The RT M184V resistance mutation clearance in the reservoir is mainly related to CD4 nadir and viral load zenith independently of therapeutic regimen type.

OBJECTIVES: Resistance associated mutations (RAMs) are archived in the HIV reservoir and can re-emerge with an inappropriate ART use limiting treatment options. However, recent studies, using ultra-deep sequencing (UDS), showed a decrease of quasispecies harbouring RAMs, suggesting that recycling some antiretrovirals could be considered. The aim of this study was to characterize, in HIV treated PLWHIV, the M184V mutation decrease kinetics in proviral DNA and associated factors of M184V mutation clearance over time. METHODS: UDS was performed on HIV-DNA from blood cells at different time points to quantify the percentage of M184V positive quasispecies. The sequence reads were analysed with a minimum coverage set at 50 and an ambiguity filter at 5% or 2%. RESULTS: At 2.5 years after the first time point, the M184V lost was observed in 50% of PLWHIV. Moreover, univariate analyses highlight that a higher nadir CD4 count and a lower zenith HIV1 RNA viral load were correlated with a faster clearance of the mutation. In multivariate analysis, a higher zenith was negatively associated with the M184V clearance at the 5% threshold. Interestingly, lamivudine/emtricitabine presence in the ART therapy regiment during the 5 years was not associated with the persistence of the M184V. CONCLUSIONS: Our study provides new information concerning the clearance speed of M184V mutation over time in PLWHIV with fully suppressed viremia, opens the discussion about the duration needed to consider a lamivudine/emtricitabine recycling and reinforces the association of the nadir and zenith values with the M184V mutation clearance.

Spike protein genetic evolution in patients at high-risk of severe COVID-19 treated by monoclonal antibodies.

BACKGROUND: High-risk patients, often immunocompromised and not responding to vaccine, continue to experience severe COVID-19 and death. Monoclonal antibodies (mAbs) were shown effective to prevent severe COVID-19 for these patients. Nevertheless, concerns about the emergence of resistance mutations were raised. METHODS: We conducted a multicentric prospective cohort study, including 264 patients with mild-to moderate COVID-19 at high risk for progression to severe COVID-19 and treated early with Casirivimab/Imdevimab, Sotrovimab or Tixagevimab/Cilgavimab. We sequenced the SARS-CoV-2 genome during follow-up and searched for emerging Spike mutations. RESULTS: Immunocompromised patients have a 6-fold increased risk of developing mutations, which are associated with a prolonged duration of viral clearance but no clinical worsening. Emerging P337S/R/L/H, E340D/K/A/Q/V/G and K356T/R substitutions in patients treated with Sotrovimab are associated with higher viral RNA loads for up to 14 days post-treatment initiation. Tixagevimab/Cilgavimab is associated with a 5-fold increased risk of developing mutations. R346K/I/T/S and K444R/N/M substitutions associated with Tixagevimab/Cilgavimab have been identified in multiple SARS-CoV-2 lineages, including BQ.1 and XBB. CONCLUSIONS: In conclusion, the probability of emerging mutations arising in response to mAbs is significant, emphasizing the crucial need to investigate these mutations thoroughly and assess their impact on patients and the evolutionary trajectory of the SARS-CoV-2.

Long-term evolution of humoral immune response after SARS-CoV-2 infection.

OBJECTIVE: We aimed to characterize the evolution of humoral immune response up to 1 year after SARS-CoV-2 infection in healthcare workers (HCWs) during the first wave of COVID-19 in Paris. METHODS: Serum samples from 92 HCWs were tested at month 0 (M0), M6, and M12 after SARS-CoV-2 infection for IgG targeting the nucleocapsid (N), IgG targeting the receptor-binding domain (RBD) of spike (S) protein, IgA targeting S, and anti-RBD neutralizing antibodies. After M6, 46 HCWs received a single dose of COVID-19 vaccine. RESULTS: We observed a significant decrease in all SARS-CoV-2 immunologic markers at M6 post-infection: median decreases were 0.26 log binding antibody units/mL (M0: 1.9 (interquartile range (IQR) 1.47-2.27); M6: 1.64 (IQR 1.22-1.92)) for anti-RBD IgG; 4.10 (index) (M0: 4.94 (IQR 2.72-6.82); M6: 0.84 (IQR 0.25-1.55)) for anti-N IgG; 0.64 (index) (M0: 2.50 (IQR 1.18-4.62); M6: 1.86 (IQR 0.85-3.54)) for anti-S IgA; and 24.4% (M0: 66.4 (IQR 39.7-82.5); M6: 42.0 (IQR 16.8-68.8)) inhibition activity for the RBD neutralizing antibodies. Between M6 and M12, anti-RBD IgG level, anti-S IgA index, and anti-RBD neutralizing activity significantly increased among COVID-19 vaccinated HCWs, whereas they remained stable among unvaccinated HCWs. Anti-N IgG index significantly decreased between M6 and M12 among both vaccinated (median: 0.73 (IQR 0.23-1.11) at M6 and 0.52 (IQR 0.20-0.73) at M12) and unvaccinated HCWs (median: 0.79 (IQR 0.21-4.67) at M6 and 0.34 (IQR 0.24-2.78) at M12). DISCUSSION: A steady decline in the anti-N IgG response was observed during the first year after SARS-CoV-2 infection among HCWs, whereas the anti-RBD IgG and the anti-S IgA responses remained stable and could be enhanced by COVID-19 vaccination.

