Investigating the expression of ALS2 and ALS9 genes along with allele frequency of ALS9 in patients with vulvovaginal candidiasis

Infect Genet Evol. 2020 Aug:82:104253. doi: 10.1016/j.meegid.2020.104253. Epub 2020 Feb 18.


Background: Vulvovaginal candidiasis (VVC) is a vaginal mucosal infection that usually infects women in their reproductive age. When the signs of VVC persist on a daily basis or last for a long time and repeat at least three times per year, the disease is considered chronic and recurrent.

Objectives: The purpose of this study was to determine the expression rate of 2 genes responsible for adhesion and virulence of candida in RVVC patients using Real-time PCR, and comparing them together and assess the presence or absence of ALS9-2 allele in these patients.

Patients/methods: The vaginal discharge was collected from 120 women aged (22-55) attending lolagar hospital which were all diagnosed with RVVC and 120 age-matched healthy controls. The expression rate of ALS2 and ALS 9 genes was quantified using real-time PCR. PCR method was used for Identification of ALS9 gene alleles.

Results: Results showed an increase in ALS2 gene expression and a decrease in ALS9 gene expression, comparing to basic level and standard sample. 42.5% (51 of total 120 samples) contained the small allele.

Conclusions: The significant difference in expression rates of ALS2 and ALS9 genes indicates their different roles in making morphogenesis changes during the virulence of Candida albicans. Emergence of heterogeneous form and detection of ALS's short allele in invasive form of fungi proves the significant pathogenic role of this allele, specially when attached to mucosal tissue. Invasive and recurrent form of the disease can be accompanied by genetic-morphologic changes in fungi. Considering the form of this disease and the reduction in ALS9 gene expression, it can be concluded that this gene plays a significant role in attachment and initiation of the pathogenic phase.

Keywords: ALS2; ALS9; ALS9–2 allele; Recurrent vulvovaginal candidiasis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Candida albicans / genetics*
  • Candida albicans / pathogenicity
  • Candidiasis, Vulvovaginal / microbiology*
  • Case-Control Studies
  • Female
  • Fungal Proteins / genetics*
  • Gene Expression Regulation, Fungal
  • Gene Frequency
  • Host-Pathogen Interactions / genetics
  • Humans
  • Middle Aged
  • Young Adult


  • Fungal Proteins