Association of demographics, HCV co-infection, HIV-1 subtypes and genetic clustering with late HIV diagnosis: a retrospective analysis from the Japanese Drug Resistance HIV-1 Surveillance Network.

INTRODUCTION: Late diagnosis of the human immunodeficiency virus (HIV) is a major concern epidemiologically, socially and for national healthcare systems. Although the association of certain demographics with late HIV diagnosis has been reported in several studies, the association of other factors, including clinical and phylogenetic factors, remains unclear. In the present study, we conducted a nationwide analysis to explore the association of demographics, clinical factors, HIV-1 subtypes/circulating recombinant form (CRFs) and genetic clustering with late HIV diagnosis in Japan, where new infections mainly occur among young men who have sex with men (MSM) in urban areas. METHODS: Anonymized data on demographics, clinical factors and HIV genetic sequences from 39.8% of people newly diagnosed with HIV in Japan were collected by the Japanese Drug Resistance HIV-1 Surveillance Network from 2003 to 2019. Factors associated with late HIV diagnosis (defined as HIV diagnosis with a CD4 count <350 cells/µl) were identified using logistic regression. Clusters were identified by HIV-TRACE with a genetic distance threshold of 1.5%. RESULTS: Of the 9422 people newly diagnosed with HIV enrolled in the surveillance network between 2003 and 2019, 7752 individuals with available CD4 count at diagnosis were included. Late HIV diagnosis was observed in 5522 (71.2%) participants. The overall median CD4 count at diagnosis was 221 (IQR: 62-373) cells/µl. Variables independently associated with late HIV diagnosis included age (adjusted odds ratio [aOR] 2.21, 95% CI 1.88-2.59, ≥45 vs. ≤29 years), heterosexual transmission (aOR 1.34, 95% CI 1.11-1.62, vs. MSM), living outside of Tokyo (aOR 1.18, 95% CI 1.05-1.32), hepatitis C virus (HCV) co-infection (aOR 1.42, 95% CI 1.01-1.98) and not belonging to a cluster (aOR 1.30, 95% CI 1.12-1.51). CRF07_BC (aOR 0.34, 95% CI 0.18-0.65, vs. subtype B) was negatively associated with late HIV diagnosis. CONCLUSIONS: In addition to demographic factors, HCV co-infection, HIV-1 subtypes/CRFs and not belonging to a cluster were independently associated with late HIV diagnosis in Japan. These results imply the need for public health programmes aimed at the general population, including but not limited to key populations, to encourage HIV testing.

Vaccine-induced neutralizing antibodies against SARS-CoV-2 Omicron variant isolated in Osaka, Japan.

To study vaccine-induced neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants isolated in Osaka, Japan, microneutralization tests were performed on serum samples from 32subjects who received a second dose of vaccination, and 10 of those who received the third dose of vaccination. Geometric mean titres (GMTs) for the D614G strain, Alpha variant, Delta variant, and Omicron BA.1 of the subjects after the second dose of vaccination were 19.5, 21.8, 6.3 and 2.0, respectively. The GMT for the Delta variant was significantly lower than that for the D614G strain and Alpha variant, and the GMT for the Omicron BA.1 was significantly lower than that for the Delta variant. Among the subjects who received three doses of vaccination, the GMTs for the Omicron BA.1 (62.8) and BA.2 (38.6) were significantly higher than that for the Omicron BA.1 after the second dose. Thus, in the present study, the second dose of vaccination induced neutralizing antibodies against SARS-CoV-2 strains, and the reactivity of neutralizing antibodies to the variants was thought to be enhanced by the third dose of vaccination. The serum samples used in this study will be useful in evaluating the reactivity of vaccine-induced antibodies to newly emerging variants.

Contribution of parvovirus B19 in suspected cases of measles/rubella in Osaka, Japan, between 2011 and 2021.

