Limited evolution of human immunodeficiency virus type 1 in the thymus of a perinatally infected child.
BACKGROUND
Involvement of the thymus during human immunodeficiency virus (HIV) infection may impair production of naive lymphocytes leading to more rapid depletion, but the characteristics of primary strains in the thymus are not well studied because of the unavailability of tissue in living individuals.


METHODS
We studied the characteristics of HIV type 1 (HIV-1) in a 5-year old perinatally infected child with thymitis and compared the genomic sequences of the HIV-1 C2-V5 region of the env gene in the thymic tissue and peripheral blood.


RESULTS
The thymus harbored predominantly viral sequences close to the founder HIV-1 variant that circulated in the blood at 2 and 3 months of age, whereas the peripheral blood virus at 5 years of age had evolved extensively. Viral sequences from circulating CD8(+) T cells at 5 years of age phylogenetically clustered with those from the thymic tissue.


CONCLUSIONS
These results indicate the existence of a distinct thymic viral reservoir and suggest that circulating CD8(+) T cells were infected in the thymus, presumably at the CD4(+)CD8(+) thymocyte stage. They also demonstrate that not all thymic HIV infections will necessarily lead to severe thymic dysfunction. The characteristics of the virus strain seeding the thymus may dictate the rate of disease progression.
Scinicariello
Franco
F
Department of Pediatrics, Emory University School of Medicine, Atlanta Georgia, USA.
Kourtis
Athena P
AP
Nesheim
Steven
S
Abramowsky
Carlos
C
Lee
Francis K
FK
D000595:Amino Acid Sequence; D001769:Blood / Q000821:virology; D002675:Child, Preschool; D016000:Cluster Analysis; D019143:Evolution, Molecular; D005260:Female; D015658:HIV Infections / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D011110:Polymorphism, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013950:Thymus Gland / Q000821:virology*; D054299:env Gene Products, Human Immunodeficiency Virus / Q000235:genetics
D054299:env Gene Products, Human Immunodeficiency Virus