title: Lymphoid follicles are sites of heightened human immunodeficiency virus type 1 (HIV-1) replication and reduced antiretroviral effector mechanisms.
abstract: The observation that HIV-1 replication is concentrated in lymphoid follicles (F) compared to extrafollicular (EF) lymphoid tissue is not fully understood. The purpose of this study was to quantify HIV-1 replication in these compartments and evaluate the hypothesis that heightened replication in F occurs because of diminished antiretroviral mechanisms. In situ hybridization for HIV-1 RNA and immunohistochemical staining for CD4, CD8, CD20, and multiple antiretroviral proteins was performed in lymph nodes from 15 HIV-1-infected individuals who were not receiving antiretroviral therapy. A median of 70% of virus-producing cells were detected in F, defined morphologically by CD20 staining, although only a minority of tissue (median, 19%) consisted of F. Frequencies of virus-producing cells were higher in F (median, 1.35 cells/mm2) compared to EF (median, 0.35 cells/mm2; p < 0.0001). A CD4+ cell in F had a median 31-fold greater likelihood of harboring HIV-1 RNA than a CD4+ cell in EF (p = 0.0006). The most highly expressed antiretroviral proteins were alpha-defensins 1, 2, and 3 (median, 4.6% tissue staining), RANTES (median, 728.4 cells/mm2), and granzyme A (median, 412.6 cells/mm2). Less alpha-defensins (p = 0.0127), RANTES (p = 0.0007), granzyme A (p = 0.0018), MIP-1alpha (p = 0.0054), interferon (IFN)-alpha (p = 0.0186), and CD8 (p < 0.0001) was expressed in F compared to EF; amounts in F ranged from 0.15 to 0.50 of those in EF. Expression of IFN-gamma (median, 3.1 cells/mm2) and perforin (median, 4.0 cells/mm2) was low and not significantly different in F and EF. Deficiencies of multiple antiretroviral proteins within F may contribute to heightened replication at that site.
authors.affiliation: University of Colorado Health Sciences Center, Division of Infectious Disease, Denver, Colorado 80262, USA.
authors.forename: Joy M
authors.initials: JM
authors.lastname: Folkvord
authors.forename: Carl
authors.initials: C
authors.lastname: Armon
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Connick
mesh_terms: D000998:Antiviral Agents / Q000378:metabolism* / Q000494:pharmacology*; D016827:CD8 Antigens / Q000378:metabolism; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018946:Chemokine CCL5 / Q000378:metabolism / Q000494:pharmacology; D053804:Granzymes; D015658:HIV Infections / Q000821:virology; D015497:HIV-1 / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D016898:Interferon-alpha / Q000378:metabolism / Q000494:pharmacology; D008198:Lymph Nodes / Q000276:immunology* / Q000821:virology*; D019402:Macrophage Inflammatory Proteins / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D012367:RNA, Viral / Q000032:analysis; D012697:Serine Endopeptidases / Q000378:metabolism / Q000494:pharmacology; D014779:Virus Replication; D023084:alpha-Defensins / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000998:Antiviral Agents; D016827:CD8 Antigens; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018946:Chemokine CCL5; D016898:Interferon-alpha; D019402:Macrophage Inflammatory Proteins; D012367:RNA, Viral; D023084:alpha-Defensins; D053804:Granzymes; D012697:Serine Endopeptidases; C509212:GZMA protein, human