Atuação odontológica no paciente cardiopata em cuidados paliativos na unidade de terapia intensiva / Dental performance in the patient with heart disease in palliative care in the intensive care unit

INTRODUÇÃO: A Organização Mundial de Saúde (OMS) define Cuidados Paliativos como uma "abordagem que melhora a qualidade de vida de pacientes e suas famílias que enfrentam problemas associados a doenças que ameaçam a vida. Previne e alivia o sofrimento, através de identificação precoce, avaliação correta e tratamento da dor e de outros problemas físicos, psicossociais ou espirituais". Pacientes com doenças ameaçadoras de vida, sobretudo os cardiopatas, apresentam sinais e sintomas bucais decorrentes da doença de base ou do seu tratamento. Portanto, o cuidado bucal deve ser considerado como parte do plano integral de cuidados paliativos, para reduzir não apenas a carga microbiana bucal, mas também o risco de acidentes, dor, infecções e complicações sistêmicas. RELATO DE CASO: Paciente do gênero masculino, com 65 anos de idade. Apresenta diagnóstico de insuficiência cardíaca perfil B, hipertensão arterial sistêmica, doença renal crônica e diabetes mellitus tipo II, com antecedente de dois infartos agudos do miocárdio e internado na unidade de terapia intensiva de um hospital cardiológico terciário, em cuidados paliativos exclusivos. Observou-se ao exame físico extraoral o paciente ser não contactuante, acamado, intubado, com abertura mandibular reduzida à manipulação, lábios ressecados; e ao exame físico intraoral, ser dentado parcial superior e inferior sem uso de próteses dentárias, ter doença periodontal, dentes incisivos central e lateral superior do lado direito com mobilidade grau 3, lesões ulceradas em mucosa labial, língua ressecada, saburra lingual e fluxo salivar reduzido. Visto isso, elaborou-se um plano de cuidados bucais visando a prevenção do risco de broncoaspiração, aliviar e controlar os sinais bucais. Foi realizada exodontia dos dentes com mobilidade, laserterapia e biópsia incisional da lesão ulcerada, higiene oral com acompanhamento odontológico diariamente. CONSIDERAÇÕES FINAIS: O caso enfatiza a importância do cirurgião-dentista inserido numa equipe de Cuidados Paliativos, que através do atendimento especializado reduziu o risco de acidente e proporcionou alívio e conforto ao paciente em sua fase final de vida.

Infecção odontogênica em paciente com infarto agudo do miocárdio em uso de tripla terapia antitrombótica: relato de caso / Odontogenic infection in a patient with acute myocardial infarction on triple antithrombotic therapy: case report

INTRODUÇÃO: As infecções odontogênicas são frequentemente causadas por diversos microrganismos e espécies bacterianas. Os pacientes possuem sinais e sintomas específicos como dor localizada, acompanhada de calor e inchaço na região afetada. Embora a maioria dos processos infecciosos em estágios iniciais sejam controlados com intervenção cirúrgica e antibioticoterapias, eles têm potencial para se disseminar por meio dos planos faciais da cabeça e pescoço, podendo causar uma piora da condição sistêmica do paciente. Esse relato apresenta um caso de infecção odontogênica em paciente internado com infarto agudo do miocárdio com supradesnivelamento do segmento ST em uso de tripla terapia antitrombótica, em que a intervenção odontológica foi imediata e de extrema relevância para a compensação clínica do paciente. RELATO DE CASO: Paciente gênero masculino, 73 anos com diagnóstico de doença arterial coronariana e fibrilação arterial persistente, internado na Unidade Coronariana em um hospital terciário de cardiologia com quadro de infarto agudo do miocárdio em uso de enoxaparina, ácido acetilsalicílico e clopidogrel com queixa de dor em cavidade oral. Ao exame físico extraoral: edema e hiperemia em face do lado direito e lábio superior. Exame físico intraoral: dentado parcial com aumento volumétrico em fundo de sulco gengival anterior superior e mucosa labial do lado direito. Realizado radiografia periapical dos dentes incisivos central e lateral superior lado direito com condutos obturados e lesões periapicais. Conduta: anestesia local, desobturação dos condutos com medicações intracanais, drenagem do abscesso, colocação de dreno após incisão em mucosa gengival, uso de selante de fibrina para hemostasia local e antibioticoterapia. Após a remoção do dreno, observa-se regressão do edema em hemiface direita e regressão total do edema em lábio superior, com ausência de sintomatologia dolorosa relatada pelo paciente. O paciente recebeu alta após 9 dias e foi acompanhado via ambulatório para finalizar os tratamentos endodônticos, medicado com amoxicilina e clavulanato de potássio por sete dias e dipirona para analgesia. CONSIDERAÇÕES FINAIS: O caso relatado demonstra o potencial lesivo de focos infecciosos em cavidade oral e a importância dos cuidados com a saúde bucal, especialmente em pacientes críticos com alterações cardiovasculares e alto risco de sangramento. O diagnóstico e tratamento odontológico imediatos foram essenciais para resolução do quadro infeccioso bucal, além de minimizar possíveis complicações sistêmicas e reduzir o tempo de hospitalização.

