Accumulation, distribution and phenotype heterogeneity of mast cells (MC) in human brains with neurocysticercosis.

Neurocysticercosis (NCC) is one of the most common parasitic brain infections in the world NCC can cause widely varied clinical manifestations, mainly due to the host immune-inflammatory response. The immunological hallmark of the infection with helminth parasites is infiltration into the inflamed mucosa of the gastrointestinal tract of numerous mast cells. It has been postulated that mediators released by activated mast cells might contribute to the local inflammatory response. Since data concerning the association of mast cells with neurocysticercosis are not available, the aim of our study is to determine the distribution and phenotypes of mast cells in human brain infested by cysticerci. The study was performed on 20 human autopsy brains. Mast cells (MC) were identified by means of immunohistochemical method using specific MC tryptase and chymase monoclonal antibodies. In the control brains, mast cells were very few and showed a very sparse distribution. They had been occasionally found in meninges and in perivascular areas of some brain blood vessels. Those cells were mainly tryptase-chymase phenotype (MCTTC). In contrast, in the brain sections with neurocysticercosis, mast cells were numerous. A striking feature of identified mast cells was their phenotype heterogeneity. The tryptase mast cells (MCT) phenotype dominated over the tryptase-chymase (MCTC) phenotype. MCT infiltrated mainly meninges and brain parenchyma around cysts with viable and necrotic parasites. MCTC infiltrated perivascular area of the blood vessels penetrating to the depth of the brain. Summarising, this is the first report which documents the accumulation and phenotype heterogeneity of mast cells in human brains with neurocysticercosis. Our findings suggest that the effector mechanism responsible for the host responses to the parasitic infection that involves numerous mast cells in the human brain may be very important for pathomechanism of this disease.