Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Genotypic Drug Resistance and Long-Term Mortality in Patients with Triple-Class Antiretroviral Drug Failure

Objective

To examine the prevalence of drug-resistance-associated mutations in HIV patients with triple-drug class virological failure (TCF) and their association with long-term mortality.

Design

Population-based study from the Danish HIV Cohort Study (DHCS).

Methods

We included all patients in the DHCS who experienced TCF between January 1995 and November 2004, and we performed genotypic resistance tests for International AIDS Society (IAS)-USA primary mutations on virus from plasma samples taken around the date of TCF. We computed time to all-cause death from date of TCF. The relative risk of death according to the number of mutations and individual mutations was estimated by Cox regression analysis and adjusted for potential confounders.

Results

Resistance tests were done for 133 of the 179 patients who experienced TCF. The median number of resistance mutations was eight (interquartile range 2–10), and 81 (61%) patients had mutations conferring resistance towards all three major drug classes. In a regression model adjusted for CD4+ T-cell count, HIV RNA, year of TCF, age, gender and previous inferior antiretroviral therapy, harbouring ≥9 versus ≤8 mutations was associated with increased mortality (mortality rate ratio [MRR] 2.3 [95% confidence interval (CI) 1.1–4.8]), as were the individual mutations T215Y (MRR 3.4 [95% CI 1.6–7.0]), G190A/S (MRR 3.2 [95% CI 1.6–6.6]) and V82F/A/T/S (MRR 2.5 [95% CI 1.2–5.3]).

Conclusions

In HIV patients with TCF, the total number of genotypic resistance mutations and specific single mutations predicted mortality.

HIV-1 subtypes in Denmark

The objective of this study was to investigate the presence of non-subtype B HIV-1 in Denmark. The C2-V3-C3 region of the env gene from proviral DNA obtained from patients suspected of being infected with non-subtype B virus was PCR-amplified and directly sequenced. The DNA sequences were aligned with full-length HIV-1 reference strains from each subtype and analysed using the phylogenetic package PHYLIP 3.1. The neighbour-joining method was used with 100 bootstraps. Of the 144 patients included in this study C2-V3-C3 sequences were obtained from 129 patients (90%). The phylogenetic analyses showed that virus from 49 patients (38%) was subtype A, 39 (30%) subtype C, 9 (7%) subtype D, 14 (11%) subtype CRF01_AE, 16 (12%) subtype B, 1 (1%) subtype F and 1 (1%) subtype J. This study demonstrates that almost all subtypes can be detected in Denmark; all non-subtype B infections could be traced to countries with a high prevalence of non-subtype B virus.

Subtype-specific problems with qualitative Amplicor HIV-1 DNA PCR test

BACKGROUND

commercial HIV-1 qualitative DNA PCR tests have the potential to detect virus in patients in whom antibody tests may be ineffective, such as patients with primary HIV infection and infants born to HIV seropositive mothers. However, the genetic diversity of HIV-1 raises concern about the ability of the PCR tests to detect all current subtypes.

OBJECTIVES

to asses the sensitivity of the Amplicor HIV-1 test on 126 whole-blood samples representing seven different subtypes and to investigate the sensitivity when the standard assay was modified by including the primer pair SK145 and SKCC1B.

RESULTS

of the 126 HIV-1 infected persons, 113 were tested positive and 13 were DNA PCR negative. On the basis of these results, the standard Amplicor HIV-1 test had a sensitivity of 90% in our cohort. In addition, 9% of the positive samples showed a low reactivity but above the cut-off of the assay. The standard assay yielded sensitivities of 100% for subtype B (n=16), D (n=9) and G (n=1), but only 83% for subtype A (n=41), 98% for subtype C (n=43), 79% for subtype E (n=14) and 0% for subtype F (n=2). All samples with low reactivity were non-B subtype. Eight of the DNA PCR negative samples, four subtype A, one C and three E were amplified with the modified Amplicor HIV-1 test with addition of SK145/SKCC1B primers. Using this modified protocol, six samples out of eight became positive. However, two samples (one A and one C) remained DNA PCR negative.