Multicomponent meningococcal serogroup B vaccination elicits cross-reactive immunity in infants against genetically diverse serogroup C, W and Y invasive disease isolates.

BACKGROUND: The multicomponent meningococcal serogroup B vaccine (4CMenB) is currently indicated for active immunization against invasive meningococcal disease caused by Neisseria meningitidis serogroup B (MenB). However, genes encoding the 4CMenB antigens are also variably present and expressed in strains belonging to other meningococcal serogroups. In this study, we evaluated the ability of antibodies raised by 4CMenB immunisation to induce complement-mediated bactericidal killing of non-MenB strains. METHODS: A total of 227 invasive non-MenB disease isolates were collected between 1 July 2007 and 30 June 2008 from England and Wales, France, and Germany; 41 isolates were collected during 2012 from Brazil. The isolates were subjected to genotypic analyses. A subset of 147 isolates (MenC, MenW and MenY) representative of the meningococcal genetic diversity of the total sample were tested in the human complement serum bactericidal antibody assay (hSBA) using sera from infants immunised with 4CMenB. RESULTS: Serogroup and clonal complex repertoires of non-MenB isolates were different for each country. For the European panel, MenC, MenW and MenY isolates belonged mainly to ST-11, ST-22 and ST-23 complexes, respectively. For the Brazilian panel, most MenC and MenW isolates belonged to the ST-103 and ST-11 complexes, respectively, and most MenY isolates were not assigned to clonal complexes. Of the 147 non-MenB isolates, 109 were killed in hSBA, resulting in an overall coverage of 74%. CONCLUSION: This is the first study in which 147 non-MenB serogroup isolates have been analysed in hSBA to evaluate the potential of a MenB vaccine to cover strains belonging to other serogroups. These data demonstrate that antibodies raised by 4CMenB are able to induce bactericidal killing of 109 non-MenB isolates, representative of non-MenB genetic and geographic diversity. These findings support previous evidence that 4CMenB immunisation can provide cross-protection against non-MenB strains in infants, which represents an added benefit of 4CMenB vaccination.

Progenitor-cell-enriched micrografts as a novel option for the management of androgenetic alopecia.

Regenerative medicine is a multidisciplinary field that combines engineering and life science principles to promote regeneration, potentially restoring the physiological condition in diseased tissues. Specifically, the developments of complex grafts enhance the intrinsic regenerative capacity of the host by altering its environment. Autologous micrografts obtained through Rigenera® micrografting technology are able to promote derma and bone regeneration. Androgenetic alopecia (AGA) leads to a progressive thinning of scalp hair affecting 60-70% of the adult population worldwide. Pharmacological treatment offers moderate results and hair transplantation represents the only permanent treatment option. The aim of this study was to demonstrate the role of dermis micrografting in the treatment of AGA by clinical and histological evaluations after 4, 6, and 12 months. Hair growth and density were improved at all indicated times. Those outcomes were also confirmed by the TrichoScan® analysis, reporting an increase of total hair count and density with an increase and reduction of anagen and telogen phases, respectively. Scalp dermoscopic analysis showed an improvement of hair density and histological analysis indicated a clear amelioration of the scalp, development of hair follicles, and a beginning of cuticle formation. Collectively, those results suggest a possible use of the micrografts as a novel therapeutic option in the management of AGA.

Correction: Magic-Factor 1, a Partial Agonist of Met, Induces Muscle Hypertrophy by Protecting Myogenic Progenitors from Apoptosis.

[This corrects the article DOI: 10.1371/journal.pone.0003223.].

Met-Activating Genetically Improved Chimeric Factor-1 Promotes Angiogenesis and Hypertrophy in Adult Myogenesis.