Primaquine as a Candidate for HHV-8-Associated Primary Effusion Lymphoma and Kaposi's Sarcoma Treatment.

Human Herpesvirus 8 (HHV-8) is associated with three main severe orphan malignancies, Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL), which present few therapeutic options. We identified the antimalarial primaquine diphosphate (PQ) as a promising therapeutic candidate for HHV-8-associated PEL and KS. Indeed, PQ strongly reduced cell viability through caspase-dependent apoptosis, specifically in HHV-8-infected PEL cells. Reactive oxygen species (ROS)- and endoplasmic reticulum (ER) stress-mediated apoptosis signaling pathways were found to be part of the in vitro cytotoxic effect of PQ. Moreover, PQ treatment had a clinically positive effect in a nonobese diabetic (NOD)/SCID xenograft PEL mouse model, showing a reduction in tumor growth and an improvement in survival. Finally, an exploratory proof-of-concept clinical trial in four patients harboring severe KS was conducted, with the main objectives to assess the efficacy, the safety, and the tolerability of PQ, and which demonstrated a positive efficacy on Kaposi's sarcoma-related lesions and lymphedema.

Spike Gene Evolution and Immune Escape Mutations in Patients with Mild or Moderate Forms of COVID-19 and Treated with Monoclonal Antibodies Therapies.

We explored the molecular evolution of the spike gene after the administration of anti-spike monoclonal antibodies in patients with mild or moderate forms of COVID-19. Four out of the 13 patients acquired a mutation during follow-up; two mutations (G1204E and E406G) appeared as a mixture without clinical impact, while the Q493R mutation emerged in two patients (one receiving bamlanivimab and one receiving bamlanivimab/etesevimab) with fatal outcomes. Careful virological monitoring of patients treated with mAbs should be performed, especially in immunosuppressed patients.

Kinetics of Archived M184V Mutation in Treatment-Experienced Virally Suppressed HIV-Infected Patients.

BACKGROUND: We aimed to assess the kinetics of drug-resistant viral variants (DRVs) harboring the M184V mutation in proviral DNA of long-term virally suppressed patients, and factors associated with DRV persistence. METHODS: Human immunodeficiency virus (HIV) DNA from blood cells stored in 2016 and 2019 was sequenced using Sanger and ultradeep sequencing (SS and UDS; detection threshold 1%) in antiretroviral therapy (ART)-treated patients with HIV RNA < 50 copies/mL for at least 5 years, with past M184V mutation documented in HIV RNA. RESULTS: Among 79 patients, by combining SS and UDS, M184V was found to be absent in 26/79 (33%) patients and persistent in 53/79 (67%). M184V-positive patients had a longer history of ART, lower CD4 nadir, and higher pretherapeutic HIV RNA. Among 37 patients with viral sequences assessed by UDS, the proportion of M184V-positive DRVs significantly decreased between 2016 and 2019 (40% vs 14%, P = .005). The persistence of M184V was associated with duration and level of HIV RNA replication under lamivudine/emtricitabine (3TC/FTC; P = .0009 and P = .009, respectively). CONCLUSIONS: While it decreased over time in HIV DNA, M184V mutation was more frequently persistent in HIV DNA of more treatment-experienced patients with longer past replication under 3TC/FTC.

