Clinical significance of autoimmune antibodies in leprosy

Clinical significance of autoimmune antibodies in leprosy

749 TRANSACTIONSOF THE ROYAL SOCIETYOF TROPICAL MEDICINE AND HYGIENE. Vol. 66. No. 5. 1972. C L I N I C A L S I G N I F I C A N C E O F A U T O I M M ...

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749 TRANSACTIONSOF THE ROYAL SOCIETYOF TROPICAL MEDICINE AND HYGIENE. Vol. 66. No. 5. 1972. C L I N I C A L S I G N I F I C A N C E O F A U T O I M M U N E A N T I B O D I E S IN L E P R O S Y T I N SHWE Department of Clinical Tropical Medicine, London School of Hygiene and Tropical Medicine and Burma Leprosy Service Introduction

The hypothesis that an autoimmune mechanism can be present in leprosy, at least during reactions, has received the attention of many workers. MATTrmWS and TP.AUTMAN (1965), BONOMO et al. (1963, 1965, 1967), WAGER (1969) and ALM~IDA (1971) called attention to the serological overl~tp between leprosy and diseases with autoimmtme phenomena, in particular those related to collagenosis. Hypergammaglobulinaemia and biological false reactions for syphilis are common findings in patients with lepromatous leprosy; and a number of autoimmune-like factors have been reported. These include rheumatoid factor (CATHCA~Tet al., 1961 ; MATTHEWS and TP~UTMAN, 1965), thyroglobulin antibodies (BoNOMO et al., 1963; MAYAMA, 1968), cold precipitated proteins (MATTHEWS and TP.AUTMA~, 1965), and LE cell and antinuclear factor (BoNoMO et al., 1965, 1967; AZOURYand GuM, 1967; SATO and M i t r e , 1968; and MAYAMA, 1968). An increasing body of evidence indicates that the occurrence of auto-antibodies is by no means a rare phenomenon, and that they may be found in the sera of patients with a variety of disorders (KtrNKEL and TAN, 1964). A study was therefore carried out to elucidate if such autoimmune antibodies commonly found in patients with lepromatous leprosy bear any significance to the clinical signs and symptoms. Patients and methods

Sera collected from 72 leprosy patients from the Hospital for Tropical Diseases, London, were used in the tests. The patients were classified according to RIDLEY and JOPLING (1966). The clinical signs and symptoms were followed for 1 year. A control group of 20 aduks who also came from the tropics were included in the study. Patients' sera and control sera were tested for rheumatoid factor, thyroglobulin, and LE cell factor by the latex agglutination technique, using the reagents from Hyland Laboratories, U.S.A. Patients' sera and control sera were tested for antinuclear factor, gastric parietal cell antibody, thyroid cytoplasmic antibody, and mitochondrial antibody by the double layer immunofluorescent technique. Frozen rat liver used as substrate for detection of antinuclear factor, and human thyroid, stomach, and kidney (kindly supplied by the Department of Immunology, Middlesex Hospital) were used as substrates for the detection of organ specific autoantibodies. Sera diluted 1 : 2 was used in testing for antinuclear factor on rat liver. In the remaining tests sera were diluted 1 : 10. Antihuman globulin conjugate (Burroughs Wellcome product) was used in the system. I express my gratitude to Professor A. W. Woodruff, Professor of Clinical Tropical Medicine, London School of Hygiene and Tropical Medicine, Dr. D. S. Ridley, Pathologist~ of the Hospital for Tropical Diseases, under whose guidance this project was done. I also wish to thank Dr. W. H. Jopling, Leprologist, Hospital for Tropical Diseases, London, Dr. D. Doniach and staff of the Department of Immunology, Middlesex Hospital, Dr. A. Voller, Senior Lecturer, London School of Hygiene and Tropical Medicine for all their help.

