FCGR3A and mixed connective tissue disease: Furthermore, the enhancement of the FcγRIIIA-stimulating activity of Ro60-containing ICs by RNase treatment was observed in samples from patients with MCTD, RA, SLE, and SS, and the enhancement of the FcγRIIIA-stimulating activity of La-containing ICs by RNase treatment was observed in samples from patients with SLE and SS (Figure 4, B and C, and Figure 7C).