Orofacial granulomatosis (OFG) is considered as an uncommon disease and nomenclature of the disease was subjected to debate for a long time. Although various aetiological agents such as food substances, food additives, dental materials and various microbiological agents have been implicated in the disease process its precise pathogenesis is yet to be elucidated. Delayed type of hypersensitivity reaction appears to play a significant role, although the exact antigen inducing the immunological reaction varies in individual patients. However, evidence for the role of genetic predisposition to the disease is sparse. The underlying immunological mechanism appears to show some similarities between OFG and Crohn's disease, emphasizing the need for more comparative studies of the two entities. Therefore, we propose the term idiopathic OFG as a better term for those cases restricted to oral region without any identifiable known granulomatous disease and the diagnosis should not be changed until the patient develops systemic manifestations of a specific granulomatous condition. This review attempts to discuss the role of different aetiological agents and certain aspects of pathogenesis of OFG.

This is the first study that shows the presence of pro-inflammatory cytokines, as well as Th1-associated chemokine receptors, in the oral ulcers of BD patients, as well as RAS patients, at a protein level. However, the expression of the Th2 cytokine IL-4 within the oral lesions of only BD patients is suggestive of a more complex antigenic stimuli in BD patients compared with RAS patients.

SUMMARYInfants undergoing open heart surgery often have all or part of their thymus removed. The activity of the immune system has not been investigated thoroughly in these children, and only shortly after the operation. Therefore, it was decided to investigate the activity of the immune system in more detail in children several years after their operation. Peripheral blood samples from 19 children who had undergone open heart surgery during their first months of life was collected (study group) and from 19 ageand gender-matched children (control group). The activity of the immune system was evaluated by measuring the number of different cell types in peripheral blood, the phenotype of lymphocytes and the response of T cells following in vitro stimulation by mitogen, tetanus toxoid and measles antigen. The study group had significantly lower counts of total lymphocytes, which was reflected in a lower number of T cells but not B cells. Furthermore, the study group had significantly lower proportion of T cells (CD3 + ) and helper T cells (CD4 + ), but not cytotoxic T cells (CD8 + ). The level of neutrophils in peripheral blood was significantly higher in the study group. This may indicate enhanced innate immunity when the acquired immunity is defective. The results indicate a shift to extrathymic T cell maturation, which is less efficient for CD4 + helper cells than for CD8 + cytotoxic cells.