Prevalence of cervical HPV infection, sexually transmitted infections and associated antimicrobial resistance in women attending cervical cancer screening in Mali.

OBJECTIVES: To assess the prevalence of sexually transmitted infections (STIs), antimicrobial resistance and cervical lesions among women from Sikasso, Mali. METHODS: Women infected with human immunodeficiency virus (HIV) (n=44) and HIV-negative women (n=96) attending cervical cancer screening were included. Screening for human papillomavirus (HPV), Chlamydia trachomatis (CT), Mycoplasma genitalium (MG), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) was performed using polymerase chain reaction assays, and herpes simplex virus (HSV-1/2) serological status was assessed using enzyme-linked immunosorbent assays. Antibiotic resistance tests were performed for MG- and NG-positive cases. RESULTS: A high prevalence of high-risk HPV (hrHPV) infection (63%) was found. This was associated with cervical lesions in 7.5% of cases. An unusual distribution was found, with HPV31, HPV56 and HPV52 being the most prevalent. The hrHPV distribution differed by HIV status, with HIV-positive cases having HPV35/31/51-52-56 and HIV-negative cases having HPV31/56/52. The seroprevalence of HSV-2 was 49%, and the prevalence of other STIs was as follows: CT, 4%; MG, 9%; NG, 1%; and TV, 7%. Five of nine MG-positive specimens and the NG strains obtained were resistant to fluoroquinolone. CONCLUSIONS: These results showed high prevalence of hrHPV and fluoroquinolone resistance in several NG and MG strains. Further studies are required to confirm these data in Mali, and to improve prevention, screening and management of cervical cancer and other STIs in women.

Presence of HIV-1 G-to-A mutations linked to APOBEC editing is more prevalent in non-B HIV-1 subtypes and is associated with lower HIV-1 reservoir.

OBJECTIVES: APOBEC3 editing activity contributes to sequences variation and viral diversification. We aimed to characterize virological and clinical factors associated with G-to-A mutations and stop codons in the HIV-1 reservoir, markers of APOBEC3 footprints, in order to better understand HIV-1 diversity among virologically suppressed HIV-1-infected patients. METHODS: Immuno-virological and clinical factors were compared between 92 patients harbouring G-to-A mutations and stop codons (APOBEC+) in the reverse transcriptase gene and 92 patients without G-to-A mutations (APOBEC-) and stop codons in their DNA genotypes. RESULTS: Patients were predominantly men (74.5%) and were mostly infected by B-subtype (69.0%), with 44.1% and 55.9% in APOBEC+ and APOBEC- groups, respectively. At time of HIV DNA genotypes, the total cell-associated HIV-1 DNA load was 2.34 log10 copies/106 cells (IQR 1.85-2.67) and 33.2% of them had a detectable ultrasensitive plasma viral load. Hypermutated sequences were identified in 28.2% of the APOBEC+ group. The median total cell-associated HIV-1 DNA level was significantly lower in APOBEC+ than APOBEC- group: 2.13 log10 copies/106 cells (IQR 1.60-2.60) versus 2.52 log10 copies/106 cells (IQR 2.19-2.71) (P < 0.001), respectively. Presence of G-to-A mutations and stop codon was independently associated with HIV-1 subtype non-B (P = 0.017). CONCLUSIONS: These results show an independent association between the presence of G-to-A mutations and stop codons with HIV-1 subtype non-B and low proviral DNA that could be explained by the APOBEC3 footprints and restriction of DNA synthesis and integration. However, further investigations are needed to study the contribution of Vif amino acid variability among HIV-1 subtypes.

No difference in HIV-1 integrase inhibitor resistance between CSF and blood compartments.

BACKGROUND: Little is known about HIV-1 integrase inhibitor resistance in the CNS. OBJECTIVES: This study aimed to evaluate integrase inhibitor resistance in CSF, as a marker of the CNS, and compare it with the resistance in plasma. METHODS: HIV integrase was sequenced both in plasma and CSF for 59 HIV-1 patients. The clinical and biological data were collected from clinical routine care. RESULTS: Among the 59 HIV-1 patients, 32 (54.2%) were under antiretroviral (ARV) treatment. The median (IQR) HIV-1 RNA in the plasma of viraemic patients was 5.32 (3.85-5.80) and 3.59 (2.16-4.50) log10 copies/mL versus 4.79 (3.56-5.25) and 3.80 (2.68-4.33) log10 copies/mL in the CSF of ARV-naive and ARV-treated patients, respectively. The patients were mainly infected with non-B subtypes (72.2%) with the most prevalent recombinant form being CRF02_AG (42.4%). The HIV-1 integrase sequences from CSF presented resistance mutations for 9/27 (33.3%) and 8/32 (25.0%) for ARV-naive (L74I, n = 3; L74I/M, n = 1; T97A, n = 1; E157Q, n = 4) and ARV-treated (L74I, n = 6; L74M, n = 1; T97A, n = 1; N155H, n = 1) patients, respectively. Integrase inhibitor resistance mutations in CSF were similar to those in plasma, except for 1/59 patients. CONCLUSIONS: This work shows similar integrase inhibitor resistance profiles in the CNS and plasma in a population of HIV-1 viraemic patients.

