Search

Convalescent plasma was proposed for passive immunization against COVID-19; but so far there are conflicting results and still open questions. However, besides antibodies, other plasma proteins may be good candidates for further research and application. Thromboinflammation frequently complicates severe COVID-19, and classical anticoagulants like heparins seem to have limited effect. The natural protease inhibitors antithrombin III (ATIII), α 1 -antitrypsin (α 1 -AT) and α 2 -macroglobulin (α 2 -M), which are found decreased in severe COVD-19, play a crucial role in prothrombotic and inflammatory pathways. While ATIII and α 1 -AT are licensed as commercially prepared therapeutic concentrates, there is no preparation of α 2 -M available. The diagnostic, prognostic, and even therapeutic potential of plasma protease inhibitors should be further explored., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Competing Interests: R.S. serves as member of the Data Safety Monitoring Board of the CAPSID and COVIC-19 trials. L.G., U.V., A.H., and W.S. have no conflicts of interest to declare.

Since the end of 2019 a new coronavirus, SARS-CoV-2, first identified in Wuhan, China, is spreading around the world partially associated with a high death toll. Besides hygienic measurements to reduce the spread of the virus vaccines have been confected, partially based on the experiences with Ebola virus vaccine, based on recombinant human or chimpanzee adenovirus carrying the spike protein and its ACE2 receptor binding domain (RBD). Further vaccines are constructed by spike protein coding mRNA incorporated in lipid nano vesicles that after entry in human cells produce spike protein. Both vaccine types induce a strong immune response that lasts for months possibly for T-cell immunity a few years. Due to mutations in the coronavirus genome in several parts of the world variants selected, that were partially more pathogenic and partially easier transmissible - variants of concern (VOC). Until now vaccinees are protected against the VOC, even when protection might be reduced compared to the Wuhan wild virus.An open field is still how long the vaccine induced immunity will be sufficient to prevent infection and/or disease; and how long the time period will last until revaccination will be required for life saving protection, whether a third vaccination is needed, and whether revaccination with an adenovirus-based vaccine will be tolerated., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

The complex COVID-19-associated coagulopathy appears to impair prognosis. Recently, we presented the hypothesis that children are to some extent protected by higher α 2 -macroglobulin (α 2 -M) levels from severe COVID-19. In addition to endothelial cells, thrombin, and platelets, neutrophil granulocytes also appear to play an important role. Neutrophils extrude extracellular nets, which are histone- and protease-coated web-like DNA structures; activate coagulation and platelets; and release radicals and proteases such as elastase. The unique phylogenetically ancient and "versatile" inhibitor α 2 -M contributes particularly during childhood to the antithrombin activity of plasma, binds a broad spectrum of proteases, and interacts with other mediators of inflammation such as cytokines. It is suggested that the scope of basic research and clinical studies would include the potential role of α 2 -M in COVID-19., (© 2020 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals LLC on behalf of International Society on Thrombosis and Haemostasis.)

We report a case of a probable HIV-1 transmission by human bite. The analyzed data from ten previously reported  suspected or allegedly confirmed HIV transmissions revealed a deep bleeding bite wound as the primary risk factor. A high HIV plasma viral load and bleeding oral lesions are present most of the time during HIV transmission by bite. HIV post-exposure prophylaxis (PEP) should be recommended in case of a bleeding wound resulting from a bite of an HIV-infected person. PEP was missed in this presented case.

Discovery of new mediators of immune cell activation and interaction facilitated elucidation of the various ways of defense against infectious agents and happened some 40 years ago. Each involved group of researchers named the mediators according to their scope of investigation; often the same molecules were published at the same time with different names. To avoid confusion resulting from using different names for the same mediators and to prevent a Babylonian confusion, standardization was implemented-as in the field of metrics, music, or science including virology. For cytokines and chemokines a standard nomenclature was proposed some 10 years ago and in conclusion it should be used. In this paper the most relevant biomarkers in HIV-1 and HBV infection and their contribution during viral pathogenesis are listed.

