Infectious diseases among patients at the Health Centre for Undocumented Migrants in Oslo. / Smittsomme sykdommer blant pasienter ved Helsesenter for papirløse migranter i Oslo.

BACKGROUND: Undocumented migrants probably fall outside the scope of public infectious disease control schemes. The article aims to describe the extent of undetected highly hazardous communicable diseases among patients at the Health Centre for Undocumented Migrants in Oslo. MATERIAL AND METHOD: We reviewed the records of all patients who attended the Health Centre for the first time in 2016 or 2017, with a view to age, sex, period of stay in Norway, country category and infection test results from the period 1 January 2016-31 December 2017. RESULTS: There were four new cases of hepatitis B among 139 patients tested, and four cases of chlamydia infection among 38 patients tested. There were no new cases of active pulmonary tuberculosis, syphilis, HIV infection or hepatitis C. INTERPRETATION: There were fewer cases of highly hazardous communicable diseases than what might be expected based on the countries from which the patients originated.

Antiretroviral treatment reverses HIV-associated anemia in rural Tanzania.

BACKGROUND: HIV-associated anemia is common and associated with poor prognosis. However, its response to antiretroviral treatment (ART) in rural Africa is poorly understood. METHODS: HIV-infected adults (≥15 years) who enrolled in HIV care at Haydom Lutheran Hospital in northern Tanzania were included in the study. The effect of ART (zidovudine/stavudine + lamivudine + efavirenz/nevirapine) on HIV-associated anemia was studied in a subset of patients who were anemic at the time they started ART and had a follow-up hemoglobin measurement 12 months later. Pregnant women were excluded from the study, as were women who had given birth within the past 6 weeks. Anemia was defined as hemoglobin <12 g/dL in women and <13 g/dL in men. We applied paired sample T-tests to compare hemoglobin levels before and one year after ART initiation, and logistic regression models to identify predictors of persistent anemia. RESULTS: At enrollment, mean hemoglobin was 10.3 g/dL, and 649 of 838 patients (77.4%) were anemic. Of the anemic patients, 254 (39.1%) had microcytosis and hypochromia. Among 102 patients who were anemic at ART initiation and had a follow-up hemoglobin measurement after 12 months, the mean hemoglobin increased by 2.5 g/dL (P < 0.001); however, 39 patients (38.2%) were still anemic after 12 months of ART. Independent predictors of persistent anemia were mean cell volume in the lower quartile (<76.0 fL; Odds Ratio [OR] 4.34; 95% confidence interval [CI] 1.22-15.5) and a zidovudine-containing initial regimen (OR 2.91; 95% CI 1.03-8.19). CONCLUSIONS: Most patients had anemia at enrollment, of whom nearly 40% had microcytosis and hypochromia suggestive of iron deficiency. The mean hemoglobin increased significantly in patients who received ART, but one third were still anemic 12 months after ART initiation indicating that additional interventions to treat HIV-associated anemia in rural Africa might be warranted, particularly in patients with microcytosis and those treated with zidovudine.

Achievements and Challenges in the Prevention of Mother-to-Child Transmission of HIV-A Retrospective Cohort Study from a Rural Hospital in Northern Tanzania.

Despite the goal of eliminating new human immunodeficiency virus (HIV) infections in children, mother-to-child transmission is still common in resource-poor countries. The aims of this study were to assess the occurrence of mother-to-child transmission of HIV (MTCT) by age 18 months, risk factors for transmission, and the implementation of the national prevention of MTCT (PMTCT) program in a rural hospital in Tanzania. Data were collated from various medical registers and records. We included 172 children and 167 HIV-infected mothers. Among 88 children (51%) with adequate information, 9 (10.2%) were infected. Increased risk of MTCT was associated with late testing of the child (>2 months) [OR = 9.5 (95% CI: 1.8-49.4)], absence of antiretroviral therapy during pregnancy [OR = 9.7 (95% CI: 2.1-46.1)], and maternal CD4 cell count <200 cells/mm3 [OR = 15.3 (95% CI: 2.1-111)]. We were unable to determine the occurrence of MTCT transmission in 84 children (49%). The results from this study highlight that there is an urgent need for enhanced efforts to improve follow-up of HIV-exposed children, to improve documentation in registries and records, and to facilitate ease of linkage between these.