No HIV-1 molecular evolution on long-term antiretroviral therapy initiated during primary HIV-1 infection.

OBJECTIVE: Most studies about HIV-1 molecular evolution have shown the lack of viral evolution on effective antiretroviral therapy (ART), although controversial results have been documented. We therefore aimed to look for evidence of HIV-1 evolution in patients who initiated ART at the time of primary HIV-1 infection (PHI). DESIGN: We included retrospectively 20 patients diagnosed at PHI, treated at the time of acute infection and with subsequent effective long-term suppressive ART (HIV viral load <20 copies/ml during at least 5 years without any blips). METHODS: Longitudinal blood samples were deep sequenced using Illumina Miseq. Drug-resistance-associated mutations were retained at 2% cutoff and interpreted using the latest Agence Nationale de Recherches sur le Sida et les Hépatites Virales resistance algorithm. Viral evolution was established when temporal structure on maximum-likelihood phylogenetic tree and significant change over time of HIV-1 genetic diversity measured as the average pairwise distance was observed. RESULTS: Emergences or disappearances of drug-resistance-associated mutations were detected in the blood cells during follow-up despite sustained virological control. In all patients, tree topologies showed an absence of segregation between sequences and blood viral populations from all time-points were intermingled. Comparison of the average pairwise distance showed the absence of significant viral diversity at the time of primary infection and afterwards during 5 years of full virological control under ART. CONCLUSION: Despite a slight variation of minority resistance-associated mutation variants, there was no clear evidence of viral evolution during a prolonged period of time in this population of highly controlled adult patients treated at time of PHI.

Characterization of viral rebounds on dual etravirine/raltegravir maintenance therapy (ANRS-163 ETRAL trial).

BACKGROUND: The ANRS-163 ETRAL trial, a switch study to an etravirine 200 mg/raltegravir 400 mg twice-daily regimen in 165 patients with HIV-1 infection, showed durable efficacy until Week 96. The aim of this work was to investigate in detail the virological rebounds (VRs), defined as at least one plasma HIV viral load (VL) >50 copies/mL. METHODS: Quantification of HIV-DNA level was assessed at baseline, Week 48 and Week 96 (n = 157). VLs were measured in seminal plasma at Week 48 (n = 26). Genotypic resistance testing by ultra-deep sequencing (UDS) for reverse transcriptase (RT) and integrase regions was performed at baseline and at the time of VR. RESULTS: In this study, 19 patients experienced VR, with 2 patients having virological failure (VF; two consecutive VLs >50 copies/mL). For the first patient with VF, UDS detected minority resistant variants only in RT (K103N, 9.6%; Y181C, 4.9%) at baseline. Some RT variants became dominant at VF (K101E, 86.3%; Y181C, 100.0%; G190A, 100.0%) and others emerged in integrase (Y143C, 2.4%; Q148R, 6.2%; N155H, 18.8%). For the second patient with VF, neither RT nor integrase mutations were detected at baseline and VF. Median HIV-DNA level was similar at baseline, Week 48 and Week 96 (2.17, 2.06 and 2.11 log10 copies/106 cells, respectively). Only one patient had a detectable seminal HIV VL (505 copies/mL). CONCLUSIONS: The dual etravirine/raltegravir regimen as maintenance therapy was effective and the emergence of mutations in cases of VF was similar to that seen in other dual-regimen studies. No HIV-DNA level modification was evidenced by Week 96.

Characterization of drug resistance and the defective HIV reservoir in virally suppressed vertically infected children in Mali.

