Global Stage Distribution of Breast Cancer at Diagnosis: A Systematic Review and Meta-Analysis.

Importance: Stage at diagnosis is a key prognostic factor for cancer survival. Objective: To assess the global distribution of breast cancer stage by country, age group, calendar period, and socioeconomic status using population-based data. Data Sources: A systematic search of MEDLINE and Web of Science databases and registry websites and gray literature was conducted for articles or reports published between January 1, 2000, and June 20, 2022. Study Selection: Reports on stage at diagnosis for individuals with primary breast cancer (C50) from a population-based cancer registry were included. Data Extraction and Synthesis: Study characteristics and results of eligible studies were independently extracted by 2 pairs of reviewers (J.D.B.F., A.D.A., A.M., R.S., and F.G.). Stage-specific proportions were extracted and cancer registry data quality and risk of bias were assessed. National pooled estimates were calculated for subnational or annual data sets using a hierarchical rule of the most relevant and high-quality data to avoid duplicates. Main Outcomes and Measures: The proportion of women with breast cancer by (TNM Classification of Malignant Tumors or the Surveillance, Epidemiology, and End Results Program [SEER]) stage group. Results: Data were available for 2.4 million women with breast cancer from 81 countries. Globally, the proportion of cases with distant metastatic breast cancer at diagnosis was high in sub-Saharan Africa, ranging from 5.6% to 30.6% and low in North America ranging from 0.0% to 6.0%. The proportion of patients diagnosed with distant metastatic disease decreased over the past 2 decades from around 3.8% to 35.8% (early 2000s) to 3.2% to 11.6% (2015 onwards), yet stabilization or slight increases were also observed. Older age and lower socioeconomic status had the largest proportion of cases diagnosed with distant metastatic stage ranging from 2.0% to 15.7% among the younger to 4.1% to 33.9% among the oldest age group, and from 1.7% to 8.3% in the least disadvantaged groups to 2.8% to 11.4% in the most disadvantaged groups. Conclusions and Relevance: Effective policy and interventions have resulted in decreased proportions of women diagnosed with metastatic breast cancer at diagnosis in high-income countries, yet inequality persists, which needs to be addressed through increased awareness of breast cancer symptoms and early detection. Improving global coverage and quality of population-based cancer registries, including the collection of standardized stage data, is key to monitoring progress.

Clinical Experience with Abemaciclib in Patients Previously Treated with Another CDK 4/6 Inhibitor in a Tertiary Hospital: A Case Series Study.

The three approved cyclin-dependent kinase 4/6 (CDK4/6) inhibitors, including abemaciclib, have shown differences in their preclinical, pharmacological, and clinical data. Abemaciclib stands out for its broader target range and more rapid and intense activity. It has demonstrated efficacy as a monotherapy or in combination with tamoxifen in endocrine-refractory metastatic breast cancer (MBC) patients with prior chemotherapy. However, the clinical data on abemaciclib after exposure to previous CDK4/6 inhibitors are limited. In this single-center retrospective case series, we identified all patients who received abemaciclib until February 2022 after experiencing documented progression on palbociclib or ribociclib. The safety profile and clinical outcomes of abemaciclib treatment in this specific patient cohort were evaluated. Eleven patients were included in this retrospective case series, nine receiving abemaciclib with tamoxifen. Eight patients had visceral involvement, and the median age was 69 (ranging from 42 to 84). The median time from the end of prior CDK4/6 inhibitor treatment to abemaciclib initiation was 17.5 months (ranging from 3 to 41 months). Patients had undergone a median of three prior therapies (ranging from 1 to 7), including chemotherapy in 54.5% of cases. The median follow-up time was six months (ranging from 1 to 22 months). The median progression-free survival (PFS) was 8 months (95% CI 3.9-12). Five patients continued abemaciclib treatment, and one patient with liver metastases achieved a complete hepatic response. The most common adverse events were diarrhea (72.7%, no grade ≥ 3) and asthenia (27.3%, no grade ≥ 3). Our preliminary findings suggest that abemaciclib could be an effective and safe treatment option for MBC patients who have previously received palbociclib or ribociclib.

Skeletal Muscle is a Source of α-Synuclein with a Sarcolemmal Non-Lipid Raft Distribution.