Drug resistance is widespread among children who receive long-term antiretroviral treatment at a rural Tanzanian hospital.

OBJECTIVES: To assess long-term virological efficacy and the emergence of drug resistance in children who receive antiretroviral treatment (ART) in rural Tanzania. PATIENTS AND METHODS: Haydom Lutheran Hospital has provided ART to HIV-infected individuals since 2003. From February through May 2009, a cross-sectional virological efficacy survey was conducted among children (<15 years) who had completed >or=6 months of first-line non-nucleoside reverse transcriptase inhibitor (NNRTI)-based ART. Genotypic resistance was determined in those with a viral load of >200 copies/mL. RESULTS: Virological response was measured in 19 of 23 eligible children; 8 of 19 were girls and median age at ART initiation was 5 years (range 2-14 years). Median duration of ART at the time of the survey was 40 months (range 11-61 months). Only 8 children were virologically suppressed (50% harboured drug resistance. Results for children were markedly poorer than for adults attending the same programme, underscoring the need for improved treatment strategies for children in resource-limited settings.

Dried blood spots perform well in viral load monitoring of patients who receive antiretroviral treatment in rural Tanzania.

BACKGROUND: Monitoring of antiretroviral treatment (ART) with human immunodeficiency virus (HIV) viral loads, as recommended in industrialized countries, is rarely available in resource-limited settings because of the high costs and stringent requirements for storage and transport of plasma. Dried blood spots (DBS) can be an alternative to plasma, but the use of DBS has not been assessed under field conditions in rural Africa. The present study investigates the performance of DBS in HIV viral load monitoring of patients who received ART in rural Tanzania. PATIENTS AND METHODS: From November 2007 through June 2008, parallel plasma and DBS specimens were obtained from patients who received ART at Haydom Lutheran Hospital in rural Tanzania. DBS specimens were stored at tropical room temperature for 3 weeks before testing with the NucliSENS EasyQ HIV-1 v1.2 assay. Results obtained with DBS were compared with results obtained with use of a gold-standard plasma assay. RESULTS: Ninety-eight plasma-DBS pairs were compared, and plasma viral loads ranged from <40 to >1,000,000 copies/mL. The correlation between plasma and DBS viral load was strong (R(2) = 0.75). The mean difference (+/- standard deviation) was 0.04 +/ 0.57 log(10) copies/mL, and only 8 samples showed >1 log(10) copies/mL difference. HIV type 1 RNA was detected in 7%, 60%, and 100% of DBS specimens with corresponding plasma viral loads of 40-999, 1000-2999, and 3000 copies/mL, respectively. CONCLUSIONS: DBS, in combination with the NucliSENS EasyQ HIV-1 v1.2 asay, performed well in monitoring HIV viral loads in patients who received ART in rural Tanzania, although the sensitivity was reduced when viral burden was low. The use of DBS can simplify virological monitoring in resource-limited settings.

Immunohaematological reference values in human immunodeficiency virus-negative adolescent and adults in rural northern Tanzania.

