Fang, Rui, Wey, Andrew, Salanti, Ali, Sama, Grace, Efundem, Canisia, Leke, Robert J I, Chen, John J, Leke, Rose G F, Taylor, Diane W, Babakhanyan, Anna, Fang, Rui, Wey, Andrew, Salanti, Ali, Sama, Grace, Efundem, Canisia, Leke, Robert J I, Chen, John J, Leke, Rose G F, and Taylor, Diane W

Abstract

BACKGROUND: Antibodies (Ab) to VAR2CSA prevent Plasmodium falciparum-infected erythrocytes from sequestrating in the placenta, i.e., prevent placental malaria (PM). The specificity of Ab to VAR2CSA associated with absence of PM is unknown. Accordingly, differences in the specificity of Ab to VAR2CSA were compared between multigravidae with and without PM who had Ab to VAR2CSA.METHODS: In a retrospective case-control study, plasma collected from Cameroonian multigravidae with (n = 96) and without (n = 324) PM were screened in 21 assays that measured antibody levels to full length VAR2CSA (FV2), individual VAR2CSA DBL domains, VAR2CSA domains from different genetic backgrounds (variants), as well as proportion of high avidity Ab to FV2.RESULTS: Multigravidae with and without PM had similar levels of Ab to FV2, the six VAR2CSA DBL domains and different variants, while the proportion of high avidity Ab to FV2 was significantly higher in women without PM at delivery (p = 0.0030) compared to women with PM. In a logistic regression model adjusted for gravidity and age, the percentage of high avidity Ab to FV2 was associated with reduced likelihood of PM in multigravidae. A 5 % increase in proportion of high avidity Ab to FV2 was associated with a nearly 15 % lower likelihood of PM.CONCLUSION: Ab avidity to FV2 may be an important indicator of immunity to PM.

Published
2015

31. The antibody response of pregnant Cameroonian women to VAR2CSA ID1-ID2a, a small recombinant protein containing the CSA-binding site

Author

Babakhanyan, Anna, Leke, Rose G F, Salanti, Ali, Bobbili, Naveen, Gwanmesia, Philomina, Leke, Robert J I, Quakyi, Isabella A, Chen, John J, Taylor, Diane Wallace, Babakhanyan, Anna, Leke, Rose G F, Salanti, Ali, Bobbili, Naveen, Gwanmesia, Philomina, Leke, Robert J I, Quakyi, Isabella A, Chen, John J, and Taylor, Diane Wallace

Abstract

In pregnant women, Plasmodium falciparum-infected erythrocytes expressing the VAR2CSA antigen bind to chondroitin sulfate A in the placenta causing placental malaria. The binding site of VAR2CSA is present in the ID1-ID2a region. This study sought to determine if pregnant Cameroonian women naturally acquire antibodies to ID1-ID2a and if antibodies to ID1-ID2a correlate with absence of placental malaria at delivery. Antibody levels to full-length VAR2CSA and ID1-ID2a were measured in plasma samples from 745 pregnant Cameroonian women, 144 Cameroonian men, and 66 US subjects. IgM levels and IgG avidity to ID1-ID2a were also determined. As expected, antibodies to ID1-ID2a were absent in US controls. Although pregnant Cameroonian women developed increasing levels of antibodies to full-length VAR2CSA during pregnancy, no increase in either IgM or IgG to ID1-ID2a was observed. Surprisingly, no differences in antibody levels to ID1-ID2a were detected between Cameroonian men and pregnant women. For example, in rural settings only 8-9% of males had antibodies to full-length VAR2CSA, but 90-96% had antibodies to ID1-ID2a. In addition, no significant difference in the avidity of IgG to ID1-ID2a was found between pregnant women and Cameroonian men, and no correlation between antibody levels at delivery and absence of placental malaria was found. Thus, the response to ID1-ID2a was not pregnancy specific, but predominantly against cross-reactivity epitopes, which may have been induced by other PfEMP1 antigens, malarial antigens, or microbes. Currently, ID1-ID2a is a leading vaccine candidate, since it binds to the CSA with the same affinity as the full-length molecule and elicits binding-inhibitory antibodies in animals. Further studies are needed to determine if the presence of naturally acquired cross-reactive antibodies in women living in malaria endemic countries will alter the response to ID1-ID2a following vaccination with ID1-ID2a.