BACKGROUND/AIMS: Alpha synuclein (αSN) is a widely distributed protein in vertebrates whose physiological significance in many tissues remains unclear, being a key protein present in neurodegenerative disease such as Parkinson's Disease, Lewy Body Dementia, and in Sporadic-Inclusion Body Myositis. We search for αSN in skeletal muscle (SM) and neuronal plasma membrane isolated from brain (BR) from young and old rats. METHODS: In isolated Sarcolemma from SM and from myelin-free neuronal plasma membrane isolated from BR, we determine by Western blot with anti-αSN (2B2D1) and anti-P-αSN (EP1536Y) the αSN membrane distribution, and the SM αSN intra and extracellular localization. RESULTS: In SM and BR, αSN is present in cytosol (CYT) as monomer and oligomer structures mainly tetramers (TM) and in plasma membranes as oligomers (TM and PM). All αSN oligomers were localized in non-lipid rafts and their distribution was unaffected by cholesterol-depletion with Methyl-ß-Cyclodextrin. Membranes with natively high cholesterol content such as Transverse Tubules in SM and myelin in BR, reduce the presence of αSN. Under the same experimental conditions, aged SM and BR plasma membranes show ≈2 folds more αSN. In SM, αSN is extruded without cell damage in young and old rats. CONCLUSION: We conclude that oligomeric αSN are regularly present in SM and BR plasma membranes of healthy young and old rats. Interestingly, low-cholesterol content membranes promote αSN interaction. SM, the largest tissue in vertebrate body is a source of αSN and may contribute to the presence of αSN in extracellular fluids.

Case Report: Bocavirus Infection Radiologically Resembling a Congestive Heart Failure in a Patient with Metastatic Castration-Resistant Prostate Cancer.

Background: Human bocavirus (HBoV) is a viral pathogen from the genus Bocaparvovirus (family Parvoviridae, subfamily Parvovirinae) discovered in 2005. Most of available literature is about HBoV in children and adults with hematological malignancies and in otherwise healthy children with respiratory infections. Information regarding infection in the adult population with solid tumors is scarce. Case Report: We report the case of a 51-year-old male with metastatic castration resistant prostate cancer undergoing chemotherapy treatment who presented with fever, dyspnea, dry cough, and pleuritic pain. Imaging techniques showed signs of congestive heart failure. Symptoms, laboratory tests and echocardiography revealed a more probable infectious etiology. Antibiotic therapy was started. A polymerase chain reaction (PCR) test of nasopharyngeal exudate for respiratory viruses was positive for HBoV. The rest of the microbiological tests were negative. Bronchoalveolar lavage (BAL) was performed. Bacterial culture of BAL was negative while respiratory virus PCR confirmed positivity for HBoV. Antibiotic therapy was discontinued. The patient gradually recovered. Conclusions: Emerging infectious diseases are a notorious threat for immunocompromised populations such as solid tumor patients. This case is unique because to our knowledge this is the first case report article of HBoV in a solid tumor patient and because imaging techniques exhibited signs of congestive heart failure that did not correlate with the rest of the tests. It shows that unusual pathogens should be considered when managing serious clinical complications with uncommon presentations in cancer patients. Notable diagnostic efforts should be made to reach a diagnosis in these cases.

Evidence of exhausted lymphocytes after the third anti-SARS-CoV-2 vaccine dose in cancer patients.

Introduction: Evidence is scant regarding the long-term humoral and cellular responses Q7 triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines in cancer patients after repeated booster doses. The possibility of T-cell exhaustion following these booster doses in this population has not yet been fully studied and remains uncertain. Methods: In this single-center prospective observational study, we explored the specific humoral and cellular response to S1 antigen in 36 patients with solid malignancies at baseline, and after the second and third doses of the mRNA-1273 vaccine. Results: A dual behavior was observed: 24 (66.7%) patients showed partial specific IFN-γ response after the second dose that was further enhanced after the third dose; and 11 (30.5%) already showed an optimal response after the second dose and experienced a marked fall-off of specific IFN-γ production after the third (4 patients negativization), which might suggest T cell exhaustion due to repetitive priming to the same antigen. One (2.8%) patient had persistently negative responses after all three doses. Seroconversion occurred in all patients after the second dose. We then studied circulating exhausted CD8+ T-cells in 4 patients from each of the two response patterns, those with increase and those with decrease in cellular response after the third booster. The patients with decreased cellular response after the booster had a higher expression of PD1+CD8+ and CD57+PD1+CD8+ exhausted T cells compared with those with an increased cellular response both in vivo and in vitro. The proportion of PD1+CD8+ and CD57+PD1+CD8+ exhausted T cells inversely correlated with IFN-γ production. Discussion: Our preliminary data show that the two-dose SARS-CoV-2 vaccine regimen was beneficial in all cancer patients of our study. An additional booster seems to be beneficial in suboptimal vaccine seroconverters, in contrast to maximal responders that might develop exhaustion. Our data should be interpreted with caution given the small sample size and highlight the urgent need to validate our results in other independent and larger cohorts. Altogether, our data support the relevance of immunological functional studies to personalize preventive and treatment decisions in cancer patients.

