Influenza-like episodes in HIV-positive patients: the role of viral and 'atypical' infections.

OBJECTIVES: To document viral and 'atypical' infections in HIV-positive patients and association with influenza-like symptoms. PATIENTS AND METHODS: Monthly culture of urine, faeces and throat swabs in 63 HIV-positive patients (30 asymptomatic and 33 with AIDS-related complex/AIDS) over 5-27 months (with 1125 patient-months of follow-up), with further sample collections during influenza-like episodes. Standard viral detection methods were used. Throat swabs were assessed for Chlamydia sp. by culture and immunoblotting, and for Mycoplasma pneumoniae by polymerase chain reaction. RESULTS: Viruses were detected in 15 (50%) and M. pneumoniae in nine (30%) out of 30 HIV-positive patients during an influenza-like illness. A close temporal relationship with symptoms was observed in 12 (40%) patients: cytomegalovirus in six (20%), M. pneumoniae in three (10%), herpes simplex virus in three (10%), and enterovirus in one (4%). Influenza-like symptoms were more frequent in asymptomatic HIV infection than in AIDS-related complex/AIDS patients (actuarial risk at 1 year, 63 versus 26%; P=0.002), particularly in those with CD4 cell counts >300 x 10(6)/l at enrolment (P=0.002). At least 44% (four out of nine) M. pneumoniae infections were asymptomatic and 78% (seven out of nine) were associated with prolonged excretion (2-17 months). Chlamydia sp. were not detected. CONCLUSIONS: Influenza-like symptoms were more likely to be reported by HIV-positive patients at early stages of disease, possibly as a result of differences in immune responses to viral infection. There was a close association in 40% of cases between the development of symptoms and detection of cytomegalovirus, herpes simplex virus, enterovirus and M. pneumoniae (a previously unrecognized association).