Case Report: Misleading Serological Diagnosis of Paracoccidioidomycosis in a Young Patient with the Acute Form Disease: Paracoccidioides brasiliensis or Paracoccidioides lutzii?

Abstract

Negative results in serological routine screening of patients with microbiologically proven Paracoccidioidomycosis (PCM) are occasionally reported. Failure in detecting anti- antibodies has been ascribed to factors either related to serological techniques or to the status of the host immune reactivity. Recently, this issue has been renewed by the recognition that the genera comprises two species, and , which have distinct antigenic profiles and, therefore, may elicit different host antibody responses. We describe a patient with the acute form PCM due to with negative results on two reference centers' routine screening for antibodies, but positive results with antigens. The present case report suggests that antibodies elicited during infection recognize antigenic fractions shared by both species, highlighting the difficulties in distinguishing the two infections by means of the currently available routine serological assays.

Comparison of clinico-epidemiological and radiological features in paracoccidioidomycosis patients regarding serological classification using antigens from Paracoccidioides brasiliensis complex and Paracoccidioides lutzii

“…In addition, these sera have 100% reactivity against CFA obtained from P. lutzii isolates [18], and 100% sensitivity (IC 80.5-100) and 100% specificity (IC 94-100) of CFAPl have been reported [6]. Although other studies show CFAPl is not specific antigen for P. lutzii [17,19], patients seropositive to CFAPl and seronegative to gp43 have PCM presumably caused by P. lutzii [6]. In contrast, patients seronegative to CFAPl and seropositive to gp43 have PCM presumably caused by the P. brasiliensis complex [6].…”

“…Although other studies show CFA Pl is not specific antigen for P . lutzii [ 17 , 19 ], patients seropositive to CFA Pl and seronegative to gp43 have PCM presumably caused by P . lutzii [ 6 ].…”

“…lutzii , since there are rare reports of molecularly confirmed PCM by P . brasiliensis complex seropositive for CFA Pl [ 19 ], or seronegative for gp43 [ 36 ]. and much rarer is the occurrence of both exceptions at the same time.…”

“…Another limitation is the non-molecular identification of the etiological agent. However, the serological strategy used in order to define PCM by P. lutzii could falsely identify a P. brasiliensis complex isolate as P. lutzii, since there are rare reports of molecularly confirmed PCM by P. brasiliensis complex seropositive for CFAPl [19], or seronegative for gp43 [36]. and much rarer is the occurrence of both exceptions at the same time.…”

Polyclonal antibodies to Paracoccidioides brasiliensis are able to recognise antigens from different strains from Paracoccidioides species complex, including Paracoccidioides lutzii LDR2

“…A recent case report demonstrated once more how difficult the serodiagnosis of PCM is. An acute PCM patient infected with P. brasiliensis did not react with this species antigens in routine testing (immunodiffusion), only with P. lutzii 's, suggesting recognition of antigens shared by both species.…”