Background: RNA viruses are associated with a high frequency of mutations because of the missing proofreading function of polymerases, such as reverse transcriptase. Between 2007 and 2010, six blood donations with false-negative nucleic acid technology (NAT) results were reported in Germany. Therefore, NAT screening in two viral genome regions was introduced by our blood donation service in 2010 on a voluntary basis and became mandatory in Germany since the beginning of 2015., Study Design and Methods: Blood donor screening was done using, in parallel, the German Red Cross (GRC) HIV-1 CE long terminate repeats (LTR) PCR kit and the GRC HIV-1 gag CE PCR kit. In total, 7 million blood donations were screened during the study period from 2010 to 2014 with the GRC dual-target human immunodeficiency virus 1 (HIV-1) NAT system. Additionally, three suspicious specimens were analyzed by four monotargeted NAT assays and by five dual-target NAT assays., Results: Three of 7 million donations tested negative using the 5'LTR-polymerase chain reaction, but they were positive if amplification was performed in the gag region. HIV antibodies were detected in all three donations. Nucleic acid sequence analysis identified a deletion of 22 bases within the 5'LTR probe binding region. Three different ltr-based monotargeted assays missed two donations, except for a low-reactive result obtained by one of the assays. In total, the detection rates for HIV-1-positive donations were 37.5% (3/8) for monotargeted assays and 100% (10/10) for dual-target assays., Conclusion: The current data demonstrate that dual-target NAT systems reduce the risk of false-negative HIV-1 NAT screening results., (© 2018 AABB.)

Transmission of infectious agents might be associated with iatrogenic actions of charitable help in health care. An example is the vaccination against yellow fever in USA that transmitted hepatitis B virus. Another example is injections of praziquantel for treatment and cure of schistosomiasis in Central and Northern Africa, with a focus in Egypt that has spread hepatitis C virus. There is no indication that human T-lymphotropic virus type 1 was spread by injection treatment for African trypanosomiasis, syphilis and treponematosis, but these treatments might have contributed to the early spread of human immunodeficiency virus type 1 (HIV-1) in Central Africa. Slave trade contributed as well to the spread of viruses from Africa to the Americas; it was stopped in 1850. Until that date HIV-1 was not transported to the Americas. By analysis of nucleic acid sequence data it can be concluded that the continental spread of HCV and HIV-1 might have started around 1920 with an exponential phase from 1940 to 1970. Further iatrogenic actions that promoted the spread of HCV and HIV-1 might be vaccinations to prevent deadly diseases. The successful vaccination was followed by diminution of the infectious agent in the population such as small pox, yellow fever and measles. Measurements to reduce the spread of plague and cholera were further benefits increasing survival of diseased subjects in a population. Thus, the reduction of exposure to deadly infectious agents might have given a chance to HIV-1 infected subjects to survive and for HIV-1 to be distributed around the world starting from Central Africa in the 1950s.

Patients with blood disorders (including leukaemia, platelet function disorders and coagulation factor deficiencies) or acute bleeding receive blood-derived products, such as red blood cells, platelet concentrates and plasma-derived products. Although the risk of pathogen contamination of blood products has fallen considerably over the past three decades, contamination is still a topic of concern. In order to counsel patients and obtain informed consent before transfusion, physicians are required to keep up to date with current knowledge on residual risk of pathogen transmission and methods of pathogen removal/inactivation. Here, we describe pathogens relevant to transfusion of blood products and discuss contemporary pathogen removal/inactivation procedures, as well as the potential risks associated with these products: the risk of contamination by infectious agents varies according to blood product/region, and there is a fine line between adequate inactivation and functional impairment of the product. The cost implications of implementing pathogen inactivation technology are also considered.