Erythema infectiosum, caused by human parvovirus B19 (B19V), is difficult to diagnose by its clinical symptoms and is often misdiagnosed as measles or rubella. Timely confirmation of measles/rubella or other viral etiologies via laboratory tests can provide an accurate picture of the infection status, which can appropriate response. The purpose of this study was to determine the contribution of B19V as an etiological agent for fever-rash in suspected cases of measles and rubella in Osaka Prefecture between 2011 and 2021. Of 1356 suspected cases, 167 were confirmed with measles and 166 with rubella using nucleic acid testing (NAT). Of the remaining 1023 cases, 970 from which blood specimens could be obtained were screened by real-time polymerase chain reaction for B19V, from which 136 (14%) tested positive. Of the positives cases, 21% were young children (9 years and younger), while 64% were adults (20 years and older). Phylogenetic tree analysis showed that 93 samples belonged to genotype 1a. The importance of B19V in the etiology of fever-rash illness was revealed in this study. The importance of laboratory diagnosis by NAT in maintaining the status of measles elimination and to eliminate rubella was reaffirmed.

Shedding of rubella virus in postsymptomatic individuals; viral RNA load is a potential indicator to estimate candidate patients excreting infectious rubella virus.

BACKGROUND: Since the first isolation of rubella virus (RuV) in 1962, comprehensive data regarding the quantitative evaluation of RuV shedding remain unavailable. In this study, we evaluated the shedding of viral RNA and infectious virus in patients with acute RuV infection. STUDY DESIGN: We analyzed 767 specimens, including serum/plasma, peripheral blood mononuclear cells (PBMCs), throat swabs, and urine, obtained from 251 patients with rubella. The viral RNA load and the presence of infectious RuV were determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and virus isolation. RESULTS: Virus excretion peaked 0-2 days after rash onset and decreased over time. The median viral RNA load dropped to an undetectable level on day 3 after rash onset in serum/plasma, day 2 in PBMCs, days 10-13 in throat swabs, and days 6-7 in urine. Infectious virus could be isolated for up to day 2 after rash onset in serum/plasma, day 1 in PBMCs, days 8-9 in throat swabs, and days 4-5 in urine. The minimum viral RNA load that allowed virus isolation was 961 copies/mL in serum/plasma, 784 copies/mL in PBMCs, 650 copies/mL in throat swabs, and 304 copies/mL in urine. A higher viral RNA load indicated a higher likelihood of the presence of infectious virus. CONCLUSION: These findings would contribute to improve algorithms for rubella surveillance and diagnosis. In addition, this study indicates that the results of RT-qPCR enable efficient rubella control by estimating candidate patients excreting infectious virus, which could help prevent viral transmission at an early stage and eliminate rubella ultimately.

Increasing seroprevalence but waning herd immunity against measles after elimination: Longitudinal seroepidemiology of measles in Osaka Prefecture, Japan, 2003-2020.

Japan is one of the countries conducting longitudinal serosurveillance of vaccine-preventable diseases. We conducted surveillance of the local measles-specific antibody titer, calculated the effective reproduction number (Re), and compared data of four terms: term 1, 2003-2006 (before the introduction of the second shot of measles-containing vaccine); term 2, 2007-2010 (early term toward measles elimination); term 3, 2011-2014 (later term toward measles elimination); and term 4, 2015-2020 (after elimination of measles in Japan). Approximately 250 sera from volunteers aged 0 to ≥ 40 years were collected and examined for measles-specific IgG using the gelatin particle agglutination (PA) method annually from 2003 to 2020. Seroprevalence and the geometric mean of the PA antibody titer were examined by term. Re was calculated using the age-dependent proportion immune and contact matrix for each term. Of the 4,716 sera, 886 in term 1, 1,217 in term 2, 1,069 in term 3, and 1,544 in term 4 were collected. The seroprevalence gradually increased from term 1 (88.3% CI 86.0-90.3) to term 4 (95.7% CI 94.6-96.7), and the seroprevalence of term 1 was significantly lower than those of other terms (Fisher's exact test, p < 0.001), with PA titer ≥ 16 as positive. By contrast, PA antibody titers significantly decreased from term 1 (median 1,024) to term 4 (median 256) (Mann-Whitney U test, p < 0.001). With the protection level (PA titer ≥ 128 and ≥ 256) as positive, Re gradually increased from term 1 (1.8 and 2.3) to term 4 (2.5 and 4.8, respectively). Waning levels of measles antibodies potentially increase the measles susceptibility in Osaka, Japan. This trend might imply a limitation of vaccine-induced immunity in the absence of a natural booster for wild strains after measles elimination. This study provides a cue for maintaining continuous measles elimination status in the future.