CONCLUSION

this study confirms that the Amplicor HIV-1 test does not detect all subtypes with equivalent sensitivity and 10% of the samples, tested negative. Thus, it is preferable to add the SK145/SKCC1B primers to the standard test, where infection with non-B subtype is suspected.

Rapid loss of specific antibodies after pneumococcal vaccination in patients with human immunodeficiency virus-1 infection

Pneumococcal infections are frequently observed in patients with human immunodeficiency virus (HIV) infection and active immunization has been recommended as prophylaxis in this patient group. We studied 103 out-patients with asymptomatic or mildly symptomatic HIV infection with respect to specific IgG and IgG2 pneumococcal antibodies before and after vaccination with a 23-valent pneumococcal polysaccharide vaccine. A significant increase ( > 2-fold) in IgG and IgG2 antibody levels was observed after 1 month in 69/103 patients (67%) with no correlation with the CD4 cell count at the time of vaccination. The response rate was not influenced by concurrent treatment with anti-retroviral monotherapy, or by age or gender. After immunization a strong correlation between IgG and IgG2 anti-pneumococcal antibodies was demonstrated. Nevertheless, 12 months after vaccination the specific antibody titres were not significantly different from pre-vaccination values. In conclusion, antibodies induced by pneumococcal vaccination in patients with HIV infection have a short duration. This raises the question as to whether vaccination will have any impact on clinical end-point in this group of patients.

Risk behaviours for HIV infection and sexually transmitted diseases among female sex workers from Copenhagen

In 1990-91, 237 female sex workers from Copenhagen were enrolled in a larger study performed in 9 European countries. None of 206 women accepting serological testing was HIV-infected despite the fact that 36 (17.5%) were injecting drug users (IDU). Whereas 95% of the women always used condoms with clients over the last 6 months, this proportion was 25% and 9% respectively for casual and regular non-paying partners (P < 0.0001 for both comparisons). Those reporting at least one STD over the last year had more non-paying sexual partners than the others (P < 0.01) and the frequency of STD was lower in women who always used condoms with non-paying partners (7% vs 31%, P = 0.01). Women working on the street were more often IDU than others (78% vs 7%, P < 0.001). Independently of drug use, street prostitutes also tended to have more clients (P = 0.007) and more STD (P = 0.05). The striking differences in condom use with clients as compared to non-paying partners and the association between STD and sexual behaviours with such partners but not with clients show that specific interventions should be designed to promote safer sex with non-paying partners.

Hepatitis C virus antibodies in homosexual men and intravenous drug users in Denmark

In order to evaluate the role of sexual transmission and parenteral transmission of hepatitis C virus (HCV) in homosexual men and intravenous drug users (IVDU) serum samples from 147 homosexual men and 126 IVDU were tested for anti-HCV. Anti-HCV was found in two (1.4%) of the homosexual men and in 123 (98%) of IVDU. The presence of anti-HCV could not be correlated to the presence of HBV markers or HIV-antibodies. HCV is widespread among Danish IVDU. Risk of sexual transmission seems low even though sexual contact is a much more prevalent risk factor than needle sharing.

Competition ELISA using a human monoclonal antibody for detection of antibodies against human immunodeficiency virus type 1

A novel competition ELISA for detection of antibodies against HIV-1 was developed. The assay is based on competition at the single epitope level and utilises a human monoclonal antibody and an E. coli-produced fragment of the transmembrane glycoprotein gp41. The sensitivity of the assay was 100% in tests on 247 serum samples obtained from 219 individuals previously shown to be HIV-1 antibody positive by both conventional indirect ELISA and the immunoblotting test. The patients represented various clinical and immunological stages of HIV-1 infection. Likewise, the specificity of the assay was 100% in tests on 105 serum samples from normal individuals previously tested negative by indirect ELISA. Further, among 105 serum samples selected due to consistent false positive reactions in the indirect ELISA only 2 samples (1.9%) demonstrated false positive reactions in the competition ELISA, i.e. 98.1% specificity. Finally, only 2 of 57 (3.5%) serum samples from HIV-2 infected individuals showed positive reactions in the assay, while 54 (94.7%) had absorbance values similar to the negative controls. These results demonstrate that human monoclonal antibodies may form the basis for highly sensitive and specific assays for detection of antibodies to HIV-1.