BACKGROUND: Myogenic progenitor cells (activated satellite cells) are able to express both HGF and its receptor cMet. After muscle injury, HGF-Met stimulation promotes activation and primary division of satellite cells. MAGIC-F1 (Met-Activating Genetically Improved Chimeric Factor-1) is an engineered protein that contains two human Met-binding domains that promotes muscle hypertrophy. MAGIC-F1 protects myogenic precursors against apoptosis and increases their fusion ability enhancing muscle differentiation. Hemizygous and homozygous Magic-F1 transgenic mice displayed constitutive muscle hypertrophy. METHODS: Here we describe microarray analysis on Magic-F1 myogenic progenitor cells showing an altered gene signatures on muscular hypertrophy and angiogenesis compared to wild-type cells. In addition, we performed a functional analysis on Magic-F1+/+ transgenic mice versus controls using treadmill test. RESULTS: We demonstrated that Magic-F1+/+ mice display an increase in muscle mass and cross-sectional area leading to an improvement in running performance. Moreover, the presence of MAGIC-F1 affected positively the vascular network, increasing the vessel number in fast twitch fibers. Finally, the gene expression profile analysis of Magic-F1+/+ satellite cells evidenced transcriptomic changes in genes involved in the control of muscle growth, development and vascularisation. CONCLUSION: We showed that MAGIC-F1-induced muscle hypertrophy affects positively vascular network, increasing vessel number in fast twitch fibers. This was due to unique features of mammalian skeletal muscle and its remarkable ability to adapt promptly to different physiological demands by modulating the gene expression profile in myogenic progenitors.

A Regenerative Approach with Dermal Micrografts in the Treatment of Chronic Ulcers.

BACKGROUND: The etiology of non-healing ulcers depends on both systemic and local factors. The introduction of advanced dressing, negative wound therapy and compression therapy have undoubtedly improved clinical outcomes. The principal aim of study was to demonstrate the efficacy of dermal micrografts in the treatment of ulcers with different etiologies. The second aim was to investigate in vitro the action of micrografts in the regenerative process. METHODS: The dermal micro-grafts were obtained from mechanical disaggregation of small pieces of skin tissue through a medical device called Rigeneracons. RESULTS: We observed in vivo the ability of dermal autologous micrografts to improve the healing of venous, diabetic, pressure and post-traumatic ulcers after few week of treatment accomplished in general with a better quality of life for the patients. In vitro results showed that these micrografts express mesenchymal stem cells (MSCS) marker such as CD34, CD73, CD90 and CD105, and are able to form a viable and proliferative biocomplex with collagen sponge. Finally, the site of ulcers displayed a different expression of epidermal growth factors, insulin-like growth factors, platelet-derived growth factors and their receptors and tumor necrosis factor-ß with respect to healthy skin samples. CONCLUSION: We reported a good outcome for the treatment of chronic ulcers using dermal autologous micrografts. Finally, we suggest that the positivity to MSCs markers and the ability to interact with a scaffold can play a key role in their regenerative properties.

Expression of factor H binding protein in meningococcal strains can vary at least 15-fold and is genetically determined.

Factor H binding protein (fHbp) is a lipoprotein of Neisseria meningitidis important for the survival of the bacterium in human blood and a component of two recently licensed vaccines against serogroup B meningococcus (MenB). Based on 866 different amino acid sequences this protein is divided into three variants or two families. Quantification of the protein is done by immunoassays such as ELISA or FACS that are susceptible to the sequence variation and expression level of the protein. Here, selected reaction monitoring mass spectrometry was used for the absolute quantification of fHbp in a large panel of strains representative of the population diversity of MenB. The analysis revealed that the level of fHbp expression can vary at least 15-fold and that variant 1 strains express significantly more protein than variant 2 or variant 3 strains. The susceptibility to complement-mediated killing correlated with the amount of protein expressed by the different meningococcal strains and this could be predicted from the nucleotide sequence of the promoter region. Finally, the absolute quantification allowed the calculation of the number of fHbp molecules per cell and to propose a mechanistic model of the engagement of C1q, the recognition component of the complement cascade.

Identification of a Monoclonal Antibody Against Pneumococcal Pilus 1 Ancillary Protein Impairing Bacterial Adhesion to Human Epithelial Cells.

