In this assay, all the three pnp mutants revealed a comparable retardation in growth

(Fig. 4a). As the expression of nlpI was not diminished in any of the three pnp mutants (Fig. 2a), the impaired cold acclimatization could not originate from nlpI, and so in subsequent experiments, we only used the ∆pnp mutant (SFR228). The ∆nlpI mutant also showed a reduced ability to grow at 15 °C comparable to the pnp mutants (Fig. 4a). As pnp expression was unaffected in this mutant, it infers that pnp and nlpI contribute individually to growth of S. Typhimurium at 15 °C. Further evidence to support this view was the observed slower growth for the pnp–nlpI double mutant (SFR394) (Fig. 4a). Complementation of pnp (pMC109) or nlpI (pSFR04) in the respective single mutants almost buy STA-9090 restored

normal growth at 15 °C (Fig. 4b). However, the introduction of either pMC109 or pSFR04 into the pnp–nlpI double mutant resulted in only a Pexidartinib partial restoration of growth at 15 °C. An almost complete restoration of growth was achieved when the pnp–nlpI double mutant was complemented with both nlpI and pnp (Fig. 4c). A second cold acclimatization assay was performed comparing growth on Luria agar plates incubated at either 15 or 37 °C. The ∆pnp, ∆nlpI and pnp–nlpI double mutants were assayed, and the results were comparable to the broth assay at 15 °C (Figs 4 and 5). The ∆pnp and ∆nlpI mutants both showed a restricted recovery when transferred to 15 °C (Fig. 5). In this assay, the growth defect of the pnp–nlpI double mutant appeared more pronounced in relation to either of the single mutants (Fig. 5). Similar to the broth assay, we also observed a restoration of growth when single mutants were complemented with the plasmids expressing the respective pnp or nlpI genes (Fig. 5). However, to restore any significant growth in the

pnp–nlpI double mutant, plasmids coding for both pnp and nlpI had to be introduced (Fig. 5). The contribution of the deaD gene to the cold acclimation response was also determined by observing the growth of mutant SFR456 (∆deaD) in both the broth and plate assays. The mutant revealed a marked growth defect at 15 °C (Figs 4d and 5), but this growth defect was, however, not complemented Aldehyde dehydrogenase by either pnp or nlpI. Altered folding as well as a controlled degradation and stabilization of ribonucleic acids constitutes important elements of bacterial adaptation to altered temperatures (Hurme & Rhen, 1998; Giuliodori et al., 2010). Such alterations also include helicases, RNA chaperons and ribonucleases (Phadtare & Severinov, 2010). Alterations in RNA folding may furthermore act as an endogenous post-transcriptional control of gene expression (Beran & Simons, 2001; Giuliodori et al., 2010). Expression and post-transcriptional regulation of PNPase have been thoroughly detailed in E. coli and serve as a model for temperature-associated post-translational gene regulation. Transcription of E.

After Incubation for one week at 30 °C, colonies were isolated and further analysed. Southern blot analysis was performed with bacterial genomic DNA, extracted with the GenElute Bacterial Genomic DNA Kit (Sigma-Aldrich) and EcoRI digested. Detection on nylon membranes (Roche, Mannheim, Germany) was carried

out using the DIG High Prime DNA Labelling and Detection Starter Kit II (Roche) according to the manufacturer’s instructions. A 1109-bp PCR fragment of the transposon sequence was amplified using specific primers (forward primer Tnp FP01 and reverse primer Tnp RP01; Table 1) and labelled with digoxigenin provided with the kit. Labelling, hybridization and chemiluminescence detection were performed according to the manufacturer’s instructions. PCR was performed using the primer

pair Tnp FP01/Tnp RP01 for detection of the transposon in the genomic DNA of putative transposon mutants. The presence BIRB 796 cell line of the plasmid pBBR1MCS-2 GFP was tested by PCR using the primer pair MCS-2 RP01/MCS-2 FP01 and taq-polymerase under standard conditions: denaturing DNA for 30 s at 94 °C, annealing selleck compound of the primers for 1 min at 58 °C and elongation for 2 min at 72 °C. These steps were repeated for 30 cycles and the results were analysed on a 1% agarose gel. For colony PCR, clones were isolated with a sterile pipette tip and heated to 95 °C for 10 min. Five microlitres were used as template in a standard PCR reaction. All 2600 mutants were tested for the presence of a flagellum, using mouse flagellum-binding monoclonal antibody CSD11. This antibody has been raised against complete A. felis by Mr William Bibb at the Centers for Disease Control and Prevention and in preliminary tests turned out to specifically recognize the Afipia flagella. To validate the transposon mutant bank, we chose to screen for the Amylase presence of flagella because flagella are known to be virulence factors in other bacteria, they are easy to detect and they require numerous gene products for their production, secretion and assembly. For