BACKGROUND: The amount of CD4 T cells is used for monitoring HIV progression and improvement, and to make decisions to start antiretroviral therapy and prophylactic drugs for opportunistic infections. The aim of this study was to determine normal reference values for CD4 T cells, lymphocytes, leucocytes and haemoglobin level in healthy, HIV negative adolescents and adults in rural northern Tanzania. METHODS: A cross sectional study was conducted from September 2006 to March 2007 in rural northern Tanzania. Participants were recruited from voluntary HIV counselling and testing clinics. Patients were counselled for HIV test and those who consented were tested for HIV. Clinical screening was done, and blood samples were collected for CD4 T cell counts and complete blood cell counts. RESULTS: We enrolled 102 participants, forty two (41.2%) males and 60 (58.8%) females. The mean age was 32.6 +/- 95% CI 30.2-35.0. The mean absolute CD4 T cell count was 745.8 +/- 95% CI 695.5-796.3, absolute CD8 T cells 504.6 +/- 95% CI 461.7-547.5, absolute leukocyte count 5.1 +/- 95% CI 4.8-5.4, absolute lymphocyte count 1.8 +/- 95% CI 1.7-1.9, and haemoglobin level 13.2 +/- 95% CI 12.7-13.7. Females had significantly higher mean absolute CD4 T cell count (p = 0.008), mean absolute CD8 T cell count (p = 0.009) and significantly lower mean haemoglobin level than males (p = 0.003) CONCLUSION: Immunohaematological values found in this study were different from standard values for western countries. Females had significantly higher mean CD4 T cell counts and lower mean haemoglobin levels than males. This raises the issue of the appropriateness of the present reference values and guidelines for monitoring HIV/AIDS patients in Tanzania.

Virological efficacy and emergence of drug resistance in adults on antiretroviral treatment in rural Tanzania.

BACKGROUND: Virological response to antiretroviral treatment (ART) in rural Africa is poorly described. We examined virological efficacy and emergence of drug resistance in adults receiving first-line ART for up to 4 years in rural Tanzania. METHODS: Haydom Lutheran Hospital has provided ART to HIV-infected patients since October 2003. A combination of stavudine or zidovudine with lamivudine and either nevirapine or efavirenz is the standard first-line regimen. Nested in a longitudinal cohort study of patients consecutively starting ART, we carried out a cross-sectional virological efficacy survey between November 2007 and June 2008. HIV viral load was measured in all adults who had completed at least 6 months first-line ART, and genotypic resistance was determined in patients with viral load >1000 copies/mL. RESULTS: Virological response was measured in 212 patients, of whom 158 (74.5%) were women, and median age was 35 years (interquartile range [IQR] 29-43). Median follow-up time was 22.3 months (IQR 14.0-29.9). Virological suppression, defined as <400 copies/mL, was observed in 187 patients (88.2%). Overall, prevalence of > or =1 clinically significant resistance mutation was 3.9, 8.4, 16.7 and 12.5% in patients receiving ART for 1, 2, 3 and 4 years, respectively. Among those successfully genotyped, the most frequent mutations were M184I/V (64%), conferring resistance to lamivudine, and K103N (27%), Y181C (27%) and G190A (27%), conferring resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs), whereas 23% had thymidine analogue mutations (TAMs), associated with cross-resistance to all nucleoside reverse transcriptase inhibitors (NRTIs). Dual-class resistance, i.e. resistance to both NRTIs and NNRTIs, was found in 64%. CONCLUSION: Virological suppression rates were good up to 4 years after initiating ART in a rural Tanzanian hospital. However, drug resistance increased with time, and dual-class resistance was common, raising concerns about exhaustion of future antiretroviral drug options. This study might provide a useful forecast of drug resistance and demand for second-line antiretroviral drugs in rural Africa in the coming years.

[Immune reconstitution inflammatory syndrome and treatment of HIV infection]. / Immunrekonstitusjonssyndrom ved behandling av hivinfeksjon.