The adhesion of Streptococcus pneumoniae is a key step during colonization of human respiratory tract mucosae. Here we demonstrate that pneumococcal type I pilus significantly increases the adhesiveness of poorly adhering highly capsulated strains in vitro. Interestingly, preincubation of bacteria with antibodies against the major pilus backbone subunit (RrgB) or the adhesin component (RrgA) impaired pneumococcal association to human epithelial cells. Screening for anti-RrgA monoclonal antibodies specifically affecting the adhesive capacity of S. pneumoniae led to the identification of the monoclonal 11B9/61 antibody, which greatly reduced pilus-dependent cell contact. Proteomic-based epitope mapping of 11B9/61 monoclonal antibody revealed a well-exposed epitope on the D2 domain of RrgA as the target of this functional antibody. The data presented here confirm the importance of pilus I for S. pneumoniae pathogenesis and the potential use of antipilus antibodies to prevent bacterial colonization.

Osteogenic Potential of Human Oral-Periosteal Cells (PCs) Isolated From Different Oral Origin: An In Vitro Study.

The periosteum is a specialized connective tissue containing multipotent stem cells capable of bone formation. In this study, we aimed at demonstrating that human oral periosteal cells derived from three different oral sites (upper vestibule, lower vestibule, and hard palate) represent an innovative cell source for maxillo-facial tissue engineering applications in terms of accessibility and self-commitment towards osteogenic lineage. Periosteal cells (PCs) were isolated from patients with different ages (20-30 yy, 40-50 yy, 50-60 yy); we then analyzed the in vitro proliferation capacity and the bone self-commitment of cell clones culturing them without any osteogenic supplement to support their differentiation. We found that oral PCs, independently of their origin and age of patients, are mesenchymal stem cells with stem cell characteristics (clonogenical and proliferative activity) and that, even in absence of any osteogenic induction, they undertake the osteoblast lineage after 45 days of culture. These results suggest that oral periosteal cells could replace mesenchymal cells from bone marrow in oral tissue-engineering applications.

Whole-Genome Sequences of Nonencapsulated Haemophilus influenzae Strains Isolated in Italy.

Haemophilus influenzae is an important human pathogen involved in invasive disease. Here, we report the whole-genome sequences of 11 nonencapsulated H. influenzae (ncHi) strains isolated from both invasive disease and healthy carriers in Italy. This genomic information will enrich our understanding of the molecular basis of ncHi pathogenesis.

Molecular and serological diversity of Neisseria meningitidis carrier strains isolated from Italian students aged 14 to 22 years.

Neisseria meningitidis is an obligate human commensal that commonly colonizes the oropharyngeal mucosa. Carriage is age dependent and very common in young adults. The relationships between carriage and invasive disease are not completely understood. In this work, we performed a longitudinal carrier study in adolescents and young adults (173 subjects). Overall, 32 subjects (18.5%) had results that were positive for meningococcal carriage in at least one visit (average monthly carriage rate, 12.1%). Only five subjects tested positive at all four visits. All meningococcal isolates were characterized by molecular and serological techniques. Multilocus sequence typing, PorA typing, and sequencing of the 4CMenB vaccine antigens were used to assess strain diversity. The majority of positive subjects were colonized by capsule null (34.4%) and capsular group B strains (28.1%), accounting for 23.5% and 29.4% of the total number of isolates, respectively. The fHbp and nhba genes were present in all isolates, while the nadA gene was present in 5% of the isolates. The genetic variability of the 4CMenB vaccine antigens in this collection was relatively high compared with that of other disease-causing strain panels. Indications about the persistence of the carriage state were limited to the time span of the study. All strains isolated from the same subject were identical or cumulated minor changes over time. The expression levels and antigenicities of the 4CMenB vaccine antigens in each strain were analyzed by the meningococcal antigen typing system (MATS), which revealed that expression can change over time in the same individual. Future analysis of antigen variability and expression in carrier strains after the introduction of the MenB vaccine will allow for a definition of its impact on nasopharyngeal/oropharyngeal carriage.

Variation of pneumococcal Pilus-1 expression results in vaccine escape during Experimental Otitis Media [EOM].

