Immunohistochemical assessment of M1/M2 macrophage phenotypes in hepatic hydatid disease

Macrophages are key immune defenders in hydatid disease. While M1 macrophages express iNOS and M2 macrophages express TGF-β, the relationship between STAT6 activation and macrophage subsets remains unclear in hydatid disease.

The study included 60 patients with visceral hydatid disease, and cyst specimens were categorized as either fertile or non-fertile hydatid cysts. Immunohistochemical analysis was performed using antibodies against CD68, iNOS, TGF-β, and STAT6.

CD68 was detected in all hydatid cases, while iNOS, TGF-β, and STAT6 were expressed in 86.7%, 78.3%, and 83.3% of cases, respectively. There was no significant difference in the expression levels of these markers between fertile and non-fertile cysts (p > 0.05). A positive serological result was significantly correlated with higher CD68 and lower TGF-β H-score expression (p = 0.024 and p = 0.047, respectively). TGF-β expression was significantly associated with cyst multiplicity (p = 0.045). CD68 H-scores were positively associated with iNOS, TGF-β, and STAT6 expression levels (p < 0.001, each). STAT6 expression was significantly associated with both iNOS and TGF-β positivity (p = 0.021 and p < 0.001, respectively).

Macrophage infiltration appears to influence the course of hydatid disease. Both M1 and M2 macrophage phenotypes are present in fertile and non-fertile hydatid cysts. STAT6 may contribute to macrophage infiltration in hydatid disease without a preferential association with a specific macrophage subtype. This observational study requires further validation using single-cell and multiplex approaches.