Immunodeficiency in HIV-2 infection: a community study from Guinea-Bissau

In a community study in Guinea-Bissau, West Africa, 47 HIV-2-seropositive cases and 87 matched controls were evaluated immunologically using immuno-alkaline phosphatase linked to avidin-biotin complex for the assessment of CD4 and CD8 status. HIV-2-seropositive individuals had significantly lower total numbers of CD4 cells and CD4/CD8 ratios, 38% having a total number of CD4 cells less than or equal to 0.5 x 10(9)/l and 36% having a CD4/CD8 ratio less than or equal to 0.8. Total numbers of CD4 cells less than or equal to 0.5 x 10(9)/l or CD4/CD8 ratio less than or equal to 0.8 were found in 53% of the HIV-2 seropositives compared with 11% among controls [odds ratio (OR) = 7.3; 95% confidence interval (CI): 3.1-17.1]. Lymphadenopathy was significantly more frequent among HIV-2 seropositives than among controls (OR = 3.4; 95% Cl: 1.5-7.6). HIV-2 seropositives with lymphadenopathy had significantly fewer lymphocytes (P = 0.008) and lower total CD4 (P = 0.029) and total CD8 number (P = 0.011) than HIV-2 seropositives without lymphadenopathy. This study indicates that HIV-2 has a significant immunosuppressive effect.

Heterosexually acquired human immunodeficiency virus infection in women in Copenhagen: sexual behavior and other risk factors

In order to describe the risk pattern including sexual behaviour among HIV-infected women in Copenhagen we studied the charts of all women tested seropositive between January 1985 and August 1988 in the three main hospitals handling HIV/AIDS. One hundred and fifteen women were positive for HIV antibodies: 35 (31%) were infected by heterosexual contact and 63 (55%) were intravenous drug users. Among the heterosexually transmitted cases 25 (71%) had intercourse with a man from a high risk group and nine women had intercourse with a known HIV antibody positive man without known risk factors. Use of condoms was claimed by 31% of the heterosexually-transmitted women before the HIV test, and by 74% (P = 0.002) after the test. In 1988 73% of the women tested HIV positive were infected by heterosexual contact, in 1985 only 14%. We conclude that among HIV infected women in Copenhagen heterosexual transmission is a problem. These women seem to change sexual behaviour when informed about HIV positivity.

Human immunodeficiency virus surveillance at a sexually transmitted disease clinic in Copenhagen

During four study periods, each of 3-4 weeks' duration in 1987 and 1988, all patients attending the Copenhagen outpatient Venereal Disease Clinic were encouraged to have a test for human immunodeficiency virus (HIV) antibody. Anonymous testing or testing for research purposes only without any data was also offered. Patients known to be HIV antibody-positive were not re-tested. A total of 1753 patients (1118 men, 635 women) were counselled and testing recommended. Testing was refused by 255 patients, 57 of whom had been tested (all negative) within the previous 3 months. HIV serology was therefore unknown in 11.7% (198 of 1696 persons), including 120 of 922 heterosexual men (13%), 16 of 159 homo/bisexual men (10%) and 62 of 615 women (10%). There was no substantial difference between the four study periods in the numbers refusing the test. Sixteen of the 1498 patients tested were HIV antibody-positive, including one woman and 3 men with a history of intravenous drug abuse and 11 homo/bisexual men; one heterosexual man with HIV antibodies had no known risk behaviour. It is concluded that HIV testing with informed consent at a sexually transmitted disease clinic will not include all persons, and therefore will not exclude a self-selection bias. Surveillance studies using unlinked HIV testing are therefore necessary and it is recommended that they should be performed in Denmark. In this study, unlinked HIV testing of the serum specimens taken for syphilis serology would have decreased the percentage of 'non-attenders' from 12.4% to 0.8% during the final study period.

