Role of PGL-I antibody detection in the diagnosis of pure neural leprosy.
Pure neural leprosy (PNL) is difficult to diagnose because skin lesions and acid-fast bacilli (AFB) in slit smears are absent. At present, the gold standard for PNL diagnosis is the histopathological examination of a peripheral nerve biopsy. Even so, detection of bacteria is difficult and histological findings may be non-specific. Furthermore, nerve biopsy is an invasive procedure that is only possible in specialized centres. Therefore, there is a need for additional diagnostic methods that may help to confirm the clinical diagnosis of PNL. In the present study, an additional laboratory test, the ELISA for anti-phenolic glycolipid I (PGL-I) IgM antibodies, was performed on 103 individuals with clinical and neurophysiological signs of peripheral neuropathy, of which 67 were diagnosed as PNL patients and 36 remained as 'not diagnosed as PNL', as well as on a control group of 34 patients with other neurological diseases. An antibody response was present in 14/67 (21%) of the patients diagnosed as PNL as compared with 3/34 (9%) of controls. Anti-PGL-I positivity was observed in 5/8 (63%) of the AFB positive cases. Patients whose diagnosis was confirmed solely by Mycobacterium leprae PCR on the nerve sample had 4/25 (16%) seropositivity. In addition, anti-PGL-I antibodies were detected in 9/40 (23%) of the PNL patients who were PCR negative for M. leprae DNA. Moreover, two patients who showed clinical and eletrophysiological manifestations suggestive of PNL were diagnosed with the help of their positive test results in the anti-PGL-I ELISA. In conclusion, detection of antibodies against PGL-I in patients with peripheral neuropathy is useful as an additional laboratory test to help PNL diagnosis.
Jardim
Marcia R
MR
Leprosy Laboratory, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil.
Antunes
Sergio L G
SL
Simons
Brian
B
Wildenbeest
Joanne G
JG
Nery
José Augusto C
JA
Illarramendi
Ximena
X
Moraes
Milton O
MO
Martinez
Alejandra N
AN
Oskam
Linda
L
Faber
William R
WR
Sarno
Euzenir N
EN
Sampaio
Elizabeth P
EP
Bührer-Sékula
Samira
S
D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology*; D006017:Glycolipids / Q000276:immunology*; D006801:Humans; D015441:Leprosy, Tuberculoid / Q000175:diagnosis* / Q000276:immunology*; D009166:Mycobacterium leprae / Q000276:immunology*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D006017:Glycolipids; C045169:phenolic glycolipid I, Mycobacterium leprae