BACKGROUND: HAART (highly active antiretroviral therapy) may trigger a condition known as IRIS (immune reconstitution inflammatory syndrome); i.e. a paradoxical reaction to latent infections associated with reconstitution of the immune system. The article provides an overview of the syndrome and discusses diagnosis, risk factors and management. MATERIAL AND METHODS: The basis for the article was literature identified through non-systematic searches in PubMed and clinical experience. RESULTS: IRIS typically occurs some weeks to months after initiation of HAART, usually in association with mycobacterial infections, cytomegalovirus, Cryptococcus neoformans and Pneumocystis jirovecii. In principle, any pathogen may cause a similar inflammatory response. Risk factors for IRIS include severe immunodeficiency, high antigen burden and rapid immune response to HAART. The prognosis is good. However, treatment of infections must not delay the initiation of HAART, as such a delay may increase morbidity and mortality. HAART should be continued unless symptoms are life-threatening or likely to cause permanent sequelae. Corticosteroids may be helpful in cases with lesions in the central nervous system, obstructive lymph nodes or increasing respiratory symptoms. INTERPRETATION: Treatment of HIV infection has improved substantially, which implies an increased number of patients developing IRIS. A quick diagnosis and correct and timely treatment of opportunistic infections is important for the prognosis.

Predictors of mortality in HIV-infected patients starting antiretroviral therapy in a rural hospital in Tanzania.

BACKGROUND: Studies of antiretroviral therapy (ART) programs in Africa have shown high initial mortality. Factors contributing to this high mortality are poorly described. The aim of the present study was to assess mortality and to identify predictors of mortality in HIV-infected patients starting ART in a rural hospital in Tanzania. METHODS: This was a cohort study of 320 treatment-naïve adults who started ART between October 2003 and November 2006. Reliable CD4 cell counts were not available, thus ART initiation was based on clinical criteria in accordance with WHO and Tanzanian guidelines. Kaplan-Meier models were used to estimate mortality and Cox proportional hazards models to identify predictors of mortality. RESULTS: Patients were followed for a median of 10.9 months (IQR 2.9-19.5). Overall, 95 patients died, among whom 59 died within 3 months of starting ART. Estimated mortality was 19.2, 29.0 and 40.7% at 3, 12 and 36 months, respectively. Independent predictors of mortality were severe anemia (hemoglobin <8 g/dL; adjusted hazard ratio [AHR] 9.20; 95% CI 2.05-41.3), moderate anemia (hemoglobin 8-9.9 g/dL; AHR 7.50; 95% CI 1.77-31.9), thrombocytopenia (platelet count <150 x 109/L; AHR 2.30; 95% CI 1.33-3.99) and severe malnutrition (body mass index <16 kg/m2; AHR 2.12; 95% CI 1.06-4.24). Estimated one year mortality was 55.2% in patients with severe anemia, compared to 3.7% in patients without anemia (P < 0.001). CONCLUSION: Mortality was found to be high, with the majority of deaths occurring within 3 months of starting ART. Anemia, thrombocytopenia and severe malnutrition were strong independent predictors of mortality. A prognostic model based on hemoglobin level appears to be a useful tool for initial risk assessment in resource-limited settings.

Pulmonary tuberculosis among people living with HIV/AIDS attending care and treatment in rural northern Tanzania.

BACKGROUND: Tuberculosis is the commonest opportunistic infection and the number one cause of death in HIV/AIDS patients in developing countries. To address the extent of the tuberculosis HIV coinfection in rural Tanzania we conducted a cross sectional study including HIV/AIDS patients attending care and treatment clinic from September 2006 to March 2007. METHODS: Sputum samples were collected for microscopy, culture and drug susceptibility testing. Chest X-ray was done for those patients who consented. Blood samples were collected for CD4+ T cells count. RESULTS: The prevalence of tuberculosis was 20/233 (8.5%). Twenty (8.5%) sputum samples were culture positive. Eight of the culture positive samples (40%) were smear positive. Fifteen (75%) of these patients neither had clinical symptoms nor chest X-ray findings suggestive of tuberculosis. Nineteen isolates (95%) were susceptible to rifampicin, isoniazid, streptomycin and ethambutol (the first line tuberculosis drugs). One isolate (5%) from HIV/tuberculosis coinfected patients was resistant to isoniazid. No cases of multi- drug resistant tuberculosis were identified. CONCLUSION: We found high prevalence of tuberculosis disease in this setting. Chest radiograph suggestive of tuberculosis and clinical symptoms of fever and cough were uncommon findings in HIV/tuberculosis coinfected patients. Tuberculosis can occur at any stage of CD4+T cells depletion.