Clinical perspectives of Treponema pallidum subsp. Endemicum infection in adults, particularly men who have sex with men in the Kansai area, Japan: A case series.

Bejel, caused by Treponema pallidum subsp. Endemicum (TEN), is a locally transmitted disease among children and juveniles in hot and dry regions. The number of adult cases of TEN infection outside of endemic areas has recently increased. We clinically examined five cases of TEN infection among adult cases previously reported in Japan. TEN infection mainly developed among young to middle-aged men who have sex with men (MSM). The clinical features of cases of TEN infection were similar to those of primary- and secondary-stage T. pallidum subsp. pallidum (TPA) infection. Genital lesions were common as the primary lesion. The clinical features and laboratory parameters of cases of TEN infection were similar to those of TPA infection. Most of the isolated strains had the A2058G mutation in 23S rDNA, which is responsible for resistance to macrolides. We also performed the systemic literature review of the TEN cases outside the endemic countries. The recent reported cases diagnosed with molecular methods shared the clinical features, occurred in young-to middle-aged sexually active persons in urban areas of developed countries and often accompanied with genital lesions, which were distinct from the classic description of bejel. This case series and the literature review provides important clinical insights and will contribute to the clinical detection of this rarely identified disease in developed countries. The surveillance of treponematoses, including TEN infection, using molecular diagnostic techniques is also warranted in developed countries, for the purpose of grasping the epidemic situation and control the local transmission.

Estimating HIV-1 incidence in Japan from the proportion of recent infections.

The first step of the UNAIDS/WHO 90-90-90 targets to encourage early diagnosis with treatment for the control of HIV-1 epidemic is to achieve 90% HIV-1 diagnosis in infected individuals. In Japan, approximately 30% of newly reported cases have been annually identified by AIDS onset, implying that substantial numbers of HIV-1-infected individuals remain undiagnosed. However, the proportion of undiagnosed cases has not yet been determined. In the present study, the proportion of recent HIV-1 infections to newly-diagnosed cases was determined from 2006 to 2015 using a recent infection assay for three metropolitan areas in Japan: Tokyo, Osaka, and Fukuoka. Estimated median periods between infection and diagnosis were 1.0, 1.8, and 2.9 years for Tokyo, Osaka, and Fukuoka, respectively. Estimation of annual HIV-1 incidence by a back-calculation method using these data as well as HIV/AIDS national surveillance data indicated proportions of undiagnosed to new HIV-1 infections from 2006 to 2015 to be 18% in Tokyo, 22% in Osaka, 38% in Fukuoka, and 28% in Japan. This is the first report estimating HIV-1 incidence in Japan using a serological biomarker in combination with national HIV/AIDS surveillance data.

Bejel, a Nonvenereal Treponematosis, among Men Who Have Sex with Men, Japan.

Bejel, an endemic treponematosis caused by infection with Treponema pallidum subspecies endemicum, has not been reported in eastern Asia and the Pacific region. We report local spread of bejel among men who have sex with men in Japan. Spread was complicated by venereal syphilis.

Circulation of Distinct Treponema pallidum Strains in Individuals with Heterosexual Orientation and Men Who Have Sex with Men.

