Genotypic Resistance in Patients on HAART with Persistently Detectable Low-Level Viremia

Technical limitations in the sensitivity of commercial genotyping methods may prevent clinicians from determining whether drug-resistant  HIV-1 is present in patients with low-level viremia.

Researchers performed ultrasensitive HIV-1 genotyping for patients with persistent plasma virus loads of 50–400 copies/mL to better define the prevalence of drug resistance and the most common resistance mutations during persistently detectable low-level viremia.

Genotyping of HIV-1 was performed with an ultrasensitive clonal genotyping method.

Results     

The investigators studied 21 patients who had persistent, detectable, low-level viremia for a median of 11 months.

Nine (43%) of 21 patients had HIV-1 isolates with significant resistance mutations.

The most common mutations were M184V, K65R, and M41L/T215Y.

Conclusions

The finding that clinically significant resistance mutations were present in some but not all patients with persistent viremia (range, 50–400 copies/mL) highlights the need to improve the sensitivity of current clinical assays for detection of drug resistance.

Departments of Medicine and Pediatrics, Johns Hopkins University School of Medicine, and Howard Hughes Medical Institute, Baltimore, Maryland.

09/29/04

Reference
R E Nettles and others. Genotypic Resistance in HIV-1–Infected Patients with Persistently Detectable Low-Level Viremia while Receiving Highly Active Antiretroviral Therapy. Clinical Infectious Diseases 39(7): 1030-1037. October 1, 2004.