Background: Scale-up of antiretroviral therapy (ART) and the growing number of long-term treated patients may favor multi-HIV drug resistance (HIVDR) in resource-limited settings. Understanding the burden of HIVDR with ART-exposure may provide new insights for an effective long-term management of infected patients., Methods: Sixty-six HIV-infected individuals (18 ART-naïve, 24 failing first-line, 24 failing second-line ART) living in Yaoundé-Cameroon were evaluated by sequencing protease-reverse transcriptase (PR-RT, n=62), envelope-V3 loop (V3, n=58) and integrase (IN, n=30) regions. Drug resistance mutations (DRMs) were interpreted using Stanford University HIV drug resistance database and geno2pheno, while viral tropism prediction was done using geno2pheno, position-specific scoring matrices (PSSM) and Net charge rule., Results: Participants, from naïve, first- to second-line, had respectively 5.30, 4.85 and 4.66 log HIV RNA, and 532, 203 and 146 CD4 cells/mm3), and infected with diverse HIV-1 non-B clades (58.1% CRF02_AG). Among ART-naïve patients, 6.7% harbored K103N, 28.6% had IN accessory-mutations (L74I, E157Q) and 26.7% carried CXCR4-tropic viruses. At first-line failure, 79.2% harbored DRMs to nucleoside and non-nucleoside RT inhibitors, 33.3% had IN accessory-mutations (L68I, L74I, T97A, E157Q), and 47.4% carried CXCR4-tropic viruses. At second-line failure, 91.3% harbored multi-DRMs to PR-RT inhibitors (with 52.2% and 4.3% DRMs to second-generation NNRTIs and darunavir/r, respectively), 27.3% had IN accessory-mutations (L74I, T97A, E157EQ), and 37.5% carried CXCR4-tropic viruses., Conclusion: Levels of PR-RT resistance increases with ART-exposure, with needs for new ART-options following second-line failure. IN inhibitors and darunavir/r are potentially suitable for a third-line regimen, while the use of maraviroc, etravirine or rilpivirine, requires individual genotypic testing.

Novel therapeutic options are urgently needed to improve global treatment of virus infections. Herbal products with confirmed clinical safety features are attractive starting material for the identification of new antiviral activities. Here we demonstrate that Cistus incanus (Ci) herbal products inhibit human immunodeficiency virus (HIV) infections in vitro. Ci extract inhibited clinical HIV-1 and HIV-2 isolates, and, importantly, a virus isolate with multiple drug resistances, confirming broad anti-HIV activity. Antiviral activity was highly selective for virus particles, preventing primary attachment of the virus to the cell surface and viral envelope proteins from binding to heparin. Bioassay-guided fractionation indicated that Ci extract contains numerous antiviral compounds and therefore has favorably low propensity to induce virus resistance. Indeed, no resistant viruses emerged during 24 weeks of continuous propagation of the virus in the presence of Ci extracts. Finally, Ci extracts also inhibited infection by virus particles pseudotyped with Ebola and Marburg virus envelope proteins, indicating that antiviral activity of Ci extract extends to emerging viral pathogens. These results demonstrate that Ci extracts show potent and broad in vitro antiviral activity against viruses that cause life-threatening diseases in humans and are promising sources of agents that target virus particles.

Coinfections with hepatitis B virus (HBV) and HIV are very frequent. Although HBV is a DNA virus, it replicates via reverse transcription like HIV. Structural similarities between the enzymatic pocket of the HBV DNA polymerase and HIV-1 reverse transcriptase are the basis that certain drugs inhibit both enzymes and thus the replication of both viruses. HBV components increase the pathogenic action of HIV and vice versa directly by certain proteins like HBsAg in the case of HBV and HIV-encoded Tat and Vpr and by disturbing the cytokine balance in affected cells. Antiretroviral therapy is highly beneficial for HIV/HBV-coinfected patients, but carries the risk of drug-induced resistance development and hepatotoxicity. Even with restoration of the immune capacity, signs of hepatic inflammation may develop even after 10 years of treatment., (© 2014 S. Karger AG, Basel.)

Considering human immunodeficiency virus type 2 (HIV-2) phenotypic data and experience from HIV type 1 and from the follow-up of HIV-2-infected patients, a panel of European experts voted on a rule set for interpretation of mutations in HIV-2 protease, reverse transcriptase, and integrase and an automated tool for HIV-2 drug resistance analyses freely available on the Internet (http://www.hiv-grade.de).

