In vasculitis of small muscular arteries, activation of vessel-infiltrating CD8 T cells seems to be antigen-independent.

The etiology of polyarteritis nodosa (PAN) and localized PAN is still unknown, although a T cell-mediated immune mechanism has been considered. CD8 T cells participate not only in the antigen-dependent adaptive immune system, but also in the antigen-independent innate immune system. Non-antigen-activated CD8 T cells express a unique phenotype: granzyme B (GrB) positive /CD25 negative /programmed death-1 (PD-1) negative. The aims of this study were to assess the participation of T cells, especially innate CD8 T cells, in the development of vasculitis. Twenty-eight consecutive cases of skin biopsy specimens with cutaneous vasculitis of small muscular arteries (CVSMA) were retrieved. The series comprises of 21 cases of cutaneous arteritis, three cases of PAN, and four cases of rheumatoid vasculitis. Cases of antineutrophil cytoplasmic antibody-associated vasculitis were excluded. The phenotypes of infiltrating lymphocytes in vasculitis lesions were evaluated by immunohistochemistry. In most cases of CVSMA, the number of CD8 T cells infiltrating the intima was higher than that of CD4 T cells, and significant numbers of GrB-positive cells, which represent activated CD8 T cells, were observed. However, GrB/CD25-double-positive cells, which correspond to antigen-activated T cells, were very few in a small number of cases. Cells positive for PD-1, which is also expressed on antigen-activated CD8 T cells, were not detected. We conclude that a T cell-mediated immune mechanism, involving cytotoxic CD8 T cells, may play a role in the development of CVSMA. Low expression of CD25 in activated CD8 T cells suggests that activation was antigen-independent.

The role of KIR2DL3/HLA-C*0802 in Brazilian patients with rheumatoid vasculitis.

OBJECTIVES: Rheumatoid arthritis is a polygenically controlled systemic autoimmune disease. Rheumatoid vasculitis is an important extra-articular phenotype of rheumatoid arthritis that can result in deep cutaneous ulcers. The objective of this study was to establish a correlation between the frequency of major histocompatibility complex class I/II alleles and killer immunoglobulin-like receptor genotypes in patients with cutaneous rheumatoid vasculitis. METHODS: Using the Scott & Bacon 1984 criteria to diagnose rheumatoid vasculitis and after excluding any other causes such as diabetes, atherosclerosis, adverse drug reactions, infection, and smoking, patients who met the criteria were selected. All of the selected rheumatoid vasculitis patients presented deep cutaneous ulcers. Identification of the major histocompatibility complex class I/II and killer immunoglobulin-like receptor genotypes was performed by polymerase chain reaction assays of samples collected from the 23 rheumatoid vasculitis patients as well as from 80 controls (40 non-rheumatoid vasculitis RA control patients and 40 healthy volunteers). RESULTS: An association between the presence of the HLA-DRB1*1402 and HLA-DRB1*0101 alleles and cutaneous lesions in rheumatoid vasculitis patients and a correlation between the inhibitor KIR2DL3 and the HLA-C*0802 ligand in rheumatoid vasculitis patients were found. CONCLUSION: An association was found between the presence of the HLA-DRB1*1402 and HLA-DRB1*0101 alleles and the development of cutaneous lesions in rheumatoid vasculitis patients. Additionally, the HLA-C*0802 ligand protects these individuals from developing cutaneous lesions.

