LYMPHOCYTE SUBPOPULATIONS, INTERLEUKIN-2 AND INTERLEUKIN-2 RECEPTOR EXPRESSION IN CHILDHOOD NEPHROTIC SYNDROME

Abnormal T lymphocyte function and reduced interleukin-2 (IL-2) produc tion have been implicated in the pathogenesis of the nephrotic syndrom e (NS). We investigated: (1) lymphocyte subpopulations and expression of IL-2 receptor (IL-2R) on T cells using two-colour flow cytometry, ( 2) serum IL-2 and (3) the soluble component of IL-2R (sIL-2R) in serum , using enzyme-linked immunosorbent assay, in 38 children with NS. All children, except those in remission, had marked proteinuria. They wer e divided into groups according to renal pathology: (1) steroid-sensit ive NS (SSNS) not receiving prednisolone therapy, (2) SSNS on predniso lone, (3) focal segmental glomerulosclerosis (FSGS), (4) SSNS in remis sion and not receiving prednisolone therapy, (5) congenital NS (CNS). Results were compared with 26 age-matched controls. Total T lymphocyte s (CD3) were reduced in groups 1 and 2; CD4 count was reduced in group s 1-4; CD8 count increased in groups 2 and 3; CD8 and CD19 (B lymphocy tes) were significantly reduced in group 5. Increased IL-2R expression (CD25) on CD4 lymphocytes was noted in groups 1, 2 and 3 implying act ivation of these cells. In patients with SSNS, increased serum sIL-2R was recorded during relapse (1,273 +/- 497 U/l vs. 913 +/- 401 U/l in remission, P <0.005) but free serum IL-2 was not detectable at any sta ge. The specific alterations in lymphocyte subpopulations in SSNS and FSGS would imply an involvement of the immune system distinct from tha t in CNS.