Insulin resistance is affected by increased levels of plasma lactate but not mitochondrial alterations in skeletal muscle in NRTI-exposed HIV-infected patients.

PURPOSE: To explore the relations between insulin resistance, plasma lactate, and mitochondrial (mt) DNA alterations in skeletal muscle in HIV-infected patients treated with nucleoside reverse transcriptase inhibitors (HIV+NRTI+). METHOD: Insulin resistance was estimated using the homeostatic model assessment (HOMA-IR). Mitochondrial dysfunction was determined by plasma lactate at rest and after subanaerobic exercise, mitochondrial/nuclear DNA (mt/nDNA) ratio, and mtDNA deletions in skeletal muscle. RESULTS: HIV+NRTI+ patients (n = 27) had higher levels of HOMA-IR, higher lactate at rest as well as after exercise, and more frequent mtDNA deletions and decreased mt/nDNA ratios compared with controls (n = 15). Only in HIV+NRTI+ patients, HOMA-IR correlated with resting lactate (r = 0.5, p = .02) and probably also lactate 3, 5, and 8 minutes after exercise (r = 0.4; p = .075, p = .048, and p = .056, respectively). In contrast, neither HOMA-IR nor the lactate levels correlated with mt/nDNA ratio and mtDNA deletions in skeletal muscle in HIV+NRTI+ patients (r < 0.1, p > .6), whereas resting lactate correlated with mt/nDNA ratio in HIV seronegative controls (r = -0.7, p = .02). CONCLUSION: In HIV+NRTI+ patients, both resting and postexercise levels of lactate were related to insulin resistance rather than mtDNA alterations in skeletal muscle.

CMV quantitative PCR in the diagnosis of CMV disease in patients with HIV-infection - a retrospective autopsy based study.

BACKGROUND: Patients with advanced HIV infection at the time of diagnosis and patients not responding to antiretroviral therapy are at risk of cytomegalovirus (CMV) disease. Earlier studies of patients with HIV infection have demonstrated that the diagnosis is often first made post-mortem. In recent years new molecular biological tests have become available for diagnosis of CMV disease. Although clinical evaluation of tests for diagnosis of CMV disease in HIV-infected individuals is suboptimal without autopsy, no results from such studies have been published. The aim of this study was to explore the diagnostic utility of CMV quantitative polymerase chain reaction (PCR) in plasma from HIV and CMV seropositive patients who died during the period 1991-2002 and in whom autopsy was performed. METHODS: Autopsy was performed in all cases, as part of routine evaluation of HIV-infected cases followed at Ullevaal University Hospital. Of 125 patients included, 53 had CMV disease, 37 of whom were first diagnosed at autopsy. CMV disease was diagnosed either by ophthalmoscopic findings typical of CMV retinitis, biopsy or autopsy. One or two plasma samples taken prior to the first diagnosis of CMV disease (alive or at autopsy) or death without CMV disease were analysed by CMV quantitative PCR. Sensitivity, specificity, positive and negative predictive values were calculated for different CMV viral load cut-offs and according to detection of viraemia in one versus two samples. RESULTS: Twenty-seven of 53 patients with CMV disease (51%) and 10 of 72 patients without CMV disease (14%) had detectable viraemia in at least one sample. Sensitivity and negative predictive value (NPV) of the test, maximised with a cut-off at the test's limit of detection of CMV viraemia (400 copies/mL), were 47% and 70%, respectively. With cut-off at 10 000 copies/mL, specificity and positive predictive value (PPV) were 100%. With a requirement for CMV viraemia in two samples, specificity and PPV were 100% in patients with CMV viraemia above the limit of detection. CONCLUSION: Our results indicate that quantitative CMV PCR is best used to rule in, rather than to rule out CMV disease in HIV-infected individuals at high risk.

