Tcell(18)and B cell(21) proliferation

levels of IgM

IgG and IgG subclasses both induced byPWM in Vitro(20) and in serum(18)

activities of B cell growth factors (BCGF

35)

B cell differencia-tion factors(BCDF

25)and interleukin- 6(IL-6.39) were measured in children with idiopathic nephroticsyndrome(INS).The results showed that comparing with normal controls

the levels of IgG

IGGI

IgG2and IgG4 were significantly decreased both in vitro and in serum in patients

but not with IgG3 andIgM

There were a predominant inhibitions of T and B cell proliferation function as well as deficientactivities of BCGF. BCDG and IL-6 to be found in children with active INS.The decreased activitv of3CGFwas correlated with B cell proliferation

while the defect activities of BCDF and IL-6were tohave a significant correlation with IgG production in vitro

These findings suggest that an aberation ofIg switch may be present in B cells from patients with active INS

which results in hypoimn1unoglob-ulinemia G

and in which the dvsfunction of T cell and their lymphokines probably plays an importantrole.