Risk factors for bacterial infections in HIV/hepatitis C virus-coinfected patients treated with interferon plus ribavirin

Interferon α-Enhanced Clearance of Group A Streptococcus Despite Neutropenia

BACKGROUND

Neutrophils and monocytes are crucial for controlling bacterial infections. More-frequent bacterial infections are accordingly encountered in neutropenic patients undergoing chemotherapy. This is not the case for pegylated interferon α (IFN-α)-induced neutropenia. We hypothesized that IFN-α induces a compensatory innate antibacterial state that prevents bacterial infections despite the neutropenia.

METHODS

To investigate whether patients with hepatitis C virus infection treated with IFN-α killed group A Streptococcus (GAS) better than before initiating therapy, whole blood was used to perform ex vivo GAS killing assays before, during, and after IFN-α therapy.

RESULTS

We found that IFN-α therapy enhanced GAS killing in whole blood ex vivo despite the decreased neutrophil and monocyte numbers during IFN-α therapy. IFN-α also boosted neutrophil- and monocyte-mediated GAS killing in vitro. Underlying mechanisms included increased production of the antibacterial properdin, a regulator of the complement activation, as well as reactive oxygen species.

CONCLUSIONS

These findings help to explain the rather discrepant facts of neutropenia but preserved antibacterial immune defenses in patients treated with IFN-α.

Cryptococcal meningitis in a patient with chronic hepatitis C treated with pegylated-interferon and ribavirin

Various adverse events have been reported during combination therapy with pegylated (PEG)-interferon-α and ribavirin, although opportunistic infections, especially cryptococcal meningitis, are very rare. A 61-year-old woman complained of headaches and a fever during treatment of a chronic hepatitis C virus (HCV) infection. She had been treated for 7 months. Her headaches were refractory to analgesics, and she developed subtle nuchal rigidity. The cerebral spinal fluid (CSF) revealed a white blood cell count of 205/mm(3), 51 mg/dL protein, 35 mg/dL glucose, and negative Cryptococcus antigen. The CSF culture resulted in no growth. Five days later, the CSF was positive for Cryptococcus antigen. We administered amphotericin B and flucytosine, followed by fluconazole. Approximately 2 months later, she was discharged. For the first time, we report a case of cryptococcal meningitis during the treatment of chronic HCV with PEG-interferon-α and ribavirin.

[Treatment of chronic hepatitis C in HIV-infected patients]

Since the pivotal trials conducted over the last few years which have used the combination of pegylated interferon along with fixed low doses (800 mg/day) of ribavirin and have provided treatment for 12 months, regardless the kinetics of hepatitis C virus (HCV) viral load during therapy, great progress has been made in the treatment of chronic hepatitis C in HIV-infected patients. Results approaching those seen in HCV-monoinfected patients can be obtained with optimal dosages of ribavirin, extension of treatment beyond 48 weeks in the absence of rapid virologic response and/or in patients older than 40 years, with severe fibrosis (METAVIR score F3 or F4) and/or with high HCV viral load and with a better management of HIV treatment in order to avoid a negative interaction between HCV and HIV therapies (interaction between abacavir and ribavirin) and to improve the tolerance of HCV therapy (Didanosine should never be used with ribavirin, Zidovudine and Stavudine should be avoided when possible with ribavirin).