Mitochondrial (mt)DNA changes in tissue may not be reflected by depletion of mtDNA in peripheral blood mononuclear cells in HIV-infected patients.

OBJECTIVES: Most data on mitochondrial toxicity have been derived from peripheral blood mononuclear cells (PBMCs). However, whether mitochondrial DNA (mtDNA) content in PBMCs reflects the mitochondrial state in tissues remains elusive. We report herein on mitochondrial toxicity in skeletal muscle in HIV-infected patients naive to antiretroviral treatment (ART [HIV+ART-naive]; n = 10) patients exposed to nucleoside reverse transcriptase inhibitors (NRTIs [HIV+NRTI+]; n = 24) and healthy controls (n = 11), and compare these tissue data with mtDNA in PBMCs. METHODS: Muscle biopsies were examined for (i) mtDNA and nuclear DNA (nDNA) content using TaqMan real-time PCR system, (ii) mtDNA deletions using long expand PCR with subsequent gel electrophoresis, and (iii) mitochondrial myopathy expressed as cytochrome c oxidase (COX)-deficient muscle fibres. RESULTS: The mt/n DNA ratio in muscle from HIV+NRTI+ patients was reduced compared with HIV-negative controls (P = 0.028). Moreover, mtDNA deletions were more frequent in HIV+NRTI+ patients than in both HIV-negative controls (P = 0.009) and HIV+ART-naive patients (P = 0.005). HIV+NRTI+ also tended to have more COX-deficient fibres than HIV-negative controls (P = 0.076). COX-deficient fibres were positively correlated with mtDNA deletions in HIV+NRTI+ patients (r = 0.83, P < 0.001). Patients with current use of didanosine (ddl) had more frequent mtDNA deletions and COX-deficient fibres than HIV+NRTI+ not on current treatment with ddl. It should be noted that mitochondrial alterations were not correlated with mtDNA/cell in PBMCs in any group. CONCLUSIONS: In skeletal muscle, HIV+NRTI+ had a reduced mt/n DNA ratio, more frequent mtDNA deletions and possibly more COX-deficient muscle fibres than HIV-negative controls. However, the mtDNA/cell in peripheral blood was decreased in both HIV+NRTI+ and HIV+ART-naive patients. Thus, mtDNA in peripheral blood may not be a relevant marker of mitochondrial toxicity in organ-specific tissue.

A randomized trial to evaluate continuation versus discontinuation of lamivudine in individuals failing a lamivudine-containing regimen: the COLATE trial.

BACKGROUND: Lamivudine (3TC) therapy can cause the emergence of M1841/V. Previous studies suggest a higher fidelity of the mutant reverse transcriptase and lower replication capacity of the mutant virus. No data exist from clinical comparative studies evaluating the benefit of M1841/V in patients receiving combination antiretroviral therapy (cART). METHODS: HIV-1-infected adults failing a 3TC-containing regimen were randomized to continue (On-3TC) or discontinue 3TC (Off-3TC) whilst receiving cART. The primary efficacy measure was the log10 average-area-under-the-curve-minus-baseline reduction in HIV RNA over 48 weeks. Cryopreserved plasma samples from patients with baseline and > or =1 follow-up sample with HIV RNA >500 copies/ml were sequenced for a nucleotide distances substudy. Evolutionary distances were compared between treatment arms and between viruses with and without M1841/V. RESULTS: The overall 48-week log10 HIV RNA change was -1.4 (95% CI: -1.6, -1.1) for On-3TC (n=65) and -1.5 (95% CI: -1.7, -1.2) for Off-3TC (n=66; P=0.51). No difference was seen in the magnitude of the CD4+ T-cell count increases (median increase: 87 vs 76 cells/ml for 3TC vs Off-3TC, respectively). Thirty-seven patients had baseline and follow-up sequencing. Overall, there were 1.2 (95% CI: -2.2, 4.6) more nucleotide substitutions from baseline for Off-3TC patients (P=0.50), and 10.7 (95% CI: 7.5, 14.0) fewer nucleotide changes in viruses containing M18411V (P<0.0001). CONCLUSION: This study found no added virological or immunological benefit of continuing 3TC in patients on cART harbouring M1841/V. Evolutionary distances from baseline were larger in viruses that did not contain M1841/V. More discernable benefits may be seen in patients with fewer drug options as potent cART may eclipse a benefit of M1841/V in COLATE.

