03046nas a2200433   4500000000100000008004100001260001300042653001500055653001000070653002600080653002400106653002200130653002000152653003800172653002900210653001100239653003000250653001000280653001100290653001200301653000900313653001600322653002500338100001400363700001200377700001300389700001400402700002100416700001200437700001500449700001500464245012200479856005100601300001100652490000700663050003200670520189600702022001402598       2007                            d  c2007 Jun10aAdolescent10aAdult10aAntibodies, Bacterial10aAntigens, Bacterial10aBlotting, Western10aCross Reactions10aEnzyme-Linked Immunosorbent Assay10aFalse Positive Reactions10aFemale10aHIV Envelope Protein gp4110aHIV-110aHumans10aleprosy10aMale10aMiddle Aged10aMycobacterium leprae1 aHussain T1 aSinha S1 aKatoch K1 aYadav V S1 aKulshreshtha K K1 aSingh I1 aSengupta U1 aKatoch V M00aSerum samples from patients with mycobacterial infections cross-react with HIV structural proteins Gp41, p55 and p18.  uhttps://leprosyreview.org/article/78/2/13-7147  a137-470 v78  aInfolep Library - available3 a<p><b>BACKGROUND: </b>Infection with Mycobacterium leprae is associated with a high frequency of false positive results in a variety of serological assays. Our studies have found cross-reactivity to HIV structural proteins in serum samples from leprosy patients, irrespective of the type of disease, treatment duration, age and gender and from a few patients with active TB disease.</p><p><b>METHODS: </b>Western blot (WB) analysis revealed that sera from HIV negative leprosy patients across the spectrum showed high reactivity with p18, Gp41 and p55 and lower reactivity with other HIV proteins. The reactivity appeared to be specific; western blot-positive samples were negative in ELISA and in several rapid tests for HIV. Cross-reactivity was not found in sera from patients with leishmaniasis or from normal healthy individuals.</p><p><b>RESULTS: </b>None of the WB reactive leprosy patients seroconverted to HIV positivity within 6 months to 1 year after Western blot testing. BLAST analysis revealed that envelope antigens of HIV (Gp41, Gp120 and Gp160) contained amino acid sequences similar to M. leprae ML0470, putative integral membrane protein, Rv0740, mmpL9 (M. tuberculosis). Core (gag) antigens (p18) had similarities to ML0406, but polymerase antigens (p52) had similarities to PE_PGRS (M. tuberculosis, H37Rv). Nucleotide sequence analysis, on the other hand, did not reveal any significant homology between M. leprae or M. tuberculosis and HIV.</p><p><b>CONCLUSIONS: </b>The occurrence of these high false-positive rates in M. leprae-infected individuals suggests a possible complication of serodiagnosis of HIV in regions where mycobacterial infections are endemic. There is a need for caution in reporting HIV infection among leprosy patients. Our observations emphasise the value of the various rapid assay kits for HIV, where this false positivity is not observed.</p>  a0305-7518