RESUMO
Blastocystis parasites are common intestinal parasites found in various hosts, including humans. This study involved two groups: the patient group, consisting of 220 samples, and the control group, consisting of 100 samples. The participants' age range was 4-40 years, and the samples were obtained from Al-Kadhimiya Teaching Hospital and Al-Shaheed Mohammed Baqir Al-Hakeem Hospital in Baghdad, Iraq. Stool samples were examined under a light microscope using Lugal's Iodine Stain and direct wet smears. The age group did not show a significant difference (P≥0.05) in patients with diarrhea infected with the Blastocystis hominis parasite compared to the control group. Furthermore, males had a higher infection rate (58.00%) compared to females (42.00%), and this rate was statistically significant (P≤0.05). The aim of this study was to evaluate the effect of Blastocystis hominis infection on the levels of certain immunological parameters. The results of the ELISA technique for immunological examinations revealed a significant increase (P≤0.01) in the levels of IL-10 and IL-17 in the serum of patients with diarrhea infected with the Blastocystis hominis parasite compared to the control group. The immunological tests also showed a significant increase (P≤0.01) in IgG, IgM antibodies, and IgA levels in patients with diarrhea infected with Blastocystis hominis parasite compared to the control group. These findings suggest that Blastocystis infection may influence immunological responses.