Antiretroviral drug resistance is mostly linked to a complex interaction of several amino acids with variable importance or a single amino acid. To facilitate the interpretation of observed mutation patterns, hospital university centers have developed several interpretation systems. All the currently available interpretation algorithms evolved, are being continuously updated and have been improved during the last decade. Some discrepancies are still evident that are partially smoothened by link of the individual programs with other systems. After the interpretation of HIV-1 group M subtype B mutations, a refined algorithm for the other group M subtypes was developed followed by the interpretation of HIV-1 group O and HIV-2 mutations. The process of improvement is ongoing, due to the better understanding and interpretation of single and cluster mutations and the availability of new antiretroviral substances. The knowledge gained from the experience of HIV drug resistance testing has been used to establish the interpretation of HBV polymerase mutations and will be extended for the treatment of HCV infected with protease inhibitors., (Copyright © 2012 S. Karger AG, Basel.)

HIV-1 is a chimpanzee virus which was transmitted to humans by several zoonotic events resulting in infection with HIV-1 groups M-P, and in parallel transmission events from sooty mangabey monkey viruses leading to infections with HIV-2 groups A-H. Both viruses have circulated in the human population for about 80 years. In the infected patient, HIV mutates, and by elimination of some of the viruses by the action of the immune system individual quasispecies are formed. Along with the selection of the fittest viruses, mutation and recombination after superinfection with HIV from different groups or subtypes have resulted in the diversity of their patterns of geographic distribution. Despite the high variability observed, some essential parts of the HIV genome are highly conserved. Viral diversity is further facilitated in some parts of the HIV genome by drug selection pressure and may also be enhanced by different genetic factors, including HLA in patients from different regions of the world. Viral and human genetic factors influence pathogenesis. Viral genetic factors are proteins such as Tat, Vif and Rev. Human genetic factors associated with a better clinical outcome are proteins such as APOBEC, langerin, tetherin and chemokine receptor 5 (CCR5) and HLA B27, B57, DRB1*1303, KIR and PARD3B., (Copyright © 2012 S. Karger AG, Basel.)

Genotypes of samples from protease inhibitor-naïve patients in Frankfurt's HIV Cohort were analyzed with five tipranavir resistance prediction algorithms. Mean scores were higher in non-B than in B subtypes. The proportion of non-B subtypes increased with increasing scores, except in weighted algorithms. Virtual and in vitro phenotype analyses of samples with increased scores showed no reduced tipranavir susceptibility. Current algorithms appear suboptimal for interpretation of resistance to tipranavir in non-B subtypes; increased scores might reflect algorithm bias rather than "natural resistance."

We report the second human immunodeficiency virus (HIV) belonging to the new HIV type 1 (HIV-1) group P lineage that is closely related to the simian immunodeficiency virus found in gorillas. This virus was identified in an HIV-seropositive male hospital patient in Cameroon, confirming that the group P virus is circulating in humans. Results from screening 1,736 HIV-seropositive specimens collected in Cameroon indicate that HIV-1 group P infections are rare, accounting for only 0.06% of HIV infections. Despite its rarity, group P shows evidence of adaptation to humans.

