Natália Carvalho

Neurological Manifestations in Human T-Cell Lymphotropic Virus Type 1 (HTLV-1)–Infected Individuals Without HTLV-1–Associated Myelopathy/Tropical Spastic Paraparesis: A Longitudinal Cohort Study

BACKGROUND Human T-cell lymphotropic virus type 1 (HTLV-1) is the agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), observed in up to 5% of infected individuals. Despite low prevalence, many HTLV-1-infected patients who do not fulfill criteria for HAM/TSP present with neurological complaints related to sensory, motor, urinary, or autonomic manifestations. The aim of this study was to determine the incidence of neurologic manifestations and risk factors associated with these outcomes. METHODS The incidence of HAM/TSP and new signs and neurologic symptoms were computed in a group of patients enrolled in a cohort study. RESULTS Of 414 subjects, 76 had definite HAM/TSP, 87 had possible or probable HAM/TSP, and 251 subjects had no neurologic manifestation and were selected for analysis. Definite HAM/TSP developed in 5 (1.47%) patients. Follow-up of at least 3 years was achieved in 51% of patients. The incidence rate was computed in 1000 person-years (206 for hand numbness, 187 for feet numbness, 130 for nocturia, and 127 for urgency). Average incidence rate in neurological exam was 76 for leg hyperreflexia, 53 for leg weakness, and 37 for Babinski sign. In the applied Expanded Disability Status Scale, the incidence rate of worsening 1 point was 134 per 1000 person-years. Kaplan-Meier curves stratified by sex and proviral load showed that females and patients with proviral load >50,000 copies/10(6) peripheral blood mononuclear cells had a higher risk of progression. CONCLUSIONS Development of neurological symptoms or signs occurred in up to 30% of asymptomatic subjects during 8 years of follow-up.

Perfil inflamatório e imunológico em pacientes com DPOC: relação com a reversibilidade do VEF 1

Objetivo: Determinar se a gravidade da DPOC se correlaciona com a contagem de celulas no escarro, atopia e asma. Metodos: Estudo transversal com 37 pacientes com DPOC e 22 individuos saudaveis com funcao pulmonar normal (controles). As contagens de celulas no escarro foram determinadas por microscopia apos a centrifugacao das amostras. Foram realizados testes cutâneos de puntura, e as citocinas sericas foram determinadas por ELISA. Resultados: Os pacientes foram estratificados pela resposta ao broncodilatador: o grupo de limitacao ao fluxo aereo nao reversivel (LFAnr) envolveu 24 pacientes sem alteracao significativa do VEF1 pos-broncodilatador, e o grupo de limitacao ao fluxo aereo parcialmente reversivel (LFApr) envolveu 13 pacientes com reversibilidade do VEF1 (aumento do VEF1 pos-broncodilatador ≥ 12%). A proporcao de eosinofilos no escarro foi maior no grupo LFApr do que no LFAnr (p < 0,01), e houve uma correlacao inversa entre a proporcao de eosinofilos e VEF1 (p < 0,05). Entretanto, nenhum dos pacientes apresentou historico de asma e os resultados dos testes cutâneos nao diferiram entre os dois grupos. Nas amostras de escarro dos pacientes, os neutrofilos predominaram. Os niveis sericos de TNF, IL-6, IL-8 e RANTES (CCL5) foram maiores nos pacientes que nos controles (p < 0,001), mas nao diferiram entre os dois grupos de pacientes. Conclusoes: Pacientes com DPOC e reversibilidade parcial do VEF1 parecem apresentar maiores contagens de eosinofilos no escarro e maior hiper-responsividade das vias aereas que aqueles sem reversibilidade do VEF1. Entretanto, a gravidade da DPOC nao se correlacionou com atopia ou perfil das citocinas.

Inflammatory and immunological profiles in patients with COPD: relationship with FEV 1 reversibility