Human treponematosis is caused by various pathogenic Treponema pallidum subspecies, including T. pallidum subsp. pallidum, T. pallidum subsp. pertenue, T. pallidum subsp. endemicum, and Treponema carateum The global prevalence of syphilis has been increasing since the 2000s. Men account for more than 90% of the cases, with the majority being men who have sex with men (MSM). In Japan, the increase in the number of syphilis patients began in 2011, a 10-year delay from the global trend. In 2017, a total of 5,829 syphilis cases (3,934 men and 1,895 women) were reported, with an outstanding increase in cases among young adult women; the number reported for women age 15 to 20 years was 1,100. Hence, a molecular epidemiological study was conducted on circulating T. pallidum strains using two strain typing methods, the enhanced CDC method and sequencing-based molecular typing. Clinical specimens from 95 adults suspected of syphilis were collected from September 2013 to August 2017 in Osaka, Japan. T. pallidum DNA was detected in specimens from 25 males and 11 females, including seven MSM. The majority of the heterosexual patients (66.7% and 90.9% of males and females, respectively) were positive for 14d/f-SSR8. In contrast, the genotypes identified in the MSM group were significantly divergent. T. pallidum subsp. endemicum was notably identified in two MSM patients. Macrolide-sensitive or Nichols-like strains were significantly associated with the MSM group. These data suggest that distinct T. pallidum strains were circulating in the heterosexual and MSM groups. Our findings imply that independent factors may contribute to the increased syphilis prevalence in heterosexual and MSM populations.

Comparative evaluation of the Geenius HIV 1/2 Confirmatory Assay and the HIV-1 and HIV-2 Western blots in the Japanese population.

Accurate diagnosis of earlier HIV infection is essential for treatment and prevention. Currently, confirmation tests of HIV infection in Japan are performed using Western blot (WB), but WB has several limitations including low sensitivity and cross-reactivity between HIV-1 and HIV-2 antibodies. To address these problems, a new HIV testing algorithm and a more reliable confirmation and HIV-1/2 differentiation assay are required. The Bio-Rad Geenius HIV-1/2 Confirmatory Assay (Geenius) has recently been approved and recommended for use in the revised guidelines for diagnosis of HIV infection by the Center for Disease Control and Prevention (USA). We made comprehensive comparison of the performance of Geenius and the Bio-Rad NEW LAV BLOT 1 and 2 (NLB 1 and 2) which are WB kits for HIV-1 and HIV-2, respectively, to examine if Geenius is a suitable alternative to these WB assays which are now being used in HIV testing in Japan. A total of 166 HIV-1 positive samples (146 from patients with established HIV-1 infection and 20 from patients with acute infection), five HIV-1 seroconversion panels containing 21 samples and 30 HIV-2 positive samples were used. In addition, a total of 140 HIV negative samples containing 10 false-positives on screening tests were examined. The sensitivity of Geenius and NLB 1 for HIV-1 positive samples was 99.3% and 98.6%, respectively. Geenius provided more positive results in the samples from acute infections and detected positivity 0 to 32 days earlier in seroconversion panels than NLB 1. NLB 2 gave positive results in 12.3% of HIV-1 positive samples. The sensitivity of both Geenius and NLB 2 for HIV-2 positive samples was 100%. The specificity of Geenius, NLB 1 and NLB 2 was 98.5%, 81.5% and 90.0%, respectively. Geenius is an attractive alternative to WB for confirmation and differentiation of HIV-1 and HIV-2 infections. The adaptation of Geenius to the HIV testing algorithm may be advantageous for rapid diagnosis and the reduction of testing costs.

Characteristics of Transmitted Drug-Resistant HIV-1 in Recently Infected Treatment-Naive Patients in Japan.