Background: The objective of this study was to assess the seroprevalence of coinfecting viruses and Treponema pallidum (T. pallidum) in a cohort of 205 antiretrovirally treated HIV-infected individuals (152 females and 53 males, aged: 19-71 years) in rural Lesotho. Furthermore agent-specific immune responses were investigated by analyzing antibody titers against herpes simplex virus type 2 (HSV-2) and against T. pallidum., Methods: Serum samples were tested by enzyme-linked immunosorbent assay for antibodies against HSV-2, cytomegalovirus, hepatitis A, B, and C viruses, and T. pallidum., Results: Seroprevalences (95% confidence intervals) were found to be 100% (98.5%-100%) for anti-cytomegalovirus, 98.5% (95.7%-99.7%) for anti-hepatitis A virus, 35.5% (28.9%-42.6%) for anti-HBc, 5.5% (2.8%-9.6%) for hepatitis B surface antigen, and 0.5% (0.0%-2.8%) for anti-hepatitis C virus. Only 78.5% (72.2%-84.0%) were anti-HSV-2 positive and 29.0% (22.8%-35.8%) had antibodies against T. pallidum. Only anti-HSV-2 titers showed gender- and CD4 cell-count dependent differences: females with >500 CD4 cells/microL had an average anti-HSV-2 titer of 446 compared with males of 398 AU/mL (not significant), but in those with 250 to 500 CD4 cells/microL, there was a significant difference with a mean titer of 467 compared to 302 AU/mL in males (P = 0.001)., Conclusions: A high seroprevalence of CMV, HAV, and HBV was found in both genders. One-third of the patients had been exposed to HBV and T. pallidum. The generally high HSV-2 prevalence showed gender- and CD4 cell count-dependent differences in HSV-2 antibody titer.

Although Cameroon, in west central Africa, has a relatively low HIV prevalence of 5-6%, all HIV-1 groups (M, N, O, and P), nearly all HIV-1 group M subtypes, and numerous intersubtype recombinant forms have been identified in Cameroon. In this report, we describe the near full-length sequence of 04CMU11421, an HIV-1 group M subtype J strain collected in Cameroon in 2004. Phylogenetic analysis of the genome sequence shows high bootstrap support with three subtype J reference sequences in the HIV Sequence database. Therefore, 04CMU11421 represents a fourth pure subtype J isolate and the first reported in Cameroon.

A transmission cluster of HIV-1 M:B was identified in 11 patients with a median age of 52 (range 26-65) in North-East Germany by C2V4 region sequencing of the env gene of HIV-1, who-except of one-were not aware of any risky behaviour. The 10 male and 1 female patients deteriorated immunologically, according to their information made available, within 4 years after a putative HIV acquisition. Nucleic acid sequence analysis showed a R5 virus in all patients and in 7 of 11 a crown motif of the V3 loop, GPGSALFTT, which is found rarely. Analysis of formation of this cluster showed that there is still a huge discrepancy between awareness and behaviour regarding HIV transmission in middle-aged patients, and that a local outbreak can be detected by nucleic acid analysis of the hypervariable env region.

Analysis of 3555 HIV-seropositive specimens, collected in Cameroon from 2002 to 2006, led to the identification of four HIV-1 group N infections based on differential seroreactivity to HIV env-derived peptides and proteins and confirmation by nucleic acid amplification. Group N prevalence continues to be low accounting for only 0.1% of HIV infections in Cameroon. Near full-length genomic sequences were obtained from viral RNA or proviral DNA by PCR amplification of overlapping fragments for three isolates, 06CM-U14296, 06CM-U14842, and 02CM-SJGddd. Two genome segments, partial pol and env-nef, were obtained from viral RNA for the fourth isolate, 02CM-TIM0217. With the four group N isolates identified in this study and group N sequences previously reported, eight near full-length and five partial genome sequences are now available. Despite genetic divergence from HIV-1 group M and O, all of the group N infections evaluated by five commercial HIV immunoassays were detected.

