Immunology Flashcards
(234 cards)
Which autoimmune conditions are palliated by pregnancy, which are exacerbated by pregnancy, and which have postpartum exacerbations?
RA and Graves disease seem to be palliated by pregnancy. SLE is exacerbated by pregnancy. Graves disease and myasthenia gravis are notorious for postpartum exacerbations.
Pregnancy increases the likelihood of SLE flares. The risk is highest in early pregnancy and during puerperium, with relative quiescence in the latter half of pregnancy. A lupus flare may be difficult to distinguish from pregnancy-induced HTN, as the features of HTN, edema, and proteinuria are shared. What lab value can help with this distinction?
Complement levels are low in SLE flare and normal in PIH.
Mortality is increased in pregnancy women with SLE, with most deaths occuring as a result of ___.
Mortality is increased in pregnancy women with SLE, with most deaths occuring as a result of pulmonary hemorrhage due to lupus pneumonitis and other complications (transverse myelitis, stroke, corticosteroid complications).
In addition to an increased incidence of IUGR and preterm labor, neonates born to mothers with SLE have a risk of congenital heart block. Why?
Antibodies to SS-A and SS-B (Ro and La) are thought to mediate this complication.
What laboratory investigations are often undertaken following two or more spontaneous abortions?
Parental karyotyping (karyotyping of an abortus is often indicated as well). Endometrial bxs may be obtained to exclude luteal phase defect (endometrial histology that is 2 or more days discrepant with dates). Endometrial culture may be obtained to exclude subclinical infection with U. urealyticum or C. trachomatis. Thyroid function tests. Tests for lupus anticoagulants.
CD5 is expressed by normal and neoplastic T cells (not expressed by very immature T cells) and a small, normally inconspicuous, B cells subset. In what non-malignant situation can patients have circulating CD19+/CD20+/CD5+ B cells?
Occasionally, patients have increased polyclonal benign circulating CD19+/CD20+/CD5+ B cells, particularly in rheumatoid arthritis.
What is the most frequent autoimmune disorder associated with ovarian teratomas?
Autoimmune encephalitis due to antibodies against the N-methyl-D-aspartate receptor (anti-NMDAR), a condition that frequently involves temporal lobes and hippocampus.
Its recognition is important, as removal of the ovarian tumor and early immunosuppressive therapy will often improve the outcome, with full recovery or only a residual mild neurologic deficit.
Goodpasture disease refers to the triad of ___, ___, and ___.
Goodpasture disease refers to the triad of pulmonary (alveolar) hemorrhage, glomerulonephritis of any severity, and serum anti-GBM production. The treatment of choice is plasmapheresis.
Goodpasture disease refers to the triad of pulmonary (alveolar) hemorrhage, glomerulonephritis of any severity, and serum anti-GBM production. What are these circulating antibodies directed against?
The NC1 domain of collagen IV in glomerular and alveolar basement membranes.
What 3 major categories of small vessel vasculitis can cause the pulmonary-renal syndrome?
Anti-GBM disease, ANCA disease, and immune complex-mediated diseases (such as SLE).
What is pulmonary-renal syndrome? What are causes of it?
The combination of acute glomerulonephritis and pulmonary hemorrhage. Causes: ANCA-positive vasculitis (granulomatosis with polyangiitis/Wegener’s, microscopic polyangiitis). Anti-GBM disease (Goodpasture’s). Pulmonary hemorrhage is a rare finding in lupus, HSP (IgAV), and infective endocarditis. Acute glomerulonephritis complicated by pulmonary edema due to fluid overload, as can occur in poststreptococcal glomerulonephritis.
What are 3 disorders in which linear IgG staining may be seen in glomeruli?
Diabetic glomerulosclerosis, fibrillary glomerulopathy, anti-GBM disease.
To what are c-ANCA and p-ANCA antibodies directed against?
c-ANCA: proteinase 3. p-ANCA: myeloperoxidase.
The Chapel Hill consensus conference recommendation on the nomenclature of systemic vasculitides is based primarily based on what?
