Rosalío Ramos-Payán

Unexpected Role for IL-17 in Protective Immunity against Hypervirulent Mycobacterium tuberculosis HN878 Infection

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), infects one third of the worlds population. Among these infections, clinical isolates belonging to the W-Beijing appear to be emerging, representing about 50% of Mtb isolates in East Asia, and about 13% of all Mtb isolates worldwide. In animal models, infection with W-Beijing strain, Mtb HN878, is considered “hypervirulent” as it results in increased mortality and causes exacerbated immunopathology in infected animals. We had previously shown the Interleukin (IL) -17 pathway is dispensable for primary immunity against infection with the lab adapted Mtb H37Rv strain. However, it is not known whether IL-17 has any role to play in protective immunity against infection with clinical Mtb isolates. We report here that lab adapted Mtb strains, such as H37Rv, or less virulent Mtb clinical isolates, such as Mtb CDC1551, do not require IL-17 for protective immunity against infection while infection with Mtb HN878 requires IL-17 for early protective immunity. Unexpectedly, Mtb HN878 induces robust production of IL-1β through a TLR-2-dependent mechanism, which supports potent IL-17 responses. We also show that the role for IL-17 in mediating protective immunity against Mtb HN878 is through IL-17 Receptor signaling in non-hematopoietic cells, mediating the induction of the chemokine, CXCL-13, which is required for localization of T cells within lung lymphoid follicles. Correct T cell localization within lymphoid follicles in the lung is required for maximal macrophage activation and Mtb control. Since IL-17 has a critical role in vaccine-induced immunity against TB, our results have far reaching implications for the design of vaccines and therapies to prevent and treat emerging Mtb strains. In addition, our data changes the existing paradigm that IL-17 is dispensable for primary immunity against Mtb infection, and instead suggests a differential role for IL-17 in early protective immunity against emerging Mtb strains.

Helminth-induced arginase-1 exacerbates lung inflammation and disease severity in tuberculosis

Parasitic helminth worms, such as Schistosoma mansoni, are endemic in regions with a high prevalence of tuberculosis (TB) among the population. Human studies suggest that helminth coinfections contribute to increased TB susceptibility and increased rates of TB reactivation. Prevailing models suggest that T helper type 2 (Th2) responses induced by helminth infection impair Th1 immune responses and thereby limit Mycobacterium tuberculosis (Mtb) control. Using a pulmonary mouse model of Mtb infection, we demonstrated that S. mansoni coinfection or immunization with S. mansoni egg antigens can reversibly impair Mtb-specific T cell responses without affecting macrophage-mediated Mtb control. Instead, S. mansoni infection resulted in accumulation of high arginase-1-expressing macrophages in the lung, which formed type 2 granulomas and exacerbated inflammation in Mtb-infected mice. Treatment of coinfected animals with an antihelminthic improved Mtb-specific Th1 responses and reduced disease severity. In a genetically diverse mouse population infected with Mtb, enhanced arginase-1 activity was associated with increased lung inflammation. Moreover, in patients with pulmonary TB, lung damage correlated with increased serum activity of arginase-1, which was elevated in TB patients coinfected with helminths. Together, our data indicate that helminth coinfection induces arginase-1-expressing type 2 granulomas, thereby increasing inflammation and TB disease severity. These results also provide insight into the mechanisms by which helminth coinfections drive increased susceptibility, disease progression, and severity in TB.

Genetic Polymorphisms of Interleukin-1 Alpha and the Vitamin D Receptor in Mexican Mestizo Patients with Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) is the most common diagnosis in patients with back pain, a leading cause of musculoskeletal disability worldwide. Several conditions, such as occupational activities, gender, age, and obesity, have been associated with IDD. However, the development of this disease has strong genetic determinants. In this study, we explore the possible association between rs1800587 (c.-949C>T) of interleukin-1 alpha (IL1A) and rs2228570 (c.2T>V) and rs731236 (c.1056T>C) of vitamin D receptor (VDR) gene polymorphisms and the development of IDD in northwestern Mexican Mestizo population. Gene polymorphisms were analyzed by polymerase chain reaction followed by restriction fragment length polymorphism, in two groups matched by age and gender: patients with symptomatic lumbar IDD (n = 100) and subjects with normal lumbar-spine MRI-scans (n = 100). Distribution of the mutated alleles in patients and controls was 27.0% versus 28.0% (P = 0.455) for T of rs1800587 (IL1A); 53.0% versus 58.0% (P = 0.183) for V of rs2228570 (VDR); and 18.0% versus 21.0% (P = 0.262) for C of rs731236 (VDR). Our results showed no association between the studied polymorphisms and IDD in this population. This is the first report on the contribution of gene polymorphisms on IDD in a Mexican population.

