Some Irritable Bowel Syndrome (IBS) patients can be shown to have Blastocystis infection, while others do not, so there is a question as to whether the finding is clinically significant, and if scientific investigation of the Blastocystis infection would yield promising results. Researchers at Aga Khan University analyzing Peripheral Blood Mononuclear Cells (PBMC) have identified which cytokines are produced in significantly different levels in IBS patients infection with Blastocystis. The study analyzed PBMC’s from 80 D-IBS (diarrhea predominant IBS patients) without Blastocystis infection, with Blastocystis sp. subtype 1, and with Blastocystis sp. subtype 3. The researchers reported that although IL-8 expression was similar in the groups, in Blastocystis sp. subtype 1, IL-8 mRNA expression was increased compared with subtype 3 and controls (P=0.001). A statistically significantly lower level of IL-10 was found in PBMC’s from D-IBS infected with Blastocystis sp. subtype 1, when compared to controls and Blastocystis sp. subtype 3 (P<0.001), and this low IL-10 production was associated with lymphocyte and plasma cell infiltration (P=0.015 and 0.002 respectively). In both Blastocystis sp. subtype 1 and 3, IL-12 was associated with goblet cell depletion. The full study is available in the journal Parasitology.