Page 723 - Clinical Immunology_ Principles and Practice ( PDFDrive )

696 Part SIX Systemic Immune Diseases

medications at the onset of pancreatitis, and most patients respond organ involvement. The diagnosis is confirmed with an increased
to steroid therapy. The clinical presentation and diagnosis of α 1 -antitrypsin level in a 24-hour stool collection or with the
pancreatitis is similar in patients with and without SLE. Specific presence of IV-administered labeled human albumin in the stool.
findings in SLE include leukopenia, thrombocytopenia, and A recent review of 112 cases reported an Asian predominance
anemia. Inflammation and necrosis are common on biopsy; there (65%) and clinical features of edema (805), ascites (38%), pleural
is a single report of pancreatic vasculitis. Mortality rates are effusion (38%), pericardial effusion (21%), and hypocomple-
reported from 18–27%; poor outcome is associated with increased mentemia (79%). Approximately half the patients experienced
systemic SLE activity (particularly, low complement and diarrhea; intestinal histology revealed a range of findings,
thrombocytopenia). including lymphangiectasis, edematous villi, inflammatory
infiltrate, vasculitis, and mucosal atrophy. Biopsy results suggest
Liver a role of TNF-α, IFN-γ, and IL-6 in the increased vascular and
The term “lupoid hepatitis” was coined in the 1950s to describe enterocyte permeability in PLE.
cases of young women with chronic active hepatitis characterized
by a lymphoplasmacytic infiltrate on biopsy, hypergammaglobu- Pulmonary Involvement
linemia, and a positive LE cell test in the blood. With the Lupus affects the lungs in diverse ways involving the pleura, lung
development of ANA testing, it became apparent that “lupoid” parenchyma, and blood vessels. The most frequent and important
and “chronic active hepatitis” were indistinguishable in terms complicating feature is infection.
of clinical presentation, pathology, and response to treatment,
and the term “autoimmune hepatitis” (AIH; Chapter 76) was Pleuritis
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endorsed in 1993. Importantly, only 10% of AIH meet criteria Pleuritis is the most common pulmonary manifestation
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for SLE, and 2.4–4.7% of SLE patients have noninfectious hepatitis of SLE, reported in 40–56% of patients. Pleural involvement
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attributed to SLE. Analysis of SLE liver pathology from 52 in up to 93% of lupus patients at autopsy suggests that
autopsies in Japan revealed a variety of findings, including much pleuritis may be asymptomatic. Clinically, patients note
congestion (40/52), fatty liver (38/52), arteritis (11/52), cholestasis typical pleuritic pain. On physical examination, the most frequent
(9/52), and a few cases each of chronic persistent hepatitis, nodular abnormality is tachypnea; a pleural friction rub is present in
regenerative hyperplasia, hemangioma, and cholangiolitis. Cir- some cases, and pleural effusions occur in more severe cases.
rhosis is an extremely rare complication of liver involvement in Pleural fluid is usually exudative with normal glucose and pH
SLE. The distinction between subclinical liver inflammation and elevated protein levels. The leukocyte count can range
related to SLE (lupus hepatitis [LH]) and AIH is important from several hundred to 20 000 cells/µL; both a lymphocytic
because therapy and prognosis are different. Whereas LH is and neutrophilic predominance are reported. When performed,
associated with mild enzyme abnormalities, AIH is a progressive immunological testing on pleural fluid may show reduced
disease frequently leading to hepatic failure. Both conditions complement levels and the presence of ANA, anti-DNA antibodies,
share a predilection for young women, and both demonstrate and LE cells. Although these tests are commonly obtained,
features of autoimmunity, including hypergammaglobulinemia, these results are neither sensitive nor specific to diagnose
arthralgias, and serum autoantibodies. Histologically, biopsies lupus pleuritis.
of LH reveal lobular and periportal lymphocytic infiltrates, in
contrast to the periportal and piecemeal necrosis with dense Lupus Pneumonitis
lymphocytic infiltrates seen in AIH with progression to panlobular Lupus pneumonitis occurs in up to 10% of patients. Patients
or multilobular necrosis and cirrhosis. Serologically, antiribosomal present with dyspnea, cough, mild pleuritic chest pain, and fever.
P antibodies have been associated with liver disease in LH, whereas Pulmonary infiltrates are present on plain radiograph or CT.
AIH is associated with antibodies to liver and kidney microsomes. This presentation must be distinguished from an infectious
Antismooth-muscle antibodies are observed in 60–80% of patients etiology. Histological examination of affected lung tissue shows
with AIH, compared with 30% of patients with LH. Although alveolar edema and hemorrhage with hyaline membrane forma-
both have a favorable response to steroids, AIH usually requires tion; immunofluorescent staining reveals immune complex
additional immunosuppressive agents. 54 deposition.
Distinguishing LH from hepatitis C (HCV) can be difficult.
Up to 30% of patients chronically infected with HCV have low Pulmonary Hemorrhage
titers of ANA and other autoantibodies (anti-DNA, anticardiolipin Pulmonary hemorrhage is a rare but potentially fatal complication
antibodies, and rheumatoid factor). They can also have cryo- of SLE. Symptoms include shortness of breath and hemoptysis
globulins and associated cryoglobulinemic vasculitis. It is necessary accompanied by a fall in hemoglobin, usually occurring in the
to confirm a positive enzyme-linked immunosorbent assay context of multiorgan involvement from SLE. Imaging may show
(ELISA) for HCV with polymerase chain reaction (PCR) in patchy infiltrates. Pulmonary function testing is marked by an
patients presenting with arthritis, cutaneous vasculitis, and a increased diffusion capacity (DL CO ) secondary to the presence
positive ANA, as SLE patients may have false-positive serological of alveolar blood, whereas arterial O 2 saturation is decreased.
tests for HCV. Histopathology shows bland intraalveolar hemorrhage and
hemosiderin-laden macrophages, although microangiitis with
Protein-Losing Enteropathy (PLE) an inflammatory infiltrate and necrosis of the alveolar septa can
Profound hypoalbuminemia in the absence of severe nephrotic occur. As hemorrhage into the lung may be secondary to throm-
syndrome, liver disease, or constrictive pericarditis should trigger botic thrombocytopenia, infections, or pulmonary hypertension,
concern for PLE. Clinically significant PLE is uncommon in demonstration of an inflammatory process in the pulmonary
SLE, with reported prevalence rates of 1–8%; it can present vessels or tissue is helpful to establish a diagnosis of primary
individually or in the context of severe disease activity with other pulmonary hemorrhage.