Adverse drug reactions to the three doses of the severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) mRNA-1273 vaccine in a cohort of cancer patients under active treatment of a tertiary hospital in Madrid, Spain.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines efficacy and safety have been tested in phase 3 studies in which cancer patients were not included or were underrepresented. Methods: The objective of this study is to evaluate the safety profile of the mRNA-1273 vaccine across cancer patients and its relationship to patients' demographics. This retrospective cohort study included patients 18-years or older with solid malignancies receiving active treatment in our hospital who had received the three-dose schedule of the mRNA9 1273 vaccine and whose side effects after each dose were recorded. Patient electronic medical records were reviewed retrospectively to collect data between April 19, 2021, and December 31, 2021. Patients with documented previous infection by SARS-Cov-2 were excluded from the study. Results: A total of 93 patients met the inclusion criteria. Local adverse drug reactions (ADRs) were reported more frequently after the first and second dose than after the third (41.9%, 43% and 31.1% of the patients respectively), while systemic ADRs followed the opposite pattern (16.1%, 34.4% and 52.6% of the patients respectively). We found a statistically significant association between sex and systemic ADRs after the third dose. Cochran-Armitage test showed a statistically significant linear trend, p = 0.012, with a higher Eastern Cooperative Oncology Group (ECOG) score associated with a lower proportion of patients suffering from systemic side effects. A logistic regression showed that women had 5.79 times higher odds to exhibit systemic ADRs after the third dose (p=0.01) compared to males. Increasing age was associated with a decreased likelihood of exhibiting ADRs (p=0.016). Conclusion: The mRNA-1273 vaccine shows a tolerable safety profile. The likelihood of ADRs appears to be associated with gender and age. Its association with ECOG scores is less evident. Further studies are needed to elucidate this data in cancer patients.

Latest culture techniques: cracking the secrets of bone marrow to mass-produce erythrocytes and platelets ex vivo.

Since the dawn of medicine, scientists have carefully observed, modeled and interpreted the human body to improve healthcare. At the beginning there were drawings and paintings, now there is three-dimensional modeling. Moving from two-dimensional cultures and towards complex and relevant biomaterials, tissue-engineering approaches have been developed in order to create three-dimensional functional mimics of native organs. The bone marrow represents a challenging organ to reproduce because of its structure and composition that confer it unique biochemical and mechanical features to control hematopoiesis. Reproducing the human bone marrow niche is instrumental to answer the growing demand for human erythrocytes and platelets for fundamental studies and clinical applications in transfusion medicine. In this review, we discuss the latest culture techniques and technological approaches to obtain functional platelets and erythrocytes ex vivo. This is a rapidly evolving field that will define the future of targeted therapies for thrombocytopenia and anemia, but also a long-term promise for new approaches to the understanding and cure of hematologic diseases.

Application of Chitosan in Bone and Dental Engineering.

Chitosan is a deacetylated polysaccharide from chitin, the natural biopolymer primarily found in shells of marine crustaceans and fungi cell walls. Upon deacetylation, the protonation of free amino groups of the d-glucosamine residues of chitosan turns it into a polycation, which can easily interact with DNA, proteins, lipids, or negatively charged synthetic polymers. This positive-charged characteristic of chitosan not only increases its solubility, biodegradability, and biocompatibility, but also directly contributes to the muco-adhesion, hemostasis, and antimicrobial properties of chitosan. Combined with its low-cost and economic nature, chitosan has been extensively studied and widely used in biopharmaceutical and biomedical applications for several decades. In this review, we summarize the current chitosan-based applications for bone and dental engineering. Combining chitosan-based scaffolds with other nature or synthetic polymers and biomaterials induces their mechanical properties and bioactivities, as well as promoting osteogenesis. Incorporating the bioactive molecules into these biocomposite scaffolds accelerates new bone regeneration and enhances neovascularization in vivo.

