POSITION-26 OF THE FIRST DOMAIN OF THE HLA-DQB1 ALLELE IN POST-SILICONE IMPLANT SCLERODERMA

Objective. To determine whether women with scleroderma (systemic scler osis, SSc) and silicone implants have the same or distinctive immunoge netic findings compared to those reported for idiopathic scleroderma. Methods. In this case-control study, 9 Caucasian women with SSc and si licone implants (7 breast, 1 chin, 1 toe) and 128 healthy Caucasian co ntrols were typed for HLA class II (DRB1,3,4,5, and DQB1) by DNA polym erase chain reaction (PCR) sequence specific oligonucleotide probes (S SOP). Results. All women with SSc had HLA-DQ5 or DQ7 (DQB10301). Thes e 2 alleles have glycine (Gly) or tyrosine (Tyr), and not hydrophobic leucine (Leu), at position 26 in the 2nd hypervariable region of the D QB1 first domain. The increased frequency of at least one Leu 26 negat ive allele (Gly+ or Tyr+) in the women with SSc (100%) compared with c ontrols (73%) was not statistically significant. In contrast, the low frequency of one Leu 26+ allele in the patients (28 vs 57%, p = 0.03, RR = -3.3) and 2 Leu 26+ alleles (0 vs 35%, p = 0.03, RR = -10.4) was significant. Conclusion. The presence of Gly 26 or Tyr 26 in the HLA-D QB1 first domain in our cases with SSc and silicone implants is consis tent with immunogenetic findings reported in Caucasians with idiopathi c SSc and anticentromere autoantibodies. Whether all the immunogenetic features in SSc associated with silicone implants remain indistinguis hable from those seen in idiopathic SSc requires confirmation.