Background: In February 2007, a 63-year-old man underwent surgery. Retrospective testing with nucleic acid testing (NAT) showed that the patient was human immunodeficiency virus Type 1 (HIV-1) positive 10 days after transfusion. The transfusion-transmitted infection had been identified by a donor-related lookback started in April 2007 after anti-HIV seroconversion., Methods: Sequence analysis was performed in the gag-pol region as well as in the V3 loop env region. Archived plasma from the transmitting donation was investigated for the individual-donation NAT with the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 test (Roche CAP/CTM HIV-1 test) and for HIV antigen/antibody combination testing (Abbott Architect). Additional testing was done on the donor's follow-up sample and on the recipient's sample., Results: The Roche CAP/CTM HIV-1 test failed to detect viral RNA by minipool NAT in the index donation (April 2007) as well as in the donation that caused the infection (January 2007). Phylogenetic analysis showed a very high genetic similarity among viral sequences from both donor and recipient, proving the HIV-1 transmission by sequence data., Conclusion: This case represents the first documented HIV-1 transmission by transfusion of red blood cells after mandatory introduction of HIV-1 NAT for blood screening in Germany. Low viral load and mismatches in the primer/probe region might explain the detection failure of the NAT screening assay. A certain risk remains that new virus variants contain mutations at positions critical for amplification or detection of viral genomes. An option to reduce the risk of a detection failure by NAT is the simultaneous use of several conserved regions as amplification targets.

The human immunodeficiency virus (HIV) had spread unrecognized in the human population as sexually transmitted disease and was finally identified by its disease AIDS in 1981. Even after the isolation of the causative agent in 1983, the burden and death rate of AIDS accelerated worldwide especially in young people despite the confection of new drugs capable to inhibit virus replication since 1997. However, at least in industrialised countries, this trend could be reversed by the introduction of combination therapy strategies. The design of new drugs is on going; besides the inhibition of the three enzymes of HIV for replication and maturation (reverse transcriptase, integrase and protease), further drugs inhibits fusion of viral and cellular membranes and virus maturation. On the other hand, viral diagnostics had been considerably improved since the emergence of HIV. There was a need to identify infected people correctly, to follow up the course of immune reconstitution of patients by measuring viral load and CD4 cells, and to analyse drug escape mutations leading to drug resistance. Both the development of drugs and the refined diagnostics have been transferred to the treatment of patients infected with hepatitis B virus (HBV) and hepatitis C virus (HCV). This progress is not completed; there are beneficial aspects in the response of the scientific community to the HIV burden for the management of other viral diseases. These aspects are described in this contribution. Further aspects as handling a stigmatising disease, education of self-responsiveness within sexual relationships, and ways for confection of a protective vaccine are not covered.

Near full-length viral genome sequences were obtained for five putative subtype G candidates identified in HIV-infected Cameroonian blood donors, based on partial genome sequences for the gag, pol, and env regions. Phylogenetic analysis of the genome sequences shows that all five strains are pure subtype G with no indication of intersubtype recombination. The Cameroon subtype G sequences did not form a geographically based subcluster and were intermixed within the subtype G branch with isolates from several different countries. HIV-1 group M subtype G accounts for only 4.5% of HIV infections in Cameroon. However, genome segments of subtype G are present in 67% of all infections and 80% of infections due to intersubtype recombinant strains in Cameroon. The addition of five subtype G genome sequences to the HIV database may contribute to a better understanding of the origins and classification of HIV-1 subtypes and CRFs.

Objective: The HIV epidemic in Cameroon is characterized by a high level of strain diversity despite a relatively low prevalence of infection. In this study, HIV strains infecting blood donors in Cameroon were characterized to determine the prevalence of subtypes and intersubtype recombinants and if strain prevalence was changing over time., Methods: From 1996 through 2004, 676 HIV-infected blood donations were collected at blood banks in Douala and Yaoundé, Cameroon. A subset of the HIV-1 group M strains (n = 574) were classified based on phylogenetic analysis of viral sequences from the gag p24, pol integrase, and env gp41 regions., Results: HIV-1 group M accounted for 97.3% (n = 658) of infections, whereas group O was present in 2.2% (n = 15) and HIV-2 in 0.4% (n = 3). Within the group M infections, 14 subtypes and circulating recombinant forms (CRFs) and unique recombinant forms (URFs) were identified. Overall, CRFO2_AG accounted for 58.2% of infections, URFs 14.8%, and levels of subtypes, A, B, C, D, F2, and G, and CRFs, 01, 06, 09, 11, 13, 22, and 37, varied from 0.2% to 6.1%. Evaluation of HIV strains present in the donor population over this 9-year period showed no substantial changes in the proportion of infections caused by each subtype and CRF, the percentage of intersubtype recombinants, or the strain composition of the URFs., Conclusions: HIV-1 strain diversity in Cameroon did not significantly change, suggesting a mature and relatively stable epidemic.

