Time between symptom and testing in relation to familial transmission of severe acute respiratory syndrome coronavirus 2 / Tempo entre o início dos sintomas e a testagem está relacionado à maior transmissão de SARS-CoV-2 entre contatos familiares

Abstract Brazil has a huge number of cases and deaths due to coronavirus disease 2019 (COVID-19); however, few studies have dealt with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among familial contacts in Brazil. Here, we report our findings on transmission in a family-based study in Bauru, São Paulo, Brazil. The study, conducted from July to November 2020, comprised 974 individuals with 233 index patients and 741 familial contacts. Familial contacts were evaluated using the rapid COVID-19 Ag ECO and reverse transcription-polymerase chain reaction (RT-PCR) tests immediately after the index patient diagnosis. The antigen-based rapid test was validated in 121 individuals using RT-PCR as the gold standard. Additionally, 30 days later, familial contacts were evaluated for IgM and IgG antibodies against SARS-CoV-2. We found 333 cases of COVID-19 among familial contacts (44.9%). A positive correlation was observed between the time elapsed from the onset of symptoms until the index patient's COVID-19 testing and the number of family contacts infected by SARS-CoV-2. Early SARS-CoV-2 testing and familial contact evaluation are relevant strategies to contain transmission.

Resumo O Brasil apresenta um alto número de casos e óbitos por coronavírus (COVID-19), apesar disso, poucos estudos tratavam da infecção pelo coronavirus-2 causador de síndrome respiratória aguda grave (SARS-CoV-2) entre contatos familiares no Brasil. Relatamos aqui nossos achados sobre a transmissão de SARS-CoV-2 em um estudo de base familiar de Bauru, no estado de São Paulo, Brasil. O estudo foi realizado de julho a novembro de 2020 e compreendeu 974 indivíduos, sendo 233 pacientes índice e 741 contatos familiares. Os contatos familiares foram avaliados por meio do teste rápido COVID-19 Ag ECO Test e RT-PCR imediatamente após o diagnóstico do paciente índice. O uso do teste rápido baseado em antígeno foi validado em 121 indivíduos utilizando RT-PCR como padrão ouro. Adicionalmente, 30 dias após a avaliação inicial, os contatos familiares foram avaliados quanto à presença de anticorpos IgM e IgG contra SARS-CoV-2. Encontramos 333 casos de COVID-19 entre contatos familiares (44,9%). Observamos uma correlação positiva entre o tempo decorrido entre o início dos sintomas e o teste para COVID-19 do paciente índice e o número de contatos familiares infectados por SARS-CoV-2. A testagem precoce da infecção por SARS-CoV-2 e a avaliação de contatos familiares são estratégias relevantes para conter a transmissão.

Association of CD209 (DC-SIGN) rs735240 SNV with paucibacillary leprosy in the Brazilian population and its functional effects

BACKGROUND Leprosy, caused by Mycobacterium leprae, is a public health problem in Brazil that affects peripheral nerves, resulting in physical disabilities. During host-pathogen interactions, the immune response determines leprosy outcomes from a localised (paucibacillary) form to a disseminated (multibacillary) form. The recognition of M. leprae involves the DC-SIGN receptor, which is present on the dendritic cells (DCs) and participates in immune activation. OBJECTIVES To evaluate the association of polymorphisms in the promoter region of the gene encoding DC-SIGN (CD209) and the clinical form of leprosy, and to investigate its functional effects. METHODS The study population included 406 leprosy patients from an endemic area in Brazil [310 multibacillary (MB); 96 paucibacillary (PB)]. A functional evaluation based on the effects of the single nucleotide variant (SNV) associated with PB leprosy on the specific immune response was also performed. RESULTS The GA genotype and the presence of the A allele of rs735240 (-939G>A) were associated with PB leprosy [OR: 2.09 (1.18-3.69) and 1.84 (1.07-3.14), respectively]. Carriers of the A allele showed reduced expression of CD209 and TGF-β1 in leprosy lesions in comparison with individuals with GG genotype, in addition to a higher response to the Mitsuda test. CONCLUSION These data suggest that rs735240 influences the immune response against M. leprae and clinical presentation of leprosy.

