Absolute Lymphocyte Counts, Cd3+ And Cd4+ T- Lymphocyte Subsets in Adult Patients with Sickle Cell Anaemia in Zaria, Nigeria

Abstract

Background: Impaired immunological function such as a reduction in the T cell component has been reported in patients with Sickle cell anaemia (SCA), leading to loss of both humoral and cell-mediated immunity. These patients become susceptible to infection leading to increased morbidity and mortality. Aims: To determine and review the level of Absolute lymphocyte counts (ALC) as well as CD3⁺ and CD4⁺ T-lymphocyte subsets in adult patients with SCA in our locality. Materials and Method: A comparative cross-sectional study of 60 participants consecutively enrolled as follows: 30 constituting the Study group (HbSS) in steady state (asymptomatic for at least 4 weeks) and 30 unmatched Controls (HbAA). Both HbSS patients and controls were HIV negative. Both groups also had automated complete blood counts and flowcytometry (BD FACS Count) for CD3⁺ and CD4⁺ T lymphocytes conducted. Results: The mean ALC (4.73 cells x 10⁹/l ±1.5) of the Study group was significantly higher than that of the Control (1.98 cells x 10⁹/l ±0.9; p =<0.0001). However, despite the significantly high ALC in the Study group, the mean CD3⁺ and CD4⁺ T lymphocyte subsets were reduced (2438µl ±843 and 1364µl ±521.3 respectively) compared to that of the Control (2673 µl ±790, p=0.27 and 1697 µl ±569, p=0.022 respectively). In contrast CD3⁺ and CD4⁺ cells were significantly correlated with ALC (r 0.792, p= 0.0001 and 0.641, p= 0.0001 respectively). Conclusion: Patients with Sickle Cell Anaemia in the study, show a reduced CD3⁺ and CD4⁺ T cell count despite a high
peripheral absolute lymphocyte count which may be responsible for increased susceptibility to infections in SCA. In light of this peculiar immune profile demonstrated in the study, it is therefore recommended to consider the functionality of CD4⁺ T lymphocytes, the potential of other peripheral blood mononuclear cells as predictive of infection and splenic status in patients with Sickle Cell anaemia for further studies.