A strong association between the HLA-B*3505 and NVP-induced skin rash provides a novel insight into the pathogenesis of drug-induced rash in the HIV-infected population. On account of its high specificity (98.9%) in identifying NVP-induced rash, it is possible to utilize the HLA-B*3505 as a marker to avoid a subset of NVP-induced rash, at least in Thai population.

HLA-B*4001 is a strong genetic risk factor for stavudine-associated lipodystrophy in HIV-infected patients in Thailand. HLA-B*4001 may be used as a genetic marker to predict which patients will develop stavudine-associated lipodystrophy, to avoid or shorten the duration of stavudine use. This finding needs to be confirmed in further replication studies.

We demonstrated that genetic variations in CCHCR1 are strongly associated with nevirapine-induced rash. A predictive model that includes genetic and clinical risk factors for nevirapine-associated rash might be useful in lowering the incidence of rash associated with nevirapine initiation among HIV-infected patients.

Nevirapine (NVP) is commonly used as a component of first-line antiretroviral therapy in resource-limited countries. We aimed to determine the risk factors for NVP-associated rash among HIV-infected patients who were initiated NVP at low CD4 cell counts in a resource-limited setting. A case-control study was conducted in HIV-infected patients who developed rash after taking NVP (case) and those who did not have rash (control). A total of 357 patients with a mean (SD) age of 36.4 (7.5) years and 52.1% male were included in the study. Mean body weight (SD) was 55.5 (10.5) kg. Of all, 179 (49.0%) patients had a history of AIDS-defining illness and 57 (16.0%) patients had history of drug allergy. Median (IQR) CD4 cell counts at the time of NVP initiation was 95 (31-226) cells/mm(3). There were 115 patients in case group and 242 patients in control group. In case group, 43.0%, 54.4%, and 2.6% of patients developed grade 2, 3, and 4 of rash, respectively. Median time to develop rash was 12 (95%CI, 10.5-13.5) days. By logistic regression, history of drug allergy (OR, 3.41; 95%CI, 1.79-6.52), body weight (OR, 1.22 per each 5 kg decrement; 95%CI, 1.08-1.38), CD4 cells counts (OR, 1.20 per each 50 cells/mm(3) increment; 95%CI, 1.12-1.30), and AIDS-defining illness (OR, 0.42; 95%CI, 0.25-0.70) were significantly associated with rash. In resource-limited settings where patients were initiated NVP at low CD4 cell counts, history of drug allergy, lower body weight, and higher CD4 cell count are the risk factors for NVP-associated rash. Initiation of NVP in patients with these risks needs closed monitoring.