- Platelets can modulate the role of lymphocytes in the development of micro- and macrovascular complications in type 1 diabetes mellitus. To clarify the status of platelet-lymphocyte aggregation in circulating blood in patients with T1DM, as well as the differences in the platelet-lymphocyte aggregation in T1DM patients with and without diabetic nephropathy. We recruited 115 T1DM patients (47 men and 68 women) aged 15-52 years. The subjects with mean albumin excretion > or = 5 microg/mg creatinine comprised group 1, and those with < 5 microg/mg creatinine comprised group 2. The matched healthy participants (n=50) served as the control group. Detection of LPA was achieved using a light microscope after Ficoll-gradient centrifugation. Immunophenotyping of lymphocytes was performed by flow cytometry. Significantly more LPA (430.4 +/- 20.6/microl) were observed in group 2 compared with group 1 (223.9 +/- 12.8/microl, P< 0.001) and the control group (296.1 +/- 22.6/microl, P=0.027). In group 1 significantly more LPA/CD4 (21.1 +/- 1.6%) and LPA/(CD4 + NK) (17.8 +/- 1.7%) were found than in group 2 and the control group. T1DM with diabetic nephropathy is associated with higher levels of LPA than T1MD without diabetic nephropathy. The role of LPA in microvascular complications in diabetes should be elucidated in further studies.