Quantitative computer image analysis of chondroitin sulfate A expression in placentas infected with Plasmodium falciparum

Most pathological conditions resulting from infection with the human malari a parasite Plasmodium falciparum occur as a consequence of the sequestratio n by several adhesion molecules of parasite-infected red blood cells (IRBCs ). Recent reports have provided evidence that placental vascular endothelia l ligands for IRBCs were mostly restricted to chondroitin sulfate A (CSA). The expression of CSA in malaria-infected placentas was investigated in a p rospective case-control study in a hypoendemic area (Dakar, Senegal). The t issue distribution of CSA was measured in the terminal villi by immunostain ing combined with image processing in 20 infected and 20 noninfected frozen sections of placenta. The villous surface immunostained by anti-CSA antibo dy was higher in infected than in noninfected placentas (p<0.03), in placen tas with active infection than in those with past chronic infection (p<0.05 ), and in infected placentas with positive imprints than in those with nega tive imprints (not significant; p=0.06). Labeling was found in the extracel lular matrix and in endothelial and stromal cells of all the placentas. Syn cytiotrophoblast immunostaining was detected in all placentas associated wi th active or active chronic infection (n=7) but in only 4/13 placentas with past chronic infection (p<0.01). The presence of P. falciparum in the impr int was significantly correlated with immunostaining of CSA in syncytiotrop hoblasts (p=0.003). These results suggest that CSA can play an important ro le in the sequestration of P. falciparum in human placentas during the acut e phase of infection.