Salivary gland disease in HIV/AIDS and primary Sjögren's Syndrome: Analysis of collagen I distribution and histopathology in American and African patients

Background: Salivary gland disease (SGD) in HIV/AIDS is clinically and histopathologically very similar to Sjögren's Syndrome (SS), although the mechanism of tissue damage is unknown. The aim of this study is to determine the prevalence of SGD in primary SS and in HIV/AIDS in USA and in West African patients, and to seek distinguishing histopathologic features that may help to elucidate underlying mechanisms. Methods: Histologic sections of minor salivary glands from 164 HIV-positive and -negative patients from Cameroon and the US, and from 17 US patients with primary SS, were evaluated following salivary gland biopsy for inflammatory changes. To confirm the presence of fibrosis, collagen I, which is the most abundant collagen type, was assessed immunohistochemically in H&E-stained sections. Results: Forty-eight per cent of patients with HIV from Cameroon had severe SGD, while it was only in 6% of patients from the US. Patients with HIV in the US had less fibrosis and collagen I deposits than Cameroonians. Seventy-six per cent of US HIV-positive patients had received anti-retroviral therapy, while none of the African patients had. SS and AIDS patients had a tendency for lymphocytes to locate in a perivascular rather than in a periductal distribution. Conclusions: The prevalence of SGD and the presence of fibrosis and collagen I in Cameroonians with HIV is significantly higher than in HIV-positive American patients, and is similar to US patients with primary SS. The impact of patient selection, anti-retroviral therapy, and pathogenic mechanisms on salivary gland pathology is discussed.