Combined deficiency of RAB32 and RAB38 in the mouse mimics Hermansky-Pudlak syndrome and critically impairs thrombosis.

The biogenesis of lysosome related organelles is defective in Hermansky-Pudlak syndrome (HPS), a disorder characterized by oculocutaneous albinism and platelet dense granule (DG) defects. The first animal model of HPS was the fawn-hooded rat, harboring a spontaneous mutation inactivating the small guanosine triphosphatase Rab38 This leads to coat color dilution associated with the absence of DGs and lung morphological defects. Another RAB38 mutant, the cht mouse, has normal DGs, which has raised controversy about the role of RAB38 in DG biogenesis. We show here that murine and human, but not rat, platelets also express the closely related RAB32. To elucidate the parts played by RAB32 and RAB38 in the biogenesis of DGs in vivo and their effects on platelet functions, we generated mice inactivated for Rab32, Rab38, and both genes. Single Rab38 inactivation mimicked cht mice, whereas single Rab32 inactivation had no effect in DGs, coat color, or lung morphology. By contrast, Rab32/38 double inactivation mimicked severe HPS, with strong coat and eye pigment dilution, some enlarged lung multilamellar bodies associated with a decrease in the number of DGs. These organelles were morphologically abnormal, decreased in number, and devoid of 5-hydroxytryptamine content. In line with the storage pool defect, platelet activation was affected, resulting in severely impaired thrombus growth and prolongation of the bleeding time. Overall, our study demonstrates the absence of impact of RAB38 or RAB32 single deficiency in platelet biogenesis and function resulting from full redundancy, and characterized a new mouse model mimicking HPS devoid of DG content.

Three-Dimensional Culture in a Methylcellulose-Based Hydrogel to Study the Impact of Stiffness on Megakaryocyte Differentiation.

The differentiation and maturation of megakaryocytes (MKs) occurs in a 3D environment where the cells must constantly adapt to the external physical and mechanical constraints during their development and migration to sinusoid vessels. In this chapter, we present a method for culture of mouse MKs from bone marrow hematopoietic progenitor cells in a methylcellulose 3D medium with a stiffness mimicking that of bone marrow. In addition, we describe how the MKs can be recovered to allow for analysis of their differentiation and maturation state by transmission electron microscopy, immunofluorescence or flow cytometry techniques and to evaluate their ability to form proplatelets. This approach allows (1) generation of MKs with a morphology that more closely resembles the MKs that differentiate in vivo, (2) recovery of megakaryocyte phenotypes sometimes observed in vivo but not found in classical liquid cultures, and (3) study of mechanotransduction pathways induced by the stiffness of the medium.

Evolución en los conocimientos sobre alimentación: una intervención educativa en estudiantes universitarios / Developments in food knowledge: an educational intervention in university studentes

To analyze the relationship between the level of knowledge about food, the degree of adherence to the Mediterranean Diet (MeDi) and nutritional status; an intervention study was performed with pre- and post-intervention evaluation after three educational sessions, designed according to the learning preferences of health science university students. Sixty-five physiotherapy and podology students participated. The mean age was 22.0 years and participants were mostly male 58.5%. The majority were normal weight (63.1%), but many (69.2%) needed to improve their eating habits in order to comply with DiMe recommendations. The statistical relationship found between the level of previous knowledge in nutrition and nutritional status (Pearson's Correlation Coefficient= 0.7; p= 0.049) suggests that nutritional education actions in this group could contribute to improving the quality of the diet, nutritional status and future health of university students. Educational sessions were able to improve the level of knowledge regarding nutrition and food in the majority of students, thus it is possible to consider the intervention as an efficient tool for the transmission of nutritional knowledge in this group.

Con el objetivo de analizar la relación entre el nivel de conocimientos en alimentación, el grado de adherencia a la Dieta Mediterránea (DiMe) y el estado nutricional; se realizó un estudio de intervención con evaluación pre y post intervención; a través de tres sesiones educativas, diseñadas según las preferencias de aprendizaje de estudiantes universitarios de ciencias de la salud. Participaron 65 estudiantes de Fisioterapia y Podología, preferentemente masculinos 58,5% y con una edad media de 22,0 años. La mayoría resultó normo peso (63,1%), pero muchos deben mejorar sus hábitos alimentarios para ajustarse a las recomendaciones de la DiMe (69,2%). La relación estadística encontrada entre el nivel de conocimientos previos en nutrición y el estado nutricional (Coeficiente de Correlación de Pearson= 0,7; p= 0,049), sugiere que las acciones de educación nutricional en este colectivo, podrían contribuir a mejorar la calidad de la dieta y con ella el estado nutricional y la salud futura de los universitarios. Las sesiones educativas consiguieron mejorar el nivel de conocimientos en nutrición y alimentación en la mayoría de estudiantes, por lo que es posible considerarlas como una herramienta eficiente en la trasmisión de conocimientos nutricionales en este colectivo.