OBJECTIVES: Progress in antiretroviral treatment has led to fewer virological failure cases, but 10%-20% of treatment-naive HIV/AIDS cases are reported to harbor drug-resistant strains, suggesting transmission of drug-resistant HIV. We aimed to determine the trend in prevalence of transmitted drug-resistant (TDR) HIV in Japan, particularly in recently infected patients. METHODS: Drug-resistance test was performed on 3904 HIV-1-infected cases newly diagnosed between 2007 and 2012. The number of cases infected within 6 months [recent seroconverters (RS)] was estimated by BED assay of 2700 plasma samples. Characteristics of RS cases were further analyzed. RESULTS: The overall prevalence of TDR was 9.1%, ranging from 7.3% in 2008% to 12.5% in 2010. Among 1403 subtype B/E/D cases with >50 CD4 T cell counts and >1000 HIV copies per milliliter, 468 (33.4%) were estimated to be RS. The prevalence of RS was significantly higher among cases who were male, Japanese, and men who have sex with men. The prevalence of TDR did not differ significantly between recent and long-term seroconverters (8.5% vs. 9.2%, respectively, P = 0.68). Common mutations in both groups were M46I/L and T215 revertants. Furthermore, sequences with these mutations, K103N and D30N/N88D formed clusters on phylogenetic trees. CONCLUSION: Our study clarified an increase in prevalence of TDR in Japan from 2007 to 2012. The phylogenetic clustering of cases with M46I/L or T215 revertants suggests that HIV with these mutations have become circulating strains. Furthermore, detailed analyses showed that Japanese men who have sex with men are more aware of their risk of HIV infection.

A cluster of rapid disease progressors upon primary HIV-1 infection shared a novel variant with mutations in the p6gag/pol and pol/vif genes.

Few studies have described the etiologic factors associated with rapid AIDS onset during primary HIV-1 infection. Our molecular epidemiological study identified a cluster of individuals infected with HIV-1 variants characterized by novel mutations in the p6 and pol/vif genes during 2011 and 2013 in Osaka, Japan. Individuals positive for the novel HIV-1 variant showed rapid disease progression, suggesting a role of viral mutations in the fostering of the clinical course of HIV-1 infection.

Identification of Novel Recombinant Forms of Hepatitis B Virus Generated from Genotypes Ae and G in HIV-1-Positive Japanese Men Who Have Sex with Men.

The rare hepatitis B virus (HBV) genotype G (HBV/G) coinfects HIV-1-positive individuals along with HBV/A and generates recombinants. However, the circulation of HBV A/G recombinants remains poorly understood. This molecular epidemiologic study examined HBV A/G recombinants in Japanese HIV-1-positive men who have sex with men (MSM). Initially, blood specimens submitted for confirmatory tests of HIV infection in Osaka and Tokyo, Japan, from 2006 to 2013 were examined for HIV-1, and HIV-1-positive specimens were screened for HBV. Among 817 specimens from HIV-1-positive individuals, HBsAg was detected in 59 specimens; of these, HBV/Ae (alternatively A2), a subgenotype of HBV/A prevalent in Europe and North America, was identified in 70.2%, HBV/C in 17.5%, and HBV/G in 10.5%, and HBV/E in 1.8% according to the core gene sequence. The full-length genome analysis of HBV was performed on HBV/G-positive specimens because some HBV A/G recombinants were historically overlooked by genotyping based on a partial genome analysis. It revealed that five of the specimens contained novel Ae/G recombinants, the core gene of which had a high sequence similarity to HBV/G. Detailed analyses showed that novel recombinants were coinfected with HBV/Ae in a recombinant-dominant fashion. No major drug-resistant mutations were found in the newly identified HBV Ae/G recombinants. Some of the individuals asymptomatically coinfected with HIV/HBV suffered mild liver injury. This study demonstrated that novel Ae/G HBV recombinants were identified in Japanese HIV-1-positive MSM. The pathogenicity of novel HBV Ae/G recombinants should be examined in a future longitudinal study. Surveillance of such viruses in HIV-1-positive individuals should be emphasized.