screening, the clones were grown in 300 μL BYE medium containing 50 μg kanamycin sulphate mL−1 in 96-well format. During the incubation for 1 week, bacteria had sedimented and 10 μL of each pellet was spotted onto nitrocellulose. Filters were air-dried, nonspecific protein-binding sites were blocked with 5% fat-free milk powder in PBS-T overnight and filters were incubated with CSD11 antibody solution (CSD11 hybridoma supernatant fivefold diluted in PBS-T+5% milk powder). Three washes with PBS-T were followed by incubation with horseradish peroxidase-coupled anti-mouse antibody and development of the blot with ECL substrate. Nucleotide sequencing was performed by GATC (Konstanz, Germany). The primer for determination of the nucleotide sequence adjacent to the transposon insertion site was KAN-2 FP01 (Table 1). Oligonucleotides were provided by Thermo Scientific (Ulm, Germany).

[25] β-catenin

(CTNNB1) mutations are found in 20–40% of cases of type I endometrial cancer.[26-28] β-catenin is a component of E-cadherin, which has an important role in cell adhesion and is involved in the Wnt signaling pathway that regulates cell proliferation and differentiation. β-catenin degradation is prevented by mutations and the transcription levels of target genes of β-catenin increase. These mutations are also detected in atypical endometrial hyperplasia; therefore, β-catenin mutations are implicated in the early stage of carcinogenesis.[29] The K-ras oncogene encodes a protein of 21 kDa that has a signaling function from activated membrane receptors in the MAPK pathway. If mutations occur, K-ras continuously functions as activated Ras and excessive signaling causes cell proliferation and induces CP 868596 carcinogenesis.[30] K-ras mutations have been detected in 6–16% of cases of endometrial hyperplasia[31] and 10–31% cases of endometrial cancer.[32, 33] Tsuda et al.[34]

showed that the selleck kinase inhibitor incidence of K-ras mutation was significantly higher in tumors with invasive proliferation (P < 0.002) and that the incidence of mutation in well-differentiated (Grade 1) tumors was significantly higher than that in moderately (Grade 2) and poorly differentiated (Grade 3) tumors (P < 0.025). These results suggest that K-ras is involved in two stages of carcinogenesis: a shift from endometrial hyperplasia to endometrial cancer and invasive proliferation of well-differentiated tumor cells. Lagarda et al.[35] found that the incidence of K-ras mutation was significantly higher in MSI-positive endometrial cancer and was related to aberrant methylation of MMR genes. Mutations in type II endometrial cancer are thought to be linked to the oncogene HER-2/neu and tumor suppressor gene p53. HER-2/neu is a tyrosine kinase membrane receptor in the epidermal growth factor (EGF)

receptor family. Mutations of this gene are also found in breast and ovarian cancers. HER-2/neu expression in endometrial cancer has a strong inverse science correlation with differentiation.[36] However, the incidence of gene amplification differs from 14% to 63% in all cancers[37-40] and overexpression of the protein ranges from 9% to 74%.[41, 42] A p53 gene mutation is the most frequent mutation in human cancer. Normal p53 regulates cell proliferation, apoptosis induction and DNA repair. Point mutations in p53 are found in 90% of cases of type II endometrial cancer, but in only 10–20% of cases of Grade 3 type I endometrial cancer. The incidence is low in endometrial hyperplasia and type I endometrial cancer of other grades.[43, 44] Feng et al.[45] showed that p53 gene mutations occurred only at sites with positive p53 protein expression in endometrioid adenocarcinoma, which were poorly differentiated regions of cancer tissues. p53 is also implicated in the early stage of carcinogenesis of serous adenocarcinoma. Zheng et al.