UNLABELLED: The pneumococcal Pilus-1 enhances attachment to epithelial cells in the respiratory tract and subsequent invasion. Pilus-1 expression is bi-stable and positively regulated by the RlrA transcriptional regulator. To delineate the role of pilus-1 in Experimental Otitis Media (EOM), we evaluated colonization and disease due to a Streptococcus pneumoniae (SP) wild type strain (Taiwan19F-14 wt) and its otherwise isogenic pilus-1 and pilus-2 deficient mutant (Taiwan19F-14 ΔPI-1/PI-2-) as well as potential for a chimeric protein (RrgB321) vaccine candidate for prevention of middle ear (ME) disease. METHODS: Chinchillas were challenged intranasally with either Taiwan19F-14 wt or Taiwan19F-14PI-1/PI-2 deficient mutant. ME status was assessed and direct cultures performed. New cohorts of animals were immunized with RrgB321 or alum. Intranasal challenge with Taiwan19F-14 wt [erythromycin susceptible E(S)] was performed. Subsequently, a second cohort of animals was immunized and challenged with either Taiwan19F-14 wt or a Pilus-1 over-expressing mutant [Taiwan19F-14+pMU1328_Pc-rlrA mutant; E resistant (R)] strain. Pilus-1 expression was analyzed in SP isolated from nasopharynx (NP) and ME fluids by flow cytometry. RESULTS: Culture positive EOM developed following challenge with either wild type SP (Taiwan19F-14) or its pilus-1 deficient mutant. Culture positive EOM developed following challenge with wild type in both RrgB321 immunized and control animals. Pilus-1 expression in ME fluids was significantly higher in controls compared to immunized chinchillas. In second cohort of immunized and control animals challenged with the over-expressing Pilus-1 mutant, delayed development of EOM in the immunized animals was observed. Pneumococci recovered from ME fluid of immunized animals were no longer E(R) signifying the loss of the pMU1328_Pc-rlrA plasmid. CONCLUSION: Pneumococcal pilus-1 was not essential for EOM. Regulation of Pilus-1 expression in ME fluids in the presence of anti RrgB321 antibody was essential for survival of S. pneumoniae. Pneumococci have evolved mechanisms of regulation of non-essential surface proteins to evade host defenses.

Expression of the Streptococcus pneumoniae pilus-1 undergoes on and off switching during colonization in mice.

Streptococcus pneumoniae pili contribute to adherence and virulence. The regulation of pilus-1 expression is bistable, thus piliated strains contain a variable proportion of pilus-1-non-expressing bacteria. We investigated whether such proportion changes during colonization. Pilus-1-expressing bacteria were quantified in nasopharyngeal washes and pharyngeal tissues from mice that received intranasally bacterial populations with high (H), medium (M) or low (L) pilus-1 expression rates. In nasopharyngeal washes, at early colonization stages, pilus-1 expression rates decreased in H population, while increased in L and M; at later stages, expression rates decreased or remained low. Similar trends were observed in pharyngeal tissues, where, however, at late stages the expression rates were medium-high. In conclusion, pilus-1 is preferentially expressed at early colonization stages, consistently with its role in adhesion, while at later stages the expression is partially switched off. Pilus-1 expression rates observed in clinical isolates in vitro may not reflect the actual rates during colonization/infection.

Immunization with the RrgB321 fusion protein protects mice against both high and low pilus-expressing Streptococcus pneumoniae populations.

RrgB321, a fusion protein of the three Streptococcus pneumoniae pilus-1 backbone RrgB variants, is protective in vivo against pilus islet 1 (PI-1) positive pneumococci. In addition, antibodies to RrgB321 mediate a complement-dependent opsonophagocytosis of PI-1 positive strains at levels comparable to those obtained with antisera against glycoconjugate vaccines. In the pneumococcus, pilus-1 displays a biphasic expression pattern, with different proportions of two bacterial phenotypes, one expressing and one not expressing the pilus-1. These two populations can be stably separated in vitro giving rise to the enriched high (H) and low (L) pilus expressing populations. In this work we demonstrate that: (i) the opsonophagocytic killing mediated in vitro by RrgB321 antisera is strictly dependent on the pilus expression ratio of the strain used; (ii) during the opsonophagocytosis assay pilus-expressing pneumococci are selectively killed, and (iii) no switch towards the pilus non-expressing phenotype can be observed. Furthermore, in sepsis and pneumonia models, mice immunized with RrgB321 are significantly protected against challenge with either the H or the L pilus-expressing population of strains representative of the three RrgB variants. This suggests that the pilus-1 expression is not down-regulated, and also that the expression of the pilus-1 could be up-regulated in vivo. In conclusion, these data provide evidence that RrgB321 is protective against PI-1 positive strains regardless of their pilus expression level, and support the rationale for the inclusion of this fusion protein into a multi-component protein-based pneumococcal vaccine.

The Streptococcus pneumoniae pilus-1 displays a biphasic expression pattern.

