Endogenous IL-7 is associated with increased thymic volume in adult HIV-infected patients under highly active antiretroviral therapy.
OBJECTIVE
Immune reconstitution after highly active antiretroviral therapy (HAART) in HIV-infected patients has led to an increase in the number of new CD4 T lymphocytes. Neolymphopoiesis in the thymus has been proposed as a mechanism in T-cell regeneration. Nevertheless, factors involved in the regeneration of T cells by thymic-dependent pathways in HIV-infected patients under HAART are still unknown and might be of relevance in HIV infection. The aim of this work was to study the role of IL-7 in the thymic rebound of HIV-infected adults under HAART.


METHODS
To study the association between IL-7 and thymic function-related markers, these variables were measured in 49 antiretroviral-naive HIV-infected patients at baseline and at weeks 12, 24, 36 and 48 of treatment.


METHODS
Thymic function-related markers: thymic volume, naive phenotype, and T-cell receptor excision circles (TREC) bearing-cells, were evaluated by computed tomography, flow cytometry, and quantitative polymerase chain reaction, respectively. IL-7 levels were evaluated using a high sensitivity colorimetric enzyme-linked immunosorbent assay.


RESULTS
At baseline, we found an inverse correlation between IL-7 levels and thymic function-associated parameters: thymic volume, naive T cells and TREC-bearing cells. After 48 weeks of therapy increased levels of thymic function-related markers along with a significant decrease in IL-7 levels were found. IL-7 levels at baseline were the only independently associated variable with respect to changes in thymic volume at weeks 12, 24 and 48 of follow-up.


CONCLUSIONS
These data suggest that IL-7 plays an important role in thymic rebound in adult HIV-infected patients under HAART.
Ruiz-Mateos
Ezequiel
E
Viral Hepatitis and AIDS Study Group, Virgen del Rocío University Hospital, Seville, Spain.
de la Rosa
Rafael
R
Franco
Jaime M
JM
Martinez-Moya
Manuel
M
Rubio
Amalia
A
Soriano
Natalia
N
Sanchez-Quijano
Armando
A
Lissen
Eduardo
E
Leal
Manuel
M
D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory; D015851:Interleukin-7 / Q000378:metabolism*; D007963:Leukocytes, Mononuclear; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D012367:RNA, Viral / Q000032:analysis; D011948:Receptors, Antigen, T-Cell; D013950:Thymus Gland / Q000276:immunology*; D014057:Tomography, X-Ray Computed / Q000379:methods
D015851:Interleukin-7; D012367:RNA, Viral; D011948:Receptors, Antigen, T-Cell