High rate of sensitization to Kathon CG, detected by patch tests in patients with suspected allergic contact dermatitis

Abstract Background: Kathon CG, a combination of methylchloroisothiazolinone and methylisothiazolinone, is widely used as preservative in cosmetics, as well in household cleaning products, industrial products such as paints and glues. It has emerged as an important sensitizing agent in allergic contact dermatitis. Objectives: This study evaluated the reactivity to this substance in patients subjected to patch tests at the Dermatology Institute in Bauru, São Paulo from 2015 to 2017 and its correlation with other preservatives, the professional activity and location of the lesions. Methods: The patients were submitted to standard series of epicutaneous tests, standardized by the Brazilian Group Studies on Contact Dermatitis. Results: Out the 267 patients tested, 192 presented positivity to at least one substance and 29 of the patients (15.10%) presented reaction to Kathon CG, with predominance of the female gender (n = 27); main professional activity associated with Kathon CG sensibilization was cleaning (17.24%), followed by aesthetic areas (13.79%) and health care (10.34%). The most prevalent sensitizations among the substances tested were nickel sulphate (56.3%), followed by cobalt chloride (23.4%), neomycin (18.2%), potassium dichromate (17.7%), thimerosal (14.5%), formaldehyde (13.2%), paraphenylenediamine (9.3%), and fragrance mix (8.3%). Study limitations: We do not have data from patients that were submitted to patch test a decade ago in order to confront to current data and establish whether or no sensitization to Kathon CG has increased. Conclusion: High positivity to Kathon CG corroborates the recent findings in the literature, suggesting more attention to concentration of this substance, used in cosmetics and products for domestic use.

Effect of Mycobacterium leprae on neurotrophins expression in human Schwann cells and mouse sciatic nerves

BACKGROUND Although Mycobacterium leprae (ML) is well characterised as the causative agent of leprosy, the pathophysiological mechanisms underlying peripheral nerve damage still need further understanding. In vitro and in vivo studies have yielded insights into molecular mechanisms of ML interaction with Schwann cells (SC), indicating the regulation of genes and proteins crucial to neural plasticity. OBJECTIVES We aimed to investigate the effect of ML on neurotrophins expression in human SC (hSC) and mice sciatic nerves to better understand their role in leprosy neuropathy, and aiming to contribute to future therapeutic approaches. METHODS We evaluated mRNA and protein expression of BDNF, NGF, NT-3, NT-4 in hSC from amputation nerve fragments, as well as in athymic nude mice, infected by ML for eight months. FINDINGS and MAIN CONCLUSIONS Our in vitro results showed a trend to decline in NGF and BDNF mRNA in ML-treated hSC, compared to controls. The immunodetection of BDNF and NT-4 was significantly downregulated in ML-treated hSC. Conversely, ML-infected mice demonstrated upregulation of NT-3, compared to non-infected animals. Our findings indicate that ML may be involved in neurotrophins regulation, suggesting that a pathogen-related imbalance of these growth factors may have a role in the neural impairment of leprosy.

Polymorphisms in the TGFB1 and IL2RA genes are associated with clinical forms of leprosy in Brazilian population

BACKGROUND Leprosy is a chronic infectious disease caused by Mycobacterium leprae, and compromises the skin and peripheral nerves. This disease has been classified as multibacillary (MB) or paucibacillary (PB) depending on the host immune response. Genetic epidemiology studies in leprosy have shown the influence of human genetic components on the disease outcomes. OBJECTIVES We conducted an association study for IL2RA and TGFB1 genes with clinical forms of leprosy based on two case-control samples. These genes encode important molecules for the immunosuppressive activity of Treg cells and present differential expressions according to the clinical forms of leprosy. Furthermore, IL2RA is a positional candidate gene because it is located near the 10p13 chromosome region, presenting a linkage peak for PB leprosy. METHODS A total of 885 leprosy cases were included in the study; 406 cases from Rondonópolis County (start population), a hyperendemic region for leprosy in Brazil, and 479 cases from São Paulo state (replication population), which has lower epidemiological indexes for the disease. We tested 11 polymorphisms in the IL2RA gene and the missense variant rs1800470 in the TGFB1 gene. FINDINGS The AA genotype of rs2386841 in IL2RA was associated with the PB form in the start population. The AA genotype of rs1800470 in TGFB1 was associated with the MB form in the start population, and this association was confirmed for the replication population. MAIN CONCLUSIONS We demonstrated, for the first time, an association data with the PB form for a gene located on chromosome 10. In addition, we reported the association of TGFB1 gene with the MB form. Our results place these genes as candidates for validation and replication studies in leprosy polarisation.

