Wegener's granulomatosis: a model of auto-antibodies in mucosal autoimmunity

Clinical manifestations of granulomatosis with polyangiitis: key considerations and major features

BACKGROUND

Granulomatosis with polyangiitis (GPA) presents a wide spectrum of manifestations from the common respiratory symptoms to infrequent neurological and cardiac complications. The challenge in diagnosis and management makes the rapidly progressive disorder one of the most challenging dilemmas in clinical medicine.

METHOD

An extensive electronic literature search was done using multiple databases (e.g. PubMed) from January 2007 to August 2017 to gather information on the etiopathogenesis, clinical presentation, and current treatment management plan of GPA. The language used was English. Search items included 'Granulomatosis with Polyangiitis symptoms,' 'Wegener's Granulomatosis,' and 'Treatment of Granulomatosis with Polyangiitis' for the databases. Inclusion criteria consisted of published articles in the English language which reported on the clinical manifestations of GPA, as well as on the treatment of the disease. Exclusion criteria included articles that: (1) did not specifically report on GPA vasculitis but also focused on discussion of other vasculitis such as MPA or Churg-Strauss; (2) reported on treatment/symptoms of GPA prior to 2007.

RESULT

This review provides an overview of work undertaken in key areas of GPA research, including its complex multifactorial etiology, clinical manifestations, treatment strategies, and treatment-related adverse effects.

CONCLUSION

Major advances in the understanding and treatment of GPA over recent decades have contributed to the notable decline in morbidity and mortality of patients. The ultimate goal is an improved prognosis through outcome measures which assesses the disease control with minimal adverse effects of intensive immunosuppressive regimens, an integral part of the clinical approach to improve the quality of life of GPA patients.

IgA- and SIgA anti-PR3 antibodies in serum versus organ involvement and disease activity in PR3-ANCA-associated vasculitis

Circulating immunoglobulin (Ig)A class anti-neutrophil cytoplasm antibodies (ANCA) directed against proteinase 3 (PR3) have been reported in ANCA-associated vasculitis (AAV) with mucosal involvement. However, secretory IgA (SIgA) PR3-ANCA has not been reported previously. In this study we compared serum levels of SIgA PR3-ANCA and IgA PR3-ANCA with IgG PR3-ANCA in relation to disease characteristics. Among 73 patients with AAV and PR3-ANCA at diagnosis, 84% tested positive for IgG PR3-ANCA, 47% for IgA-ANCA and 36% for SIgA PR3-ANCA at the time of sampling for the present study. IgA and IgG PR3-ANCA were represented similarly among patients with different organ manifestations, i.e. upper airway, lung or kidney at time of sampling. However, SIgA PR3-ANCA was significantly less represented among patients with upper airway involvement. During active disease, the proportions of IgA PR3-ANCA and SIgA PR3-ANCA-positive patients were significantly higher compared to inactive disease. Eight patients were sampled prospectively during 24 months from onset of active disease. In these patients, IgA PR3-ANCA and SIgA PR3-ANCA turned negative more often after remission induction compared to IgG PR3-ANCA. Our findings suggest that serum IgA PR3-ANCA and SIgA PR3-ANCA are related more closely to disease activity in AAV compared to IgG PR3-ANCA. Further studies are required to reveal if this has implications for disease activity monitoring. The mean number of PR3-ANCA isotypes increased along with disease activity, suggesting a global B cell activation during active disease.

The spectrum of nasal involvement in systemic lupus erythematosus and its association with the disease activity

The purpose of this study was to determine the spectrum of nasal involvement in systemic lupus erythematosus (SLE) and its association with the disease activity of SLE based on the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). This was a cross-sectional and observational study involving 73 stable SLE patients. All subjects were evaluated for the SLEDAI scores and had nasal endoscopic examination. The most commonly reported symptom was nasal congestion (31.5%) followed by nasal itchiness (26.0%), runny nose (20.5%) and nasal dryness (19.2%). Almost half (42.9%) of the subjects had nasal mucosal abnormalities, which included mucositis, crusting, ulceration, bifid middle turbinate, septal spur, Jacobson's organ, deviated nasal septum, bilateral inferior turbinate hypertrophy, everted uncinate process, nasopharynx cleft and torus palatinus. The median SLEDAI score for subjects with nasal symptoms was significantly higher than subjects without nasal symptoms (p < 0.05). Similarly, subjects with moderate to high activity (SLEDAI scores of 6-19) had a significantly higher frequency of both nasal symptoms and nasal mucosal abnormalities (p < 0.05) compared to subjects with no to mild activity (SLEDAI scores of 0-5).