BACKGROUND: In the perspective of ART-free HIV remission, vertically infected children treated with suppressive ART from early infancy represent an optimal population model to better understand the genetic complexity of the reservoir. OBJECTIVES: To evaluate the proportion of defective viral population and the genotypic resistance patterns in cell-associated HIV DNA. METHODS: In a cohort including 93 ART-treated vertically HIV-infected (VHIV) children in Mali with plasma HIV-1 RNA ≤50 copies/mL for at least 6 months, we studied total HIV DNA, percentage of defective genomes and resistance by reverse transcriptase and protease bulk sequencing from whole blood in dried blood spots. RESULTS: Children had a median age of 9.9 years at the time of inclusion (IQR = 7.6-13.4) and 3.3 years (IQR = 2-7) at ART initiation; median ART duration was 5.5 years (IQR = 3.7-7.3). The median level of total HIV DNA was 470 copies/106 cells with one patient presenting undetectable HIV DNA (<66 copies/106 cells). We observed the presence of at least one stop codon in viruses from 34 patients (37%). The presence of stop codons was not correlated with the level of HIV DNA or duration of ART. We showed a high prevalence of HIV-1 resistance in DNA with 26% of children harbouring virus resistant to at least one NRTI and 40% to at least one NNRTI. CONCLUSIONS: While these VHIV children were successfully treated for a long time, they showed high prevalence of resistance in HIV DNA and a moderate defective HIV reservoir.

Discovery, SAR study and ADME properties of methyl 4-amino-3-cyano-1-(2-benzyloxyphenyl)-1H-pyrazole-5-carboxylate as an HIV-1 replication inhibitor.

Inspired by the antiviral activity of known pyrazole-based HIV inhibitors, we screened our in-house library of pyrazole-based compounds to evaluate their in cellulo activity against HIV-1 replication. Two hits with very similar structures appeared from single and multiple-round infection assays to be non-toxic and active in a dose-dependent manner. Chemical expansion of their series allowed an in-depth and consistent structure-activity-relationship study (SAR) to be built. Further ADME evaluation led to the selection of 4-amino-3-cyano-1-(2-benzyloxyphenyl)-1H-pyrazole-5-carboxylate with an advantageous pharmacokinetic profile. Finally, examination of its mode of action revealed that this compound does not belong to the three main classes of anti-HIV drugs, a feature of prime interest in the context of viral resistance.

New mechanisms of resistance in virological failure to protease inhibitors: selection of non-described protease, Gag and Gp41 mutations.

OBJECTIVES: To further characterize HIV-1 viruses of patients experiencing unexplained virological failure (VF) on PI-containing regimens, ultradeep sequencing was performed on protease, gag and gp41 genes in patients failing a first-line treatment. METHODS: All naive patients initiating an antiretroviral treatment based on boosted darunavir, atazanavir or lopinavir and experiencing VF without any transmitted drug resistance mutation detected by Sanger sequencing on protease and reverse transcriptase genes were selected. Ultradeep sequencing (IlluminaTM Nextera®) was performed on protease, gag and gp41 genes in plasma before initiation of treatment and at VF to identify emergent mutations. RESULTS: Among the 32 patients included in the study, emergent and previously undescribed mutations in the viral protease gene were identified in five patients at VF: 64M (1 CRF02_AG), 64M/70R with mutation 15V (2 CRF02_AG), 79A (1 CRF06_cpx) and 79A with mutation 15V (1 CRF02_AG). Two patients showed the emergence of R286K in the gag region, outside of cleavage sites (2 CRF02_AG). In the gp41 region, the V321I mutation emerged inside the cytoplasmic tail (1 subtype A and 1 subtype B). All these patients were treated with a darunavir/ritonavir-based regimen. CONCLUSIONS: In some cases of VF to PIs, we observed the emergence of protease, Gag or Gp41 mutations that had not previously been associated with VF or PI resistance. These mutations should be further studied, in particular the 15V/64M/70R pattern in the protease gene identified among CRF02_AG viruses.

Caution is needed in interpreting HIV transmission chains by ultradeep sequencing.