[25] β-catenin

(CTNNB1) mutations are found in 20–40% of cases of type I endometrial cancer.[26-28] β-catenin is a component of E-cadherin, which has an important role in cell adhesion and is involved in the Wnt signaling pathway that regulates cell proliferation and differentiation. β-catenin degradation is prevented by mutations and the transcription levels of target genes of β-catenin increase. These mutations are also detected in atypical endometrial hyperplasia; therefore, β-catenin mutations are implicated in the early stage of carcinogenesis.[29] The K-ras oncogene encodes a protein of 21 kDa that has a signaling function from activated membrane receptors in the MAPK pathway. If mutations occur, K-ras continuously functions as activated Ras and excessive signaling causes cell proliferation and induces GSI-IX concentration carcinogenesis.[30] K-ras mutations have been detected in 6–16% of cases of endometrial hyperplasia[31] and 10–31% cases of endometrial cancer.[32, 33] Tsuda et al.[34]

showed that the PF-2341066 incidence of K-ras mutation was significantly higher in tumors with invasive proliferation (P < 0.002) and that the incidence of mutation in well-differentiated (Grade 1) tumors was significantly higher than that in moderately (Grade 2) and poorly differentiated (Grade 3) tumors (P < 0.025). These results suggest that K-ras is involved in two stages of carcinogenesis: a shift from endometrial hyperplasia to endometrial cancer and invasive proliferation of well-differentiated tumor cells. Lagarda et al.[35] found that the incidence of K-ras mutation was significantly higher in MSI-positive endometrial cancer and was related to aberrant methylation of MMR genes. Mutations in type II endometrial cancer are thought to be linked to the oncogene HER-2/neu and tumor suppressor gene p53. HER-2/neu is a tyrosine kinase membrane receptor in the epidermal growth factor (EGF)

receptor family. Mutations of this gene are also found in breast and ovarian cancers. HER-2/neu expression in endometrial cancer has a strong inverse SDHB correlation with differentiation.[36] However, the incidence of gene amplification differs from 14% to 63% in all cancers[37-40] and overexpression of the protein ranges from 9% to 74%.[41, 42] A p53 gene mutation is the most frequent mutation in human cancer. Normal p53 regulates cell proliferation, apoptosis induction and DNA repair. Point mutations in p53 are found in 90% of cases of type II endometrial cancer, but in only 10–20% of cases of Grade 3 type I endometrial cancer. The incidence is low in endometrial hyperplasia and type I endometrial cancer of other grades.[43, 44] Feng et al.[45] showed that p53 gene mutations occurred only at sites with positive p53 protein expression in endometrioid adenocarcinoma, which were poorly differentiated regions of cancer tissues. p53 is also implicated in the early stage of carcinogenesis of serous adenocarcinoma. Zheng et al.

Under similar treatment Ibrutinib concentration conditions, Bouyer et al. (2007) have also observed an enhanced gentamicin resistance after passage into amoebae. The latter authors suggested a possible role of the vesicle membrane in the protection of Legionella, but also considered a partial intrinsic resistance. This resistance was intrinsic to the differentiated MIFs and was not due to physical barriers imposed by the pellet configuration, as we released the MIFs from the pellets and tested them as free bacteria. This resistance was also conserved in MIFs released from pellets aged for 90 days in Osterhout’s buffer. Garduno et al.

(2002) previously observed that MIFs recovered from HeLa cells were also resistant to gentamicin. Taken together, these observations

suggest that MIFs produced in amoeba or in ciliates share a common phenotype regarding gentamicin resistance. Survival of Legionella in the freshwater environment must include an ability to resist starvation Enzalutamide in vivo for long periods. Thus, we studied the long-term survival in a low-nutrient environment of Legionella pellets and SPFs. For the two types of suspensions, we observed a rapid decrease of culturability in the encystment buffer up to 11 days (Fig. 3). After that, evident differences appeared. Culturability of SPFs legionella continue to decrease strongly until 90 days, when no more culturable bacteria were detected, as previously reported by Bouyer et al. (2007). In contrast, Tetrahymena-derived pellets of MIFs still contained culturable Legionella after 4 months (Fig. 3). It is Dapagliflozin therefore clear that pellets protect Legionella from starvation. However, whether the pellet structure itself contributes to starvation resistance is not yet known, as the intrinsic starvation resistance of MIFs that had been released from pellets was not measured separately. We observed by optical microscopy that large aggregates after an aging period of 90 days are still present (data not shown), suggesting that these structures could persist in the environment. MIF obtained from HeLa cells have previously been reported to be highly infectious

in macrophages or HeLa cells (Garduno et al., 2002). We observed here that MIFs derived from Tetrahymena are also infectious in pneumocytes (Fig. 4). Furthermore, our results showed that these MIFs retained their infectivity after an aging period of 90 days, being capable of exhibiting a higher capacity to multiply into pneumocytes, in relation to SPFs freshly grown in vitro. Our results demonstrate that Tetrahymena, as previously reported for amoeba, could participate in determining the environmental fitness and infectivity of Legionella, and thus play a critical role in the dissemination of these bacteria. To our knowledge, this work is the first report concerning the behaviour of Legionella expelled from Tetrahymena, a field of research that should be more studied in more detail.

