[MBL quality control survey of autoantibodies--25 years of activity and its achievement--mainly antinuclear antibodies].

Annual MBL Quality Control Survey of Autoantibodies has continued to this day since it started in 1983 as the only quality control survey of autoantibodies in Japan. The survey has aimed at unification and standardization of measurement value, as well as finding out between-laboratory differences in results through reporting the results of tabulation to the participating laboratories. For carrying out the survey, we intend to make our efforts to promote assurance and standardization of the quality control of the autoantibodies. The number of participant on this survey has been increasing every year and more than 500 laboratories participate not only in Japan but also from Asia and European countries. The laboratories that participated in this survey are the ones that usually perform ANA test, anti-DNA antibodies test, anti-ENA antibodies test, AMA test, ASMA test, anti-cardiolipin antibodies test and anti-CCP antibodies test. The purpose of the survey is to standardize antinuclear antibodies testing value in semi quantitative assay using ANA control serum or our titer control HEPASERA-1. We got 12% increase from 79% to 91% in 1986 using ANA control serum. Additionally, we reached 97% (86% to 97%) of convergence in 2001 by using HEPASERA-1, which contains 4 major pattern titer controls from 1993. In 2007, coefficient of variation (CV) for anti-dsDNA antibodies was 13%, showing better result than 25% of the first survey in 1993. We started secondary survey for laboratories which reported a result far apart. In the secondary survey, we made investigation for cause and improvement action. We conclude quality control survey is useful for autoantibodies testing for its result convergence.

Generation of CD4(+)CD25(+) regulatory T cells from autoreactive T cells simultaneously with their negative selection in the thymus and from nonautoreactive T cells by endogenous TCR expression.

Normal T cell repertoire contains regulatory T cells that control autoimmune responses in the periphery. One recent study demonstrated that CD4(+)CD25(+) T cells were generated from autoreactive T cells without negative selection. However, it is unclear whether, in general, positive selection and negative selection of autoreactive T cells are mutually exclusive processes in the thymus. To investigate the ontogeny of CD4(+)CD25(+) regulatory T cells, neo-autoantigen-bearing transgenic mice expressing chicken egg OVA systemically in the nuclei (Ld-nOVA) were crossed with transgenic mice expressing an OVA-specific TCR (DO11.10). Ld-nOVA x DO11.10 mice had increased numbers of CD4(+)CD25(+) regulatory T cells in the thymus and the periphery despite clonal deletion. In Ld-nOVA x DO11.10 mice, T cells expressing endogenous TCR alpha beta chains were CD4(+)CD25(-) T cells, whereas T cells expressing autoreactive TCR were selected as CD4(+)CD25(+) T cells, which were exclusively dominant in recombination-activating gene 2-deficient Ld-nOVA x DO11.10 mice. In contrast, in DO11.10 mice, CD4(+)CD25(+) T cells expressed endogenous TCR alpha beta chains, which disappeared in recombination-activating gene 2-deficient DO11.10 mice. These results indicate that part of autoreactive T cells that have a high affinity TCR enough to cause clonal deletion could be positively selected as CD4(+)CD25(+) T cells in the thymus. Furthermore, it is suggested that endogenous TCR gene rearrangement might critically contribute to the generation of CD4(+)CD25(+) T cells from nonautoreactive T cell repertoire, at least under the limited conditions such as TCR-transgenic models, as well as the generation of CD4(+)CD25(-) T cells from autoreactive T cell repertoire.

Peripheral tolerance to a nuclear autoantigen: dendritic cells expressing a nuclear autoantigen lead to persistent anergic state of CD4+ autoreactive T cells after proliferation.

It remains unknown why the T cell tolerance to nuclear autoantigens is impaired in systemic autoimmune diseases. To clarify this, we generated transgenic mice expressing OVA mainly in the nuclei (Ld-nOVA mice). When CD4+ T cells from DO11.10 mice expressing a TCR specific for OVA(323-339) were transferred into Ld-nOVA mice, they were rendered anergic, but persisted in vivo for at least 3 mo. These cells expressed CD44(high), CD45RB(low), and were generated after multiple cell divisions, suggesting that anergy is not the result of insufficient proliferative stimuli. Whereas dendritic cells (DCs) from Ld-nOVA (DCs derived from transgenic mice (TgDCs)), which present rather low amount of the self-peptide, efficiently induced proliferation of DO11.10 T cells, divided T cells stimulated in vivo by TgDCs exhibited a lower memory response than T cells stimulated in vitro by peptide-pulsed DCs. Furthermore, we found that repeated transfer of either TgDCs or DCs derived from wild-type mice pulsed with a lower concentration of OVA(323-339) induced a lower response of DO11.10 T cells in Ag-free wild-type recipients than DCs derived from wild-type mice. These results suggest that peripheral tolerance to a nuclear autoantigen is achieved by continuous presentation of the self-peptide by DCs, and that the low expression level of the peptide might also be involved in the induction of hyporesponsiveness.