It is based on the caliber of the most inflamed/affected vessels (the system does additionally incorporate IF findings and selected clinical/lab parameters). Small vessel vasculitis refers to changes found in distal vascular branches including arterioles, capillaries and venules. Medium vessel vasculitis is found in the main muscular arterial segments with multiple medial smooth muscle layers. Large vessel vasculitis is seen in the aorta and its largest branches.
What is the most common form of vasculitis in patients older than 50?
Giant cell arteritis (formerly termed temporal arteritis).
Giant cell arteritis (formerly termed temporal arteritis) is a granulomatous form of ANCA-negative large vessel vasculitis. What vessels does it tend to affect?
The aorta and its major branches, especially the extracranial arteries.
Giant cell arteritis (formerly termed temporal arteritis) tends to affect the aorta and its major branches, especially the extracranial arteries. Histologic appearance?
The inflammatory process, composed of mononuclear cells with a predominance of macrophages and lymphocytes, originates in the media and extends into the intima and adventitia. Multinucleated giant cells, of either the Langerhans or foreign body type, are found in about half of cases, often adjacent to the fragmented internal elastic lamina. Fibrinoid vascular wall necrosis is an infrequent observation and, when present, it patchy in distribution. GCA involves arteries in a segmental fashion, so a minimum of a 3 cm long segment should be obtained for an adequate histologic examination.
Giant cell arteritis is an ANCA-negative large vessel vasculitis. Is extensive fibrinoid necrosis consistent with giant cell arteritis?
No. In GCA, fibrinoid vascular wall necrosis is an infrequent observation and, when present, is patchy in distribution. The presence of extensive fibrinoid necrosis should raise the possibility of another type of systemic ANCA-negative vasculitis found in medium-sized vessels, such as polyarteritis nodosa.
When are antiphospholipid syndromes classified as primary, and when are they classified as secondary?
APS are classified as primary if they present with only a hypercoagulable state, and are classified as secondary if they are accompanied by other autoimmune disorders, such as SLE or other connective tissue diseases.
In antiphospholipid antibody syndrome, venous thrombosis is typically seen in deep leg veins (__%), as well as renal, hepatic, and retinal veins. Arterial thrombosis is typically seen in cerebrovascular (__%), coronary (__%), as well as ocular, mesenteric, deep leg, and renal arteries.
In antiphospholipid antibody syndrome, venous thrombosis is typically seen in deep leg veins (55%), as well as renal, hepatic, and retinal veins. Arterial thrombosis is typically seen in cerebrovascular (50%), coronary (25%), as well as ocular, mesenteric, deep leg, and renal arteries.
What is “catastrophic antiphospholipid syndrome”?
In rare instances (less than 1% of cases), multiple organ sites are affected by thrombosis simultaneously with dramatic clinical consequences and a mortality rate of up to 50%.
Thrombotic microangiopathy -a descriptive term- characterizes stenosing and/or thrombotic changes in small vessels (capillaries, arterioles, pre-arterioles, and small arteries). Veins and larger arteries with multiple layers of medial smooth muscle cells are characteristically spared. What are histologic features of the acute phase of a TMA?
The acute phase of a TMA is characterized by various changes that can be seen individually or in combination: (1) endothelial cell swelling and “mucoid” intimal widening with severe narrowing of vascular lumens; (2) intraluminal fibrin thrombi and/or fragmented RBCs in the intima and media; (3) necrosis of individual endothelial or medial smooth muscle cells; (4) PAS-positive nodular proteinaceous deposits replacing single necrotic arteriolar smooth muscle cells. Note: fibrin thrombi may sometimes be detected but they are not essential for establishing the diagnosis of a TMA.
Why is the “thrombotic” in thrombotic microangiopathy sometimes a misnomer?
Fibrin thrombi may sometimes be detected but they are not essential for establishing the diagnosis of a TMA.
The thrombotic microangiopathies are microvascular occlusive disorders characterized by systemic or intrarenal aggregation of platelets, thrombocytopenia, and mechanical injury to erythrocytes. TTP and HUS are both TMAs; What distinguishes them?
TTP affects mainly adults, with systemic microvascular aggregation of platelets affecting primarily the brain. HUS affects mainly children, with platelet–fibrin thrombi occluding predominantly the renal circulation.