To probe the significance of specific IgG4 in sera of patients with cerebral cys ticercosis for diagnosis and therapeutic evaluation Methods Specific IgG4 in sera of patients with cerebral cysticercosis was assessed using colloidal gold labeled mouse anti human IgG4 McAb as probe The results wer e compared with the CT image manifestation Results The specific IgG4 positive rate in sera of patients with cerebral cysticercosis was 97 8%, whereas sera from patients with other kinds of parasitosis or centra l nerve system disease and the control group were all negative, except for a wea k cross reaction of sera from patients with hepatic echinococoosis The determ ination of specific IgG4 in sera of patients with cerebral cysticercosis during different times of treatment showed that along with an increase in treatment tim e and improvement of clinical symptoms, specific IgG4 level gradually decreased The positive rate and intensity of specific IgG4 in sera from patients with c erebral cysticercosis were consistent with the number of cysticercus parasites i n the brain and pathologic changes, such as survival, disintegration, death and calcification Survival of cysticercus in the brain was ABSTRACTly evaluated u sing this technique Conclusions The determination of specific IgG4 in sera is a practical method for diagnosis a nd therapeutic evaluation of cerebral cysticercosis