C1 Inhibitor, C3 Activator, IgG, IgA, and IgM Titers in Nigerian Sickle Cell Disease Patients with Plasmodium falciparum

Background: Sickle cell disease (HbSS) is a major health problem in Nigeria and ma-laria has been implicated as a leading cause of morbidity/mortality in sickle cell disease patients. Few reasons were put forward to explain the observed morbidity/mortality of HbSS subjects due to Plasmodium falciparum (P. falciparum) malaria. Objectives: To determine the level of immunoglobulin classes (IgM, IgA, and IgG) and regulators of complement system (C1 inhibitor and C3 activator) in Nigerian HbSS patients with and without P. falciparum parasitemia. Methods: A total of 64 subjects were considered, including 10 HbSS genotypic subjects with P. falciparum parasitemia (HbSS+PfM), 18 HbAA genotypic subjects with P. falciparum parasitemia (HbAA+PfM), 20 HbSS without P. falciparum parasitemia (HbSS-PfM), and 16 HbAA genotypic subjects with-out P. falciparum parasitemia (HbAA-PfM). IgM, IgA, IgG, C1 inhibitor, and C3 acti-vator titers were quantified by single radial immunodiffusion method. Results: The mean levels of IgG in HbSS+PfM (2373.90±1772.81mg/dl) and HbAA+PfM (1868.80±0.00mg/dl) were significantly higher compared with HbSS-PfM (644.55±171.15mg/dl) or HbAA-PfM (659.75±158.01mg/dl) patients. HbAA-PfM sub-jects had the lowest level of IgM (67.27±63.7mg/dl), though no significant difference was observed comparing mean levels of IgM between the four groups. IgA titer was significantly higher in HbSS-PfM patients (249.00±94.8mg/dl) compared with HbAA-PfM (p