Elevated serum concentrations of ganglioside antigen CA19-9 has been often found in poorly-controlled diabetes mellitus. However, this phenomenon is not constantly observed in all cases. To analyse the mechanism of CA19-9 and CA50 elevation, eighteen poorly-controlled diabetic patients who were confirmed not to have malignancy by thorough examinations, were investigated for Lewis phenotypes (Le), because Lea has the same epitope as CA19-9. Patients were divided into three groups according to the phenotype of Lewis blood type as follows: group A (A): 6 patients with Le (a+b-); group B (B): 8 patients with Le (a-b+); and group C (C): 4 patients with Le (a-b-). Each group was similar in age range (A: 55.7+12.8, B: 46.0±15.6, C: 62.0±21.0 years old), hemoglobin Al c level (A: 12.78±0.89, B: 12.03±1.02, C: 13.58+3.21%) and serum fructosamine level (A: 5.33±0.28, B: 4.81±0.59, C: 5.45±1.46 mmol/l). The CA19-9 levels were highest in A (91.7±45.9 U/m l), moderately elevated in B (27.9±8.6 U/m/) and low in C (6.3±1.9 U/ml)(A vs B: p<0.01, A vs C and B vs C: p<0.05). The CA50 levels were highest in A (43.3±20.6 U/ml), moderately elevated in B (17.1±13.9 U/m l) and low in C (1.2±0.5 U/ml)(A vs B: p<0.01, A vs C and B vs C: p<0.05).
These results indicate that elevated serum CA19-9 level in diabetic patients with poor metabolic states is closely related to Lewis phenotype and suggest that the mechanism of CA19-9 and CA50 elevation in diabetic patients is different from that in patients with neoplasms such as pancreatic cancer.