Evaluation of PIMA point-of-care CD4 analyzer in Yunnan, China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>CD4 count is used to determine antiretroviral therapy (ART) eligibility. In China, flow cytometers are mostly located in urban areas with limited access by patients residing in remote areas. In an attempt to address this issue, we conducted a study to validate the performance of Alere PIMA point-of-care CD4 analyzer.</p><p><b>METHODS</b>Venous and finger-prick blood specimens were collected from HIV-positive participants from two voluntary counseling and testing sites in Yunnan Province. Both venous and finger-prick blood specimens were tested with the PIMA analyzer. Venous blood specimens tested with the Becton Dickinson FACSCalibur were used as a reference.</p><p><b>RESULTS</b>Venous specimens from 396 and finger-prick specimens from 387 persons were available for analysis. CD4 counts by PIMA correlated well with those from FACSCalibur with an R2 of 0.91 for venous blood and 0.81 for finger-prick blood. Compared to FACSCalibur, the PIMA analyzer yielded lower counts with a mean bias of - 47.0 cells/μl (limit of agreement, [LOA]: -204-110 cells/μl) for venous blood and -71.0 cells/μl (LOA: -295-153 cells/μl) for finger-prick blood. For a CD4 threshold of 350 cells/μl, the positive predictive value (PPV) of PIMA was 84.2% and 75.7% and the negative predictive value (NPV) was 97.6% and 95.8% for venous and finger-prick blood, respectively. For an ART threshold of 500 cells/μl, the corresponding PPV was 90.3% and 84.0% and NPV was 94.3% and 93.4%, respectively.</p><p><b>CONCLUSIONS</b>CD4 counting using venous blood with PIMA analyzers is a feasible alternative to a large flow cytometer to determine ART eligibility.</p>

Estimation on the HIV-1 incidence among high risk groups using the pooling RNA technique / 中华流行病学杂志

<p><b>OBJECTIVE</b>To timely identify the HIV-1 infection in window-period and to estimate the HIV-1 incidence among people who came for voluntary counseling and testing (VCT) service as well as men who have sex with men (MSM), respectively.</p><p><b>METHODS</b>HIV antibody negative samples that were determined by screening tests between January and October 2012, were collected and tested with pooling HIV-1 RNA testing technique (2-staged pooling by 50:1, 10:1). Positive cases were followed-up for HIV antibody testing while HIV incidence was calculated under Ron Brookmeyer' s method, among VCT and MSM populations.</p><p><b>RESULTS</b>Among 1400 HIV antibody negative samples of VCT, two showed HIV-1 RNA positive during the antibody window period with the HIV-1 incidence as 1.87% per year (95% CI: 1.23%-2.65% ). Among 500 HIV antibody negative samples from MSM population, two showed HIV-1 RNA positive in the antibody window period, with HIV-1 incidence as 5.31% per year (95% CI: 3.52%-7.45% ).</p><p><b>CONCLUSION</b>Pooling HIV-1 RNA testing seemed a powerful tool for HIV antibody testing in the window-period. Measures should be taken to strengthen the HIV diagnostic programs among MSM and other high risk groups,during the HIV antibody window-period. More frequent detection approach as pooling HIV-1 RNA testing might be a good choice.</p>

Evaluation of PIMA analyzer detecting CD4 cell count of venous and capillary blood in HIV-infected individuals / 中华预防医学杂志

