IGHA1 and systemic lupus erythematosus: Beyond total IgA fraction, this antibody isotype consists of two subclasses in humans where their proportions vary depending on the mucosal site: in saliva, we usually detect around 60% of IgA1 and close to 40% of IgA2 in healthy individuals (30); however, there was no previous data on salivary IgA subtypes in autoimmune diseases such as SLE.