Position 26 of the first domain of the HLA-DQB1 allele in post-silicone implant scleroderma

Objective. To determine whether women with scleroderma (systemic sclerosis, SSc) and silicone implants have the same or distinctive immunogenetic findings compared to those reported for idiopathic scleroderma. Methods. In this case-control study, 9 Caucasian women with SSc and silicone implants (7 breast, 1 chin, 1 toe) and 128 healthy Caucasian controls were typed for HLA class II (DRB1,3,4,5, and DQB1) by DNA polymerase chain reaction (PCR) sequence specific oligonucleotide probes (SSOP). Results. All women with SSc had HLA-DQ5 or DQ7 (DQB1*0301). These 2 alleles have glycine (Gly) or tyrosine (Tyr), and not hydrophobic leucine (Leu), at position 26 in the 2nd hypervariable region of the DQB1 first domain. The increased frequency of at least one Leu 26 negative allele (Gly+ or Tyr+) in the women with SSc (100%) compared with controls (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-DQB1 first domain in our cases with SSc and silicone implants is consistent with immunogenetic findings reported in Caucasians with idiopathic SSc and anticentromere autoantibodies. Whether all the immunogenetic features in SSc associated with silicone implants remain indistinguishable from those seen in idiopathic SSc requires confirmation.