<p><b>OBJECTIVE</b>This study is aimed at evaluating the utility of the portable CD4 analyzers (PIMA).</p><p><b>METHODS</b>The paired finger prick blood (25 µl) and 5 ml venous blood samples were collected from 196 HIV infected patients, who came to Yunnan CDC voluntary counseling and testing (VCT) clinic for CD4 test services, from May to August, 2012. The absolute CD4 cell counts were measured by PIMA (using venous and finger-prick blood) and by Calibur (using venous blood) as the reference. The PIMA and Calibur CD4 results were compared using the Wilcoxon matched-pairs test, and the Spearman's rank correlation coefficients were estimated. The Bland-Altman plots were used to assess the consistency of the two methods.</p><p><b>RESULTS</b>The median absolute CD4 counts of 196 venous blood samples obtained by PIMA and by Calibur were 268 (range:169-403) cells/µl and 302 (range:181-474) cells/µl respectively, which showed significant difference (Z = -7.31, P < 0.01). The median absolute CD4 counts measured by PIMA and by Calibur (using 188 finger-prick and venous blood samples respectively) were 271 (range: 165-450) cells/µl and 304 (range:188-476) cells/µl, which also showed significant difference (Z = -7.60, P < 0.01). The CD4 counts obtained by PIMA CD4 analyzer (using venous and finger-prick blood) showed strong positive correlation with the CD4 counts obtained by the reference method (using venous blood), and the r values were 0.94 and 0.92 respectively (P < 0.01) . The mean biases (limit of agreement) were -38.7 (-210.9-133.5)cells/µl and -45.4 (-221.8-131.0) cells/µl, respectively.Using 350 CD4 counts as the threshold for ART treatment initiation, the sensitivity and specificity of PIMA were 99.1% and 79.3% for venous blood samples, and 97.2%and 78.5% for finger-prick blood samples, respectively.</p><p><b>CONCLUSION</b>The CD4 counts obtained by PIMA are lower than that obtained by Calibur, while the sensitivity is high.</p>

Survey on the transmission of HIV drug resistance in Kunming, Yunnan province in 2010 / 中华流行病学杂志

Objective To study the HIV drug resistance (HIVDR) transmission in Kunming city of Yunnan province in 2010.Methods Referring to the guidelines for HIV drug resistance threshold survey (HIVDR-TS) set by WHO,62 plasma samples of recently reported HIV-infected individuals who were older than 25 years of age,were collected from January to August 2010.Genotyping of pol genetic mutations associated with HIVDR with reverse transcriptional PCR was performed and the prevalence of HIV-1 drug resistance transmission was evaluated.Results Of the 62 plasma samples,54 were successfully sequenced and genotyped on pol sequence.Based on the pol sequences,HIV subtypes including CRF08_BC ( 53.2％ ),CRF07_BC ( 25.5％ ),CRF01_AE ( 19.1％ )and C (2.1％) were identified.According to the time of sampling,the first 47 sequenced samples were used for drug resistance prevalence analysis.A protease inhibitor (PI) relative mutation was found in one sample.Based on the WHO standard,the prevalence of transmitted HIV-1 drug resistance was ＜5％.Conclusion HIV-1 drug resistant strains transmission was still catalogued as low prevalence level in Kunming.To prevent the increase of HIVDR prevalence,normative treatment and scientific management to AIDS patients seemed to be quite important.

Distribution of HIV-1 subtypes among different populations in Dehong prefecture, Yunnan province, in 2011 / 中华流行病学杂志

Objective To investigate the distribution of HIV-1 subtypes in Dehong prefecture,Ymnan province,in 2011.Methods 300 HIV-1 positive plasma samples were collected from Jan.2011 to May 2011 in Dehong prefecture.HIV-1 gag genes and env genes were amplified by nestedpolymerase chain reaction (PCR) from viral RNA,After sequencing,the HIV-1 subtypes were determined by phylogenetic analysis.Results Based on the phylogenetic trees of gag gene and env gene fragments,a total of 222 samples were genotyped.Subtype C was the predominant strain in Dehong (43.2％,96/222),followed by unique recombinant forms (URFs,27.0％,60/222),CRF01 _AE ( 21.2％,47/222 ),C R F08_BC ( 5.0％,11/222 ),B,( 2.3％,5/222 ) and CRF07 BC ( 1.4％,3/222).Subtype C strains were predominant in both heterosexually transmitted population and intravenous drug users (IDUs),but different subtype distribution patterns were found in these two populations.All 6 genotypes including subtype C (40.7％,70/172),CRF01_AE (25.0％,43/172),and URFs (25.0％,43/172 ) found in this area among hcterosexually transmitted population,which showed the diversity of genotypes in this population.Except subtype B' and CRF07_BC,the other 3 subtypes and URFs were detected among IDUs,mainly including subtype C (54.8％,23/42) and U R Fs (38.1％,16/42),vhich shoved the concentration trend of genotypes distribution among IDUs.The proportion of URFs increased significantly in this area,including the new BC recombinants (41.7％,25/60) and CRF01_AE relative URFs (58.3％,35/60).However,the distributions of these two URFs among heterosexually transmitted population and IDUs showed no statistical significance.Conclusion The distribution of HIV-1 strains prevailing in Dehong prefecture was diversity,including 5 subtypes and a variety of URFs,of which subtype C was the predominant strain.The distribution patterns of subtype were different among different populations.