The role of KIR2DL3/HLA-C*0802 in Brazilian patients with rheumatoid vasculitis

OBJECTIVES: Rheumatoid arthritis is a polygenically controlled systemic autoimmune disease. Rheumatoid vasculitis is an important extra-articular phenotype of rheumatoid arthritis that can result in deep cutaneous ulcers. The objective of this study was to establish a correlation between the frequency of major histocompatibility complex class I/II alleles and killer immunoglobulin-like receptor genotypes in patients with cutaneous rheumatoid vasculitis. METHODS: Using the Scott & Bacon 1984 criteria to diagnose rheumatoid vasculitis and after excluding any other causes such as diabetes, atherosclerosis, adverse drug reactions, infection, and smoking, patients who met the criteria were selected. All of the selected rheumatoid vasculitis patients presented deep cutaneous ulcers. Identification of the major histocompatibility complex class I/II and killer immunoglobulin-like receptor genotypes was performed by polymerase chain reaction assays of samples collected from the 23 rheumatoid vasculitis patients as well as from 80 controls (40 non-rheumatoid vasculitis RA control patients and 40 healthy volunteers). RESULTS: An association between the presence of the HLA-DRB1*1402 and HLA-DRB1*0101 alleles and cutaneous lesions in rheumatoid vasculitis patients and a correlation between the inhibitor KIR2DL3 and the HLA-C*0802 ligand in rheumatoid vasculitis patients were found. CONCLUSION: An association was found between the presence of the HLA-DRB1*1402 and HLA-DRB1*0101 alleles and the development of cutaneous lesions in rheumatoid vasculitis patients. Additionally, the HLA-C*0802 ligand protects these individuals from developing cutaneous lesions. .

Streptococcal-vimentin cross-reactive antibodies induce microvascular cardiac endothelial proinflammatory phenotype in rheumatic heart disease.

Rheumatic heart disease (RHD) is characterized by the presence of anti-streptococcal group A antibodies and anti-endothelial cell antibodies (AECA). Molecular mimicry between streptococcal antigens and self proteins is a hallmark of the pathogenesis of rheumatic fever. We aimed to identify, in RHD patients, autoantibodies specific to endothelial autoantigens cross-reactive with streptococcal proteins and to evaluate their role in inducing endothelial damage. We used an immunoproteomic approach with endothelial cell-surface membrane proteins in order to identify autoantigens recognized by AECA of 140 RHD patients. Cross-reactivity of purified antibodies with streptococcal proteins was analysed. Homologous peptides recognized by serum cross-reactive antibodies were found through comparing the amino acid sequence of streptococcal antigens with human antigens. To investigate interleukin (IL)-1R-associated kinase (IRAK1) and nuclear factor-κB (NF-κB) activation, we performed a Western blot analysis of whole extracts proteins from unstimulated or stimulated human microvascular cardiac endothelial cells (HMVEC-C). Adhesion molecule expression and release of proinflammatory cytokines and growth factors were studied by multiplex bead based immunoassay kits. We observed anti-vimentin antibodies in sera from 49% RHD AECA-positive patients. Cross-reactivity of purified anti-vimentin antibodies with heat shock protein (HSP)70 and streptopain streptococcal proteins was shown. Comparing the amino acid sequence of streptococcal HSP70 and streptopain with human vimentin, we found two homologous peptides recognized by serum cross-reactive antibodies. These antibodies were able to stimulate HMVEC-C inducing IRAK and NF-κB activation, adhesion molecule expression and release of proinflammatory cytokines and growth factors. In conclusion, streptococcal-vimentin cross-reactive antibodies were able to activate microvascular cardiac endothelium by amplifying the inflammatory response in RHD.

Associação do HLA-DRB5*01 com proteção contra manifestação cutânea da vasculite reumatoide em pacientes brasileiros / Association of HLA-DRB5*01 with protection against cutaneous manifestations of rheumatoid vasculitis in Brazilian patients