[Evaluation of an immunochromatographic fourth generation test for the rapid diagnosis of acute HIV infection].

The early diagnosis of human immunodeficiency virus (HIV) infection is important to provide effective antiviral treatment and to prevent transmission of HIV. One of the key issues to achieve this goal is to shorten the so-called "diagnostic window period" when the humoral immune response toward the virus is not fully developed during the acute phase of HIV-1 infection. In 2008, the Espline HIV Ag/Ab test kit (E4G, Fujirebio Inc. Japan) was marketed in Japan belonging to the fourth generation of HIV test kits characterized by its ability to detect both viral antigens (Ag) and anti-HIV-1/2 antibodies (Ab). E4G is the first and only fourth generation immunochromatographic HIV test kit approved in Japan at present. To evaluate its performance to diagnose acute HIV infection (AHI), E4G was compared with fourth generation Ag/Ab ELISA test kits, a third generation PA test kit, WB and real-time PCR for the testing of 25 AHI clinical specimens. E4G detected HIV infection in 18/25 specimens (sensitivity : 72.0%), of which the viral Ag was detected in only 2 specimens (8.0%) bearing a viral load > 10 million copies/mL. No spesimens were simultaneously reactive to both Ag and Ab against HIV. The third generation PA achieved a positive score of 17/ 25 specimens (68.0%), which was almost the same as the E4G figure. In contrast the fourth generation Ag/ Ab ELISA scored all the 25 AHI specimens positive (sensitivity : 100%). Overall, although having the merit of offering a rapid diagnostic test for HIV infection, E4G does not provide a sensitivity in AHI diagnosis superior to test kits currently available.

Novel anti-HIV-1 activity produced by conjugating unsulfated dextran with polyL-lysine.

A conjugate of polyL-lysine (PLL) with unsulfated dextran produced by reductive amination was found to have remarkable anti-HIV-1 activity against both the macrophage-tropic R5 virus Ba-L and T-cell line tropic X4 virus IIIB strains, although neither PLL nor dextran has such activity. The conjugate is a pseudoproteoglycan (pseudoPG) that simulates the structure of a proteoglycan. Conjugation with dextran was found to produce an antiviral effect in three kinds of assay systems including a human CD4(+) T-cell line, and the pseudoPG synthesized using 10 kDa PLL and 10 kDa dextran showed EC(50) 4-40 times lower than that of sulfated dextran or heparin against Ba-L and EC(50) equal to that against IIIB, indicating that PLL-dextran (PLL-Dex) was more effective against R5 virus than sulfated polysaccharides. PLL-Dex significantly suppressed a clinically isolated R5 virus from primary peripheral blood mononuclear cells. PLL-Dex interacted with the virus during adsorption to the cell and also decreased virus entry into the cell, suggesting PLL-Dex has multiple preventive mechanisms against HIV-1.

Trends in transmitted drug-resistant HIV-1 and demographic characteristics of newly diagnosed patients: nationwide surveillance from 2003 to 2008 in Japan.

The emergence and transmission of drug-resistant human immunodeficiency virus-1 (HIV-1) compromises antiretroviral treatment for HIV-1. Thus, testing for drug resistance is recommended at diagnosis and before initiating highly active antiretroviral treatment. We conducted an epidemiological study enrolling newly diagnosed patients between 2003 and 2008 in our nationwide surveillance network. In the 6-year study period, the prevalence of drug-resistant HIV-1 among 2573 patients, consisting mainly of Japanese men in their late-30s and infected through male-to-male sexual contacts, followed an increasing trend from 5.9% (16/273) in 2003 to 8.3% (50/605) in 2008. Nucleoside reverse transcriptase inhibitor-associated mutations predominated in each year, with T215 revertants being the most abundant. The predictive factor for drug-resistant HIV-1 transmission was subtype B (OR=2.36; p=0.004), and those for recent HIV-1 infection were male gender (OR=3.79; p=0.009), MSM behavior (OR=1.67; p=0.01), Japanese nationality (OR=2.31; p=0.008), and subtype B (OR=5.64; p<0.05). Continued activities are needed to raise awareness of the risks of HIV-1 infection and complications of drug-resistant strains. Continued surveillance is also needed to understand trends in the HIV-1 epidemic.

