Furthermore, the paracrine signals produced by cultured synovial tissues correspond to prior work where high G-CSF concentrations were found in the serum and synovial fluid of patients with RA and OA (Nakamura et al., 2000; Mabey et al., 2014), and where raised VEGF levels in RA and OA patients correlated with disease severity (Ballara et al., 2001; Mabey et al., 2014), demonstrating that the synovial tissue fragments can long-term retain their in vivo paracrine signature in the 3D culture setting. The gene discussed is CSF3; the disease is rheumatoid arthritis.