The sensitivity and discriminatory power of the 151 and 215 amplification refractory mutation system (ARMS) were evaluated, and their performance for the detection of drug resistance in mixed genotypic populations of the reverse transcription (RT) gene of HIV-1 were compared with T7 sequencing, cycle sequencing, the line probe assay (LiPA) HIV-1 RT test, and the recombinant virus assay (RVA). ARMS and the LiPA HIV-1 RT test were shown to be able to detect minor variants that in particular cases comprised only 1%. T7 sequencing on an ALF semiautomated sequencer could correctly score mixtures only when variants were present at 50%. Cycle sequencing on an ABI PRISM 310 improved the sensitivity for mixtures to about 25%. Using RVA, it was shown that at least 50% of the virus population needed to carry the resistance mutation at codon 184 to afford phenotypic resistance against lamivudine. The two point mutation assays therefore proved to be more sensitive methods than sequencing and RVA to reliably determine a gradual shift in HIV-1 drug resistance mutations in follow-up of patients infected with HIV-1. In 4 of 5 treated patients who were followed by ARMS, a gradual shift in resistant genotypic populations was observed during a period of 6 to 19 months. For 1 patient, a shift from wild to mutant type at position 151 occurred within 2 months, without mixed genotypic intermediate type's being detected.

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MddNR resistant HIV-1 can be found in European patients. MddNR is characterized by a specific set of drug resistance mutations, cross-resistance to most ddN analogues and a fast clinical progression. MddNR can be associated with protease inhibitor or NNRTI resistance.

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A DNA-free subunit herpes simplex virus (HSV) vaccine was administered to 15 volunteers without past evidence of HSV infection and to 25 patients with severe recurrent HSV infection. The immune response to the vaccine in these patients was compared to the immunological status of 20 non-vaccinated control patients with recurrent HSV infection. The vaccine elicited antibody and cell-mediated immunity (CMI) in the 15 subjects without past evidence of HSV infection and this response was similar to that observed after a natural infection. Among the 25 patients who were suffering from recurrent HSV infection the vaccine elicited complement dependent cytotoxic antibodies in 13 of these patients who did not possess these antibodies and increased significantly the titers of these antibodies in the 12 other patients. The vaccine gave a significant increase of the titers of the other specific antibodies as well as the level of cell-mediated immunity. The increase of the immunity level in these latter patient was not due to normal variations since in the non-vaccinated control group the antibody titers and CMI remained stable during the same period of time.

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