Increased expression of interferon‐gamma in hyperplastic lymph nodes from HIV‐infected patients
Polyclonal B cell activation is characteristic of HIV infection and occurs in the presence of severe CD4+ lymphocyte depletion. In contrast, CD4+ lymphocytes are the dominant T cell in the reactive lymphoid tissues of patients not infected with HIV. In this study, lymph node biopsies from eight HIV‐infectcd patients with persistent generalized lymphadenopathy syndrome (PGL) were assessed for IL‐lβ, IL‐2, IL‐4, IL‐6, IL‐10, interferon‐gamma (IFN‐γ) and tumour necrosis factor‐beta (TNF‐β) gene expression using the polymerase chain reaction (PCR). The cytokine gene expression of two cases of reactive adenopathy in patients not infected with HIV was assessed for comparison. IFN‐γ was expressed much more strongly in the PGL samples than in control reactive lymphoid tissues, whereas the other cytokines were expressed to a similar extent in both types of tissues. IFN‐γ may have an important role in maintaining the adenopalhy of HIV‐infected patients. Expression of cytokines such as IL‐2, IL‐4 and IL‐10 in HIV nodes may be adequate to allow the recruitment of naive B cells to the reactive process.