Although aflatoxins (AFs) have been shown to be immune-suppressive agents in animals, the potential role of AFs in modifying the distribution and function of leukocyte subsets in humans has never been assessed. We examined the cellular immune status of 64 Ghanaians in relation to levels of aflatoxin B1 (AFB1)–albumin adducts in plasma. The percentages of leukocyte immunophenotypes in peripheral blood, CD4+ T cell proliferative response, CD4+ Th and CD8+ T cell cytokine profiles and monocyte phagocytic activity were measured using flow cytometry. NK cell cytotoxic function was determined by perforin and tumor necrosis factor-α expression in CD3−CD56+ NK cells. AFB1–albumin adducts levels ranged from 0.3325 to 2.2703 (mean = 0.9972 ± 0.40, median = 0.9068) pmol mg−1 albumin. Study participants with high AFB1 levels had significantly lower percentages of CD3+ and CD19+ cells that showed the CD69+ activation marker (CD3+CD69+ and CD19+CD69+) than participants with low AFB1 levels (P = 0.002 for both). Also, the percentages of CD8+ T cells that contained perforin or both perforin and granzyme A were significantly lower in participants with high AFB1 levels compared with those with low AFB1 (P = 0.012 for both). Low levels of CD3+CD69+ (r = −0.32, P = 0.016) and CD19+CD69+ (r = −0.334, P = 0.010) cells were significantly associated with high AFB1 levels using correlation analysis. By multivariate analysis, there were strong negative correlations between the percentages of these cells (CD3+CD69+: b = −0.574, P = 0.001, and CD19+CD69+: b = −0.330, P = 0.032) and AFB1 levels. These alterations in immunological parameters in participants with high AFB1 levels could result in impairments in cellular immunity that could decrease host resistance to infections.
12 January 2010 in Tropical Medicine & International Health
Both aflatoxin and the human immunodeficiency virus (HIV) cause immune suppression and millions of HIV-infected people in developing countries are chronically exposed to aflatoxin in their diets. We investigated the possible interaction of aflatoxin and HIV on immune suppression by comparing immune parameters in 116 HIV positive and 80 aged-matched HIV negative Ghanaians with high (0.91 pmol/mg albumin) and low (0.91 pmol/mg albumin) aflatoxin B1 albumin adduct (AF-ALB) levels. AF-ALB levels and HIV viral load were measured in plasma and the percentages of leukocyte immunophenotypes and cytokine expression were determined using flow cytometry. The cross-sectional comparisons found that (1) among both HIV positive and negative participants, high AF-ALB was associated with lower perforin expression on CD8+ T-cells (); (2) HIV positive participants with high AF-ALB had significantly lower percentages of CD4+ T regulatory cells (Tregs;) and naive CD4+ T cells () compared to HIV positive participants with low AF-ALB; and (3) HIV positive participants with high AF-ALB had a significantly reduced percentage of B-cells () compared to those with low AF-ALB. High AF-ALB appeared to accentuate some HIV associated changes in T-cell phenotypes and in B-cells in HIV positive participants.
1 January 2015 in North American Journal of Medical Sciences
Background: Cervical cancer is the second most common cancer among women worldwide and is the leading cause of deaths in developing countries. Despite the strong evidence that cervical cancer screening results in decreased mortality from this disease, the uptake for cervical screening among Jamaican women remains low. Aims : This study was carried out to identify factors associated with Jamaican women's decisions to screen for cervical cancer. Materials and Methods: Cross-sectional descriptive study of 403 women aged 19 years and older from Portland, Jamaica. An interviewer-administered questionnaire assessed the women's cervical cancer screening history, as well as their knowledge, attitudes, and practices regarding the disease and screening. Results: Of the 403 women interviewed, 66% had a Papanicolaou (Pap) smear and only 16% had a Pap test within the past year. Significant predicators of uptake of screening were being married, age, parity, discussing cancer with health provider, perception of consequences of not having a Pap smear, and knowing a person with cervical cancer. Women who did not know where to go for a Pap smear were 85% less likely to have been screened (prevalence odds ratio (POR): 0.15, 95% confidence interval (CI): 0.04, 0.52). Conclusions: This study showed suboptimal uptake of cervical cancer screening among Jamaican women. Multipronged approaches are needed to address barriers to screening, as well as identify and support conditions that encourage women's use of reproductive health services, thereby reducing incidence and mortality rates from cervical cancer.
Outbreaks of vector-borne diseases (VBDs) such as dengue and malaria can overwhelm health systems in resource-poor countries. Environmental management strategies that reduce or eliminate vector breeding sites combined with improved personal prevention strategies can help to significantly reduce transmission of these infections. The aim of this study was to assess the knowledge, attitudes, and practices (KAPs) of residents in western Jamaica regarding control of mosquito vectors and protection from mosquito bites. A cross-sectional study was conducted between May and August 2010 among patients or family members of patients waiting to be seen at hospitals in western Jamaica. Participants completed an interviewer-administered questionnaire on sociodemographic factors and KAPs regarding VBDs. KAP scores were calculated and categorized as high or low based on the number of correct or positive responses. Logistic regression analyses were conducted to identify predictors of KAP and linear regression analysis conducted to determine if knowledge and attitude scores predicted practice scores. In all, 361 (85 men and 276 women) people participated in the study. Most participants (87%) scored low on knowledge and practice items (78%). Conversely, 78% scored high on attitude items. By multivariate logistic regression, housewives were 82% less likely than laborers to have high attitude scores; homeowners were 65% less likely than renters to have high attitude scores. Participants from households with 1 to 2 children were 3.4 times more likely to have high attitude scores compared with those from households with no children. Participants from households with at least 5 people were 65% less likely than those from households with fewer than 5 people to have high practice scores. By multivariable linear regression knowledge and attitude scores were significant predictors of practice score. The study revealed poor knowledge of VBDs and poor prevention practices among participants. It identified specific groups that can be targeted with vector control and personal protection interventions to decrease transmission of the infections.