ABSTRACT Objective: To determine whether COPD severity correlates with sputum cell counts, atopy, and asthma. Methods: This was a cross-sectional study involving 37 patients with COPD and 22 healthy subjects with normal lung function (controls). Sputum cell counts were determined by microscopy after centrifugation of samples. Skin prick tests were performed, and serum cytokines were determined by ELISA. Results: Patients were stratified by bronchodilator response: a non-reversible airflow limitation (nonRAL) group comprised 24 patients showing no significant post-bronchodilator change in FEV1; and a partially reversible airflow limitation (partialRAL) group comprised 13 patients showing FEV1 reversibility (post-bronchodilator FEV1 increase ≥ 12%). The proportion of eosinophils in sputum was higher in the partialRAL group than in the nonRAL group (p < 0.01), and there was an inverse correlation between the proportion of eosinophils and FEV1 (p < 0.05). However, none of the patients had a history of asthma and skin prick test results did not differ between the two groups. In the patient sputum samples, neutrophils predominated. Serum levels of TNF, IL-6, IL-8, and RANTES (CCL5) were higher in patients than in controls (p < 0.001) but did not differ between the two patient groups. Conclusions: COPD patients with partial FEV1 reversibility appear to have higher sputum eosinophil counts and greater airway hyperresponsiveness than do those with no FEV1 reversibility. However, we found that COPD severity did not correlate with atopy or with the cytokine profile.

Impairment of humoral and cellular immune response to tetanus toxoid in HTLV-1 infected individuals

The human T cell lymphotropic virus type-1 (HTLV-1) infect mainly T cells, dendritic cells and macrophages inducing T cell proliferation and increasing production of chemokines and cytokines by peripheral blood mononuclear cells (PBMC). However, as HTVL-1 may modify the immune response to other infectious agents, the aim of this study was to evaluate the humoral and cellular immune response before and after vaccination with tetanus toxoid (TT). Participants included 14 HTLV-1 carriers and 12 healthy subjects (HS). These individuals were immunized with two doses of tetanus toxoid vaccine. Antibodies to TT were determined by ELISA and the frequency of T cells expressing cytokines as well as the frequency of monocytes expressing co-stimulatory molecules were determined by FACS. The IgG titers anti-TT increased after immunization in both groups (p = 0.001), but HTLV-1 patients had lower levels of IgG anti-TT after immunization when compared with HS (p = 0.007). The frequency of CD4+ T cells expressing IFN-g, TNF and IL-10, after stimulation with TT, was lower in HTLV-1 infected subjects than the HS after immunization (p < 0.05). TNF and IL-12 expression by monocytes after stimulation with TT were higher in the HTLV-1 group than in HS. However there was an impairment in the HLA-DR expression by monocytes from HTLV-1 infected subjects. These results indicate that HTLV-1 infected subjects have a decreasing in humoral response and an impairment in both antigen presenting cells and T cell functions to a biased antigen. Financial Support: INCT-DT, CNPq, NIH R01.

Impaired TNF, IL-1β, and IL-17 production and increased susceptibility to Mycobacterium tuberculosis infection in HTLV-1 infected individuals

IFN-γ and TNF play critical roles in the control of Mycobacterium tuberculosis infection. Despite leading to an exaggerated production of inflammatory cytokines, HTLV-1 infection increases the risk of developing tuberculosis (TB). However, the immune mechanisms accounting for this phenomenon are still unclear. The aim of this study was to evaluate immunological aspects of the HTLV-1/M. tuberculosis co-infection. In this cross-sectional study, the levels of TNF, IL-1β, and IL-17 were determined by ELISA in the supernatants of either unstimulated or tuberculin purified protein derivative (PPD) stimulated peripheral blood mononuclear cells. Cells from HTLV-1 infected individuals produced lower levels of TNF following PPD stimulation compared to unstimulated cells. IL-1β and IL-17 production by cells from HTLV-1/M. tuberculosis co-infected individuals was lower than in cells from patients with TB. Impairment in TNF, IL-1β, and IL-17 production upon stimulation with mycobacterial antigens may contribute to the increased susceptibility to M. tuberculosis infection observed in HTLV-1 infected individuals.

HTLV-1 infection interferes with immune responses to Mycobacterium tuberculosis antigens