Mycobacterium smegmatis proteoliposome induce protection in a murine progressive pulmonary tuberculosis model.

Tuberculosis (TB) remains an important cause of mortality and morbidity. The TB vaccine, BCG, is not fully protective against the adult form of the disease and is unable to prevent its transmission although it is still useful against severe childhood TB. Hence, the search for new vaccines is of great interest. In a previous study, we have shown that proteoliposomes obtained from Mycobacterium smegmatis (PLMs) induced cross reactive humoral and cellular response against Mycobacterium tuberculosis (Mtb) antigens. With the objective to evaluate the protective capability of PLMs, a murine model of progressive pulmonary TB was used. Animals immunized with PLMs with and without alum (PLMs/PLMsAL respectively) showed protection compared to non-immunized animals. Mice immunized with PLMsAL induced similar protection as that of BCG. Animals immunized with BCG, PLMs and PLMsAL showed a significant decrease in tissue damage (percentage of pneumonic area/lung) compared to non-immunized animals, with a more prominent effect in BCG vaccinated mice. The protective effect of the administration of PLMs in mice supports its future evaluation as experimental vaccine candidate against Mtb.

Importance of environmental stiffness for megakaryocyte differentiation and proplatelet formation.

Megakaryocyte (MK) differentiation occurs within the bone marrow (BM), a complex 3-dimensional (3D) environment of low stiffness exerting local external constraints. To evaluate the influence of the 3D mechanical constraints that MKs may encounter in vivo, we differentiated mouse BM progenitors in methylcellulose (MC) hydrogels tuned to mimic BM stiffness. We found that MKs grown in a medium of 30- to 60-Pa stiffness more closely resembled those in the BM in terms of demarcation membrane system (DMS) morphological aspect and exhibited higher ploidy levels, as compared with MKs in liquid culture. Following resuspension in a liquid medium, MC-grown MKs displayed twice as much proplatelet formation as cells grown in liquid culture. Thus, the MC gel, by mimicking external constraints, appeared to positively influence MK differentiation. To determine whether MKs adapt to extracellular stiffness through mechanotransduction involving actomyosin-based modulation of the intracellular tension, myosin-deficient (Myh9-/-) progenitors were grown in MC gels. Absence of myosin resulted in abnormal cell deformation and strongly decreased proplatelet formation, similarly to features observed for Myh9-/- MKs differentiated in situ but not in vitro. Moreover, megakaryoblastic leukemia 1 (MKL1), a well-known actor in mechanotransduction, was found to be preferentially relocated within the nucleus of MC-differentiated MKs, whereas its inhibition prevented MC-mediated increased proplatelet formation. Altogether, these data show that a 3D medium mimicking BM stiffness contributes, through the myosin IIA and MKL1 pathways, to a more favorable in vitro environment for MK differentiation, which ultimately translates into increased proplatelet production.

Recognition of a multiple antigen peptide containing sequence from mimotope of the dengue type 3 virus NS4B protein by human antibodies.

OBJECTIVE: To evaluate the recognition of NS4B mimotope, as multiple antigen peptide (MAP), by dengue antibodies presents in serum samples from patients with different serotype infections. METHODS: A MAP containing mimotope sequence was synthesized and used to evaluate the recognition of NS4B mimotope as MAP by a panel of 66 human sera from dengue cases by an indirect ELISA assay. RESULTS: The MAP differentiated between sera from dengue viruses infected patients and sera from healthy individuals and the best reactivity was shown by serum from dengue type 3 virus patients. The recognition was more intense with serum from patients with secondary infection. CONCLUSIONS: The findings suggest the potential use of NS4B mimotope on the development of a multi-epitope diagnostic tool. These results are important for further immunogenicity studies.

Protective capacity of proteoliposomes from Mycobacterium bovis BCG in a mouse model of tuberculosis.

