Antibodies against SM can be considered as pathognomonic for SLE, along with antibodies against dsDNA, nucleosomes and ribosomal P-protein. SM antibodies are detected in 5% to 40% of SLE patients. Whereas the prevalence in caucasians is approximately 10%, it is much higher in other ethnic groups, e.g. of Arabic, Chinese or Black African background. In American studies investigating a high proportion of non-caucasians, prevalences of 20% to 40% were found.