Objective. To determine whether malariotherapy （an old therapy for treatment of neurosyphilis） improves some clinical and laboratory parameters of HIV positive patients without iatrogenic complications. Methods. Total 8 asymptomatic HIV 1 positive subjects whose CD4 cell counts were over 250×10 6 cells/L were selected for the phase 1 studies of malariotherapy and were intravenously injected Plasmodia vivax to induce artificial malaria. Malaria was terminated with chloroquine after 10～20 malarial fever episodes. Cell bound CD4 levels were measured by APAAP （a solid phase enzyme essay） and levels of neopterin （NPT）

beta 2 microglobulin （B2M）

soluble tumor necrosis factor receptor 2（sTNF RII）

interleukin 2（IL 2） and HIV P24 antigen were measured by ELISA. Patients were followed up to 24～30 months. Results.CD4 levels increased in 5

NPT decreased in 7 of 8 patients; IL 2 increased in 5 of 6 patients after malariotherapy. The total trends of B2M and sTNF RII basically remained stable. HIV P24 antigen remained undetectable in 6

remained detectably low level in 1 and experienced increase in 1 of 8 patients after malariotherapy. No any severe complications occurred in all 8 patients. Conclusions. The results indicate that malariotherapy basically is safe for HIV infection and it seems that the therapy improves some immunological parameters of HIV patients.