The alteration of sister chromatid exchange frequencies in Behçet's disease with and without HLA-B51.

BACKGROUND

The analysis of sister chromatid exchange (SCE) is a cytogenetic technique used to show DNA damage as a result of an exchange of DNA fragments between sister chromatids. It is known that there is an increased SCE frequency in Behçet's disease (BD).

OBJECTIVE

To investigate whether human leucocyte antigen (HLA)-B51-positive patients with Behçet's disease exhibit higher SCE frequencies than those without HLA-B51.

METHODS

Lymphocytes from 75 patients (38 women, 37 men) and from 50 controls (28 women, 22 men) were cultured in darkness for 72 h in the presence of bromodeoxyuridine. Metaphase chromosomes were stained with a fluorescence plus Giemsa technique after a standard harvest procedure. For HLA-B51 typing, DNA was extracted from ethylenediaminetetraacetic acid blood samples and HLA-B5 allele genotyping was performed by the polymerase chain reaction (PCR)-sequence specific primer method.

RESULTS

Thirty-nine of 75 patients with BD (52%) and 15 of 50 controls (30%) were found HLA-B51-positive. The SCE frequencies in HLA-B51-positive patients were higher than in HLA-B51-negative ones (P < 0.001), whereas no difference was detected in the control group.

CONCLUSION

This study revealed that there was a significant association between elevated SCE frequencies and existence of HLA-B51 patients with BD.