Development of a dendrimer PAMAM-based gold biochip for rapid and sensitive detection of endogenous IFN-γ and anti-IFN-γ IgG in patients with hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare but severe disease characterized by immune hyperactivation and cytokine storm. Given the high mortality rate of HLH, there is a need for more effective diagnostic tools and treatments. The present study developed a dendrimer-based protein biochip for rapid, sensitive and simultaneous detection of serum interferon (IFN)-γ and endogenous anti-IFN-γ antibody (Ab) in patients with HLH. A gold biochip was modified with 1, 4-phenylene diisothiocyanate (PDITC), polyamidoamine (PAMAM) or PDITC-activated PAMAM. The optimal immobilization concentration for Ab capture and the reaction concentration for detecting Ab on the PDITC-activated PAMAM-modified biochip were 6.25 and 3.12 µg/ml, respectively; the limit of detection of IFN-γ protein was 50 pg/ml. The efficiency of the protein-probed biochip in detecting IFN-γ and anti-IFN-γ Ab in serum samples from 77 patients with HLH was evaluated; the positive rates for IFN-γ and anti-IFN-γ IgG Ab were 63.6% (49/77) and 61.0% (47/77), respectively. The present results demonstrated that the PDITC-activated PAMAM-modified biochip might be a sensitive tool for the specific detection of IFN-γ and anti-IFN-γ Ab in serum, and might have clinical applicability for the diagnosis of HLH.