Ana Cvetanovic

Deleterious versus protective autoimmunity in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disorder of central nervous system, in which myelin specific CD4(+) T cells have a central role in orchestrating pathological events involved in disease pathogenesis. There is compelling evidence that Th1, Th9 and Th17 cells, separately or in cooperation, could mediate deleterious autoimmune response in MS. However, the phenotype differences between Th cell subpopulations initially employed in MS pathogenesis are mainly reflected in the different patterns of inflammation introduction, which results in the development of characteristic pathological features (blood-brain barrier disruption, demyelination and neurodegeneration), clinically presented with MS symptoms. Although, autoimmunity was traditionally seen as deleterious, some studies indicated that autoimmunity mediated by Th2 cells and T regulatory cells could be protective by nature. The concept of protective autoimmunity in MS pathogenesis is still poorly understood, but could be of great importance in better understanding of MS immunology and therefore, creating better therapeutic strategies.

High dose chemotherapy with stem cell support in the treatment of testicular cancer.

Testicular germ cell cancer (TGCC) is rare form of malignant disease that occurs mostly in young man between age 15 and 40. The worldwide incidence of TGCC is 1.5 per 100000 man with the highest rates in North Europe. After discovery of cisplatin cure rates of TGCC are very favorable between 90%-95% and unlike most solid tumors, cure rate for metastatic TGCC is around 80%. Metastatic TGCC is usually treated with 3-4 cycles of bleomycin, etoposide, cisplatinum chemotherapy with or without retroperitoneal surgery and cure rates with this approach are between 41% in poor risk group and 92% in good risk group of patients. Cure rates are lower in relapsed and refractory patients and many of them will die from the disease if not cured with first line chemotherapy. High dose chemotherapy (HDCT) approach was used for the first time during the 1980s. Progress in hematology allowed the possibility to keep autologous haematopoietic stem cells alive ex-vivo at very low temperatures and use them to repopulate the bone marrow after sub-lethal dose of intesive myeloablative chemotherapy. Despite the fact that there is no positive randomized study to prove HDCT concept, cure rates in relapsed TGCC are higher after high dose therapy then in historical controls in studies with conventional treatment. Here we review clinical studies in HDCT for TGCC, possibilities of mobilising sufficient number of stem cells and future directions in the treatment of this disease.

IL-17 signalling in astrocytes promotes glutamate excitotoxicity: Indications for the link between inflammatory and neurodegenerative events in multiple sclerosis

OBJECTIVE Th-17 cells have been exclusively referred to inflammatory events in multiple sclerosis (MS), while their importance in the development of glutamate excitotoxicity and the consequent neurodegeneration has been a completely unexplored concept. Accordingly, the objective of our study was to assess IL-17A effect on astrocyte ability to metabolize and release glutamate, considering that astrocytes had the central role in glutamate homeostasis. METHODS By using primary rat astrocyte cultures, astrocyte ability to uptake glutamate was estimated by the alterations of glutamate transporters (GLAST and GLT-1) expression, whereas changes in glutamine synthetase expression were used to estimate the ability to metabolize glutamate. Gene expression was determined by real time polymerase chain reaction (rtPCR). IL-17A effect on astrocyte ability to produce glutamate was investigated directly, by measuring the level of released glutamate using high performance liquid chromatography (HPLC). RESULTS Lower concentrations of IL-17A reduced the expressions of both glutamate transporters and glutamine synthetase; however, this effect was lost when IL-17A was applied in a higher dose. IL-17A did not significantly modify glutamate release from astrocyte in basal conditions, but following Ca2+ stimulation, as well as Ca2+ removal from the culture medium, IL-17A stimulated glutamate release in dose-dependent manner. CONCLUSION Together, these results support that IL-17A could promote glutamate excitotoxicity by decreasing astrocyte ability to uptake and convert glutamate to non-toxic glutamine, but also by stimulating Ca2+ dependent glutamate release. Such interactions between IL-17A and glutamate excitotoxicity implicate the potential link between inflammation and neurodegeneration during MS pathogenesis, and identify astrocytes as a potential target in achieving neuroprotective effects in MS.

