Differential expression of major histocompatibility complex class I in developmental glioneuronal lesions

Purpose: the expression of the major histocompatibility complex class i (mhc-i) in the brain has received considerable interest not only because of its fundamental role in the immune system,but also for its non-immune functions in the context of activity-dependent brain development and plasticity.methods: in the present study we evaluated the expression and cellular pattern of mhc-i in focal glioneuronal lesions associated with intractable epilepsy. mhc-i expression was studied in epilepsy surgery cases with focal cortical dysplasia (fcd i,n = 6; fcd iia,n = 6 and fcd iib,n = 15),tuberous sclerosis complex (tsc,cortical tubers; n = 6) or ganglioglioma (gg; n = 15) using immunocytochemistry. evaluation of t lymphocytes with granzyme-b+ granules and albumin immunoreactivity was also performed.results: all lesions were characterized by mhc-i expression in blood vessels. expression in both endothelial and microglial cells as well as in neurons (dysmorphic/dysplastic neurons) was observed in fcd ii,tsc and gg cases. we observed perivascular and parenchymal t lymphocytes (cd8+,t-cytotoxic) with granzyme-b+ granules in fcd iib and tsc specimens. albumin extravasation,with uptake in astrocytes,was observed in fcd iib and gg cases.conclusions: our findings indicate a prominent upregulation of mhc-i as part of the immune response occurring in epileptogenic glioneuronal lesions. in particular,the induction of mhc-i in neuronal cells appears to be a feature of type ii fcd,tsc and gg and may represent an important accompanying event of the immune response,associated with blood-brain barrier dysfunction,in these developmental lesions. © 2013 prabowo et al.; licensee biomed central ltd.