Not long after, in 1999, it was realized that the exosome was in fact the yeast equivalent of an already described complex in human cells called the PM/Scl complex, which had been identified as an autoantigen in patients with certain autoimmune diseases years earlier (see below).
Non moito tempo despois, en 1999, comprobouse que o exosoma era de feito o equivalente do complexo xa descrito en células humanas, coñecido como complexo PM/Scl, que fora identificado como un autoantíxeno en pacientes con certas doenzas autoinmunes en anos anteriores.