BACKGROUND Maxadilan (Max) is a salivary component in the sandfly
Lutzomyia longipalpis
(Lutz & Neiva 1912), a vector of
visceral leishmaniasis. Max has a powerful vasodilatory effect and is a candidate vaccine that has been tested in experimental
leishmaniasis.
Nyssomyia neivai (Pinto 1926) is a vector of the pathogen responsible for American tegumentary leishmaniasis
(ATL) in Brazil.
OBJECTIVE We searched for Max expression in
Ny. neivai and for antibodies against Max in ATL patients.
METHODS cDNA and protein were extracted from the cephalic segment, including salivary glands, of
Ny. neivai and analysed
by polymerase chain reaction, DNA sequencing, and blotting assays. The results were compared with data obtained from
Lu.
longipalpis samples. We quantified antibodies against Max in serum samples from 41 patients with ATL (31 and 10 with the
cutaneous and mucocutaneous forms, respectively) and 63 controls from the endemic northeastern region of São Paulo state,
using enzyme-linked immunosorbent assay.
FINDINGS Recognition of a Max-simile peptide by specific antibodies confirmed expression of a Max sequence in
Ny. neivai
(GenBank EF601123.1). Compared to controls, patients with ATL presented higher levels of antibodies against Max (p = 0.004);
24.4% of the patients with ATL and 3.2% of the controls presented anti-Max levels above the cutoff index (p = 0.014). The anti-
Max levels were not associated with the specific clinical form of ATL, leishmanin skin test response, absence or presence of
amastigotes in histopathologic exam, results of indirect immunofluorescence testing for leishmaniasis, or duration of cutaneous
form disease.
MAIN CONCLUSION High serum anti-Max levels did not protect patients against ATL, but confirmed previous natural exposure
to Ny. neivai bites in this ATL endemic region.
