Browsing by Author "Payne, Helen"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Observed full blood count and lymphocyte subset values in a cohort of clinically healthy South African children from a semi-informal settlement in Cape Town
    (Health & Medical Publishing Group, 2015-09) Lawrie, Denise; Payne, Helen; Nieuwoudt, Martin; Glencross, Deborah Kim
    Background. The paediatric full blood count and lymphocyte subset reference intervals used by the National Health Laboratory Service (NHLS), South Africa (SA), are taken from two international reference interval publications. Differences in reference intervals suggest that international data sets may not be appropriate for use in SA. Objective. To study immunohaematological values of a group of clinically healthy children from an informal settlement in Cape Town, SA, to assess whether international paediatric reference intervals used by the NHLS are appropriate. Methods. A cross-sectional study of 207 female and 174 male HIV-uninfected children living in an informal settlement in Cape Town was performed. Full blood counts, automated differential counts and lymphocyte subset analysis were done using internationally accepted technologies. Data were categorised by age and reference intervals compiled using medians and 95% confidence intervals (CIs). Gender comparisons were calculated by non-parametric tests. Results. Although median and 95% CI values differed slightly, physiological trends for red cell, platelet, white blood cell differential and lymphocyte subsets were similar to international reference intervals currently in use at the NHLS. Benign ethnic neutropenia was not a significant finding, and gender-specific intervals were not necessary until 12 years of age. Lower overall median values for haemoglobin and haematocrit, and higher median values for mean cell volume and red cell distribution width, were noted. Assessment of haemoglobin, red cell distribution width and calculated Mentzer ratios suggested underlying iron deficiency in 14.2% of participants. Conclusion. Paediatric immunohaematological reference intervals observed in this study are similar to, and support continued use of, international paediatric reference intervals. Underlying iron and related nutritional deficiencies may be contributing to lower haemoglobin levels noted in local children. A larger nationwide study, including all ethnic groups, is recommended.
  • Thumbnail Image
    Item
    Thymic output and CD4 T-cell reconstitution in HIV-infected children on early and interrupted antiretroviral treatment : evidence from the children with HIV early antiretroviral therapy trial
    (Frontiers, 2017-09) Lewis, Joanna; Payne, Helen; Walker, A. Sarah; Otwombe, Kennedy; Gibb, Diana M.; Babiker, Abdel G.; Panchia, Ravindre; Cotton, Mark F.; Violari, Avy; Klein, Nigel; Callard, Robin E.
    Objectives: Early treatment of HIV-infected children and adults is important for optimal immune reconstitution. Infants’ immune systems are more plastic and dynamic than older children’s or adults’, and deserve particular attention. This study aimed to understand the response of the HIV-infected infant immune system to early antiretroviral therapy (ART) and planned ART interruption and restart. Methods: Data from HIV-infected children enrolled the CHER trial, starting ART aged between 6 and 12 weeks, were used to explore the effect of ART on immune reconstitution. We used linear and non-linear regression and mixed-effects models to describe children’s CD4 trajectories and to identify predictors of CD4 count during early and interrupted ART. Results: Early treatment arrested the decline in CD4 count but did not fully restore it to the levels observed in HIV-uninfected children. Treatment interruption at 40 or 96 weeks resulted in a rapid decline in CD4 T-cells, which on retreatment returned to levels observed before interruption. Naïve CD4 T-cell count was an important determinant of overall CD4 levels. A strong correlation was observed between thymic output and the stable CD4 count both before and after treatment interruption. Conclusion: Early identification and treatment of HIV-infected infants is important to stabilize CD4 counts at the highest levels possible. Once stabilized, children’s CD4 counts appear resilient, with good potential for recovery following treatment interruption. The naïve T-cell pool and thymic production of naive cells are key determinants of children’s CD4 levels.