Kawasaki disease

B Cells at the Cross-Roads of Autoimmune Diseases and Auto-Inflammatory Syndromes

Whereas autoimmune diseases are mediated primarily by T and B cells, auto-inflammatory syndromes (AIFS) involve natural killer cells, macrophages, mast cells, dendritic cells, different granulocyte subsets and complement components. In contrast to autoimmune diseases, the immune response of patients with AIFS is not associated with a breakdown of immune tolerance to self-antigens. Focusing on B lymphocyte subsets, this article offers a fresh perspective on the multiple cross-talks between both branches of innate and adaptive immunity in mounting coordinated signals that lead to AIFS. By virtue of their potential to play a role in adaptive immunity and to exert innate-like functions, B cells can be involved in both promoting inflammation and mitigating auto-inflammation in disorders that include mevalonate kinase deficiency syndrome, Kawasaki syndrome, inflammatory bone disorders, Schnitzler syndrome, Neuro-Behçet's disease, and neuromyelitis optica spectrum disorder. Since there is a significant overlap between the pathogenic trajectories that culminate in autoimmune diseases, or AIFS, a more detailed understanding of their respective roles in the development of inflammation could lead to designing novel therapeutic avenues.

Antibodies and Immunity During Kawasaki Disease

The cause of Kawasaki disease (KD), the leading cause of acquired heart disease in children, is currently unknown. Epidemiology studies support that an infectious disease is involved in at least starting the inflammatory cascade set off during KD. Clues from epidemiology support that humoral immunity can have a protective effect. However, the role of the immune system, particularly of B cells and antibodies, in pathogenesis of KD is still unclear. Intravenous immunoglobulin (IVIG) and other therapies targeted at modulating inflammation can prevent development of coronary aneurysms. A number of autoantibody responses have been reported in children with KD and antibodies have been generated from aneurysmal plasma cell infiltrates. Recent reports show that children with KD have similar plasmablast responses as other children with infectious diseases, further supporting an infectious starting point. As ongoing studies are attempting to identify the etiology of KD through study of antibody responses, we sought to review the role of humoral immunity in KD pathogenesis, treatment, and recovery.

B Cells and Antibodies in Kawasaki Disease

The etiology of Kawasaki disease (KD), the leading cause of acquired heart disease in children, is currently unknown. Epidemiology supports a relationship of KD to an infectious disease. Several pathological mechanisms are being considered, including a superantigen response, direct invasion by an infectious etiology or an autoimmune phenomenon. Treating affected patients with intravenous immunoglobulin is effective at reducing the rates of coronary aneurysms. However, the role of B cells and antibodies in KD pathogenesis remains unclear. Murine models are not clear on the role for B cells and antibodies in pathogenesis. Studies on rare aneurysm specimens reveal plasma cell infiltrates. Antibodies generated from these aneurysmal plasma cell infiltrates showed cross-reaction to intracellular inclusions in the bronchial epithelium of a number of pathologic specimens from children with KD. These antibodies have not defined an etiology. Notably, a number of autoantibody responses have been reported in children with KD. Recent studies show acute B cell responses are similar in children with KD compared to children with infections, lending further support of an infectious disease cause of KD. Here, we will review and discuss the inconsistencies in the literature in relation to B cell responses, specific antibodies, and a potential role for humoral immunity in KD pathogenesis or diagnosis.

Presence of IFN-gamma does not indicate its necessity for induction of coronary arteritis in an animal model of Kawasaki disease

Kawasaki disease is the most common cause of vasculitis affecting children, and the leading cause of acquired heart disease in the developed world. To date, studies on the role of IFN-gamma in the pathogenesis of Kawasaki disease have focused on peripheral production of IFN-gamma, and have yielded conflicting results. Affected heart tissue is not available from children with Kawasaki disease. In this study, we use an animal model of Kawasaki disease, Lactobacillus casei cell wall extract (LCWE)-induced coronary arteritis, to examine the role of IFN-gamma in the development of coronary artery lesions. We report the presence of IFN-gamma, both at the mRNA and protein levels, in the affected vessels. Its biphasic expression, first at days 3-7 and again at days 28-42 post-LCWE injection, corresponds to the first appearance of inflammatory infiltrate in coronary arteries, and later to vascular wall disruption and aneurysm formation, respectively. Interestingly, ablation of IFN-gamma expression did not dampen the inflammatory response, and IFN-gamma-deficient lymphocytes proliferated more vigorously in response to LCWE than those of wild-type animals. Of more importance, the incidence of coronary arteritis was the same in IFN-gamma-deficient and wild-type mice. Taken together, our findings demonstrate that IFN-gamma regulates the immune response during development of coronary arteritis, but is not required for the induction of coronary artery disease.