HIV testing in Denmark: a nominator-denominator study

In order to describe prevalence and trends of HIV infection, demographic variables, risk factors, and reasons for seeking testing, and self-administered anonymous questionnaire was distributed to approximately 75% of all individuals tested for antibodies to HIV on a voluntary basis, in all parts of the Danish health-care system, in November 1987 and in April 1988. The number of questionnaires returned was 2143 (55%). Overall, HIV prevalence was 1.2% and was highest among homosexual and bisexual men: 6% in November and 9% in April, with no statistical difference. Sixteen per cent of the men reported homosexual behaviour, 7% reported intravenous drug use, and 60% more than one opposite-sex partner within the last 12 months. No substantial difference was observed between reported risk factors in November and April. Overall, 18% had been tested at least once before; this figure rose to approximately 50% among homosexual men and intravenous drug abusers, a substantial number of whom had engaged in risk behaviour since the latest test. Sixty percent of men and 75% of women were tested at general practitioners', and 22% and 13% at sexually transmitted disease clinics; only 6% of men and 3% of women had used alternative test sites. It is concluded that studies of anti-HIV-tested people can give detailed information about patterns of HIV testing and indications of trends in HIV infection rates, thereby supplementing other forms of HIV surveillance.

Antigen-antibody reaction in solution in capture competition immunoassay for human immunodeficiency virus antibodies

In the capture competition immunoassay, undiluted serum was reacted in solution with purified human immunodeficiency virus (HIV) antigen in wells of microtest plates coated with anti-HIV immunoglobulin G antibodies (HIV capture antibodies). HIV antibodies present in the serum being tested combined with the HIV antigen and thus blocked (completely or partially) the fixation of the antigen to the capture layer. Unblocked antigenic activity was measured in subsequent steps by the use of biotinylated anti-HIV immunoglobulin G and peroxidase-conjugated avidin. The assay was evaluated in comparison with indirect enzyme-linked immunosorbent assay and Western (immuno-) blot (WB). A total of 180 serum samples which reacted repeatedly as positive in indirect enzyme-linked immunosorbent assay but negative in WB were found to be negative by the capture competition assay. Of 54 serum samples showing dubious reactions (single p24 bands in WB), 53 were clearly separated into positive or negative reactions, whereas 1 serum sample gave a borderline reaction. It was concluded that a characteristic feature of this kind of inhibition assay is a very low frequency of equivocal results.

Prevalence of and mortality from human immunodeficiency virus type 2 in Bissau, West Africa

In a community based prevalence study of HIV infection in Bissau, West Africa, 1987, the population in 100 randomly selected "houses" was asked to participate. 89% (1329/1499) were examined and had a blood sample taken. None was HIV-1 seropositive but 4.7% were seropositive for HIV-2 (0.6% in children, 8.9% in those aged 15 years and over, and 20% in those aged 40 years and over). There was no significant difference in seroprevalence between areas or ethnic groups or between individuals of different civil status when age was taken into account. Sexual contact and blood transfusions were the dominant transmission routes, and no case of vertical transmission was identified. The HIV-2 seroprevalence in spouses of HIV-2 seropositive index persons was 40%. For a history of blood transfusion the relative risk of being HIV-2 seropositive was 103.6 in children and 2.4 for adults. After exclusion of spouses, no clustering of HIV-2 seropositivity was seen. At follow-up, after a mean observation time of 325 days, there was an excess mortality for HIV-2 seropositives. The relative risk of dying for HIV-2 seropositive children was 60.8 and for adults 5.0.

