Long-term non-progressive HIV infection, characterized by low but detectable viral load and stable CD4 counts in the absence of antiviral therapy, is observed in about 5% of HIV-infected patients. Here we identified four therapy naïve individuals who are strongly seropositive for HIV-1 but who lack evidence of detectable HIV p24 antigen, plasma RNA, and proviral DNA in routine diagnostic testing. With an ultrasensitive PCR, we established that frequencies of pol proviral DNA sequences were as low as 0.2-0.5 copies/10(6) PBMC. HIV could not be isolated using up to 30x10(6) patient PBMC. One individual was heterozygous for CCR5 Delta32, but CCR5 expression on CD4+ T cells was normal to high in all four individuals. In vitro R5 and X4 HIV-1 susceptibility of CD8-depleted PBMC of all study subjects was significantly lower than the susceptibility of CD8-depleted PBMC of healthy blood donors. All individuals expressed protective HLA-B*58s alleles and showed evidence of HIV-specific cellular immunity either by staining with HLA-B*57 tetramers folded with an HIV RT or gag peptide or after stimulation with HIV-1 p24 gag, RT, or nef peptides in ELIspot analysis. HIV-specific CD4+ T helper cells were demonstrated by proliferation of CD4+ T cells and intracellular staining for IL-2 and IFNgamma after stimulation with an HIV-gag peptide pool. Sera of all individuals showed antibody-mediated neutralization of both R5 and X4 HIV-1 variants. These data implicate that very low-level antigen exposure is sufficient for sustained HIV-specific immunity and suggest the possibility of a multi-factorial control of HIV infection.

We compared the efficacy of combination antiretroviral therapy (cART) of Antillean HIV-1-infected patients treated on the Caribbean island of Curaçao (CUR-AN) with Antillean (NL-AN), Surinam (NL-SUR), and Dutch (NL-NL) patients treated in The Netherlands. In total 2118 therapy-naive patients who started cART between January 2005 and August 2008 were included in the comparison. The CUR-AN patients initiated cART at a median CD4 cell count of 141 cells/mm(3) and 63% had counts below 200 cells/mm(3). Within 12 months of the start of cART 76% of the CUR-AN patients achieved viral suppression, defined as HIV-1 RNA plasma levels below 80 copies/ml. The percentage achieving viral suppression was higher in patients treated in The Netherlands (NL-AN = 87%, NL-SUR = 93%, and NL-NL = 96%). Lost to follow-up after 30 months of cART was 10% among CUR-AN patients and was higher than observed among patients treated in The Netherlands (NL-AN = 8%, NL-SUR = 3%, and NL-NL = 2%). A similar pattern was found for progression to AIDS and death (10% of CUR-AN vs. 5%, 6%, and 7% of NL-AN, NL-SUR, and NL-NL patients, respectively). Late start of cART and limited viral suppression after the start of cART determine the higher rate of disease progression to AIDS and death among Antillean patients treated in Curaçao. The high percentage of lost to follow-up may result in an underestimation of AIDS and AIDS-related death among HIV-1-infected Antilleans treated in Curaçao.

Retention in care is one of the major challenges to scaling up and maximizing the effectiveness of combination antiretroviral therapy (cART). High attrition rates have been reported in the Caribbean region, varying from 6% to 23%. We studied the incidence of and risk factors for intermittent care in a cohort of adult HIV-1-positive patients, who entered into care in Curaçao between January 2005 and July 2009. A total of 214 therapy-naïve HIV-1-infected patients aged 15 years or older, entered HIV care between January 2005 and July 2009. Intermittent care was defined as at least one period of 365 days or longer in which there was no HIV care contact in Curaçao. Cox regression models were used to identify characteristics associated with time to intermittent care. In all, 203 (95%) patients could be classified as having intermittent or continuous care. The incidence of intermittent care before starting cART was 25.4 per 100 person years observation (PYO), whilst it was 6.1 per 100 PYO after starting cART. Being born outside Curaçao was associated with intermittent care before and after starting cART. Time from diagnosis to entry into care was an independent predictor for intermittent care before starting cART. Younger age was independently associated with intermittent care after starting cART. Half of the patients returned to care after intermitting care. Upon returning to care, median CD4 count was 264 cells/mm(3) (IQR, 189-401) for those who intermitted care before starting cART, and 146 cells/mm(3) (IQR, 73-436) in those who intermitted care after starting cART. In conclusion, the incidence of intermitting care is high in Curaçao, especially before starting cART, and intermitting care before starting cART is an independent predictor for starting cART late.

We estimated the impact of loss to follow-up (LTFU) on the mortality rate among HIV-1-infected patients in Curaçao. A total of 214 therapy-naive HIV-1-infected patients aged 15 years or older upon entering into HIV care between January 2005 and July 2009 were included. Persons who discontinued follow-up for more than 365 days were defined as LTFU and traced with the aim of registering their vital status. If no personal contact could be made, data were matched with the Curaçao National Death Registry. Mortality rates were estimated before and after starting combination antiretroviral therapy (cART). We used log-rank tests to compare survival rates among patients LTFU and patients who experienced continuous follow-up. Pre-cART mortality in patients LTFU was similar to pre-cART mortality in those with continuous follow-up (p=0.79). All pre-cART deaths occurred within 6 months after entry. Low CD4 cell count was predictive of a shorter time to death after entry. Adjusting for those who were LTFU, the mortality rate after starting cART increased from 4.3 to 5.5 per 100 person years of observation (p=0.06). Mortality after starting cART was highest in the first 2 months after starting cART, especially for those who had late disease stage. Mortality rates were lower in patients with continuous follow-up compared to LTFUs (p<0.001). Mortality rates in HIV-1-infected patients who have started cART in Curaçao are underestimated as a result of inefficient patient administration combined with people starting cART at a very late disease stage. Monitoring HIV treatment could help in reducing the risk of LTFU and may improve the effect of treatment.