BACKGROUNDThe correlation between HIV-1 Nef-specific CD8 T-cell responses and markers of HIV-1 disease progression still remains unclear. This study analysed and compared the role of HIV-1 Nef-specific CD8 T-cell responses in patients with different disease status.

METHODSTwo groups of patients with HIV-1 subtype B infection were selected according to CD4 count and clinical manifestations: long-term nonprogressors (LTNPs, n = 20) and advanced progressors (APs, CD4 count < 500 cells/microl, n = 34). Nef-specific CD8 T-cell responses were studied by interferon-gamma ELISpot assay against 3 pools of HIV-Nef peptides.

RESULTSNef-specific CD8 T-cell responses did not correlate with viral load or CD4 count in all patients and no significant differences were found in the magnitude of Nef-specific CD8 T-cell responses between groups LTNPs and APs (670 SFC/10(6) peripheral blood mononuclear cells vs 1107 SFC/10(6) peripheral blood mononuclear cells, P = 0.255). Further comparisons showed that there were also no significant correlations observed in group LTNPs, but Nef-specific CD8 T cells correlated negatively with viral load (r = -0.397, P = 0.020) and positively with CD4 count (r = 0.364, P = 0.034) in group APs.

CONCLUSIONThese data suggest that different correlation patterns between Nef-specific CD8 T-cell responses and disease progression exist in LTNPs and APs. Although a negative association was observed with concurrent plasma HIV RNA in APs, Nef-specific CD8 T-cell responses might fail to play a protective role in different stages of HIV-1 infection.

Acquired Immunodeficiency Syndrome ; immunology ; Adult ; CD4 Lymphocyte Count ; CD8-Positive T-Lymphocytes ; immunology ; Disease Progression ; Female ; Gene Products, nef ; immunology ; HIV-1 ; classification ; Humans ; Male ; Middle Aged ; RNA, Viral ; blood ; nef Gene Products, Human Immunodeficiency Virus

Bexarotene is a synthetic analogue of retinoic acid and exerts protective effects on the nervous system. However, low bioavailability and poor solubility of the crystal type I form severely limits the application of bexarotene in the clinic. A co-amorphous sample of bexarotene-PVP-K30 was prepared and the structure was characterized by X-ray diffraction and infrared spectroscopy. To determine the pharmacokinetics and tissue distribution of bexarotene, an LC-MS method was established to profile and quantify bexarotene in plasma and tissues of SD rats. In vitro dissolution indicated that the co-amorphous form improved the dissolution of bexarotene in pure water 4.17-fold. After rats were orally administered bexarotene or bexarotene-PVP-K30 co-amorphous (equivalent to 30 mg·kg^-1 bexarotene) the AUC of bexarotene was 7 034.89 and 10 174.03 μg·L^-1·h respectively, the peak time was advanced from 7.33 h to 0.9 h with the amorphous form, and C_max was enhanced from 627.76 to 3 011.88 μg·L^-1. The co-amorphous form yielded higher concentrations of bexarotene in various tissues, especially brain, liver and kidney. Animal welfare and experimental procedures complied with the rules of the Animal Ethics Committee of the Institute of Materia Medica, Chinese Academy of Medical Sciences. The results indicate that bexarotene-PVP-K30 co-amorphous improves the pharmacokinetic characteristics of bexarotene and provides preclinical data in support of bexarotene-PVP-K30 for the treatment of brain diseases.