In vitro responses of PBMC and fibroblasts from patients with TRIF deficiency after TRIF dependent and independent stimuli

We report here unrelated HSE patients with autosomal recessive (AR) or autosomal dominant (AD) TRIF deficiency. The AR form of the disease is due to a homozygous nonsense mutation, resulting in a complete absence of the TRIF protein. Both the TLR3 and the TRIF-dependent TLR4 signaling pathways are abolished. The AD form of TRIF deficiency is due to a heterozygous missense mutation resulting in a dysfunctional protein. The TLR3 signaling pathway is impaired, whereas the TRIF-dependent TLR4 pathway is unaffected. Both patients however showed reduced capacity to respond to cytosolic double stranded RNA, consistent with recent reports of TRIF’s involvement in the DExD/H-box helicases pathway. Skin fibroblast cell lines were derived from healthy controls (n=3), patient with deficiencies for TRIF (n=1), MYD88 (n=1), and TLR3 (n=1) and cultured for 4 hours in the presence of IL1B (20ng/ml) or poly I:C (25ng/ml) or left unstimulated for the same length of time. PBMCs (previously frozen) collected from a healthy control (n=1) and patients with deficiencies for TRIF (n=1), and MYD88 (n=1) were cultured together with LPS (10ng/ml) or R848 (3ug/ml) for 2hrs or left unstimulated for the same length of time.