30 for PGN_1587, respectively, which were consistent www.selleckchem.com/products/epz015666.html with their positions on the 2D gels. At least 16 protein spots, which were present in the particle-free culture supernatant of the kgp rgpA rgpB strain, were absent or faint in that of the kgp rgpA rgpB porK mutant (Fig. 1). Relative amounts (kgp rgpA rgpB porK versus kgp rgpA rgpB) of the protein spots were calculated (Table 2). The protein spots

were then subjected to MALDI-TOF mass analysis. PMF analysis of the spots, in comparison with the genome database of P. gingivalis ATCC 33277T (Naito et al., 2008), allowed the identification of 10 proteins (Table 2). An immunoreactive 46-kDa antigen (PGN_1767) was identified in two different protein spots [spot 10 (33 kDa) and spot 8 (42 kDa)]. Both 33- and 42-kDa PGN_1767 proteins contained the D42-R66 fragment at the most N-terminal position, whereas the 42-kDa protein possessed the G403-R418 fragment in the CTD, but the 33-kDa protein did not, suggesting that the 42-kDa PGN_1767 protein was processed at the C-terminal end to yield the 33-kDa PGN_1767 protein. PGN_0659 (35-kDa hemin binding

protein, HBP35) was identified in four different spots [one (spot 9) with a molecular mass of 36 kDa and Akt inhibitor three (spots 12, 13 and 14) with a molecular mass of 28 kDa] in 2D-PAGE. The three 28-kDa protein spots had different isoelectric points. All of Buspirone HCl the 28- and 36-kDa HBP35 proteins contained the A61-K87 fragment at the most N-terminal position, whereas the 36-kDa protein possessed the D244-R329 fragment at the C-terminal end, but the 28-kDa proteins had the E234-K273 or D244-K273 fragment, suggesting that the 36-kDa HBP35 protein was processed at the C-terminal end to yield the 28-kDa HBP35 proteins. HBP35 exhibits thioredoxin and hemin-binding activities and has an important role in heme acquisition for growth (Shoji et al., 2010). PGN_0898 (spot 15) is a bacterial peptidylarginine deiminase (PAD). Wegner et al. (2010) showed that deletion of the PAD (PGN_0898)-encoding

gene resulted in complete abrogation of protein citrullination. Inactivation of Arg-gingipains, but not Lys-gingipain, led to decreased citrullination, suggesting that host peptides generated by proteolytic cleavage at Arg-X peptide bonds by Arg-gingipains were citrullinated at the C terminus by PAD. Citrullinated bacterial and host peptides may cause the autoimmune response in rheumatoid arthritis (Lundberg et al., 2010). CPG70 (PGN_0335, spot 4) exhibits Lys- and Arg-specific metallocarboxypeptidase activity. A previous study (Chen et al., 2002) suggested that CPG70 may have an important role in C-terminal processing of cell surface proteins containing Arg-gingipains, Lys-gingipain and adhesins of P. gingivalis. TapA (PGN_0152) was identified in two different protein spots [spot 7 (44 kDa) and spot 6 (48 kDa)].

Suppression of the effects of the lack of RpoS by overexpression of SOD or catalase indicated that the damage caused by ROS reduces survival and increases the mutation frequency in a starving P. putida RpoS-deficient strain. Interestingly, although the absence of RpoS in starved P.

putida affected the spectrum of mutations, the spectrum was different from that identified in P. putida lacking the GO repair system (Saumaa et al., 2007). Thus, it is possible that the accumulation of oxidative DNA damage other than GO could elevate the frequency of mutation in these bacteria. There is also another, not exclusive explanation for these differences. It is known that oxidative damage of proteins and membrane components, but not that of selleckchem DNA, is a major reason for mortality of cells (Nyström, 2004). Oxidative damage to components of protein synthesis selleck products increases mistranslation, and

