A statistical comparison is presented in Table 2. When compared with sialolithiasis (non-autoimmune control), VH clones of SS were frequently unmutated (P = 0.0005) as they were with IgG4-related sclerosing sialadenitis (P < 0.0001). For VH3 family clones, rates of unmutated clones in cases of SS and IgG4-related sclerosing sialadenitis were significantly higher than in the sialolithiasis cases (P = 0.002 and P < 0.0001, respectively). In contrast, there were no significant differences in non-VH3 family clones. In our study, we retrieved typical

clinical cases of SS, IgG4-related sclerosing sialadenitis and sialolithiasis. Selleck EPZ-6438 We then analysed VH fragments of B cells infiltrating these three types of lesions. After PCR amplification of rearranged IgH genes, at least 50 clones per case and more than 500 clones in total were sequenced for VH fragments, and the data obtained showed that VH fragments of SS and IgG4-related

sclerosing sialadenitis cases were frequently unmutated. We employed sialolithiasis tissues as a non-autoimmune control and observed chronic inflammation together with many mature lymphoid and plasma cells. In previous VH analyses [17, 18], peripheral blood B cells have been used as a control. However, as about 70% of peripheral blood B cells are naïve or unmutated [19], we consider that local non-specific inflammatory lesions (e.g. those of sialolithiasis) would be a more appropriate control in analysing local inflammation in autoimmune diseases. Hansen et al. reported that the VH3 family was preferentially used in a patient with SS (VH3 > VH1 ≥ VH4 > others) [18]. In this study, a similar VH usage was observed in SS GDC-0973 cell line and IgG4-related sclerosing sialadenitis cases: the VH3 family was the most frequently used and VH3-23 was the most often used among VH3 fragments. However, this usage of the VH3 family and a tendency towards use of VH3-23 was also found in the sialolithiasis controls, suggesting that the VH usage patterns observed in SS and IgG4-related sclerosing sialadenitis were not specific. Most interestingly, VH clones Phospholipase D1 were often unmutated in SS

and IgG4-related sclerosing sialadenitis and the percentage ratios of unmutated/total clones were 30% and 39%, respectively. These rates were significantly higher than that of sialolithiasis clones (14%). In addition, the unmutated clones appeared to be derived mainly from the VH3 family because VH3 family clones were often unmutated in SS (36%) and IgG4-related sclerosing sialadenitis (48%), when compared with those in sialolithiasis (15%). In contrast, when non-VH3 family fragments were analysed, the unmutation ratios were uniformly low (11–16%) in all three lesions. Unfortunately, owing to the small number of clones analysed, we were unable to determine which fragment of the VH3 family contributed most to the higher rates of unmutated clones in SS and IgG4-related sclerosing sialadenitis cases.