OBJECTIVES: Molecular epidemiology is applied to various aspects of HIV transmission analyses. With ultradeep sequencing (UDS), in-depth characterization of transmission episodes involving minority variants is permitted. We explored HIV-1 epidemiological linkage and evaluated characteristics of transmission dynamics and transmitted drug resistance (TDR) detection through the added value of UDS. DESIGN: HIV pol gene fragments were sequenced by UDS and Sanger sequencing on samples of 70 HIV-1-infected, treatment-naive recently diagnosed MSM. METHODS: Pairwise genetic distances and maximum likelihood phylogenies were computed. Transmission events were identified as clades with branch support at least 70% and intraclade genetic difference less than 4.5%. TDR mutations were recognized from the TDR consensus list. Transmission directionality, directness and inoculum size were inferred from tree topologies. RESULTS: Both datasets concurred in the identification of seven transmission pairs and one cluster of three patients. With UDS, direction of transmission was inferred in four out of eight chains. Evidence for multiple founder viruses was found in two out of eight chains. No transmission of minority-resistant variants was evidenced. TDR mutations prevalence in protease and reverse transcriptase fragments was 4.3% with Sanger sequencing and 18.6% with UDS. CONCLUSION: Although Sanger sequencing and UDS identified the same transmission chains, UDS provided additional information on founder viruses, direction of transmission and levels of TDR. Nevertheless, topology of clusters was not always consistent across gene fragments, calling for a cautious interpretation of the data. Moreover, unobserved intermediary links cannot be excluded. Phylogenetic analysis use as a forensic technique for HIV transmission investigations is risky.

Qualitative and quantitative HIV antibodies and viral reservoir size characterization in vertically infected children with virological suppression.

Background: Absence of detectable viraemia after treatment cessation in some vertically HIV-infected (VHIV) children suggests that early initiation of HAART could lead to functional cure. Objectives: We described the factors associated with HIV antibody levels and the viral reservoir size in HAART-treated VHIV children. Methods: Study included 97 VHIV children with virological suppression, in Bamako, Mali. The anti-gp41 antibody activities and HIV serostatus were assessed. The viral reservoir size was measured by quantifying total cell-associated HIV DNA. Results: Among the children studied, the median total HIV DNA level was 445 copies/10 6 cells (IQR = 187-914) and the median anti-gp41 antibody activity was 0.29 OD (IQR = 0.18-0.75). Low activity of anti-gp41 antibodies was associated with a younger age of HAART initiation ( P = 0.01). Overall, eight HIV-1 seroreversions were identified. Conclusions: Study identified potential candidates with low viral reservoir and low antibody levels or activities for future trials aiming to reduce HIV-1 reservoir to limit HAART duration.

TLR-2 Recognizes Propionibacterium acnes CAMP Factor 1 from Highly Inflammatory Strains.

BACKGROUND: Propionibacterium acnes (P. acnes) is an anaerobic, Gram-positive bacteria encountered in inflammatory acne lesions, particularly in the pilosebaceous follicle. P. acnes triggers a strong immune response involving keratinocytes, sebocytes and monocytes, the target cells during acne development. Lipoteicoic acid and peptidoglycan induce the inflammatory reaction, but no P. acnes surface protein interacting with Toll-like receptors has been identified. P. acnes surface proteins have been extracted by lithium stripping and shown to induce CXCL8 production by keratinocytes. METHODOLOGY AND PRINCIPAL FINDINGS: Far-western blotting identified two surface proteins, of 24.5- and 27.5-kDa in size, specifically recognized by TLR2. These proteins were characterized, by LC-MS/MS, as CAMP factor 1 devoid of its signal peptide sequence, as shown by N-terminal sequencing. Purified CAMP factor 1 induces CXCL8 production by activating the CXCL8 gene promoter, triggering the synthesis of CXCL8 mRNA. Antibodies against TLR2 significantly decreased the CXCL8 response. For the 27 P. acnes strains used in this study, CAMP1-TLR2 binding intensity was modulated and appeared to be strong in type IB and II strains, which produced large amounts of CXCL8, whereas most of the type IA1 and IA2 strains presented little or no CAMP1-TLR2 binding and low levels of CXCL8 production. The nucleotide sequence of CAMP factor displays a major polymorphism, defining two distinct genetic groups corresponding to CAMP factor 1 with 14 amino-acid changes from strains phylotyped II with moderate and high levels of CAMP1-TLR2 binding activity, and CAMP factor 1 containing 0, 1 or 2 amino-acid changes from strains phylotyped IA1, IA2, or IB presenting no, weak or moderate CAMP1-TLR2 binding. CONCLUSIONS: Our findings indicate that CAMP factor 1 may contribute to P. acnes virulence, by amplifying the inflammation reaction through direct interaction with TLR2.