Early detection of HIV infection with Dried Blood Spot testing among infants in Yunnan province / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the application of Dried Blood Spot (DBS) testing for early detection of HIV infection among infants.</p><p><b>METHODS</b>All of the infants aged between 6 weeks and 18 months and born by HIV positive mothers from 14 Maternity and Child Health Care Hospitals in Kunming, Dali, Dehong, Lincang of Yunnan province were investigated from 2010 to 2011. By using DBS and Roche HIV-1 DNA test techniques, 286 infants were tested for HIV early diagnosis and compared with HIV antibody results of 18 months infants. DBS from uninfected infants were taken periodically and screened of HIV antibody to find their time of antibody-disappearing. The information of treatment for pregnant women and feeding methods for infants was also investigated.</p><p><b>RESULTS</b>A total of 286 infants were tested with HIV-1 DNA among which 148 infants were male and 138 infants female, and 8 infants were HIV-1 DNA positive and the infection rate was 2.8% (8/286) that was in accord with their antibodies results in 18 months old; the other 278 infants whose HIV-1 DNA was negative was also negative with their antibodies. By following up the antibody test of 143 HIV negative infants the cumulate rates of antibody-disappearing at the age of 6, 9, 12 and 18 months were 14.0% (20/143), 61.5% (88/143), 88.1% (126/143) and 100.0% (143/143), respectively. Among 286 HIV positive pregnant women, the group with anti-viral treatment had a lower rate of HIV infection with their infants that was 2.14% (6/280) while the group without anti-viral treatment had a high rate of HIV infection with their infants that was 33.33% (2/6). There was significantly different in the rates of two groups (P < 0.01). The HIV infection rate of infants fed with milk powder was 2.55% (7/274) and the rate was 8.33% (1/12) with breast milk.</p><p><b>CONCLUSION</b>The HIV-1 DNA detection techniques with DBS sample was effective for the early diagnosis of HIV in infants from 6 weeks to 18 months.</p>

The analysis of human immunodeficiency virus-1 subtypes in Yunnan province / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze the geographical distribution and risk factors of HIV-1 subtypes in Yunnan province.</p><p><b>METHODS</b>Blood samples from 1319 HIV positives were collected in Yunnan Province from 2001 to 2006. The nested polymerase chain reaction was used to amplify the gag (p24)-protease fragments from RNA extracted from plasma or sera. The sequences were used for subtype determination by phylogenetic tree analysis.</p><p><b>RESULTS</b>Among 1319 samples studied, the subtypes has been successfully obtained from 644 samples that were constituted of seven subtypes: CRF08_BC, CRF07_BC, CRF07/08_BC, CRF01_AE, C, B' and URFB/C. C/CRF07_BC/CRF08_BC were distributed in the whole province, but CRF01_AE were mainly distributed in the boarding areas with Myanmar such as Dehong, Baoshan, Xishuangbanna and Puer. Moreover, injecting drugs users accounted for 61.6% (270/438) among C/CRF07_BC/CRF08_BC infections, while only 8.5% (15/177) among CRF01_AE infections.</p><p><b>CONCLUSION</b>Our data indicated that at least seven subtypes were identified in Yunnan province, the relationship between subtypes and transmission routes were analyzed, and the geographic difference of subtypes was also observed.</p>