An oligonucleotide consisting of from 15 to 21 nucleotides, more particularly from 15 to 20 nucleotides, wherein the sequence of said oligonucleotide comprises the sequence GTGTTC, which is complementary to positions 146 to 151 of the RORC2 nucleic acid coding sequence of SEQ ID NO. 1, wherein said oligonucleotide inhibits the expression of RORC2, and wherein the oligonucleotide consists of a sequence selected from the group consisting of +T*+T*+C*A*A*T*T*T*G*T*G*T*+T*+C*+T (SEQ ID NO.2), +T*+T*+T*G*T*G*T*T*C*T*C*A*T*G*+A*+C*+T (SEQ ID NO.3), +T*+T*+T*G*T*G*T*T*C*T*C*A*T*+G*+A*+C (SEQ ID NO.4), +A*+C*T*+T*C*A*A*T*T*T*G*T*G*T*+T*+C*+T (SEQ ID NO.6), +C*+A*+C*T*T*C*A*A*T*T*T*G*T*G*+T*+T*+C (SEQ ID NO.7), +T*+C*A*+A*T*T*T*G*T*G*T*T*C*+T*+C*+A (SEQ ID NO.8), +G*+T*G*T*T*C*T*C*A*T*G*A*+C*T*+G (SEQ ID NO.9), +A*+T*+T*T*G*T*G*T*T*C*T*C*A*T*+G*+A*+C (SEQ ID NO. 10), +T*+C*A*A*T*T*T*G*T*G*T*T*C*+T*+C*A*+T (SEQ ID NO.11), +T*+T*+C*A*A*T*T*T*G*T*G*T*T*C*+T*+C*+A (SEQ ID NO.23), +G*+T*+G*T*T*C*T*C*A*T*G*A*C*T*+G*+A*+G (SEQ ID NO.24), +G*+T*G*T*T*C*T*C*A*T*G*A*C*+T*+G*+A (SEQ ID NO.25), +T*+C*A*A*T*T*T*G*T*G*T*T*C*+T*+C*+A (SEQ ID NO.26), +T*+T*+T*G*T*G*T*T*C*T*C*A*T*G*A*C*+T*+G*+A (SEQ ID NO.53), +T*+T*+G*T*G*T*T*C*T*C*A*T*G*A*C*+T*+G*+A (SEQ ID NO.54), +A*+T*+T*T*G*T*G*T*T*C*T*C*A*T*G*A*C*+T*+G*+A (SEQ ID NO.55), +T*+C*+A*C*T*T*C*A*A*T*T*T*G*T*G*T*T*+C*+T*+C (SEQ ID NO.56), +C*+A*+C*T*T*C*A*A*T*T*T*G*T*G*T*T*+C*+T*+C (SEQ ID NO.57), +T*+G*+A*G*T*T*C*A*A*T*T*T*G*T*G*T*+T*+C*+T (SEQ ID NO.58), +T*+C*+A*C*T*T*C*A*A*T*T*T*G*T*G*+T*+T*+C (SEQ ID NO.59), +T*+T*+C*A*A*T*T*T*G*T*G*T*T*C*T*+C*+A*+T (SEQ ID NO.60), +T*+C*+A*C*T*T*C*A*A*T*T*T*G*T*G*T*T*C*+T*+C*+A (SEQ ID NO.61) and +A*+T*+T*T*G*T*G*T*T*C*T*C*A*T*G*+A*+C*+T (SEQ ID NO.62); particularly from the group consisting of +T*+T*+C*A*A*T*T*T*G*T*G*T*+T*+C*+T (SEQ ID NO.2), +T*+T*+T*G*T*G*T*T*C*T*C*A*T*G*+A*+C*+T (SEQ ID NO.3), +T*+T*+T*G*T*G*T*T*C*T*C*A*T*+G*+A*+C (SEQ ID NO.4), +A*+C*T*+T*C*A*A*T*T*T*G*T*G*T*+T*+C*+T (SEQ ID NO.6), +C*+A*+C*T*T*C*A*A*T*T*T*G*T*G*+T*+T*+C (SEQ ID NO.7), +T*+C*A*+A*T*T*T*G*T*G*T*T*C*+T*+C*+A (SEQ ID NO.8), +G*+T*G*T*T*C*T*C*A*T*G*A*+C*T*+G (SEQ ID NO.9), +T*+T*+C*A*A*T*T*T*G*T*G*T*T*C*+T*+C*+A (SEQ ID NO.23), +T*+T*+T*G*T*G*T*T*C*T*C*A*T*G*A*C*+T*+G*+A (SEQ ID NO.53), +T*+T*+G*T*G*T*T*C*T*C*A*T*G*A*C*+T*+G*+A (SEQ ID NO.54), +A*+T*+T*T*G*T*G*T*T*C*T*C*A*T*G*A*C*+T*+G*+A (SEQ ID NO.55), +T*+C*+A*C*T*T*C*A*A*T*T*T*G*T*G*T*T*+C*+T*+C (SEQ ID NO.56), +C*+A*+C*T*T*C*A*A*T*T*T*G*T*G*T*T*+C*+T*+C (SEQ ID NO.57), +T*+G*+A*G*T*T*C*A*A*T*T*T*G*T*G*T*+T*+C*+T (SEQ ID NO.58), and +T*+C*+A*C*T*T*C*A*A*T*T*T*G*T*G*+T*+T*+C (SEQ ID NO.59); more particularly from the group consisting of +T*+T*+C*A*A*T*T*T*G*T*G*T*+T*+C*+T (SEQ ID NO.2), +T*+T*+T*G*T*G*T*T*C*T*C*A*T*G*+A*+C*+T (SEQ ID NO.3), +T*+T*+T*G*T*G*T*T*C*T*C*A*T*+G*+A*+C (SEQ ID NO.4), +A*+C*T*+T*C*A*A*T*T*T*G*T*G*T*+T*+C*+T (SEQ ID NO.6), +C*+A*+C*T*T*C*A*A*T*T*T*G*T*G*+T*+T*+C (SEQ ID NO.7), +T*+T*+T*G*T*G*T*T*C*T*C*A*T*G*A*C*+T*+G*+A (SEQ ID NO.53), +T*+T*+G*T*G*T*T*G*T*G*A*T*G*A*G*+T*+G*+A (SEQ ID NO.54), and +A*+T*+T*T*G*T*G*T*T*C*T*C*A*T*G*A*C*+T*+G*+A (SEQ ID NO.55), wherein + indicates a LNA modification and * a phosphorothioate, wherein optionally one or more of the phosphorothioates are independently replaced by an unmodified phosphate or a modified phosphate other than a phosphorothioate, particularly a methylphosphonate.