vice versa, mistranslated proteins are more susceptible to oxidative damage (Dukan et al., 2000). Mistranslation is increased 10–100-fold in E. coli due to amino acid starvation (Sørensen, 2001). Importantly, mistranslation of DNA repair and replication proteins has been demonstrated to create a transient mutator phenotype (Humayun, 1998; Balashov & Humayun, 2002, 2003; Al Mamun et al., 2006). For example, hypermutagenesis in E. coli mutA cells mistranslating aspartate as glycine due to a mutation in the glycine tRNA anticodon was mediated by modifications of DNA polymerase Pol III due to elevated mistranslation (Al Mamun et al., 2006). Additionally, oxidative modification of replication proteins and inactivation of the components of repair pathways have been reported in eukaryotic systems (Graziewicz et al., 2002; Men et al., 2007; Montaner et al., 2007; Bae et al., 2008; Jarrett et al., 2008). Hence, because the elevated mutation frequency Flavopiridol (Alvocidib) observed by Tarassova et al. (2009) in starving RpoS-deficient

P. putida was associated with an increased death of bacteria and the spectrum of mutations did not resemble that induced by oxidative damage of DNA, the higher mutation frequency in the surviving populations observed in this study might primarily be caused by a decline in DNA replication and repair fidelity due to the oxidative damage of enzymes and/or the errors occurring during the translation of proteins. So far, the role of oxidative damage to proteins in DNA integrity has been underestimated in stationary-phase mutagenesis. It certainly needs more comprehensive investigations. Bacteria have multiple DNA polymerases, each of those with a specific role. DNA polymerase Pol III is a replicative polymerase, and its inactivation is lethal to bacteria. Pol I is involved in Okazaki fragments’ processing and DNA repair synthesis (Okazaki et al., 1971; Cooper & Hanawalt, 1972). Additionally, E.

Other preventive measures should focus on strong educational messaging surrounding cough etiquette and hand hygiene, availability of tissues and facilities to cleanse hands in common areas, and voluntary isolation of mild cases at home until 24 hours after resolution of symptoms.6 Regarding other epidemic-prone vaccine-pre-ventable diseases, a measles outbreak that started in early 2009 in Gauteng Province has spread to a number of other regions,7 although the number of new cases being reported currently would seem to be decreasing. Although a mass measles immunization campaign planned countrywide for April 2010 is likely to reduce the measles incidence further, pretravel measles immunization Epacadostat should

be considered for those who may not be immune through prior immunization or disease. No cases of wild-type polio have been confirmed in South Africa since 1989, but the country remains vulnerable to reintroduction of the disease, given suboptimal vaccine coverage in some areas. Polio boosters are advised for all persons traveling to South Africa from polio-endemic countries, notably Nigeria, Pakistan, India, and Afghanistan, and for persons aged less than 15 years from countries where reinfection with polio

has occurred. These include Angola, Cameroon, Cote d’Ivoire, Ghana, and Niger.8 Sporadic cases of meningococcal infection are seen year-round in South Africa, with a moderate seasonal increase from May to October. L-gulonolactone oxidase The dominant serogroup is W135. While the risk to World Cup attendees is likely Selleckchem DAPT to be low, given the expected crowded conditions at some of the venues and the severity and rapid progression of disease, consideration may be given to pre-exposure vaccination. The extensive outbreaks of meningococcal disease seen in the African meningitis belt, however, are not a feature of the epidemiology of this infection in South Africa. The debate surrounding whether to legalize prostitution in South Africa during the World Cup has once again focused attention on the perceived increased risk of acquiring a sexually transmitted infection (STI) during mass gatherings. This is of particular

relevance to countries such as South Africa, where the antenatal human immunodeficiency virus (HIV) prevalence rate in 15- to 49-year old women stands at 29%.9 During the 2000 Sydney Olympic Games, there was an increased demand for sexual health services.10 However, the benefits of active education campaigns focusing on safe sex and the provision of condoms to reduce the risk of STIs were felt at the 2007 Cricket World Cup in the Caribbean and 1996 Atlanta Olympic Games. In 1996, no increase in STIs was reported in the Atlanta metropolitan area during the Olympic Games, at which posters, pamphlets, badges communicating safe sex messages in 17 languages, and 50,000 condoms in Olympic colors were distributed to visitors.

It is a moderate halophile that grows optimally at 50 g L−1 NaCl and produces methane from H2 + CO2 and formate (Ollivier et al., 1998). Metagenomic studies of the microbial community of the hypersaline (290 g L−1 salt) Lake Tyrell, Australia, revealed the existence of a novel major lineage of Archaea.

