Objective. Antibodies to Th/To ribonucleoprotein (anti-Th/To) have been det
ected almost exclusively in patients with systemic sclerosis. Therefore, we
aimed to determine the prevalence of anti-Th/To in patients with localized
scleroderma.
Methods. Seventy serum samples from patients with localized scleroderma wer
e examined by RNA immunoprecipitation and indirect immunofluorescence analy
sis using HEp-2 cells as substrate.
Results. Three (4%) of 70 sera from patients with localized scleroderma imm
unoprecipitated 7-2 (Th) RNA and 8-2 (To) RNA. Indirect immunofluorescence
analysis demonstrated that all the sera positive for anti-Th/To showed main
ly nucleolar staining. In one patient, the coexistence of anti-histone anti
body with anti-Th/To was detected by enzyme-linked immunosorbent assay for
anti-histone antibody and confirmed using an absorption test with histones
followed by indirect immunofluorescence analysis. Moreover, the localized s
cleroderma patients with anti-Th/To tended to have significantly fewer scle
rotic lesions than those without.
Conclusion. Anti-Th/To is one of the serological abnormalities in localized
scleroderma, and the presence of anti-Th/To may be a serological indicator
of a mild form of cutaneous involvement.