Kawasaki disease: an update

Kawasaki disease is one of the commonest vasculitides seen in children. It presents with prolonged fever and a polymorphic exanthem. It is a major cause of acquired heart disease in western society. Its exact cause is not known, but exposure to a superantigen has been suggested as a possible aetiological factor. Diagnosis of Kawasaki disease still relies on clinical criteria (Table 1) and investigations are done mainly to exclude other diseases and to detect early or established cardiac complications. Coronary complications can be reduced significantly by the use of intravenous immunoglobulin therapy combined with oral aspirin. The serious consequences of Kawasaki disease require a heightened awareness of this condition when dealing with childhood exanthems.

Anterior uveitis as the initial sign of adult Kawasaki syndrome (mucocutaneous lymph node syndrome)

PURPOSE

To report anterior uveitis as the initial sign of adult Kawasaki syndrome (mucocutaneous lymph node syndrome).

METHODS

Case report.

RESULTS

Kawasaki syndrome was diagnosed in an 18-year-old woman with reduction of vision caused by anterior uveitis, fever, erythemateous cutaneous rash, conjunctival injection, and cervical lymph adenopathy, after medical examination including serologic tests. Aspirin and intravenous immunoglobulin were given, resulting in improvement of the condition.

CONCLUSION

Slit-lamp examination should be useful in the evaluation of patients with suspected Kawasaki syndrome, differentiating this condition from streptococcal and staphylococcal toxin-mediated diseases, viral infections, and drug reactions, not commonly associated with anterior uveitis.

Kawasaki disease: an update

Kawasaki disease is the leading cause of acquired heart disease in children in many parts of the world. It is an acute systemic vasculitis of unknown etiology predominantly affecting children under 5 years of age. It is diagnosed clinically by the presence of a constellation of manifestations and exclusion of other diseases with similar findings. Children develop a spectrum of cardiovascular manifestations including coronary artery involvement in 30-35% of untreated cases with myocardial infarction and death in < or = 2% of them. Acute stage treatment is by administration of intravenous immunoglobulin and aspirin. Those with coronary artery involvement need long-term cardiac risk stratification and management because many of them will become the part of a growing pool of adults with ischemic heart disease.

Facial palsy in Kawasaki syndrome

Facial nerve palsy, a very rare complication of Kawasaki syndrome, has been reported in only 25 patients. We treated a 12-week-old boy with bilateral coronary artery aneurysms due to Kawasaki syndrome who developed marked unilateral peripheral facial nerve palsy on day 36 of illness. None of the 25 previously reported patients with this complication were treated with immunoglobulin; they required 7 to 90 days to recover. In our patient, treatment with this agent was associated with complete resolution of facial nerve palsy within 36 hours. Review of prior cases demonstrates that children with Kawasaki-associated facial nerve palsy have more than twice the risk for coronary artery aneurysm (52% vs <25%) as that of children who do not develop this neurological complication. Unexplained facial nerve paralysis in young children with a prolonged febrile illness should provoke consideration of Kawasaki syndrome and of echocardiography to exclude coronary artery aneurysms. Although facial palsy appears likely to resolve in all patients that survive the acute phase of Kawasaki syndrome, treatment with intravenous immunoglobulin appears to considerably shorten the time to full recovery and provides an important clue to the mechanisms of neurological injury in this illness.

Kawasaki disease: update on diagnosis, treatment, and a still controversial etiology

Diagnosis of Kawasaki syndrome still relies solely on clinical criteria because the etiology is unknown. However, the function and structure of different bacterial superantigens as potential pathogens are discussed. In this regard, the recent determination of the crystal structure of the toxic shock syndrome toxin-1 superantigen complexed with major histocompatibility complex class II suggests potential implications for the controversial findings concerning a role of those superantigens in Kawasaki disease. Although a specific therapy is not available, coronary complications can be significantly reduced with the help of intravenous immunoglobulin therapy combined with oral aspirin.