Serological markers of primary HIV infection

39 persons with an incidentally discovered seroconversion from HIV antibody negative (Ab-) to antibody positive (Ab+) state as measured by an enzyme-linked immunosorbent assay (ELISA) were investigated for the presence of (1) HIV antigen (Ag) and (2) immunoblotting test (IBT) Ab in serum samples collected within the year before seroconversion. 13 (33%) of the patients were HIV Ag+ at some time before seroconversion. However, the collection of samples was not done systematically and the samples from patients who had at least 1 sample collected within 3 months before seroconversion were thus compiled separately. This group consisted of 58 samples from 19 patients and among these none were HIV Ag+ earlier than 11 weeks before seroconversion, but the prevalence of HIV Ag+ samples was rising towards seroconversion and 10 patients (53%, 95% confidence limits: 29-76%) became HIV Ag+ in this 11-week period. Further, among all patients 13 (33%) were IBT Ab+ 4-50 days (median: 14 days) before seroconversion. Finally, among 18 patients with signs and symptoms consistent with an acute HIV infection 10 were HIV Ag+, as opposed to 4 HIV Ag+ patients among 21 without symptoms (p = 0.041).

Quantitative evaluation of iodine-123 hippuran gamma camera renography in normal children

In a retrospective study of 39 normal children submitted to [123I]hippuran gamma camera renography, a quantitative evaluation of the recorded data showed that: (a) the rate constant for renal plasma clearance of [123I]hippuran was -0.166 +/- 0.043 min-1 corresponding to a hippuran plasma clearance of 518 +/- 142 ml/min per 1.73 m2; (b) the fractional renal clearance of [123I]hippuran was 0.51 +/- 0.03 and 0.49 +/- 0.03 for the left and the right kidney, respectively; and (c) the mean values for the mean transit times of [123I]hippuran through the whole kidney, the renal parenchyma, and the renal pelvis, respectively, were 4.2, 1.9, and 2.5 min. Five kidneys (in four patients) showed prolonged renal mean transit times of [123I]hippuran. Follow-up renographies were performed in three of the four children and gave normal results. Patients with renal mean transit times above the present 5% significance limit of 8.2 min should not necessarily be considered having an abnormal renal function.

Imipramine treatment of painful diabetic neuropathy

Twelve patients with severe, painful diabetic neuropathy in the lower extremities were treated with imipramine and placebo in a fixed-dose, double-blind, crossover study of five plus five weeks. Seven patients experienced notable improvement while receiving imipramine and none while receiving placebo. The rating of specific symptoms at the end of each treatment period showed a beneficial effect of imipramine on pain, paresthesia, dysesthesia, numbness, and nocturnal aggravation. The plasma levels of imipramine and its metabolite desipramine were significantly higher in patients who benefited from imipramine treatment.

Imipramine metabolites in blood of patients during therapy and after overdose

Plasma or serum concentrations of imipramine and five of its nonconjugated metabolites (desipramine, 2-OH-imipramine, 2-OH-desipramine, imipramine-N-oxide, and didesipramine) were followed in three cases of imipramine overdose and during steady state in 24 patients on continuous imipramine treatment. In the overdose cases the imipramine and desipramine concentrations declined monoexponentially with t 1/2s of 12 to 21 and 31 to 37 hr. The 2-OH-imipramine and 2-OH-desipramine levels were lower and declined in parallel with their corresponding parent compounds. In the patients on continuous imipramine treatment, the steady-state levels of 2-OH-imipramine and 2-OH-desipramine were very low or immeasurable (less than 15 nmol/l) in five patients. In most patients (n = 18) the hydroxymetabolite levels were much higher with 2-OH-imipramine/imipramine ratios of 0.09 to 0.45 and 2-OH-desipramine/desipramine ratios of 0.36 to 0.86. In one patient there were particularly high ratios (2-OH-imipramine/imipramine, 0.85; 2-OH-desipramine/desipramine, 1.30). The patients with very low hydroxymetabolite levels had considerably higher desipramine levels than the others, indicating that the low metabolite levels were due to poor hydroxylation. In one of these poor hydroxylators a desipramine t 1/2 of about 120 hr was estimated after imipramine discontinuation. With increased imipramine dose the 2-OH-imipramine levels tended to rise little or not at all. Imipramine-N-oxide could only be detected in the overdose cases during the first 6 to 12 hr and didesipramine was generally present only when the desipramine levels were above 200 nmol/l.