OBJECTIVETo explore the single nucleotide polymorphism(SNP) of mitochondrial DNA (mtDNA) D-LOOP region in peripheral blood lymphocytes of immuno-related pancytopenia (IRP) patients and its correlation with immune parameters.

METHODSThe D-LOOP region in mitochondrial DNA of lymphocytes in peripheral blood mononuclear cells from 43 patients with untreated IRP was detected by polymerase chain reaction(PCR). The PCR products were sequenced by the pros and cons direct sequencing methods. The sequencing results were compared with the revised Cambridge reference sequence (rCRS) and the Polymorphic Sites of Human Mitochondrial Genome Database.

RESULTSAmong total of 110 variant positions of D-LOOP region in 43 patients, 62 was SNP sites and 48 was mutation sites, of which 14 were the new mutation sites not yet registered in the database, 516 base variations were observed at 110 positions, the most common variations were base substitutions, among them T/C and A/G was 184/410 and 113/410 respectively. In the 110 variant positions, the high frequency variation sites were 73 and 263 for 43/43,311 for 32/43,310 and 16 224 for 27/43,16 519 for 25/43, 489 and 16 362 for 24/43. By the analysis of mitochondrial DNA D-LOOP polymorphism and related clinical immunology indicators of the patient's lymphocytes, it was found that D-loop in adult patients (age≥ 18 years old) significantly correlated with CD15 IgM, GLYCoACells IgM, CD34CellsIgG, CD34Cells IgM correlation.

CONCLUSIONThe high frequency of polymorphism exists in mitochondrial DNA D-loop region of lymphocytes in IRPA patients, and was significantly correlates with the autoantibodies in bone marrow mononuclear cells in adult patients, which may be associated with the IRP occurrence.