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A great effort for developing AIDS vaccine has been carried out in the world, designed by various new ideas based on basic research information obtained in recent virology and immunology. Withall it, to obtain effective AIDS vaccine is considered skeptical. One of the reasons of its difficulty is a lack of experimental animals susceptible to HIV-1. In our laboratory, we have succeeded in developing chimeric SIV having 3' half of HIV-1 genome including env (SHIV), which is infectious to macaque monkeys. One of SHIVs has been proved nonpathogenic in monkeys from various aspects and it afforded protective immunity to monkeys against pathogenic SHIV challenge infection. Now, we are trying to develop anti-HIV live attenuated vaccines using the nonpathogenic SHIV as a starting material. In the history of virus vaccine, live attenuated vaccines have been proved most effective in measles and polio-myelitis. However, it is not clear whether nonpathogenic HIV exists or not. Futhermore, even if nonpathogenic HIV could be obtained, there is possibility that it will easily mutate to pathogenic one. Therefore, to develop live attenuated AIDS vaccine is considered dangerous. In this article, We will introduce our research on SHIV pathogenicity using monkeys and hypothesize possibility to obtain nonpathogenic HIV which is speculated from the origin and evolution of HIV/SIV. To clarify virulence and nonvirulence of HIV and to obtain nonpathogenic virus are not only applied research but also basic science to dissolve the fundemental question why HIV can induce the disease.

A 5-year-old boy had an intracerebral hematoma evacuated from the left parieto-occipital region at a local hospital. There was a difficulty in hemostasis during the operation. Postoperatively his neurological state gradually deteriorated. CT scans showed a gradual increase in intracerebral hemorrhage at the operated site. He was transferred to our clinic for further treatment. The preoperative blood coagulation profile showed that the activity of factor XIII was only 4%. The hematoma was removed without any trouble under administration of factor XIII. Postoperative course was also uneventful although the plasma level of factor XIII did not go up higher than 26% in spite of its daily administration. Although factor XIII administration was terminated one month after cranioplasty, the patient showed good recovery and the level of factor XIII spontaneously normalized in 6 months. The cause of the extremely low level of factor XIII in this case is not known, but it could be ascribed to massive hemorrhage.

Vertical transmission of HTLV-1 (human T-cell leukemia virus type 1) from HTLV-1 carrier mothers to their newborns has been reported with transmission rates, ranging from 6% to 78%. This study was undertaken to identify the high risk group of vertical transmission by detecting viral antigen in cultured lymphocytes and provirus obtained from carrier mothers. Subjects of this study were 70 HTLV-1 carrier mothers who attended the department of obstetrics and gynecology of hospital located in the Kanto area (ATL non endemic area). HTLV-1 antigen was detected in 40 out of 55 (72.7%) in peripheral blood lymphocytes of carrier mothers. HTLV-1 antigen was detected in 2 out of 40 (5.0%) in cord blood lymphocytes of infants born of carrier mothers. These two infants were born from carrier mothers with positive antigen detection study. It seems that carrier mothers whose peripheral lymphocytes are positive for antigen expression by culture are a high risk group for vertical transmission.