Cases of HIV type 1 acute infection at STI-related clinics in Osaka.

Since 1992 we have investigated HIV antibodies in persons with a venereal disease who worked for a sex business or engaged in sexual behavior with a high risk of HIV infection at five clinics of venereology, urology, and gynecology in Osaka Prefecture. Starting at the end of 2000, we performed a nucleic acid-amplification test (NAT) on antibody-negative samples with the aim of detecting cases in the window period covering the early phase of infection. Three cases that were thought to be in this phase were found in 2006. All were confirmed to be positive in an NAT, although they were negative in initial screening for HIV performed using the IC method. Gene analysis of the env-C2V3 region of HIV-1 showed that the three samples had different origins.

Recent diversity of human immunodeficiency virus type 1 in individuals who visited sexually transmitted infection-related clinics in Osaka, Japan.

By human immunodeficiency virus type 1 (HIV-1) antibody screening of people who visited sexually transmitted infection (STI)-related clinics (venereology, urology, and gynecology) and were considered to conduct high-risk sexual activities for HIV-1 infection in Osaka, Japan, during 1992 to 2004, a total of 54 HIV-1 infected individuals (51 Japanese males and 3 non-Japanese females) were identified. Based on the sequencing at env-C2V3 and pol regions, Japanese males were mostly of subtype B (50/51 cases), with the one remaining case being a recombinant circulating form, CRF01_AE, while 3/3 viruses in non-Japanese females were of CRF01_AE. Analysis of subtype B cases since 2001 showed that these viruses became wider in their genetic variation, including amino acid insertions and also deletions, than that of the cases before 2000. Thus, it was suggested that HIV-1 spreading in Osaka has been increasing in genetic variability. Although all these infected individuals were first recognized to be infected with HIV-1 by our screening, some of them were carriers of HIV-1 with drug-resistant pol sequences, indicating that they could be infected with drug-resistant HIV-1 mutants.

Performance and quality assurance of genotypic drug-resistance testing for human immunodeficiency virus type 1 in Japan.

Highly active antiretroviral therapy (HAART) can suppress human immunodeficiency virus type 1 (HIV-1) replication and plasma HIV-1 to below detectable levels. However, HAART becomes ineffective when drug-resistant viruses emerge during HAART. Monitoring drug-resistance mutations in viruses is necessary for selecting new drugs or therapies effective at inhibiting such HIV-1 variants. Most laboratories in Japan perform the tests using in-house protocols. However, the quality of these tests has never been assessed. Our study assessing the accuracy and reliability of HIV-1 genotypic drug-resistance testing in 15 laboratories in Japan revealed that the quality was very high (97.3% accurate). The errors, though rare, were caused by human errors, poor electropherograms, and the use of inadequate primers. Here, we propose troubleshooting procedures to improve testing accuracy and reliability in Japan.

[Two cases of HIV-1 acute infection with antibody negative by immunochromatography method].

We found two cases of HIV-1 acute infection, confirmed by nucleic amplification test (NAT) and/or RT-PCR, with HIV-1 antibody negative by immunochromatography (IC) method but weakly positive by particle agglutination (PA) test. These cases suggested that IC method was less sensitive than PA test in the detection of acute infections. It is necessary to execute the post counseling that considers the possibility of the acute infection in public health centers and testing places where IC method is used for the screening test. It is also important to recommend taking the following re-examination after a certain period to a person who seems to have had a chance of infection in a short time before testing.