29 DEC 2018 · Acute Rheumatic Fever ARF is characterized by non suppurative inflammatory lesions of the joints, heart, subcutaneous tissue, and central nervous system.   The risk of developing rheumatic fever after an episode of streptococcal pharyngitis has been estimated at 0.3 to 3%.  T helper 1 and cytokine Th17 appear to be key mediators of rheumatic heart disease. Cardiac involvement is the most serious complication of rheumatic fever. ARF is most common among children aged 5 to 15 years. 5% to 60% of patients with rheumatic fever recall having any upper respiratory symptoms in the preceding several weeks. ARF is reduced by approximately 80% with a course of penicillin. Overall, arthritis occurs in approximately 75% of first attacks of ARF.   The likelihood increases with the age of the patient, and arthritis is a major manifestation of ARF in 92% of adults. The arthritis of ARF is usually symmetrical and involves large joints, such as the knees, ankles, elbows, and wrists.   The small joints of the hands and the spine are rarely involved. Unlike the rheumatoid athritis which involves the small joints and peaks between age 35 and 50. Monoarticular arthritis may occur if anti-inflammatory agents are used early in the course. The arthritis is classically described as migratory. One resolves before another begins, but, in many cases, new joints are affected before the previously involved joints improve, leaving the appearance of an additive arthritis. Of first attacks of ARF, carditis occurs in 30% to 60% of cases. It is more common in younger children but does occur in adults.   Carditis occurs in up to 25% of ARF cases in children but is very rare in adults. It is more common in girls.  Carditis is usually a pancarditis involving the pericardium, myocardium, and endocardium. Pericarditis characterized by pericardial friction rub, and or pericardial effusion. Myocarditis by cardiac enlargement. Endocarditis by the development of new murmurs. high-pitched, blowing, holosystolic, apical murmur of mitral regurgitation; the low-pitched, apical, mid-diastolic, flow murmur (Carey-Coombs murmur); and a high-pitched, decrescendo, diastolic murmur of aortic regurgitation. Sydenham chorea in ARF is likely due to molecular mimicry, with autoantibodies reacting with brain ganglioside. Like the polyarthritis, Sydenham chorea usually resolves without permanent damage but occasionally lasts 2 to 3 years.   Erythema marginatum occurs in approximately 10%. The lesions may be macular and can develop and disappear in minutes. Subcutaneous nodules are rarely noticed by the patient. They are found primarily over the bony surfaces or prominences and in tendon sheaths. The common sites include the elbows, knees, wrists, ankles, over the Achilles tendon, the back of the scalp, and spinous process of the vertebrae.

24 DEC 2018 · Interluekins (IL) are signaling molecules mostly produced by CD4 cells.

24 DEC 2018 · B cells develop and mature in the bone marrow but are activated in the secondary lymphoid tissues by two important factors 1. Antigen binding to BCR 2. The antigen laden B cell MHC II binding with TCR to tell the T cell to release IL 2. IL 2 activate the B cells by dividing them and differentiating them. The also stimulate them to produce antibodies.

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