Serum IgG antibodies to human herpesvirus-6 (HHV-6) do not predict the progression of HIV disease to AIDS. Italian Seroconversion Study group.
OBJECTIVE
To evaluate if different levels of human herpesvirus 6 (HHV-6) antibodies can predict HIV disease progression.


METHODS
Longitudinal study of individuals with a documented date of HIV seroconversion.


METHODS
Clinical centers located throughout Italy.


METHODS
Individuals who serconverted for HIV between 1983 and 1995 in Italy.


METHODS
Sera were tested for IgG antibodies to HHV-6 using a commercial enzyme immunoassay. A serum sample with an optical density (OD) > or =242 (i.e. the mean value of 10 negative controls +4x standard deviation) was considered as HHV-6 positive; the progression of HIV disease was evaluated estimating the relative hazards (RH) of AIDS (by Cox models) for individuals with higher levels vs. lower levels of HHV-6 antibodies or considering levels of antibodies based on 10% increase of the distribution (deciles). Rates of CD4 decline fitting linear regression were also estimated.


RESULTS
A total of 381 persons were followed for a median time of 4 years (range: 0.15-9 years) following the date of collection of the serum sample. The median OD value of HHV-6 antibodies was 306, with an interquartile range of 241-440 and a range of 48-2330. A slight inverse correlation was found between HHV-6 antibody levels and age of the individual at the time of serum collection (Spearman rank correlation coefficient, -0.16; p = 0.0013). No association was found between HHV-6 and CD4 level or between HHV-6 and CD8 level at the date of serum collection. The unadjusted RH of progression to AIDS was 0.63 (95% CI: 0.42-0.96) for HHV-6 positive individuals vs. HHV-6 negative; when adjusting for possible confounders (CD4, age, pre-AIDS HIV-related pathologies at the date of sera collection, and previous anti-herpes treatment), the RH of AIDS increased to 0.80 (95% CI: 0.51-1.23). No particular association with HIV disease progression was found when using the deciles of the distribution of HHV-6 antibodies. The median CD4 cell loss was 5.0x10(6) cells/l per month among HHV-6 positive individuals and 5.7x10(6) cells/l per month among the others.


CONCLUSIONS
The presence of high levels of HHV-6 antibodies does not seem to predict the clinical or immunologic progression of HIV disease.
Dorrucci
M
M
Centro Operativo AIDS - Istituto Superiore di Sanità, Rome, Italy.
Rezza
G
G
Andreoni
M
M
Pezzotti
P
P
Nicastri
E
E
Ventura
L
L
Zignani
M
M
Alliegro
M B
MB
Tarantini
G
G
Salassa
B
B
Colangeli
V
V
Mazzarello
G
G
Ursitti
M A
MA
Barbanera
M
M
Pristerà
R
R
Castelli
F
F
Ortona
L
L
D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood*; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D018450:Disease Progression; D015658:HIV Infections / Q000276:immunology*; D006679:HIV Seropositivity; D015654:Herpesvirus 6, Human / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis*; D008137:Longitudinal Studies; D008875:Middle Aged
D000914:Antibodies, Viral; D015704:CD4 Antigens; D016827:CD8 Antigens; D007074:Immunoglobulin G