[HIV/AIDS--from lethal syndrome to chronic disease]. / Fra dødelig syndrom til kronisk sykdom.

BACKGROUND: At its discovery in 1981, AIDS was a fatal syndrome that rapidly led to death. Combination treatment with at least three drugs has radically improved the prognosis. MATERIAL AND METHODS: The study includes all HIV-patients controlled at the Department of Infectious Diseases, Ullevål University Hospital from 1982 to 2005. Development of immune deficiency, morbidity and causes of death were registered prospectively. Possible connections between death and HIV-infection and treatment were evaluated. RESULTS: 1632 patients were followed at our department. 32 % of these patients have died. The number of patients who died annually during the 5 years from 1986 to 1990 was 47 % and this was reduced to 11 % in 2001 - 05. Many patients still die because they either present too late for treatment or have received insufficient treatment. 22 patients have died during the last 10 years irrespective of starting treatment with at least 3 antiretroviral drugs: 7 died from cancers, 6 from treatment failure, one from unknown cause and 8 from other causes. The 6 patients who died from treatment failure had very low CD4 counts and serious opportunistic infections that could not be treated effectively at the time of diagnosis. INTERPRETATION: Patients who start and adhere to treatment with 3 HIV-medications have a good prognosis, but they may still have an increased risk of non-AIDS defining cancers and cardiovascular disease. HIV/AIDS has become a chronic disease with a good prognosis.

Divergent in vitro and in vivo correlates of HIV-specific T-cell responses during onset of HIV viraemia.

BACKGROUND: Cellular immune responses to HIV-1 have been examined mainly in peripheral blood mononuclear cells (PBMC). During onset of HIV replication and antigenaemia after discontinuation of highly active antiretroviral therapy (HAART), PBMC may theoretically contain HIV-specific T cells that are qualitatively and quantitatively different from specific T cells dominating in the tissues. PBMC responses throughout HIV immunotherapy trials may therefore be skewed during recurrent viraemia. OBJECTIVE: To compare cellular HIV-specific in vitro responses in PBMC during onset of HIV viraemia with corresponding in vivo responses, represented by classical delayed-type hypersensitivity tests (DTH). METHODS: HIV patients (n = 38), pre-immunized with four HIV-1 p24-like consensus peptides (Vacc-4x) during HAART, were subjected to a 14-week treatment interruption with recurrent HIV viraemia. Proliferative T-cell responses to Vacc-4x p24 peptides, HIV p24 protein, and cytomegalovirus (CMV) proteins were measured in PBMC. Corresponding Vacc-4x peptide DTH were expressed as skin infiltrate areas after 48 h. RESULTS: After 14 weeks without HAART, HIV-1 RNA increased to 72,500 copies/ml (median). The Vacc-4x p24 peptide- and HIV-1 p24 protein-induced T-cell proliferation concurrently decreased by 81 and 93% in PBMC during viraemia (medians, P < or = 0.03), whereas proliferative responses to CMV antigens were stable. In contrast, the Vacc-4x DTH areas, rather tended to increase by 36% (P = 0.08) and contained infiltrates dominated by proliferating T cells and macrophages. CONCLUSIONS: Divergent in vitro and in vivo HIV-specific cellular immune responses were found during recurrent HIV viraemia. The clinical relevance of both surrogate markers for HIV-related immune responses should be compared in future studies.