Benign monoclonal expansion of CD8+ lymphocytes in HIV infection.
BACKGROUND
A transient expansion of the CD8+ T cell pool normally occurs in the early phase of HIV infection. Persistent expansion of this pool is observed in two related settings: diffuse infiltrative lymphocytosis syndrome (DILS) and HIV associated CD8+ lymphocytosis syndrome.


OBJECTIVE
To investigate a group of HIV infected patients with CD8+ lymphocytosis syndrome with particular emphasis on whether monoclonality was present.


METHODS
A group of 18 patients with HIV-1 infection and persistent circulating CD8+ lymphocytosis was compared with 21 HIV positive controls. Serum samples were tested for antinuclear antibodies, antibodies to extractable nuclear antigens, immunoglobulin levels, paraproteins, human T lymphotropic virus type 1 (HTLV-1), Epstein-Barr virus, and cytomegalovirus serology. Lymphocyte phenotyping and HLA-DR typing was performed, and T cell receptor (TCR) gene rearrangement studies used to identify monoclonal populations of T cells. CD4+ and CD8+ subsets of peripheral blood lymphocytes were purified to determine whether CD8+ populations inhibited HIV replication in autologous CD4+ cells.


RESULTS
A subgroup of patients with HIV-1 infection was found to have expanded populations of CD8+ T cell large granular lymphocytes persisting for 6 to 30 months. The consensus immunophenotype was CD4- CD8+ DRhigh CD11a+ CD11c+ CD16- CD28+/- CD56- CD57+, consistent with typical T cell large granular lymphocytes expressing cellular activation markers. Despite the finding of monoclonal TCR gene usage in five of 18 patients, there is evidence that the CD8+ expansions are reactive populations capable of mediating non-cytotoxic inhibition of HIV replication.


CONCLUSIONS
A subgroup of HIV positive patients has CD8+ lymphocytosis, but despite the frequent occurrence of monoclonal TCR gene usage there is evidence that this represents an immune response to viral infection rather than a malignant disorder.
Smith
P R
PR
Department of Genitourinary Medicine, Royal Hospitals NHS Trust, Whitechapel, London, UK.
Cavenagh
J D
JD
Milne
T
T
Howe
D
D
Wilkes
S J
SJ
Sinnott
P
P
Forster
G E
GE
Helbert
M
M
D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000276:immunology*; D015497:HIV-1; D006801:Humans; D007111:Immunity, Cellular; D008218:Lymphocytosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D016201:Receptors, Lymphocyte Homing / Q000276:immunology; D013577:Syndrome; D016176:T-Lymphocyte Subsets / Q000276:immunology*
D000911:Antibodies, Monoclonal; D016201:Receptors, Lymphocyte Homing