Clinical utilization of Chondroitin Sulphate-A to determine the susceptibility of pregnant women to malaria
People living in areas with stable transmission of Plasmodium falciparum parasites acquire protective immunity to malaria following multiple disease episodes. Immunity acquired this way is mediated by IgG with specificity for parasite-encoded, clonally variant surface antigens (VSA) on the surface of infected erythrocytes (IEs). However, women in endemic areas become susceptible to P. falciparum infection during pregnancy, particularly for the first time, regardless of acquired protective immunity. Aggregation of erythrocytes infected by P. falciparum in the intervillous spaces of the placenta using chondroitin sulphate A (CSA) as the dominant placental adhesion receptor has been identified. Chondroitin sulfate A is a sulfated glycosaminoglycan (GAG) composed of a chain of alternating sugars. It is usually found attached to proteins as part of a proteoglycan. This study sought to investigate the role of chondroitin sulphate A in malaria susceptibility in pregnant women. A total of 160 clients attending two selected health facilities, namely Kaneshie Polyclinic and Our Lady of Grace Hospital, were recruited. They were stratified into three groups: Pregnant women with malaria (n=80), non-pregnant women with malaria (n=40) and pregnant women without malaria (n=40). Full blood count (FBC), malaria RDT, thick film for malaria parasites and ELISA for chondroitin sulphate-A concentration were conducted for each volunteer. The mean haemoglobin count in pregnant women with malaria was 9.6 ± 1.4 g/dl and that of non-pregnant women with malaria was 10.3 ± 1.6 g/dL and the pregnant women without malaria was 11.5 ± 1.1 g/dL. The median CSA concentration in non-pregnant women with malaria was 2.24 ng/mL; that of pregnant women with malaria was 50.76 ng/mL, and pregnant women without malaria was 44.94 ng/mL. There were significant differences between non-pregnant women with malaria and pregnant women with malaria (P=0.0001) and also between non-pregnant with malaria and pregnant women with no malaria (P=0.0001) but no difference between pregnant women with malaria and pregnant women without malaria (P=0.084). Haemoglobin and haematocrit concentrations were significantly associated with malaria infection. The parasite count in pregnant women with malaria compared with that in non-pregnant women with malaria was significantly lower (P=0.0001). Malaria infection was associated with reduction in haemoglobin concentration, which worsened when pregnancy was present. In conclusion, CSA was elicited in pregnant women but had inverse correlation with peripheral malaria parasitaemia.
A thesis submitted in fulfillment of the requirements for the degree of Master of Philosophy in the Department of Clinical Microbiology, School of Medical Sciences, College of Health Sciences, 2015