Reduced frequency of blood group Lewis a−b− in female Type 1 diabetes patients

Aims To examine a disputed association between the Lewis(a−b−) phenotype and Type 1 diabetes (T1D). Methods Lewis red blood cell phenotyping was performed for 97 T1D White patients and 100 control subjects using monoclonal antibodies. Two historical cohorts were also included as a control population. Results T1D patients had a lower frequency (4.1%) of Lewis(a−b−) blood group compared with simultaneously tested healthy control subjects (10.0%) and the historical control group (11.1%, P = 0.02). Male T1D patients showed a Lewis(a−b−) frequency of 8.0%, which was similar to both matched healthy male donors (9.8%) and historical (9.5%) male control subjects. Unexpectedly, none of the female T1D patients displayed Lewis(a−b−) phenotype, vs. 10.3% and 10.8% of female control subjects (P = 0.039 and 0.017). Conclusions The Lewis(a−b−) phenotype occurs less frequently in T1D compared with healthy control subjects with a strong female gender bias.