Tuberculosis (TB) is one of the most important causes of mortality and morbidity due to infectious diseases. BCG, the vaccine in use, is not fully protective against TB. In a previous study, we have shown that proteoliposomes (outer membrane extracts), obtained from BCG (PLBCG) were able to induce humoral immune responses against Mycobacterium tuberculosis (Mtb) antigens. With the objective to evaluate the protective capability of PLBCG alone or as a booster with BCG, a murine model of progressive pulmonary TB was used. Animals immunized with PLBCG adjuvanted with alum (PLBCG-Al) showed similar protection to that conferred by BCG. The group immunized with PLBCG-Al as a booster to BCG gave superior protection than BCG as evidenced by a reduction of bacterial load in lungs 2 months after infection with Mtb. Animals immunized with BCG, PLBCG-Al and this formulation as a booster of BCG, showed a significant decrease of tissue damage (percentage of pneumonic area/lung) compared with non-immunized animals. These results demonstrate that immunization with PLBCG-Al alone or as a booster to BCG induce appropriate protection against challenge with Mtb in mice and support the future evaluation of PLBCG as a promising vaccine candidate against Mtb.

Protective effect of a lipid-based preparation from Mycobacterium smegmatis in a murine model of progressive pulmonary tuberculosis.

A more effective vaccine against tuberculosis (TB) is urgently needed. Based on its high genetic homology with Mycobacterium tuberculosis (Mtb), the nonpathogenic mycobacteria, Mycobacterium smegmatis (Ms), could be an attractive source of potential antigens to be included in such a vaccine. We evaluated the capability of lipid-based preparations obtained from Ms to provide a protective response in Balb/c mice after challenge with Mtb H37Rv strain. The intratracheal model of progressive pulmonary TB was used to assess the level of protection in terms of bacterial load as well as the pathological changes in the lungs of immunized Balb/c mice following challenge with Mtb. Mice immunized with the lipid-based preparation from Ms either adjuvanted with Alum (LMs-AL) or nonadjuvanted (LMs) showed significant reductions in bacterial load (P < 0.01) compared to the negative control group (animals immunized with phosphate buffered saline (PBS)). Both lipid formulations showed the same level of protection as Bacille Calmette and Guerin (BCG). Regarding the pathologic changes in the lungs, mice immunized with both lipid formulations showed less pneumonic area when compared with the PBS group (P < 0.01) and showed similar results compared with the BCG group. These findings suggest the potential of LMs as a promising vaccine candidate against TB.

Four monoclonal antibodies against capsular polysaccharides of Neisseria meningitidis serogroups A, C, Y and W135: its application in identity tests.

Murine hybridoma monoclonal antibodies (MAbs) were produced against the capsular polysaccharide (CPs) of serogroups A, C, W135 and Y meningococci (MenA, MenC, MenW, MenY) in order to develop immunological reagents for the identification of meningococcal polysaccharides. Each serogroup-specific MAb reacted with the CPs from its homologous serogroup only and did not react with CPs from the other three serogroups. The affinity constant (Ka) of the four MAbs measured by non-competitive ELISA was 6.62 × 10(9), 2.76 × 10(9), 1.48 × 10(9) and 3.8 × 10(9) M(-1) for MenA, MenC, MenW and MenY MAbs respectively. The application of these MAbs for identity tests was demonstrated by their abilities to correctly identify the CPs from serogroups A, C, W135 and Y in meningococcal CPs-based vaccines through ELISA. The MAbs obtained in this work are a very valuable set of tools for study meningococcal polysaccharides vaccines.

Passive administration of purified secretory IgA from human colostrum induces protection against Mycobacterium tuberculosis in a murine model of progressive pulmonary infection.

BACKGROUND: Immunoglobulin A is the most abundant isotype in secretions from mucosal surfaces of the gastrointestinal, respiratory and genitourinary tracts and in external secretions such as colostrum, breast milk, tears and saliva. The high concentration of human secretory IgA (hsIgA) in human colostrum strongly suggests that it should play an important role in the passive immune protection against gastrointestinal and respiratory infections. MATERIALS AND METHODS: Human secretory IgA was purified from colostrum. The reactivity of hsIgA against mycobacterial antigens and its protective capacity against mycobacterial infection was evaluated. RESULTS: The passive administration of hsIgA reduces the pneumonic area before challenge with M. tuberculosis. The intratracheal administration of M. tuberculosis preincubated with hsIgA to mice greatly reduced the bacterial load in the lungs and diminished lung tissue injury. CONCLUSIONS: HsIgA purified from colostrum protects against M. tuberculosis infection in an experimental mouse model.