Published
2014

33. High levels of antibodies to multiple domains and strains of VAR2CSA correlate with the absence of placental malaria in Cameroonian women living in an area of high Plasmodium falciparum transmission

Author

Tutterrow, Yeung L, Avril, Marion, Singh, Kavita, Long, Carole A, Leke, Robert J, Sama, Grace, Salanti, Ali, Smith, Joseph D, Leke, Rose G F, Taylor, Diane W, Tutterrow, Yeung L, Avril, Marion, Singh, Kavita, Long, Carole A, Leke, Robert J, Sama, Grace, Salanti, Ali, Smith, Joseph D, Leke, Rose G F, and Taylor, Diane W

Abstract

Placental malaria, caused by sequestration of Plasmodium falciparum-infected erythrocytes in the placenta, is associated with increased risk of maternal morbidity and poor birth outcomes. The parasite antigen VAR2CSA (variant surface antigen 2-chondroitin sulfate A) is expressed on infected erythrocytes and mediates binding to chondroitin sulfate A, initiating inflammation and disrupting homeostasis at the maternal-fetal interface. Although antibodies can prevent sequestration, it is unclear whether parasite clearance is due to antibodies to a single Duffy binding-like (DBL) domain or to an extensive repertoire of antibodies to multiple DBL domains and allelic variants. Accordingly, plasma samples collected longitudinally from pregnant women were screened for naturally acquired antibodies against an extensive panel of VAR2CSA proteins, including 2 to 3 allelic variants for each of 5 different DBL domains. Analyses were performed on plasma samples collected from 3 to 9 months of pregnancy from women living in areas in Cameroon with high and low malaria transmission. The results demonstrate that high antibody levels to multiple VAR2CSA domains, rather than a single domain, were associated with the absence of placental malaria when antibodies were present from early in the second trimester until term. Absence of placental malaria was associated with increasing antibody breadth to different DBL domains and allelic variants in multigravid women. Furthermore, the antibody responses of women in the lower-transmission site had both lower magnitude and lesser breadth than those in the high-transmission site. These data suggest that immunity to placental malaria results from high antibody levels to multiple VAR2CSA domains and allelic variants and that antibody breadth is influenced by malaria transmission intensity.

Published
2012

35. Cord Blood Vγ2Vδ2 T Cells Provide a Molecular Marker for the Influence of Pregnancy-Associated Malaria on Neonatal Immunity

Author

Cairo, Cristiana, primary, Longinaker, Nyaradzo, additional, Cappelli, Giulia, additional, Leke, Rose G. F., additional, Ondo, Manuel Mve, additional, Djokam, Rosine, additional, Fogako, Josephine, additional, Leke, Robert J., additional, Sagnia, Bertrand, additional, Sosso, Samuel, additional, Colizzi, Vittorio, additional, and Pauza, C. David, additional

Published
2013
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37. High Levels of Antibodies to Multiple Domains and Strains of VAR2CSA Correlate with the Absence of Placental Malaria in Cameroonian Women Living in an Area of High Plasmodium falciparum Transmission

Author

Tutterrow, Yeung L., primary, Avril, Marion, additional, Singh, Kavita, additional, Long, Carole A., additional, Leke, Robert J., additional, Sama, Grace, additional, Salanti, Ali, additional, Smith, Joseph D., additional, Leke, Rose G. F., additional, and Taylor, Diane W., additional

Published
2012
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40. Longitudinal Studies of Plasmodium falciparum Malaria in Pregnant Women Living in a Rural Cameroonian Village with High Perennial Transmission

Author

Leke, Rose F. G., primary, Bioga, Jude D., additional, Nama, Charles, additional, Tchinda, Viviane, additional, Fouda, Genevieve G., additional, Sama, Grace, additional, Bomback, Germaine, additional, Gwanmesia, Philomina, additional, Bobbili, Naveen, additional, Fogako, Josephine, additional, Zhou, James, additional, Diouf, Ababacar, additional, Leke, Robert J. I., additional, Taylor, Diane Wallace, additional, and Megnekou, Rosette, additional

Published
2010
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44. Plasmodium falciparum and placental cytokine profiles among pregnant women in relation to their HIV-1 status: possible implications for mother-to-child transmission (MTCT) of HIV-1 in Cameroon

Author

Kfutwah, Anfumbom, primary, Mary, Jean Yves, additional, Lemen, Brigitte, additional, Leke, Robert, additional, Rousset, Dominique, additional, Barré-Sinoussi, Françoise, additional, Nerrienet, Eric, additional, Menu, Elisabeth, additional, and Ayouba, Ahidjo, additional

Published
2008
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