Elevated adenosine deaminase activity in patients with HIV and tuberculous peritonitis.

OBJECTIVE: To evaluate the diagnostic potential of the ADA(T), ADA isoenzymes (ADA1 and ADA2) and the interferon-gamma (IFN-gamma) test in HIV-seropositive patients with tuberculous peritonitis. METHODS: Ascitic ADA(T), ADA1, ADA2 and IFN-gamma were prospectively evaluated in HIV-seronegative patients with tuberculous peritonitis (n = 17), HIV-seropositive patients with tuberculous peritonitis (n = 6) and in patients with cirrhosis (n = 22) and malignancy (n = 5). RESULTS: ADA(T) and ADA2 isoenzyme activities of HIV-seronegative (ADA(T) = 109 U/l; ADA2 = 94 U/l) and HIV-seropositive (ADA(T) = 109.5 U/l; ADA2 = 95.5 U/l) patients with tuberculous peritonitis, respectively, were significantly different (P < 0.001) from patients with cirrhosis (ADA(T) = 10.5 U/l; ADA2 = 8 U/l) and malignancy (ADA(T) = 13 U/l; ADA2 = 11 U/l). There was no significant difference in ADA(T) and ADA2 activities between HIV-seropositive and seronegative patients with tuberculous peritonitis. There was no significant correlation between ADA, its isoenzymes and IFN-gamma. CONCLUSIONS: The diagnosis of tuberculous peritonitis can be made by a sensitive, relatively non-invasive procedure in both HIV-seronegative and seropositive patients with minimal risk to the patient and the investigator. The diagnostic value of ADA(T) is not enhanced by measuring ADA isoenzymes or IFN-gamma.