Thus, we showed that in MCTD not only do the anti-U1 C-RNP- and -RNP 68 (U1 snRNP68/70) antibodies belong quite frequently to the IgE-type – as already reported -, but also the anti-Sm/RNP B- and -RNP A- autoantibodies. Here, IGHE is linked to mixed connective tissue disease.