42. SYSTEMIC LUPUS ERYTHEMATOSUS

Question 1

Genetic predisposition:

Answer 1

HLA-DRB1, HLA-DQB, HLA-DR2, HLA-DR3
+ higher risk in those with c1q, c2, c4 deficiency

Question 2

Serology:

Answer 2

ANA or anti-dsDNA antibodies
Positive anti-Smith nuclear antigen
Positive lupus anticoagulant
False-positive serologic test for Treponema pallidum

Antiphospholipid antibodies

Question 3

Drug-induced lupus serology:

Answer 3

Antihistone antibodies
High ANA titer
Negative anti-DNA antibodies
Normal complement

Question 4

Drug-induced lupus etiology:

Answer 4

Anticonvulsants
Sulfonamides
Antiarrhythmic drugs

Question 5

Treatment:

Answer 5

Diffuse:
Glucocorticosteroids in high doses and cyclophosphamide (500-800mg/m2)

+ immunosuppressant - methotrexate, leflunomide, azathioprine, myclophenolate mofetil

Hydroxychloroquine 5-7mg/kg/day to 400mg/day

Question 6

Pathogenesis:

Answer 6

SLE = multisystem autoimmune disorder with impaired adaptive and innate immunity. characterised by production of large amounts of circulating autoantibodies and hypergammaglobulinemia

🡪This antibody production may be due to loss of T-lymphocyte control on B-lymphocyte activity, leading to hyperactivity of B lymphocytes, which leads to nonspecific and specific antibody and autoantibody production
🡪 autoantibodies form immune complexes that deposit on vessel walls, and inadequate clearance of these complexes results in immune response with tissue inflammation and ischaemia manifested as lupus nephritis and vasculitis