Another mutation was found at position 1282 V to I, which represents the flanking region of patient��s HLA-A02* restricted NS3 1284�C1296 epitope [12]. Also in patient 2 and 3 sequence variations were found within known CTL epitopes, NS3 HLA-A02* 1321�C35 [13], HLA-B35* NS 3 1359�C67 [14], NS3 1382-1397 [5], HLA-B08* NS3 1395�C1403 [15] Rapamycin or the direct flanking region of known CTL epitope HLA-C14*1371-80 [5]). In patient 2 at week 2 patient��s HLA-A02* restricted NS3 1321�C35 TDSTSILGIGTVLDQ was found, at week 3 a sequence variation at position 1323 was detected, NS3 1321�C35 TDATSILGIGTVLDQ. 6 weeks later again the initial sequence came up. Mutations were also found in epitopes which did not match with patient��s HLA. NS 3 1359�C67 epitope HSNIEEVAL was sequenced at week 2.

Amino acid exchange at position 1360 could be detected at week 3 HPNIEEVAL. Again at week 9 the initial sequence was found. The same phenomenon was observed within NS3 1382�C97. IETIKGGRHLIFCH (week 2) to LEVIKGGRHLIFCH (week 3) and back to IETIKGGRHLIFCH (week 9). At position 1369, the flanking region of NS3 1371�C80, amino acid exchange N (week 2) to T (week 3) to N (week 9) was found. In patient 3 matching HLA-A02* restricted NS3 1321�C35 TDSTTILGIGTVLDQ and NS3 1321�C35 TDSTSILGIGTVLDQ were found at week 3 and 4. Another sequence variation was observed within patient��s HLA-B08* restricted NS3 1395�C1403 epitope. HSKRKCDEL and HSRKKCDEL were present at week 3 and 4. This mutation has been described frequently in the presence of HLA B*08 allele [7,16].

At position 1370, the flanking region of NS3 1371�C80, amino acid exchange I (week 3) to T (week 4) was found. Thus all sequence variations in NS3 were observed within known CTL epitopes or in their flanking regions. The ongoing variation was seen mainly in patient��s HLA restricted epitopes. Only in patient 2 variations were found in patient��s HLA non-restricted epitopes (NS3 1359�C67, NS3 1382�C97). For the HLA-C14 restricted NS3 1371�C80 epitope the patient��s corresponding HLA was unknown. At least in patient 2 the sequence variation found might reflect different pre-existing strains since the main sequence at week 2 and 9 were identical. In addition the main sequence found in week 3 differed at 8 positions from the main sequence at week 2/9.

Furthermore the main sequence with the KLVALGINAV epitope is usually found in genotype 1a infected patients in contrast to the KLSGLGINAI sequence usually found in genotype 1b infected patients [17]. In addition variations were found in patient��s HLA non-restricted epitopes indicating different strains Batimastat rather than ongoing selection pressure. As another variation KLSGLGLNAV occurred in 4/22 clones either as a consequence of mutations from week 2 sequences or also as already pre-existing so far undetected variation.