Objective To study the immune function of T-lymphocyte and erythrocyte in the peripheral blood of children with febrile convulsion. Methods Eighty-two children with typical febrile convulsion, 40 children with acute upper respiratory tract infection (URI) and 40 normal children were enrolled. The proliferation reaction of T-lymphocyte to PHA, distribution of T-lymphocyte phenotype subsets, expression of activation markers CD25 (IL-2R) and HLA-DR, and level of γ-interferon induced by PHA were assayed. Erythrocyte immune function was simultaneously measured by rosette formation rates of RBC-C3bR and RBC-IC. Results The counts per minute (CPM) and stimulation index (SI), the measurements expressing T-lymphocyte proliferation assay in simple febrile convulsion (SFC) children, were 5 609.4± 3 587.4 and 20.5± 15.6, and 2 817.3± 2 422.8 and 11.0± 8.4 in complex febrile convulsion (CFC) children. They were significantly lower than those in the normal controls ( 20 305.9± 12 810.3 and 69.2± 45.2) and in the URI group ( 9 785.2± 7 509.8 and 44.5± 39.8) (P< 0.05). The CD3, CD4 and CD4/CD8 ratio in the SFC children were ( 40.0± 8.2)%, ( 26.1± 9.0)% and 1.1± 0.4 and ( 932.8± 6.9)%, ( 17.8± 4.9)% and 0.8± 0.1 in the CFC children. They were all significantly lower than those in the normal controls [( 64.1± 6.7)%, ( 47.7± 5.5)% and 1.9± 0.8] and in the URI group [( 63.0± 9.3), ( 42.4± 8.2)% and 1.6± 0.4] (P< 0.01). The expression rates of CD25 (IL-2R) and HLA-DR antigen in the spontaneous condition in the SFC children were ( 8.9± 3.6)% and ( 16.2± 5.6)% and ( 6.3± 1.9)% and ( 12.4± 3.4)% in the CFS children. They were lower than those in the normal controls [( 12.8± 2.5)% and ( 20.2± 5.2)%]and in the URI group [( 15.0± 3.0)% and ( 20.5± 2.8)%] (P< 0.01) and there were also differences in the SFC children and in the CFS children (P< 0.05). After PHA induction, the expression rates of CD25 (IL-2R) and HLA-DR antigen in the SFC children were ( 57.0± 5.1) and ( 57.8± 6.0) and ( 53.0± 12.0)% and ( 54.7± 9.7)% in the CFC children. They were significantly lower than those in the normal controls [( 65.7± 5.7)% and ( 68.8± 6.2)%] (P< 0.05) and in the URI group [( 64.3± 6.4)% and ( 67.1± 8.6)%](P< 0.01). The γ-IFN level of PBMC induced by PHA in the SFC and CFC children [( 1.80± 0.4) and ( 1.6± 0.1) ng/ml] was significantly lower than that in the normal controls [( 2.4± 0.9) ng/ml](P< 0.05). No difference was found compared with the URI group. The rate of rosette formation of RBC-C3b in the SFC children was ( 9.1± 4.9)% and it was significantly lower than that in the normal controls and the URI group [( 15.8± 5.7)% and ( 13.5± 5.1)%](P< 0.01), but there was no difference in the SFC children, the normal controls and the URI group. The rate of rosette formation of RBC-IC in the SFC children and the CFC children [( 3.0± 1.0) and ( 2.6± 0.7)%] was significantly lower than that in the normal controls [( 3.7± 1.3)%] and the URI group [( 3.9± 1.4)%](P< 0.05). Conclusions Both T-lymphocyte immune function and erythrocyte immune function in the children with FC were significantly impaired. The impair was more severe in the CFC children than that in the SFC children. Objective To study the immune function of T-lymphocyte and erythrocyte in the peripheral blood of children with febrile convulsion. 40 Methods Eighty-two children with typical febrile convulsion, 40 children with acute upper respiratory tract infection (URI) and 40 normal children were enrolled. The proliferation reaction of T-lymphocyte to PHA, distribution of T-lymphocyte phenotype subsets, expression of activation markers CD25 (IL-2R) and HLA-DR, and level of γ-interferon induced by PHA were assayed. Erythrocyte immune function was done measured by rosette formation rates of RBC-C3bR and RBC-IC. Results The counts per minute (CPM) and stimulation index (SI), the measurements expressing T-lymphocyte proliferation assay in simple febrile convulsion (SFC) children, were 5 609.4 ± 3 587.4 and 20.5 ± 15.6, and 2 817.3 ± 2 422.8 and 11.0 ± 8.4 in complex febrile convulsion (CFC) children. They were significantly lower than those in the normal controls (20 305.9 ± (P <0.05). The CD3, CD4 and CD4 / CD8 ratio in the SFC children were (40.0 ± 8.2)%, (26.1 ± 9.0)% and 1.1 ± 0.4 and (932.8 ± 6.9)%, (17.8 ± 4.9)% and 0.8 ± 0.1 in the normal controls [(64.1 ± 6.7) %, (47.7 ± 5.5)% and 1.9 ± 0.8] and in the URI group [(63.0 ± 9.3), (42.4 ± 8.2)% and 1.6 ± 0.4] 2R) and HLA-DR antigen in the spontaneous condition in the SFC children were (8.9 ± 3.6) and (16.2 ± 5.6)% and (6.3 ± 1.9)% and (12.4 ± 3.4)% in the CFS children. lower than those in the normal controls [(12.8 ± 2.5)% and (20.2 ± 5.2)%] and in the URI group [(15.0 ± 3.0)% and (20.5 ± 2.8)%] also differences in the SFC children and in the CFS children (P <0.05). After PHA induction, the expression rates o f CD25 (IL-2R) and HLA-DR antThey were significantly lower than those in the normal controls [(65.7 ± 5.1) and (57.8 ± 6.0) and (53.0 ± 12.0)% and (54.7 ± 9.7)% in the CFC children (P <0.05) and in the URI group [(64.3 ± 6.4)% and (67.1 ± 8.6)%] (P <0.01) by PHA in the SFC and CFC children [(1.80 ± 0.4) and (1.6 ± 0.1) ng / ml] was significantly lower than that in the normal controls [(2.4 ± 0.9) ng / ml] The rate of rosette formation of RBC-C3b in the SFC children was (9.1 ± 4.9)% and it was significantly lower than that in the normal controls and the URI group [(15.8 ± 5.7) % and (13.5 ± 5.1)%] (P <0.01), but there was no difference in the SFC children, the normal controls and the URI group. The rate of rosette formation of RBC-IC in the SFC children and the CFC children [(3.0 ± 1.0) and (2.6 ± 0.7)%] was sign (3.7 ± 1.3)%] and the URI group [(3.9 ± 1.4)%] (P <0.05). Conclusions Both T-lymphocyte immune function and erythrocyte immune function in the children with FC were significantly impaired. The impairment was more severe in the CFC children than that in the SFC children.