Investigation of Fecal Secretory Immunoglobulin A in Patients with Intestinal Parasitic Infections

Background: Immunoglobulin A is the most abundant antibody isotype at mucosal surfaces in mammals. It protects intestinal epithelium against enteric toxins and pathogenic microorganisms by interfering with invasion and modifying intestinal inflammatory response to maintain gut homeostasis ‘first line of defense’. Additionally, IgA influences intestinal microbiota composition. Objectives: This cross-sectional research aimed to assess fecal secretory immune globulin A (SIgA) among 70 patients with intestinal parasitic infections and 19 healthy volunteers as noninvasive fecal biomarker. Methodology: Part of each stool sample was examined macroscopically and microscopically to detect enteric parasites and ova (direct and concentrated wet mount). Modified Ziehl-Neelsen stain was used for coccidia detection. The other part was used in fecal SIgA measurement by ELISA. Results: Among patients’ group, 40% were males and 60% were females, 45.7% were from urban areas while 54.3% were from rural areas, with no statistical significance compared with healthy volunteers’ group. Frequency of diarrhea, constipation and abdominal colic increased significantly (P< 0.05), while nausea and vomiting were insignificant statistically compared to healthy volunteers. Within patients, 77.1% were infected with Blastocystis spp., 5.7% were coinfected Entamoeba histolytica and Blastocystis, 5.7% were infected with Entamoeba histolytica, 7.1% were infected with Giardia duodenalis and 4.3% were coinfected Giardia duodenalis and Blastocystis. Fecal SIgA concentration was significantly reduced in patients infected with Giardia duodenalis, Blastocystis or Entamoeba histolytica in comparison with healthy volunteers (P < 0.001). Conclusion: Secretory immunoglobulin A concentration was lower in intestinal parasitic infections including Blastocystis spp., Giardia duodenalis, Entameba histolytica compared with healthy volunteers.