Recombinant forms of HIV-1 contribute significantly to the ongoing epidemic. In the present study, we characterized the near full-length genome of one candidate HIV-1 CRF25_cpx strain originating in Cameroon, 06CM-BA-040. Viral RNA was extracted from plasma, and the genome was obtained using RT-PCR amplification to generate 10 overlapping fragments. Bootscanning, recombination breakpoint analysis, and phylogenetic trees confirmed that 06CM-BA-040 had a genomic structure consistent with two available CRF25_cpx reference sequences. The CRF25_cpx mosaic composition consisted of nine segments derived from subtypes A and G as well as unclassified (U) regions. Subtype G and CRF25_cpx clusters diverged from each other with long branch lengths but were distinct from other known subtypes with high bootstrap support (94%). The epidemiological significance of CRF25_cpx strains is unknown; however, the availability of additional genomic sequences will improve our understanding of the overall genetic diversity within this recombinant form of HIV-1.

A unique HIV-2 intergroup recombinant strain was identified in Cameroon. The virus, CM-03-510-03, was amplified from blood collected from a 47-year-old female patient in Douala, Cameroon in 2003 who was seroreactive for HIV-2. A near full-length genome 9089 nucleotides in length was amplified from proviral DNA. The genome for CM-03-510-03 is composed of segments of HIV-2 groups A and B with four recombination break-points and has open reading frames for all the structural and regulatory genes. A comparison of CM-03-510-03 to the only previously reported HIV-2 intergroup recombinant shows that the two strains share one recombination breakpoint but are otherwise distinct from each other. Similar to HIV-1, HIV-2 intergroup recombination is an indication that coinfection with more than one strain has occurred in individuals and is a mechanism that increases strain genetic diversity.

Given the worldwide increasing spread of HIV-1 genetic variants, it is mandatory that assays used for nucleic acid testing for HIV-1 detect all existing groups and subtypes of HIV-1. In this report the development and evaluation of a quantitative real-time HIV-1 RT-PCR assay that targets a conserved region within the pol integrase domain is described. As an internal control reaction, endogenous glyceraldehyde-3-phosphate-dehydrogenase transcripts were detected in a multiplex configuration. The detection limit (95% cut-off value) was determined by probit analysis and calculated as 281 IU/ml of HIV-1 RNA. Within-run and between-run coefficients of variation were below 15 and 27%, respectively, indicating high reproducibility. The described assay detected all tested HIV-1 isolates representing groups M, O and N. Within group M, quantitative test results correlated well with viral loads as determined by the automated Abbott RealTime HIV-1 assay. Based on the testing of 1206 confirmed HIV-1 RNA negative blood donor samples, assay specificity was found to be 100%. The rate of inhibition was 0.37%. The described HIV-1 real-time RT-PCR was validated according to regulatory guidelines and is applicable to the screening of blood donors as well as the determination of HIV-1 viral load.

Recombinant forms of HIV-1 contribute significantly to the ongoing epidemic. In the present study, we characterized the near full-length genomes of three candidate HIV-1 CRF13_cpx strains originating in Cameroon, 04CM-173-9, 04CM-632-28, and 02CM-A1394. Bootscanning, recombination breakpoint analysis, and phylogenetic trees confirmed similar genomic structures with identical breakpoint positions compared to the three available CRF13_cpx sequences. The candidate and reference sequences formed a distinct cluster well separated from other group M subtypes and had a mosaic structure derived from subtypes A1, G, J, and CRF01_AE. The similarity in genomic composition and position of recombination breakpoints suggest that these isolates share a common ancestor. The epidemiological significance of CRF13_cpx strains in Cameroon is unknown; however, the availability of three additional genomic sequences will improve our understanding of the overall genetic diversity within this recombinant form of HIV-1.