Autoimmunity: from black water fever to regulatory function

Autoimmunity is a field that has only been around for a little over a century. Initially, it was thought that autoimmunity could not happen, that the body would never turn on itself (i.e. "horror autotoxicus"). It was only around the First World War that autoimmunity was recognized as the pathogenesis of various diseases, including rheumatoid arthritis. The discovery of Compound E led to successful treatment of patients with autoimmune diseases, but it was not till later that the adverse effects of this class of drugs were elucidated. The "modern" age of autoimmunity began around 1945 with the description of blackwater fever, and most of the subsequent research on hemolytic anemia and the role of an autoantibody in its pathogenesis led to a description of the anti-globulin reaction. The lupus erythematous (LE) cell was recognized in the mid-1940s by Hargreaves. His research carried on into the 1960s. Rheumatoid factor was also first described in the 1940s as yet another serum factor with activity against globulin-coated sheep red blood cells. The concept of autoimmunity really gained a foothold in the 1950s, when autoimmune thyroid disease and idiopathic thrombocytopenia were first described. Much has happened since then, and our understanding of autoimmunity has evolved now to include mechanisms of apoptosis, signaling pathway derangements, and the discovery of subsets of T cells with regulatory activity. The modern day study of autoimmunity is a fascinating area of research, and full understanding of the pathogenesis of autoimmune diseases is far from being completely elucidated.

Characterization of TLR4-mediated auto-antibody production in a mouse model of histidyl-tRNA synthetase-induced myositis

We have previously shown that intramuscular immunization with a recombinant fragment of murine histidyl-tRNA synthetase (HRS) in the absence of exogenous adjuvant generates Ag-specific, IgG class switched Abs a murine model of myositis. Markedly diminished IgG anti-HRS auto-Ab responses in TLR4 signaling-deficient C3H/HeJ mice indicate that TLR4 is required for auto-Ab formation and/or class switching in this system. Comparative time course assessment of HRS-immunized C3H/HeOuJ (wild type) and C3H/HeJ (TLR4 mutant) mice shows here that despite significant impairment of class switched IgG anti-HRS responses in TLR4-deficient C3H/HeJ mice, production of IgM anti-HRS auto-Abs is relatively preserved-suggesting that TLR4-mediated signals modulate IgG class switching rather than auto-Ab formation in this genetic background. In C57BL/6-derived knockout mice lacking either MyD88 (B6.MyD88(-/-)) or TRIF (B6.TRIF(-/-)) adaptor molecules, immunization studies indicate that TRIF exerts a dominant role in the generation of HRS-specific IgG auto-Abs. Complementing these analyses, in vitro stimulation of unfractionated, as well as T cell-depleted, C3H/HeOuJ splenocytes with recombinant murine HRS reveals that TLR4-mediated generation of class switched auto-Abs can occur independently of T cell help. Overall, these findings support a broader role for TLR4 in the breakdown of immune tolerance and development of autoimmunity.

Central retinal artery occlusion in Wegener's granulomatosis: a diagnostic dilemma

PURPOSE

To report a case of central retinal artery occlusion (CRAO) in a patient with biopsy-verified Wegener's granulomatosis (WG) with positive C-ANCA.

METHODS

A 55-year-old woman presented with a 3-day history of acute painless bilateral loss of vision; she also complained of fever and weight loss. Examination showed a CRAO in the left eye and angiographically documented choroidal ischemia in both eyes.

RESULTS

The possibility of systemic vasculitis was not kept in mind until further studies were carried out; methylprednisolone pulse therapy was then started. Renal biopsy disclosed focal and segmental necrotizing vasculitis of the medium-sized arteries, supporting the diagnosis of WG, and cyclophosphamide pulse therapy was administered with gradual improvement, but there was no visual recovery.

CONCLUSION

CRAO as presenting manifestation of WG, in the context of retinal vasculitis, is very uncommon, but we should be aware of WG in the etiology of CRAO. This report shows the difficulty of diagnosing Wegener's granulomatosis; it requires a high index of suspicion, and we should obtain an accurate medical history and repeat serological and histopathological examinations. It emphasizes that inflammation of arteries leads to irreversible retinal infarction, and visual loss may occur.