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CLINICALSIGNIFICANCEOF AUTOIMMUNEANTIBODIESIN LEPROSY Results

Using latex-globulin reagent (Hyland RA-Test) 14 out of 56 lepromatous leprosy patients (25.0%) showed positive tests for rheumatoid factor. Among the patients with positive rheumatoid factor none with the clinical syndrome of rheumatoid arthritis was detected. Using Latex thyroglobnlin reagent (Hyland TA-test) 9 out of 56 lepromatous leprosy patients (16.0%) showed a positive test for thyroglobulin autoprecipitin associated with Hashimoto's thyroiditis. Among the patients with positive TA-test none of the patients had any clinical signs and symptoms relating to thyroid abnormality. Using latex-nucleoprotein reagent (Hyland LE-test) 10 out of 56 lepromatous leprosy patients (17.9%) showed positive tests for LE serum factor. Using rat liver as substrate antinuclear factor in homogenous pattern was detected in 10 out of 56 lepromatous leprosy patients (17.8%) but the sera dilution was not more than 1 : 2. Among the patients with positive tests either by the LE test, or by the fluorescent antibody technique none showed signs and symptoms of systemic lupus erythematosus or other connective tissue disorders. No positive tests were observed in the tuberculoid group of patients or in controls. The difference in the prevalence of positives in the above tests as between lepromatous leprosy and the other groups is statistically significant (p = <0-05). Out of the tests for organ specific autoantibodies, 2 patients with lepromatous leprosy gave positive reactions to gastric parietal cell autoantibody. 1 patient with lepromatous leprosy also showed a positive reaction to thyroid cytoplasmic autoantibody. The control sera and non-lepromatous leprosy sera did not give a positive reaction to the above tests. None of the sera from leprosy patients or from controls gave a positive reaction to mitochondrial antibody. The results are summarized in Tables I and II. TABLE I. Autoimmune antibodies in leprosy. (Latex fixation tests).

Patient's group

RAtest LE test No. of No. % patients No. % tested positive p >sitive positive positive 0-0

0

0"0

0

0 0

12

3

2

17

3

Controls

20

TT and BT

11

0

BB

6

BL LL no reaction L L in reaction

27

0

)

~ 25"0

6

8

% positive

0

0-0

0 0

)

. 17.8

3 4

I 16"0 j

I

J

No. positive

0.0 )

2

TA test

0.0 0.0

Discussion

Rheumatoid factor consists of a group of autoantibodies commonly associated with rheumatoid arthritis. Latex agglutination tests and sheep cell agglutination tests are commonly used to detect rheumatoid factor. In this study the latex agglutination test

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751

was positive in 25.0% of the patients with lepromatous leprosy. In leprosy CATHCART et al. (1961) reported that 44 out of 101 patients gave a positive reaction to rheumatoid factor by latex fixation test, and 14.7% of the same patients a positive reaction in the sheep cell agglutination test. MATTHEWSand TRAUTMAN(1965) also found that 58% of the patients gave a positive reaction to rheumatoid factor by the latex agglutination method. TABLE II. Autoimmune antibodies in leprosy. Fluorescent antibody technique). Organ specific autoantibody

Patient's group

Antinuclear factor No. of patients (rat liver)

Controls

20

0

TT and BT

11

0

BB

6

0

BL

12

0

LL no reaction

17

2

LL in reaction

27

8

% A.N.F. positive

Gastric parietal cell

Mitochondrial Thyroid autocytoplasmic antibody

0.0 0.0

t

17-8

Rheumatoid factor is not specific for the diagnosis of rheumatoid arthritis; it is also found in patients with connective tissue diseases, and in patients with chronic infections (GoUDIE, 1970). In this study among the patients positive for rheumatoid factor none with the clinical syndrome of rheumatoid arthritis was detected. Rheumatoid arthritis is one of the main causes of amyloidosis in the western world (DowmE and BUCHANAN, 1969) and leprosy is often associated with amyloidosis, but in this study the only patient with leprosy and amyloidosis gave a negative reaction to rheumatoid factor. Therefore the significance of rheumatoid factor in leprosy remains obscure. CATHCART et al. (1961) in their study on 101 leprosy patients also had been unable to define the significance of rheumatoid factor in leprosy. LE cell and antinuclear factor are autoantibodies associated with systemic lupus erythematosus. The LE cell test, latex agglutination test, and immunofluorescent techniques are commonly used to detect the presence of antinuclear antibodies. In this study 17-8% of patients with lepromatous leprosy gave positive reactions to latex agglutination and immnnofluorescent tests. BONOMOet al. (1965), AZOURIand GuM (1967), M I u ~ (1968) and MAYA~ (1968) have also reported a high prevalence of antinuclear antibodies in patients with lepromatous leprosy. Thus there is no doubt that antinuclear antibody tests may be positive in lepromatous leprosy. The tests for antinuclear antibodies are highly sensitive and are not specific for systemic lupus erythematosus. Antinudear factor is found in 50% of patients with sderoderma or dermatomyositis, 25% o f patients with rheumatoid arthritis or liver disease, in some patients with drug reactions and in some normal subjects (Gomm~, 1970). The finding of antinudear antibody~ if only in high titre, is thus suggestive of the presence of a connective tissue disease.

