Immunosuppression-reverting oligonucleotides inhibiting the expression of CD39

An oligonucleotide capable of hybridizing with a nucleic acid sequence of the ectonucleotidase (NTPdase) CD39 of SEQ ID NO.1 (human) consisting of a sequence selected from the group consisting of SEQ ID NO. 89, SEQ ID NO.91, SEQ ID NO.3, SEQ ID NO.4, SEQ ID NO.97, SEQ ID NO.93, SEQ ID NO.94, SEQ ID NO.23, SEQ ID NO.7, SEQ ID NO.8, SEQ ID NO.9, SEQ ID NO.10, SEQ ID NO.11, SEQ ID NO.12, SEQ ID NO.13, SEQ ID NO.14, SEQ ID NO.15, SEQ ID NO.16, SEQ ID NO.17, SEQ ID NO.18, SEQ ID NO.19, SEQ ID NO.20, SEQ ID NO.21, SEQ ID NO.22, SEQ ID NO.24, SEQ ID NO.25, SEQ ID NO.26, SEQ ID NO.27, SEQ ID NO.28, SEQ ID NO.29, SEQ ID NO.30, SEQ ID NO.31, SEQ ID NO.32, SEQ ID NO.33, SEQ ID NO.34, SEQ ID NO.35, SEQ ID NO.36, SEQ ID NO.37, SEQ ID NO.38, SEQ ID NO.39, SEQ ID NO.40, SEQ ID NO.41, SEQ ID NO.42, SEQ ID NO.43, SEQ ID NO.44, SEQ ID NO.45, SEQ ID NO.46, SEQ ID NO.47, SEQ ID NO.48, SEQ ID NO.49, SEQ ID NO.50, SEQ ID NO.51, SEQ ID NO.52, SEQ ID NO.88, SEQ ID NO.90, SEQ ID NO.92, SEQ ID NO.95, SEQ ID NO.96 and combinations thereof, wherein at least one nucleotide of the oligonucleotide is LNA modified.