Investigation of TCR-Vβ CDR3 Spectrotypes in CD4 and CD8 Lymphocytes from Paroxysmal Nocturnal Hemoglobinuria (PNH) Patients.

Abstract

PNH is one disorder of bone marrow failure syndromes, including aplastic anemia and myelodysplastic syndrome. It is considered that immunologic mechanisms by cytotoxic T lymphocytes (CTLs) and interferon-γ (IFN-γ) contribute to hypoplastic bone marrow of these disorders. In addition, PNH is an acquired clonal disorder of the hematopoietic stem cell. Recently, it has been reported that analysis of T cell-antigen receptor (TCR)-Vβ repertoires, especially TCR-Vβ CDR3 (complementarity- determining region 3) spectrotypes, is an effective tool to study immunologic mechanisms by CTLs in pathophysiology of PNH (Karadimitris et al, Blood, 2000; Kook et al, Blood, 2002; Risitano et al, Blood, 2002). In the present study, we investigated 21 kinds of TCR-Vβ repertoires by flow cytometry in CD4 and CD8 lymphocytes from 5 PNH patients and a healthy volunteer and the TCR-Vβ CDR3 spectrotypes using polymerase chain reaction assay in CD4 and CD8 lymphocytes from 3 of 5 PNH patients and the control. We also quantitated intracellular IFN-γ in CD4 and CD8 lymphocytes from 5 PNH patients and the control according to the method by Sloand et al (Blood, 2002). We found no specific TCR-Vβ repertoires in CD4 and CD8 lymphocytes from PNH patients compared with the control. The TCR-Vβ repertoires with relative increase of CD4 or CD8 lymphocytes (over 10 of ratio of the proportion of each TCR-Vβ repertoire in a PNH patient/the proportion of the same TCR-Vβ repertoire in a healthy volunteer) were 13.6 or 4 and 22 in Case 1, 3 and 11 or 1 in Case 2, 3 and 13.6 or 3 in Case 3, 5.3 and 7.2 or 2, 3, 7, and 18 in Case 4, and 4, 5.2, 13.6, 16, and 23 or 1 and 14 in Case 5, respectively. TCR-Vβ CDR3 spectrotyping showed that in CD4 lymphocytes most CDR3 patterns were chiefly polyclonal, except for one oligoclonal (Case 1) and one monoclonal (Case 3) patterns of TCR-Vβ25; in CD8 lymphocytes most CDR3 consisted of polyclonal, oligoclonal, and/or monoclonal patterns, suggesting the possibility that CD8 lymphocytes recognize much more antigens of abnormal cells, probably including PNH clones, than CD4 lymphocytes. Unfortunately, we found the same patterns as described above in CD8 lymphocytes from the control, although CD4 lymphocytes from the control presented only polyclonal pattern of CDR3. Quantitative analyses of IFN-γ showed that index values of IFN-γ in CD4 and CD8 lymphocytes from PNH patients were higher than those from the control. However, we did not find any significant correlations between the spectrotypes of TCR-Vβ CDR3 and the index values of IFN-γ in PNH patients, suggesting that TCR-Vβ repertoires with monoclonal and oligoclonal CDR3 patterns do not necessarily produce much IFN-γ. In conclusion, our findings suggest that TCR-Vβ CDR3 spectrotyping is more effective tool to resolve some immune mechanisms of pathophysiology in PNH, especially by auto-reactive CTLs.