Granulocyte-macrophage colony-stimulating factor as a mediator of autoimmunity in multiple sclerosis

Autoreactive, myelin-specific, CD4+ T cells have a central role in multiple sclerosis (MS) pathogenesis; however the exact phenotype characteristics of these cells remain elusive. Recently, granulocyte-macrophage colony-stimulating factor (GM-CSF) expression has emerged as the main pathological signature of the encephalogenicity in both T and B cell compartment. In this review we have summarized the current data supporting GM-CSF relevance in MS pathophysiology, in the context of both immunomodulatory and neuroinflammatory processes; as well as the potential cellular sources of this stimulating factor, including different T and B cell subsets.

Immunohistochemical and karyometric similarities and differences of salivary gland tumors between pleomorphic adenoma, basal cell adenoma and polymorphous low grade adenocarcinoma

Uvod: Tumori pljuvačnih žlezda su veoma retke neoplazme. S obzirom na njihovu patohistološku sliku, ovi tumori predstavljaju veoma veliki dijagnostički izazov. Cilj: istaživanja je diferencijacija ova tri tipa tumora primenom imunohistohemijske i morfometrijske analize, kao i određivanje visine Ki67 proliferativnog indeksa. Materijal i metode: Istraživanje je obuhvatilo 44 tumora, 20 pleomorfnih adenoma, 12 adenoma bazalnih ćelija i 12 polimorfnih adenokarcinoma niskog gradusa. Analizirana je ekspresija Ki67, p53 i HER-2 antigena, kao markera proliferacije. U sklopu diferencijalne dijagnostike, analizirana je ekspresija CEA, EMA, GFAP, p63, vimentina, CK14, α-SMA, S-100 protein i WT1 antigena. Morfometrijska analiza vršena je u softverskom paketu „ImageJ” verzija 1.43u. Rezultati: Neoplastične ćelije u pleomorfnom adenomu su pokazale jaku ekspresiju GFAP, p63, WT1, vimentin i S100. U grupi od dvanaest polimorfnih adenokarcinoma niskog gradusa prisutna je difuzna ekspresija CK14, S100, vimentin i EMA su bili apsolutno eksprimirani, dok je αSMA bio negativan. Adenom bazalnih ćelija pokazuje pozitivnost na S-100, CEA, p63 i vimentin. Analizom vrednosti proliferativnog Ki67 indeksa ustanovljena je statistički značajna razlika u grupi pleomorfnog adenoma, što se dovodi u vezu sa čestim recidiviranjem. Morfometrijskom analizom se uočavaju veće vrednosti u grupi polimorfnog adenokarcinoma niskog gradusa, ali su statistički značajne razlike nađene samo za Feretov dijametar i integrisanu optičku gustinu u odnosu na pleomorfni adenom (p<0,05). U grupi adenoma bazalnih ćelija tumorske ćelije su pokazale statistički veće vrednosti za integrisanu optičku gustinu u odnosu na pleomorfni adenom (p<0,001). Zaključak: Za diferencijalnu dijagnozu tumora pljuvačnih žlezda, pored osnovne mikromorfološke, neophodna je i imunohistohemijska i morfometrijska analiza.

Tumor-Infiltrating Lymphocytes and Breast Cancer: Are Immune Checkpoint Inhibitors Ready for Prime Time in Breast Cancer?

Summary In recent years, results obtained from different studies with large cohorts have revealed a bond between the presence of extensive lymphocytic infiltration and favourable prognostic associations in the early-stage of breast cancer (BC) and high response rates to neoadjuvant chemotherapy. Examiners used tumors from large cohorts of patients who took part in randomized neoadjuvant and adjuvant clinical trials. The importance of tumor infiltrating lymphocytes (TILs) appears to be subtype-specific and varies depending on the histological characteristics of the tumor. TILs have proven to be a good prognostic marker, but only in highly proliferative breast tumors such as triple negative breast tumors (TNBC) or HER 2 positive BC. In the era when standard, well-known, prognostic and predictive biomarkers are ever changing and the use of molecular profiling analyses are increasing, we are looking for techniques to improve our understanding of tumor biology and improve patient outcome. The relevance of TILs cannot be ignored but needs to be properly evaluated in larger prospective studies which must encompass the parameters set out in previous studies. The use of TILs as prognostic biomarkers in early breast cancer may represent a new dawn, and use of immunotherapy, especially immune checkpoint inhibitors, probably is the future for the breast cancer but it is not yet ready for prime time.