Detection of lupus pleuritis: a tale of lights and shadows.
In our clinical setting, we encountered a 42-year-old African-American male who presented with acute shortness of breath and new facial rash, which was associated with substernal, dull, intermittent, and non-radiating chest pain. Patient had experienced fever and 10-pound weight loss during this time with a past history of congestive heart failure, hypertension, chronic renal insufficiency, hypothyroidism, and anemia of chronic disease. He related a history of untreated SLE, and was believed to be in remission for many years due to lack of joint involvement. Recurrent pneumonia with pleuritis requiring previous hospital admissions had occurred in the past year.
On examination, the patient was in mild distress with diffuse rhonchi in bilateral lung fields. A chest radiograph demonstrated bilateral alveolar and interstitial opacities, blunting of the costophrenic angles bilaterally, and bilateral pleural effusions. Impression was bilateral pneumonia with stable pulmonary edema and bilateral pleural effusion (see Image 1). Worsening dyspnea necessitated surgical drainage of the pleural effusion. Approximately 500 mL of serosanguinous fluid was removed and sent for laboratory evaluation. On examination of a Wright-Giemsa stained cytospin preparation, a single lupus erythematosus (LE) cell was identified, characterized by homogenous nuclear material engulfed by a neutrophil (see Image 2a). The cell was present in a background of numerous segmented neutrophils, lymphocytes, plasma cells, and macrophages. A summary of laboratory values is given in Table 1 on page 14.
Table 1. Test Patient's result Reference interval Hematology: White blood cell count 19.24 4.1 x 103/[mu]L to 10.8 x 103/[mu]L Differential: Neutrophils 83.40 44.0% to 78.0% Lymphocytes 12.20 12.0% to 44.0% Monocytes 4.30 3.0% to 12.0% Hemoglobin 8.7 13.4 g/dL to 17.3 g/dL Hematocrit 38.10 38.6% to 50.5% Mean corpuscular 86.6 81.4 fL to 97.6 fL volume Platelet count 265 155 x 103/[micro]L to 367 x 103/[micro]L Pleural-fluid cell Clotted, unable to None count enumerate Pleural-fluid None differential Neutrophils 99.0 None Lymphocytes 1.0 None Monocytes 0 None Chemistry: Blood urea nitrogen 32 7.0 mg/dL to 20 mg/dL Serum creatinine 1.7 0.8 mg/dL to 1.5 mg/dL Calcium 7.5 8.4 mg/dL to 10.2 mg/dL Troponin T 0.29 0.0 ng/mL to 0.1 ng/mL C3 66.6 80 mg'dL to 150 mg/dL C-reactive protein 19.9 DO mg/dL to 0.05 mg'dL Serum total protein 6.6 6.3 g/dL to 8.2 g/dL Serum lactate 371 310 U/L to 620 U/L dehydrogenase Blood glucose 84 65 mg/dL to 110 mg/dL Pleural-fluid total 2.2 G/dL None protein Pleural-fluid lactate 98,824 U/L None dehydrogenase Pleural-fluid glucose < mg/dl None Fluid: serum protein 0.3 < 0.5 for transudate ratio Fluid: serum glucose 0.24 < 0.5 for transudate ratio Fluid: serum lactate 266.4 < 0.6 for transudate dehydrogenase ratio Immunology Serum ANA 1:2560, speckled Negative Anti-native DNA (double 1;320 Negative stranded) Pleural Fluid ANA 1:640, speckled Negative
This patient presented with substernal chest pain and shortness of breath, accompanied by productive cough and fever, typical of lupus pleuritis. Several diagnostic possibilities exist when a patient presents with acute pleuritis manifesting as severe chest pain, fever, dyspnea, and pleural effusions. The clinician must consider pulmonary embolus, viral infection, parapneumonic effusion, tuberculosis, congestive heart failure, and collagen vascular disorders--such as SLE or rheumatoid arthritis--in the differential diagnosis. Chemistry analysis revealed the fluid to be an exudate by Light criteria, with very high lactate dehydrogenase (LDH) and elevated-fluid-to-serum-LDH ratio, rather than a simple transudate due to congestive heart failure. (3) Pleural effusion due to lupus pleuritis is typically an exudate and may be unilateral or bilateral. In most cases the glucose is > 60 mg/dL and the complement levels are frequently low. When an LE cell is seen in pleural fluid, and this finding correlated with immunologic studies for SLE, the observation can be helpful in establishing lupus pleuritis.