Identification of novel mutation in cathepsin C gene causing Papillon-Lefèvre Syndrome in Mexican patients.

BackgroundPapillon-Lefèvre Syndrome (PLS) is a type IV genodermatosis caused by mutations in cathepsin C (CTSC), with a worldwide prevalence of 1–4 cases per million in the general population. In México, the prevalence of this syndrome is unknown, and there are few case reports. The diagnosis of twenty patients in the state of Sinaloa highlights the need to characterize this syndrome in Mexicans.MethodsTo understand the basis of PLS in Mexicans, the gene expression, enzymatic activity and mutational analysis of CTSC were assayed in nine PLS patients and their relatives. Frequencies of CTSC gene polymorphisms and HLA alleles were determined in these patients, their relatives, and the population.ResultsPatients showed normal CTSC gene expression, but a deep reduction (up to 85%) in enzymatic activity in comparison to unrelated healthy individuals. A novel loss-of-function mutation, c.203 T >; G (p.Leu68Arg), was found in all patients, and some carried the polymorphism c.458C >; T (p.Thr153Ile). Allelic frequencies in patients, relatives and controls were 88.89%, 38.24% and 0.25% for G (c.203 T >; G); and 11.11%, 8.82% and 9.00% for T (c.458C >; T). HLA-DRB1*11 was found significantly more frequent (P = 0.0071) in patients than controls (33.33% vs. 7.32%), with an estimated relative risk of 6.33.ConclusionsThe novel loss-of function mutation of CTSC gene (c.203 T >; G) found in patients correlated with their diminished enzymatic activity, and HLA-DRB1*11 was found to be associated with PLS. The study of more PLS patients may give more insights into the etiology of the disease as well as its prevalence in México.

Kernicterus by glucose-6-phosphate dehydrogenase deficiency: a case report and review of the literature.

IntroductionGlucose-6-phosphate dehydrogenase deficiency is an X-linked recessive disease that causes acute or chronic hemolytic anemia and potentially leads to severe jaundice in response to oxidative agents. This deficiency is the most common human innate error of metabolism, affecting more than 400 million people worldwide.Case presentationHere, we present the first documented case of kernicterus in Panama, in a glucose-6-phosphate dehydrogenase-deficient newborn clothed in naphthalene-impregnated garments, resulting in reduced psychomotor development, neurosensory hypoacousia, absence of speech and poor reflex of the pupil to light.ConclusionMutational analysis revealed the glucose-6-phosphate dehydrogenase Mediterranean polymorphic variant, which explained the development of kernicterus after exposition of naphthalene. As the use of naphthalene in stored clothes is a common practice, glucose-6-phosphate dehydrogenase testing in neonatal screening could prevent severe clinical consequences.

Tetralogy of Fallot associated with macrocephaly-capillary malformation syndrome: a case report and review of the literature

IntroductionMacrocephaly-capillary malformation syndrome is characterized by cutaneous vascular lesions, including cutis marmorata telangiectatica and hemangiomas, associated with congenital anomalies, including macrocephaly, macrosomia, asymmetry and mental retardation. In addition to these cardinal signs, several other clinical conditions have been reported in people with this condition. However, to the best of our knowledge, the presence of tetralogy of Fallot has not previously been reported in association with this syndrome.Case presentationWe present a case of a Mexican newborn girl with tetralogy of Fallot associated with macrocephaly-capillary malformation. We discuss the clinical treatment of the patient and its consequences.ConclusionSince physiologic cutis marmorata is a common condition in newborns, the information provided in this report could be helpful in future cases in preventing severe clinical consequences or sudden death in patients with similar symptoms.

The Cellular Bases of Antibody Responses during Dengue Virus Infection.