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CLINICAL SIGNIFICANCE OF AUTOIMMUNE ANTIBODIES IN LEPROSY

In this study among the patients with positive results either for the LE test or the fluorescent antibody technique none showed signs and symptoms of systemic lupus erythematosus or other connective tissue disorders. Renal failure is a common complication in patients with either systemic lupus erythematosus, or leprosy. However, the patients with renal failure or proteinuria in leprosy did not have positive antinuclear factor (TIN SHVcX,in preparation). Thyroid autoantibodies in the serum suggests the presence of chronic thyroiditis. In this study using the latex agglutination technique 16.0% of the patients with lepromatous leprosy had positive reactions to thyroglobulin. Using the immunofluorescent technique only 1 out of 56 lepromatous leprosy patients gave a positive reaction to thyroid cytoplasmic antibody. BONOMO et al. (1963) also reported that 42.0% of the leprosy patients had positive latex fixation tests for thyroglobulin. MAYAMA(1968) found 54~o of lepromatous leprosy patients during ENL reactions gave positive latex agglutination tests to thyroglobulin. Thyroid autoantibody in the serum always suggests the presence of chronic thyroiditis. Unfortunately to obtain the greatest diagnostic accuracy separate tests have to be performed using 3 distinct thyroid specific antigens, and, when positive, further tests are necessary to determine the titre of the antibody (GoUDIE, 1970). Thyroglobulin alone can no longer be regarded as a secluded antigen since it is detected in trace amounts in up to 60% of normal individuals and all pregnant women and in cord blood (DomACH and ROlTT, 1968). Moreover in this study none of the patients showed any clinical signs and symptoms relating to thyroid abnormality. BONOMO et al. (1963) also found no relation between the presence of thyroglobulin antibodies and the age or duration of the disease. This suggests that the presence of thyroglobulin in leprosy cannot be regarded as important from the clinical point of view. As regards gastric parietal cell antibody, this is present in 86~/o of cases of pernicious anaemia, and in 11% of the normal adult population (TAYLOR et al., 1962). In this study 2 patients with lepromatous leprosy showed positive reactions. The difference in the prevalence of gastric parietal cell antibody between patients with lepromatous leprosy and other groups of patients is not significant. These 2 patients had no history of anaemia and their haemoglobin estimations were normal. The conclusion is that the finding of antibody to gastric parietal cell has no clinical significance in leprosy. Mitochondrial antibodies are found in 90% of the patients with biliary cirrhosis often in high titre, and in 25-30% of patients with 2 other liver disorders connected with autoimmtmity, i.e. chronic hepatitis, and cryptogenic cirrhosis (DoNIACH et al., 1966). Such antibodies are not detected in leprosy. Finally, as false positive reactions for syphilis can occur in patients with lepromatous leprosy non-organ specific autoantibodies may also be present in the sera of patients with lepromatous leprosy, but they bear no clinical significance to the disease. The sustained antigenic stimulation due to chronic infection with Mycobacteriumlepraemay be responsible for the autoantibodies in leprosy.

Summary Specimens of sera from 73 leprosy patients and from 20 controls were tested for rheumatoid factor, antinuclear factor, thyroglobulin antibody and for certain organ specific antibodies (gastric parietal cell, thyroid cytoplasmic, and mitochondrial antibodies). A significant proportion of the lepromatous leprosy patients showed positive reactions to rheumatoid factor, thyroglobulin, and antinuclear factor in low titre. The presence of non-organ specific autoantibodies bears no clinical significance to the d]sea~. Organ specific autoantibodies were not common in leprosy sera.

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