CD45 ISOFORMS EXPRESSION ON CD4(-BLOOD T-LYMPHOCYTES IS RELATED TO AUTOIMMUNE PROCESSES AND HEMATOLOGICAL MANIFESTATIONS IN SYSTEMIC LUPUS-ERYTHEMATOSUS() AND CD8(+) PERIPHERAL)

We investigated whether, in systemic lupus erythematosus (SLE), the CD 45 isoforms expression on peripheral blood T-lymphocytes (T-PBL) is re lated to the auto-immune processes and hematological manifestations. T he CD45RA/RO patterns of CD4(+) and CD8 bright(+) T-PBL were determine d by three-colour flow cytometry. The serum levels of antinuclear (ANA ), anti-double stranded DNA (ds DNA) and anti-cardiolipin (CL) autoant ibodies were quantified by ELISA. The hematological parameters were ro utinely assessed. 72% of SLE patients (n = 29) had reduced lymphocyte counts, which correlated with more severe physician's assessment of di sease activity. increased ANA and anti-ds DNA autoantibodies. The lymp hopenia preferentially affected the CD4(+) T-PBL and, among them, the ''naive'' CD45RA(+), RO(-) cells. Thus, compared with healthy women (n = 29), SLE patients had less naive and more ''transient'' CD45RA(+), RO(+) cells among CD4(+) T-PBL. Meanwhile, on average, the CD45 isofor ms expression on CD8(+) T-PBL was unchanged. Interestingly, in 3 patie nts who were repeatedly evaluated, increases of transient CD8(+) T-PBL paralleled the elevation of anti-ds DNA. In addition, high anti-CL wa s associated with more transient CD4(+) and CD8(+) T-PBL. The loss of naive and increase of transient CD8(+) T-PBL was associated with incre ased disease activity and possibly hemolytic anemia. Thus, in SLE, the enhanced phenotypic switch from naive CD45RA(+), RO(-) to ''memory'' CD45RO(+) T-PBL patterns paralleled the auto-immune processes characte ristic of this disease.