Results of the pleural-fluid cell count included the finding of the LE cell. Subsequent pleural-fluid and serum antinuclear-antibody (ANA) tests were performed, along with other immunologic tests that confirmed the diagnosis of SLE. Intravenous steroid therapy was initiated, after which the bilateral pleural effusions dramatically improved. Serous effusions as a result of SLE tend to be more common in the chronic stage of the disease, and the presence of LE cells in an effusion is associated with the presence of active disease.
LE cells are neutrophilic phagocytes that contain intracytoplasmic hematoxylin bodies. The hematoxylin bodies are thought to be formed by the opsonization of cells by ANA typically found in SLE patients. These antibodies lead to the denaturation of dead or injured cells, forming homogenous oval-shaped bodies that are referred to as "hematoxylin bodies" because they stain blue with common cytologic stains such as Wright-Giemsa, Papanicolaou, and hematoxylin and eosin stains. The hematoxylin bodies are engulfed by neutrophils, creating LE cells. In cytologic preparations, LE cells must be distinguished from "tart cells" or "pseudo-LE cells," which result from the phagocytosis of nuclear debris by macrophages, rather than neutrophils, and are generally seen in effusion fluid--independent of the cause of the effusion. The phagocytosed debris within the tart cell is smaller, and has a non-homogenous (clumped) appearance in contrast to the smooth homogenous character of the hematoxylin bodies in true LE cells (see Image 2b).
LE cells are also seen in bone-marrow aspiration material, synovial fluid, cerebrospinal fluid, and pericardial fluid of SLE patients. The presence of LE cells in any of these specimens, in conjunction with the appropriate clinical picture and laboratory values, would contribute to the diagnosis of SLE.
The features that in the past, were most helpful to distinguish lupus pleuritis from other causes of effusions were immunologic, such as reduced levels of complement, presence of ANA, and LE cells. (4) Various studies, however, have shown that neither reduced levels of complement nor the presence of ANA in pleural fluid is a sensitive or specific predictor of lupus pleuritis.
First, complement level may be decreased in the fluid and is helpful in differentiating effusions caused by connective-tissue disease from those resulting from other causes of pleural effusions but is not specific to lupus pleuritis--although reduced complement values have been reported in SLE. Hunder, et al, suggested that pleural-fluid complement depletion may be socondary to immunologic activation and that immune complexes probably contribute to the development of pleuritis in lupus. (5)
Second, presence of ANA in pleural effusion has been suggested to a sensitive and specific marker for active pleurisy due to SLE. (6) In a series of 100 patients with pleural effusions of unknown etiology, the ANA was positive in seven patients with SLE and in one patient with drug-induced LE but not in patients with other diagnoses. In a study of 18 patients with SLE and pleural effusions, however, two of the patients with pleural effusions from causes other than lupus had ANA in the pleural fluid, although in lower titer compared to patients with lupus pleuritis. Khare, et al, in a study of 82 patients with pleural effusions, found a higher false-positive rate (10.8%) when using pleural-fluid ANA to diagnose lupus pleuritis. (7) A helpful feature was that a lower pleural-fluid ANA titer was seen in the majority of the patients without lupus pleuritis, making higher titers of pleural-fluid ANA (> 1:160) more suggestive of lupus pleuritis. A pleural-fluid-to-serum-NA ratio of 1.0 or more is reported to be strongly suggestive of lupus pleuritis. The finding is not a constant in lupus pleuritis, however, as Khare, et al, reported, only three of eight patients with lupus pleuritis has a pleural-fluid-to-serum-ANA ratio of 1.0 or more. (7)
Similarly, Wang, et al, showed only five of 10 patients with lupus serositis had a pleural-fluid-to-serum-ANA ratio of 1.0 or more. (8) Although the ratio was less than 1.0 in patients with SLE who had effusions from other causes, Wang, et al, found that 10 of 13 non-SLE patients with high ANA titers also had ratios of 1.0 or higher. These findings suggest that pleural-fluid-to-serum-ANA ratio has no additional value over the ANA to identify lupus pleuritis in patients with high-effusion ANA titers.