The involvement of endothelial mediators in leprosy

Leprosy is a chronic infectious disease that requires better understanding since it continues to be a significant health problem in many parts of the world. Leprosy reactions are acute inflammatory episodes regarded as the central etiology of nerve damage in the disease. The activation of endothelium is a relevant phenomenon to be investigated in leprosy reactions. The present study evaluated the expression of endothelial factors in skin lesions and serum samples of leprosy patients. Immunohistochemical analysis of skin samples and serum measurements of VCAM-1, VEGF, tissue factor and thrombomodulin were performed in 77 leprosy patients and 12 controls. We observed significant increase of VCAM-1 circulating levels in non-reactional leprosy (p = 0.0009). The immunostaining of VEGF and tissue factor was higher in endothelium of non-reactional leprosy (p = 0.02 for both) than healthy controls. Patients with type 1 reaction presented increased thrombomodulin serum levels, compared with non-reactional leprosy (p = 0.02). In type 2 reaction, no significant modifications were observed for the endothelial factors investigated. The anti-inflammatory and antimicrobial activities of the endotfhelial factors may play key-roles in the pathogenesis of leprosy and should be enrolled in studies focusing on alternative targets to improve the management of leprosy and its reactions.

Activation and cytokine profile of monocyte derived dendritic cells in leprosy: in vitro stimulation by sonicated Mycobacterium leprae induces decreased level of IL-12p70 in lepromatous leprosy

Dendritic cells (DCs) play a pivotal role in the connection of innate and adaptive immunity of hosts to mycobacterial infection. Studies on the interaction of monocyte-derived DCs (MO-DCs) using Mycobacterium leprae in leprosy patients are rare. The present study demonstrated that the differentiation of MOs to DCs was similar in all forms of leprosy compared to normal healthy individuals. In vitro stimulation of immature MO-DCs with sonicated M. leprae induced variable degrees of DC maturation as determined by the increased expression of HLA-DR, CD40, CD80 and CD86, but not CD83, in all studied groups. The production of different cytokines by the MO-DCs appeared similar in all of the studied groups under similar conditions. However, the production of interleukin (IL)-12p70 by MO-DCs from lepromatous (LL) leprosy patients after in vitro stimulation with M. lepraewas lower than tuberculoid leprosy patients and healthy individuals, even after CD40 ligation with CD40 ligand-transfected cells. The present cumulative findings suggest that the MO-DCs of LL patients are generally a weak producer of IL-12p70 despite the moderate activating properties ofM. leprae. These results may explain the poor M. leprae-specific cell-mediated immunity in the LL type of leprosy.

Increased hepcidin expression in multibacillary leprosy

Iron is essential for all organisms and its availability can control the growth of microorganisms; therefore, we examined the role of iron metabolism in multibacillary (MB) leprosy, focusing on the involvement of hepcidin. Erythrograms, iron metabolism parameters, pro-inflammatory cytokines and urinary hepcidin levels were evaluated in patients with MB and matched control subjects. Hepcidin expression in MB lesions was evaluated by quantitative polymerase chain reaction. The expression of ferroportin and hepcidin was evaluated by immunofluorescence in paucibacillary and MB lesions. Analysis of hepcidin protein levels in urine and of hepcidin mRNA and protein levels in leprosy lesions and skin biopsies from healthy control subjects showed elevated hepcidin levels in MB patients. Decreases in haematologic parameters and total iron binding capacity were observed in patients with MB leprosy. Moreover, interleukin-1 beta, ferritin, soluble transferrin receptor and soluble transferrin receptor/log ferritin index values were increased in leprosy patients. Hepcidin was elevated in lepromatous lesions, whereas ferroportin was more abundant in tuberculoid lesions. In addition, hepcidin and ferroportin were not colocalised in the biopsies from leprosy lesions. Anaemia was not commonly observed in patients with MB; however, the observed changes in haematologic parameters indicating altered iron metabolism appeared to result from a mixture of anaemia of inflammation and iron deficiency. Thus, iron sequestration inside host cells might play a role in leprosy by providing an optimal environment for the bacillus.