The Streptococcus pneumoniae pilus-1 is encoded by pilus islet 1 (PI-1), which has three clonal variants (clade I, II and III) and is present in about 30% of clinical pneumococcal isolates. In vitro and in vivo assays have demonstrated that pilus-1 is involved in attachment to epithelial cells and virulence, as well as protection in mouse models of infection. Several reports suggest that pilus-1 expression is tightly regulated and involves the interplay of numerous genetic regulators, including the PI-1 positive regulator RlrA. In this report we provide evidence that pilus expression, when analyzed at the single-cell level in PI-1 positive strains, is biphasic. In fact, the strains present two phenotypically different sub-populations of bacteria, one that expresses the pilus, while the other does not. The proportions of these two phenotypes are variable among the strains tested and are not influenced by genotype, serotype, growth conditions, colony morphology or by the presence of antibodies directed toward the pilus components. Two sub-populations, enriched in pilus expressing or not expressing bacteria were obtained by means of colony selection and immuno-detection methods for five strains. PI-1 sequencing in the two sub-populations revealed the absence of mutations, thus indicating that the biphasic expression observed is not due to a genetic modification within PI-1. Microarray expression profile and western blot analyses on whole bacterial lysates performed comparing the two enriched sub-populations, revealed that pilus expression is regulated at the transcriptional level (on/off regulation), and that there are no other genes, in addition to those encoded by PI-1, concurrently regulated across the strains tested. Finally, we provide evidence that the over-expression of the RrlA positive regulator is sufficient to induce pilus expression in pilus-1 negative bacteria. Overall, the data presented here suggest that the observed biphasic pilus expression phenotype could be an example of bistability in pneumococcus.

Human neural crest-derived postnatal cells exhibit remarkable embryonic attributes either in vitro or in vivo.

During human embryonic development, odontogenic tissues, deriving from the neural crest, remain undifferentiated until the adult age. This study was aimed at characterising the cells of the follicle enveloping the dental germ, due to its direct origin from neural crests. Sixty dental follicles were collected from patients aged 18 to 45 years. This research has clarified that dental follicles, if extracted in a very early stage, when dental roots did not start to be formed, contain a lineage of cells, characterised by a high degree of plasticity in comparison with other adult stem cell populations. In particular, we found that these cells share the following features with ES: (i) high levels of embryonic stem cell markers (CD90, TRA1-60, TRA1-81, OCT-4, CD133, and SSEA-4); (ii) mRNA transcripts for Nanog and Rex-1; (iii) broader potency, being able to differentiate in cell types of all three germ layer, including smooth and skeletal muscle, osteoblasts, neurons, glial cells, and adipocytes; (iv) high levels of telomerase activity; (v) ability to form embryoid bodies; (vi) ability, after injection in murine blastocysts, to be localised within the inner cell mass; (vii) no teratoma formation after injection; (viii) in vivo tissue formation after transplantation. Our results demonstrate that these cells represent a very easy accessible and extraordinary source of pluripotent cells and point out the fact that they own the cardinal feature of embryonic stem cells.

Coordinated involvement of cathepsins S, D and cystatin C in the commitment of hematopoietic stem cells to dendritic cells.

The identity of biochemical players which underpin the commitment of CD34(+) hematopoietic stem cells to immunogenic or tolerogenic dendritic cells is largely unknown. To explore this issue, we employed a previously established cell-based system amenable to shift dendritic cell differentiation from the immunogenic into the tolerogenic pathway upon supplementation with a conventional cytokine cocktail containing thrombopoietin (TPO) and IL-16. We show that stringent regulation of cathepsins S and D, two proteases involved in antigen presentation, is crucial to engage cell commitment to either route. In response to TPO+IL-16-dependent signaling, both cathepsins undergo earlier maturation and down-regulation. Additionally, cystatin C orchestrates cathepsin S expression through a tight but reversible interaction that, based on a screen of adult stem cells from disparate origins, CD14(+) cells, primary fibroblasts and the MCF7 cell line, appears unique to CD34(+) stem cells from peripheral and cord blood. As shown by CD4(+) T cell proliferation in mixed-lymphocyte reactions, cell commitment to either pathway is disrupted upon cathepsin knockdown by RNAi. Surprisingly, similar effects were also observed upon gene overexpression, which prompts atypically accelerated maturation of cathepsins S and D in cells of the immunogenic pathway, similar to the tolerogenic route. Furthermore, RNAi studies revealed that cystatin C is a proteolytic target of cathepsin D and has a direct, causal impact on cell differentiation. Together, these findings uncover a novel biochemical cluster that is subject to time-controlled and rigorously balanced expression to mediate specific stem cell commitment at the crossroads towards tolerance or immunity.