Table 1.

Infectious agents involved in the pathogenesis of Behcet's disease (adopted from Umair K. and Taimur S [4].

Agents	Pertinent rationale or refutation for involvement in Behcet's disease
Hepatitis A, B, C, E viruses	Serological evidence of previous HAV, HCV and HEV infections showed no significant difference in patients with Behcet's disease compared to controls. Previous HBV infection, however, seen in a remarkably lower number of patients with Behcet's disease as compared with healthy controls.
Herpes simplex virus (HSV)	Anti-HSV-1 antibodies were found more commonly in patients with Behcet's disease than controls. DNA of HSV was detected in genital and intestinal ulcers but not in oral aphthous ulcers.
Parvovirus B19	Parvovirus B19 IgG antibodies were reported more in patients with Behcet's disease as compared to controls
Helicobacter pylori	Almost the same proportion of patients with Behcet's disease and controls were found to have H. pylori infection following eradication therapy.
Chlamydia pneumoniae	IgG seropositivity for C. pneumoniae between cases and controls was not significantly different. However, the proportion of seropositive cases with higher IgG titres was greater.
Streptococcus sanguis, Streptococcus mitis and Streptococcus salivarius	Decline of skin and arthritic involvement in Behcet's disease after antibiotic administration. Hypersensitivity to cutaneous streptococcal antigens was reported. Aggravation of symptoms after dental procedures. Treatment of chronic oral infections positively impacts long term prognosis of disease.
Saccharomyces cerevisiae	Unclear role, distribution and pathogenetic relationship of ASCA antibodies in patients with Behcet's disease
Heat shock proteins	Heat shock proteins of mycobacteria and streptococci were suggested to have a role in Behcet's disease. Model of molecular mimicry thought to be responsible for manifestations of Behcet's disease.