Phylogenetically, the organisms selleck chemicals belong to the Euryarchaeota, but are not closely related to any of the classes recognized so far; therefore, a new class was proposed: Nanohaloarchaea (candidate genera ‘Candidatus Nanosalinarum’ and ‘Candidatus Nanosalina’), which appears to be worldwide distributed (Narasingarao et al., 2012). 16S rRNA gene sequences belonging to this lineage were also reported in several earlier studies (Grant et al., 1999; Baati et al., 2010; Oh et al., 2010). Based on the genome annotation, these organisms are expected to have a predominantly aerobic heterotrophic lifestyle (Narasingarao et al., BIBF 1120 purchase 2012). A similar finding has been reported by Ghai et al. (2011) in a 19% salinity layer of a crystallizer pond near Alicante (Spain). A low GC euryarchaeote, resembling

the novel nanohaloarchaeal organisms described in Lake Tyrell, has been revealed by a single-cell genome approach. 16S rRNA gene sequence analysis showed that the virtual microbe reconstructed from genomic data in Alicante (‘Candidatus Haloredivivus’) is 90% and 88%, respectively, identical with the new candidate genera ‘Candidatus Nanosalinarum’ and ‘Candidatus Nanosalina’ detected in Lake Tyrell (Ghai et al., 2011). The Halobacteriaceae typically lead an aerobic heterotrophic life style. However, in spite of their common requirement for high salt concentrations for growth, their nutritional demands and metabolic pathways are quite diverse. Some species possess complex dietary needs that can be met in culture by including high concentrations of yeast extract or other rich sources of nutrients

to their growth medium (e.g. Halobacterium salinarum). By contrast, some species grow well on single carbon sources while using ammonia as a nitrogen source. Haloferax mediterranei can grow on simple compounds such as acetate, tuclazepam succinate, etc. while supplying its need for nitrogen, sulfur, and other essential elements from inorganic salts. Such simpler growth demands are generally detected in species of the genera Haloferax and Haloarcula (Oren, 2002b). An even more extreme case is Halosimplex carlsbadense, an organism that only grows in defined medium with acetate and glycerol, acetate and pyruvate, or pyruvate alone. Carbohydrates, amino acids, fats, and proteins do not support its growth (Vreeland et al., 2002). Interestingly, pyruvate is also a preferred substrate of the flat square Haloquadratum walsbyi (Burns et al., 2007).

Compared to immune competent patients the age of presentation tends to be younger, with worse performance status and higher LDH. Often the patients present with multifocal disease. In the HIV population the incidence of PCNSL has fallen dramatically since the introduction of HAART [13,14]. In immune competent individuals, the treatment of choice is chemotherapy, with the antimetabolites methotrexate and cytarabine forming the backbone of the majority

of PCNSL regimens Gefitinib and is the current regimen of choice for de novo immune competent patients [15] with PCNSL. However, in the HIV population this is rarely feasible due to poor performance status and concerns over toxicity with the combination of two chemotherapeutic agents. Therefore single modality use of intravenous methotrexate is the most utilized treatment yielding median overall survival of 8–9 months in most small series of patients [16,17]. In these situations, it is recommended to utilize growth factors such as G-CSF to prevent enhanced haematological toxicity in this population. In patients with well-controlled HIV viral load and good performance status,

and in the absence of comorbidities, ideally the treatment of choice would be combination therapy with a methotrexate and AraC combination. ABT-888 order In those cases where treatment is tolerated and chemosensitive disease demonstrated, consolidation of an autologous stem transplant may be considered.

Because of the association with EBV and HIV-related PCNSL, investigators have tried to develop antiviral-based regimens including nucleoside analogues such as AZT and ganciclovir [18]. However, although ORR rates of 56% were reported, outcome measures remain disappointing with OS reported of 4 months [17], which is inferior to single-agent methotrexate. In the future, further knowledge however of the biological basis of EBV and its association with PCNSL may facilitate novel targeted approaches. The use of HAART is mandatory, and has been demonstrated in three small series to be correlated with enhanced OS [17,19,20]. Part of its effect may be to induce restoration of an immune response to EBV. Therefore it is recommended to initiate HAART in all newly diagnosed patients with HIV PCNSL. Newer antiviral agents with minimal drug–drug interaction may facilitate the ability to administer standard or intensive chemotherapy agents. Radiotherapy is a useful palliative treatment modality for control of symptoms or should be considered as an alternative first-line treatment modality in those patients where the risks of toxicity from high-dose intravenous agents are considered unacceptable [21]. We recommend that all patients with PCNSL should be started on HAART if not already on it (level of evidence 1C).