Association between CD4 T cell counts and the immune status among adult critically ill HIV-negative patients in intensive care units in Uganda

Abstract

Background: Cluster of differentiation 4 (CD4) T cells play a central role in regulation of adaptive T cell-mediated immune responses. Low CD4 T cell counts are not routinely reported as a marker of immune deficiency among HIV-negative individuals, as is the norm among their HIV positive counterparts. Despite evidence of mortality rates as high as 40% among Ugandan critically ill HIV-negative patients, the use of CD4 T cell counts as a measure of the immune status has never been explored among this population. This study assessed the immune status of adult critically ill HIV-negative patients admitted to Ugandan intensive care units (ICUs) using CD4 T cell count as a surrogate marker. Methods: A multicentre prospective cohort was conducted between 1st August 2017 and 1st March 2018 at four Ugandan ICUs. A total of 130 critically ill HIV negative patients were consecutively enrolled into the study. Data on sociodemographics, clinical characteristics, critical illness scores, CD4 T cell counts were obtained at baseline and mortality at day 28. Results: The mean age of patients was 45± 18 years (mean±SD) and majority (60.8%) were male. After a 28-day follow up, 71 [54.6%, 95% CI (45.9-63.3)] were found to have CD4 counts less than 500 cells/mm³, which were not found to be significantly associated with mortality at day 28, OR (95%) 1 (0.4–2.4), p = 0.093. CD4 cell count receiver operator characteristic curve (ROC) area was 0.5195, comparable to APACHE II ROC area 0.5426 for predicting 24-hour mortality. Conclusions: CD4 T cell counts were generally low among HIV-negative critically ill patients. Low CD4 T cells did not predict ICU mortality at day 28. CD4 T cell counts were not found to be inferior to APACHE II score in predicting 24 hour ICU mortality.