Tuberculosis (TB) is still a major health problem. IFN-γ and TNF are critical cytokines in the control of Mycobacterium tuberculosis (Mtb) infection. It has already been demonstrated that human T cell lymphotropic virus type 1 (HTLV-1) infection leads to a spontaneous IFN- γ and TNF production, however HTLV-1 infected subjects possess a 2-4 fold increased risk of developing tuberculosis. Nevertheless, the immune mechanisms involved in this phenomenon are still unclear. The aim of this study was to evaluate immunological features of the association between HTLV-1/Mtb in order to better understand the events leading to higher susceptibility to TB observed in HTLV-1 infected subjects. This was a cross-sectional study evaluating four groups: healthy control (HC group), HTLV-1 infected subjects without TB (HTLV-1 group) or with TB (HTLV-1 + TB group), and individuals with only TB (TB group). TNF, IL-1β, and IL-17 levels were measured in supernatants of non-stimulated or PPD stimulated peripheral blood mononuclear cells (PBMCs) by ELISA. PBMCs from HTLV-1 infected individuals had a decrease (p<0.05) in TNF production following PPD stimulation (median 114.5 pg/ml, IQ range 47-189 pg/ml) compared to non-stimulated cells (202 pg/ml, IQ range 100-250 pg/ml). When we normalized the data to non-stimulated cells, IL-1β production following PPD stimulation by individuals in the HTLV-1 + TB group (3 pg/ml, IQ range 0-43 pg/ml) was lower (p<0.05) than in patients with TB (87 pg/ml, IQ range 14-151 pg/ml). Similarly, HTLV-1/Mtb co-infected individuals had lower (p<0.05) production of IL-17 (9 pg/ml, IQ range 0-41 pg/ml) when compared to TB patients (43 pg/ml, IQ range 13-150 pg/ml). Impairment in TNF, IL-1β, and IL-17 production upon stimulation with mycobacterial antigens may contribute to the higher susceptibility to Mtb infection observed in HTLV-1 infected subjects. Financial support: CNPq, CAPES.

Prevalence and influence of tuberculosis in the neurologic manifestations of the Human T cell lymphotropic virus type 1 (HTLV-1)

HTLV-1 infects mainly T cells, leading to activation and cellular proliferation with exaggerated production of pro-inflammatory cytokines. The majority of HTLV-1 infected patients are considered as HTLV-1 carriers, but 5% will develop HTLV-1 associated myelopathy (HAM) and about 15% overactive bladder, an oligosymptomatic form of HAM. HTLV-1 is associated with increased susceptibility to Mycobacterium tuberculosis infection but up to now it is unknown if HTLV-1 influences the severity of tuberculosis and if tuberculosis may influence the outcome of HTLV-1. The aims of this study were to determine the prevalence and severity of tuberculosis (TB) in HTLV-1 infected patients and analyze whether TB influences the outcome of HTLV-1 infection. This is a cross-sectional study, in which the prevalence of tuberculosis was analyzed in 166 HTLV-1 infected individuals. Cytokine productions were determined by ELISA, the proviral load was evaluated by PCR. Tuberculosis occurred in 33 (22%) of cases and 70 (42%) had a positive tuberculin skin test (TST) (latent tuberculosis). The majority of the cases did not have severe tuberculosis. There was no difference in the proviral load, but there was a higher frequency of HAM/TSP in the group with tuberculosis than in HTLV-1 infected subjects without TB (P<0.05). This study shows that the prevalence of M.tuberculosis infection is 6 fold higher in HTLV-1 infected individuals than that described in the Brazilian population the majority of co-infected had latent tuberculosis and HTLV-1 may influence progression from infection to HAM/TSP.

In Vitro Immunomodulatory Activity of a Transition-State Analog Inhibitor of Human Purine Nucleoside Phosphorylase in Cutaneous Leishmaniasis

Cutaneous leishmaniasis (CL) is the most common clinical form of American tegumentary leishmaniasis caused by Leishmania (Viannia) braziliensis. CL is associated with a strong Th1 immune response. This exacerbated inflammatory response is correlated with severity of disease and delays the healing time of the ulcer. The fourth-generation immucillin derivative (DI4G), a potent inhibitor of purine nucleoside phosphorylase, has been proposed as a promising agent in the treatment of diseases associated with T cell activation. Herein, we evaluated the in vitro immunomodulatory activity of DI4G in cells of patients presenting with CL. Peripheral blood mononuclear cells (PBMC) from CL patients were stimulated with soluble leishmania antigen (SLA), in the presence or absence of DI4G, and IFN-γ, TNF, CXCL9, and CXCL10 levels were determined by ELISA. Lymphocyte proliferation in the presence or absence of DI4G was also evaluated, using flow cytometry. DI4G was able to decrease (p < 0.05) IFN-γ production but did not change the TNF, CXCL9, and CXCL10 levels. DI4G decreased (p < 0.05) the lymphoproliferative response mediated by CD8+ T cells, but not that by CD4+ T cells. DI4G is able to attenuate the exaggerated immune response in CL, exhibiting immunomodulatory activity in IFN-γ production and in CD8+ T cell proliferation.