OBJETIVO: Avaliar a frequência do HLA classes I e II e sua associação com a manifestação cutânea da vasculite reumatoide (VR) em pacientes brasileiros. PACIENTES E MÉTODOS: Durante um ano foram selecionados 130 pacientes com artrite reumatoide (AR), classificados de acordo com os critérios do American College of Rheumatology de 1987. Os pacientes foram submetidos a um questionário clínico e laboratorial para exclusão de outras causas de vasculopatia cutânea (neoplasia, infecções, uso de drogas ilícitas, diabetes mellitus e tabagismo). Setenta e três foram excluídos por apresentarem algum fator de risco para outras causas de vasculopatias. Cinquenta e sete foram incluídos no estudo sem fator de risco para outras causas de vasculopatia, dos quais 17 apresentavam VR de acordo com os critérios de 1984 de Scott e Bacon. Foram analisados dados demográficos, tempo de diagnóstico de AR, atividade da doença (DAS28) e presença de fator reumatoide e de anticorpos antipeptídeo citrulinado cíclico. Alelos HLA foram tipificados usando-se a reação em cadeia da polimerase-DNA amplificada por hibridização de baixa resolução com sequências específicas de sondas. RESULTADOS: A comparação entre os 40 pacientes sem VR e os 17 pacientes com VR demonstrou uma frequência aumentada do HLA-B*14 (Pc = 0,168) e do HLA-Cw*08 (Pc = 0,084) em pacientes com VR, e uma frequência aumentada do HLA-DRB5*01 (Pc = 0,048) em pacientes sem VR. CONCLUSÃO: O HLA-DRB5*01 pode conferir proteção contra essa manifestação extra-articular da AR.

OBJECTIVE: To evaluate the frequency of HLA classes I and II and their association with the cutaneous manifestation of rheumatoid vasculitis (RV) in Brazilian patients. PATIENTS AND METHODS: During one year we selected 130 patients with rheumatoid arthritis (RA) classified according to the American College of Rheumatology, 1987. All patients underwent a clinical and laboratory questionnaire to exclude other causes of cutaneous vasculopathy (neoplasia, infections, illicit drug use, diabetes mellitus, and tobaccoism). Seventy-three patients with any risk factor for other causes of vasculopathy were excluded. Fifty-seven without risk factors for other causes of vasculopathy were included in the study, 17 with RV according to Scott and Bacon's criteria, 1984. Demographic data, time of RA diagnosis, disease activity (DAS28), presence of rheumatoid factor, and anti-cyclic citrullinated peptide antibodies were analyzed. The HLA alleles were typed using the DNA-amplified polymerase chain reaction with low-resolution hybridization and sequence-specific primers. RESULTS: The comparison between the 40 patients without RV and the 17 patients with RV showed an increased frequency of HLA-B*14 (Pc = 0.168) and HLA-Cw*08 (Pc = 0.084) in patients with RV and an increased frequency of HLA-DRB5*01 (Pc = 0.048) in patients without RV. CONCLUSION: The HLA-DRB5*01 may confer protection against that extra-articular manifestation of RA.

Association of HLA-DRB5*01 with protection against cutaneous manifestations of rheumatoid vasculitis in Brazilian patients.

OBJECTIVE: To evaluate the frequency of HLA classes I and II and their association with the cutaneous manifestation of rheumatoid vasculitis (RV) in Brazilian patients. PATIENTS AND METHODS: During one year we selected 130 patients with rheumatoid arthritis (RA) classified according to the American College of Rheumatology, 1987. All patients underwent a clinical and laboratory questionnaire to exclude other causes of cutaneous vasculopathy (neoplasia, infections, illicit drug use, diabetes mellitus, and tobaccoism). Seventy-three patients with any risk factor for other causes of vasculopathy were excluded. Fifty-seven without risk factors for other causes of vasculopathy were included in the study, 17 with RV according to Scott and Bacon's criteria, 1984. Demographic data, time of RA diagnosis, disease activity (DAS28), presence of rheumatoid factor, and anti-cyclic citrullinated peptide antibodies were analyzed. The HLA alleles were typed using the DNA-amplified polymerase chain reaction with low-resolution hybridization and sequence-specific primers. RESULTS: The comparison between the 40 patients without RV and the 17 patients with RV showed an increased frequency of HLA-B*14 (Pc = 0.168) and HLA-Cw*08 (Pc = 0.084) in patients with RV and an increased frequency of HLA-DRB5*01 (Pc = 0.048) in patients without RV. CONCLUSION: The HLA-DRB5*01 may confer protection against that extra-articular manifestation of RA.