Dengue virus (DENV) is one of the most significant human viral pathogens transmitted by mosquitoes and can cause from an asymptomatic disease to mild undifferentiated fever, classical dengue, and severe dengue. Neutralizing memory antibody (Ab) responses are one of the most important mechanisms that counteract reinfections and are therefore the main aim of vaccination. However, it has also been proposed that in dengue, some of these class-switched (IgG) memory Abs might worsen the disease. Although these memory Abs derive from B cells by T-cell-dependent processes, we know rather little about the (acute, chronic, or memory) B cell responses and the complex cellular mechanisms generating these Abs during DENV infections. This review aims to provide an updated and comprehensive perspective of the B cell responses during DENV infection, starting since the very early events such as the cutaneous DENV entrance and the arrival into draining lymph nodes, to the putative B cell activation, proliferation, and germinal centers (GCs) formation (the source of affinity-matured class-switched memory Abs), till the outcome of GC reactions such as the generation of plasmablasts, Ab-secreting plasma cells, and memory B cells. We discuss topics very poorly explored such as the possibility of B cell infection by DENV or even activation-induced B cell death. The current information about the nature of the Ab responses to DENV is also illustrated.

Lack of Association of the Polymorphisms IL-17A (-197G/A) and IL-17F (+7488A/G) with Multibacillary Leprosy in Mexican Patients.

Background. Leprosy is a chronic infectious disease caused by the intracellular acid-fast bacilli Mycobacterium leprae; it has been determined that genetic factors of the host play an important role in the disease susceptibility. Thus, in this case-control study, we evaluated the possible association between the IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780) gene SNPs and susceptibility to leprosy disease in Mexican population. Methods. Seventy-five leprosy patients and sixty-nine control subjects were included. Both SNPs were genotyped with the polymerase chain reaction-restriction fragment length polymorphism technique. Results. We found nonsignificant differences in genotype and allele frequencies related to IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780) gene SNPs in MB as well as subclinical forms of leprosy disease versus healthy individuals. Conclusions. Since the sample size is not large enough, it is difficult to sustain an association of susceptibility to leprosy with genotypes or allele frequencies of IL-17A G-197A (rs227593) and IL-17F A7488G (His161Arg, rs763780), suggesting that IL-17 polymorphisms have no significant role in the genetic susceptibility to development of this disease in the Mexican Mestizo population.

Characterization of Cry toxins from autochthonous Bacillus thuringiensis isolates from Mexico

BACKGROUND Chemical pesticides, widely used in agriculture and vector-borne disease control, have shown toxic effects on the environment and the people in contact with them. Bacillus thuringiensis is a widely used bacterium for alternative and safer control of insect pests. Its toxins are specific for insects but innocuous for mammals and may be used as powerful adjuvants when applied with vaccines. The objective of this work was to characterize some autochthonous B. thuringiensis strains, which could be used for the control of a local pest (Diatraea considerata Heinrich) that affects sugar cane crops in Sinaloa, Mexico. Also, to evaluate these strains as a source of Cry toxins, which may be used in the future as adjuvants for some vaccines. METHODS Eight strains from field-collected dead insects were isolated. These were microbiologically identified as B. thuringiensis and confirmed by amplification and sequencing of 16S rDNA. Bioassays were performed to evaluate their pathogenicity against D. considerata, and Cry toxins were identified by proteomic analyses. RESULTS An increased mortality among larvae infected with strain Bt-D was observed, and its toxin was identified as Cry1Ac. CONCLUSIONS The observed data showed that the selected strain was pathogenic to D. considerata and seemed to produce Cry1Ac protein, which has been reported as an adjuvant in different types of immunization.

Parasitaemia levels in Plasmodium chabaudi infected-mice modify IFN-γ and IL-10 expression after a homologous or heterologous challenge

CB6F1 mice infected with the nonlethal Plasmodium chabaudi chabaudi AS suffer parasitaemia levels up to 40% (full parasitaemia, FP) and develop both homologous and heterologous (against the lethal Plasmodium yoelii 17XL) protective immunity. However, if mice are treated with anti‐malarial drug when parasitaemia is below 10% (low parasitaemia, LP), they only develop homologous immunity. For the better understanding of this interesting dissociation related to the degree of parasitaemia, in this work, we studied the genetic expression of some cytokines. We found that during primary parasitaemia both FP and LP mice showed at first a TNF‐α, IL‐2 and IFN‐γ response which is followed by an IL‐4 and IL‐10 response. When FP and LP mice were challenged with either the homologous (FP + AS and LP + AS mice) or the heterologous parasite (FP + 17XL and LP + 17XL mice), we observed that LP + 17XL mice, which failed to develop heterologous immunity and succumbed to the challenge, showed a stronger IFN‐γ and a weaker IL‐10 expression than FP + 17XL mice, which developed heterologous immunity and survived the challenge. The importance and the possible implications of these findings are discussed.