We aimed to evaluate whether the occurrence of cryptic species of
Paracoccidioides brasiliensis
,
S1, PS2, PS3 and
Paracoccidioides lutzii
, has implications in the immunodiagnosis of paracoccidioidomycosis (PCM). Small quantities of the antigen
gp43 were found in culture filtrates of
P. lutzii strains and this molecule appeared to be more variable within
P. lutzii because the synonymous-nonsynonymous mutation rate was lower, indicating an evolutionary process different from that of the remaining genotypes. The production of
gp43 also varied between isolates belonging to the same species, indicating that speciation events are important, but not sufficient to fully explain the diversity in the production of this antigen. The culture filtrate antigen
AgEpm83, which was obtained from a
PS3 isolate, showed large quantities of
gp43 and reactivity by immunodiffusion assays, similar to the standard antigen (
AgB-339) from an
S1 isolate. Furthermore,
AgEpm83 was capable of serologically differentiating five serum samples from patients from the Botucatu and Jundiaí regions. These patients had confirmed
PCM but, were non-reactive to the standard antigen, thus demonstrating an alternative for serological diagnosis in regions in which
S1 and
PS2 occur. We also emphasise that it is not advisable to use a single antigen preparation to diagnose
PCM, a disease that is caused by highly diverse pathogens.
