IL-5 expressed by CD4+ lymphocytes from Echinococcus multilocularis-infected patients

Area of Science:

• Immunology
• Parasitology
• Molecular Biology

Background:

• Interleukin-5 (IL-5) is crucial for B lymphocyte differentiation and eosinophil regulation.
• Peripheral blood mononuclear cells (PBMC) from alveolar echinococcosis (AE) patients express IL-5 mRNA after stimulation with Echinococcus multilocularis (E.m.) antigen.
• Characterizing lymphocyte subpopulation responses to E.m. antigen is key to understanding AE pathogenesis.

Purpose of the Study:

• To investigate the specific lymphocyte subpopulations responsible for IL-5 mRNA expression in AE patients.
• To correlate IL-5 expression with clinical disease status in AE patients.
• To elucidate the type of immune response (Th1 vs. Th2) in chronic E. multilocularis infection.

Main Methods:

• Peripheral blood mononuclear cells (PBMC) from AE patients were cultured with E.m. crude antigen.
• PBMC subpopulations (CD4+, CD8+) were isolated using fluorescence-activated cell sorting (EPICSorter) and magnetic cell sorting (MACS).
• Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect mRNA expression of various cytokines (IFN-gamma, IL-2, IL-3, IL-4, IL-5, IL-6, IL-10).

Main Results:

• IL-4 and IFN-gamma were expressed in all stimulated CD4+ T cell samples.
• IL-5 mRNA was detected in 58% of CD4+ samples from AE patients, but not in other subpopulations or controls.
• IL-5 expression, along with Th2 cytokines IL-3 and IL-10, was significantly higher in critically ill patients compared to cured or stabilized patients.

Conclusions:

• Specific antigenic challenge of AE patients' PBMC induces an IL-5 response primarily in CD4+ lymphocytes.
• The observed Th2-type immune response, marked by IL-5, IL-3, and IL-10 expression, is significantly associated with progressive alveolar echinococcosis.
• Elevated IgE levels in critically ill patients further support a Th2-dominant immune response in active E. multilocularis infection.