Monozygotic twins are discordant for chronic periodontitis: white blood cell counts and cytokine production after ex vivo stimulation.

OBJECTIVES

The aim of this study was to investigate the extent of concordance in the number of leucocytes and their cytokine secretion after ex vivo stimulation in a twin population discordant for the amount of periodontal breakdown.

MATERIAL AND

METHODS

Venous blood was collected from 18 adult twin pairs (10 monozygotic and eight dizygotic twins). Each twin pair consisted of a diseased twin (proband) and his/her co-twin. In venous blood, leucocytes were counted. The cytokines interleukin (IL)-1beta, IL-6, IL-8, IL-10 and IL-12p40 were assessed after stimulation of monocytic cells, while IL-13 and interferon (IFN)-gamma were determined after lymphocytic stimulation.

RESULTS

In the study population as a whole, probands showed higher total numbers of leucocytes and lower IL-12p40 levels compared with their co-twins. In monozygotic twins, no difference was found in the leucocyte counts, but probands secreted more IL-6 than their co-twins; an opposite trend was found for IL-12p40.

CONCLUSION

The results suggest that the observed discordance in periodontal breakdown in the studied monozygotic twin population may be related to the relatively high levels of IL-6 and the low levels of IL-12p40 secretion after ex vivo stimulation of whole-blood cell cultures. This cytokine secretion profile may be regarded as a risk indicator of periodontitis.