Differential effects of legacy and new-generation perfluoro-alkyl substances on in vitro differentiation and immunoglobulins production by B cells.

Perfluoro-alkyl substances (PFAS) are persistent environmental pollutants suggested to impair antibody response. Legacy PFAS, such as perfluoro-octanoic acid (PFOA), are largely investigated but little is known about the role of emerging alternatives such as C6O4. This study investigated the differential effects of PFOA and C6O4 on human B cell differentiation, activation, and immunoglobulin production in vitro. Peripheral blood mononuclear cells and purified B lymphocytes from healthy donors were exposed to increasing concentrations (20-100 ng/mL) of PFOA or C6O4. T cell-dependent interferon-γ release and CD40L expression were unaffected by the exposure to either compounds. However, CD69 mean fluorescence intensity showed a dose-dependent reduction upon PFOA exposure, in addition to a halved IL-4 secretion compared to stimulated controls. PFOA 100 ng/mL also reduced B cell proliferation by approximately 30%, significantly decreased CD69 + and CD83 + B cells by 25-40%, and altered subset composition with a 20% increase in naïve cells and a 15% reduction in marginal zone-memory cells. In long-term B cell cultures, PFOA was associated with delayed and smaller cluster formation, with halved cluster area from day 5 onwards and suppressed IgG secretion by 30-45% at all time points. C6O4 was associated with 20% reductions in IgG release at days 3-6. PFOA seems to impact the immune function by both impairing T cell-dependent IL-4 production and by directly affecting B cell maturation and antibody production, resulting in robust immunosuppression. Differently, C6O4 appears less impactful. These findings underscore the need for compound-specific risk assessment of PFAS, supporting the continuity of monitoring.