Fungal colonization and ASCA/p-ANCA positivity in inflammatory bowel disease: a cross-sectional study from Turkey.

INTRODUCTION

Recent research indicates that individuals with inflammatory bowel disease (IBD) exhibit distinct intestinal fungal communities compared with healthy individuals. This study examined the relationship among anti-Saccharomyces cerevisiae antibodies (ASCA), perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA), and Candida spp. colonization to assess their utility in diagnosing IBD, differentiating subtypes, and predicting disease localization.

METHODOLOGY: Serum samples from 240 patients with IBD and 61 healthy controls were tested for ASCA and p-ANCA using indirect immunofluorescence assay (IIFA). Fecal samples were cultured to identify Candida species.

RESULTS

ASCA positivity was significantly higher in Crohn's disease (CD) (61.7%), whereas p-ANCA positivity was more frequent in ulcerative colitis (UC) (51.6%) (p = 0.005 and p = 0.002, respectively). Fluorescence intensity showed stronger ASCA reactivity in CD and higher p-ANCA intensity in UC. Candida colonization (≥ 5 CFU) was detected in 64.2% of IBD patients, with Candida albicans the most common species. Saccharomyces cerevisiae was detected exclusively in IBD patients (3.7%, p = 0.038). Higher colonization rates were observed in UC with pancolitis (78.9%) and in CD with colonic involvement (80%). ASCA intensity inversely correlated with Candida load in CD (p = 0.021), whereas p-ANCA intensity positively correlated with Candida load in UC (p = 0.038). No significant differences in Candida species diversity were observed between subtypes.

CONCLUSIONS

These findings support the diagnostic value of ASCA and p-ANCA in distinguishing IBD subtypes and highlight their association with Candida colonization. Further studies are warranted to elucidate fungal antigen-antibody interactions and to refine subtype-specific diagnostic and therapeutic strategies.