Different patterns of ANA immunofluorescence were first noted by Beck, et al, in 1961. (9) Khare, et al, suggested that the homogenous staining pattern in pleural fluid was predominantly found in patients with lupus pleurities, and a speckled staining pattern in pleural fluid suggested an alternative diagnosis. (7) Wang, et al, however, found that only five of 10 patients with lupus serositis has a homogenous staining pattern, and the other five had a speckled pattern. Furthermore, seven of 35 non-SLE patients had a homogenous pattern. These observations suggest that a reduced level of pleural-fluid complement, pleural-fluid-to-serum-ANA ratio, and homogenous ANA staining pattern are neither sensitive nor specific predictors of lupus pleuritis, and results of these laboratory parameters require correlation with patient presentation and other laboratory immunologic findings.
This case demonstrates that the cytologic examination of pleural fluid is important as a diagnostic study. The finding of the single LE cell was helpful in establishing the previously unsuspected diagnosis of lupus pleuritis, so that beneficial treatment could be initiated. In the past, a test was performed by the laboratory for the identification of LE cells and was known as the LE preparation. This test was considered specific for SLE, simple to perform, and recommended when the cause of pleural effusion was unknown. Advanced immunologic assays for SLE have replaced the labor intensive and insensitive LE preparation, but LE cells may still be encountered in preparations for fluidcell counts or cytopathology examination (see Image 3). Nevertheless, recognition and reporting of these cells, when found incidentally, can still be valuable as illustrated in this case of laboratory microscopic lights and radiographic imaging shadows.
Purva Gopal, MD, MS; Santosh K. S. Math, MD, MS; and Sandra C. Hollensead, MD, are all associated with the Department of Pathology and Laboratory Medicine at University of Louisville School of Medicine in Louisville, KY.
(1.) Mulherin D, Bresnihan B. Systemic lupus erythematosus. Baillieres Clin Rheumatol 1993;7:31-57,
(2.) Brasington RD, Furst DE. Pulmonary disease in systemic lupus erythematosus. Clin Exp Rheumatol. 1985;3:269-276.
(3.) Light RW. Pleural Effusions: The Diagnositc Separation of Transudates and Exudates. Ann Intern Med. 1972;77;:507-513.
(4.) Good JT Jr, King TE, Antony VB, Sahn SA. Lupus pleuritis. Clinical features and pleural fluid characteristics with special reference to pleural fluid antinuclear antibodies. Chest. 1983;84:714-718
(5.) Hunder GG, McDuffie FC, Huston KA, Elveback LR, Hepper NG. Pleural fluid complement, complement conversion, and immune complexes in immunologic and nonimmunologic diseases. J Lab Clin Med. 1977;90:971-980
(6.) Leechawengwong M, Berger HW, Sukumaran M. Diagnostic significance of antinuclear antibodies in pleural effusion. Mt Sinai J Med. 1979;46:137-139
(7.) Khare V, Baethge B, Lang S, Wolf RE, Campbell GD Jr. Antinuclear antibodies in pleural fluid. Chest. 1994;106:866-871
(8.) Wang DY, Yang PC, Yu WL, Shiah DC, Kuo HW, Hsu NY. Comparison of different diagnostic methods for lupus pleuritis and pericarditis: a prospective three-year study. J Formos Med Assoc. 2000;99:375-380
(9.) Beck JS. Variations in the morphological patterns of "autoimmune" nuclear fluorescence. lancet 1961;1:1203-1205
To earn CEUs, see current test at www.mlo-online.com under the CE Tests tab.
Upon completion of this article, the reader will be able to:
1. Recognize symptoms and features associated with systemic lupus erythematosus and lupus pleuritis.
2. Analyze laboratory tests performed for the diagnosis of lupus pleuritis.
3. Discuss findings that might be helpful in the detection of lupus pleuritis.
4. Describe LE cells in lupus pleuritis and its differences from tart cells.
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|Author:||Gopal, Purva; Math, Santosh K.S.; Hollensead, Sandra C.|
|Publication:||Medical Laboratory Observer|
|Article Type:||Clinical report|
|Date:||Nov 1, 2008|
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