Low copy numbers of human T-cell lymphotropic virus type I (HTLV-I) tax-like DNA detected in the salivary gland of seronegative patients with Sjögren's syndrome in an HTLV-I endemic area.
To evaluate the hypothesis, proposed in previous reports from HTLV-I non-endemic areas, that HTLV-I is involved in a significant proportion, about a quarter, of Sjögren's syndrome patients who lack serum antibodies to the virus, we examined for the presence or absence of HTLV-I in DNA samples isolated from salivary gland tissues of 17 seronegative as well as 7 seropositive patients with Sjögren's syndrome in Nagasaki, Japan, where the virus is highly endemic. The nested two-step polymerase chain reaction (PCR), with a sensitivity capable of detecting a single DNA molecule, failed to amplify the HTLV-I tax sequence from DNA of 14 of the 17 seronegative patients. The tax was only amplifiable from the tissue DNA of the remaining three seronegative patients. The detection rate, 3/17 (18%), was, unexpectedly, less than those previously reported from the HTLV-I non-endemic areas. Moreover, in contrast to high viral loads (10(-1) to 10(-3) per cell) in the salivary gland of the seropositive patients, a semiquantitative PCR revealed that the copy number of the HTLV-I tax in the gland tissue of these seronegative patients was very low, 10(-5) per cell. This level is unlikely to be sufficient to promote an inflammatory reaction in the tissue. Our findings might argue against the involvement of "prototype" HTLV-I in the pathogenesis of Sjögren's syndrome in seronegative patients.
Mizokami
A
A
Department of Bacteriology, Nagasaki University School of Medicine, Japan.
Eguchi
K
K
Moriuchi
R
R
Futsuki
Y
Y
Terada
K
K
Nakamura
H
H
Miyamoto
T
T
Katamine
S
S
D000328:Adult; D000368:Aged; D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D004279:DNA, Viral / Q000032:analysis*; D019353:Endemic Diseases; D005260:Female; D018628:Gene Dosage; D016356:Gene Products, tax / Q000737:chemistry / Q000235:genetics*; D015490:HTLV-I Infections / Q000453:epidemiology; D015368:Human T-lymphotropic virus 1 / Q000302:isolation & purification*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011533:Proviruses / Q000737:chemistry; D012469:Salivary Glands / Q000821:virology*; D012859:Sjogren's Syndrome / Q000821:virology*
D017931:DNA Primers; D004279:DNA, Viral; D016356:Gene Products, tax