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| ORIGINAL ARTICLE |
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| Year : 1988 | Volume
: 36
| Issue : 1 | Page : 22-26 |
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Alpha-1 antitrypsin and serum albumin levels in tear fluid of healthy subjects and in persons with conjunctival diseases
DK Sen, GS Sarin, MD Mathur
V/4, Maulana Azad Medical College Campus, Kotla Road New Delhi-110 002, India
Correspondence Address:
D K Sen
V/4, Maulana Azad Medical College Campus, Kotla Road New Delhi-110 002
India
 Source of Support: None, Conflict of Interest: None  | Check |
PMID: 3267008 
Alpha-1 antitrypsin and serum albumin levels were measured in the tear fluids in 81 healthy subjects and 142 patients with conjunctival diseases. The levels of the two proteins were independent of age and sex. They were found to be increased in all the conjunctival diseases studied excepting epithelial xerosis. The extent of the increase correlated well with the severity of the diseases. The alpha-1 antitrypsin and serum albumin levels in tears showed return to normal levels with clinical improvement. The present study indicates that the markedly raised level of alpha-1 antitrypsin in tears in inflamed eyes is mainly due to the passive leakage of the protein from the congested conjunctival blood vessels in to tear fluids and not due to local release or production.
How to cite this article:
Sen D K, Sarin G S, Mathur M D. Alpha-1 antitrypsin and serum albumin levels in tear fluid of healthy subjects and in persons with conjunctival diseases. Indian J Ophthalmol 1988;36:22-6 |
Alpha-1 antitrypsin or protease inhibitor is an enzyme that controls, the activity of diverse proteolytic enzymes like trypsin, chymotrypsin, collagenase, thrombin, fibrinolysin, granulocytic proteases [2], and caseinas [3] by cleaving catalytic sites [1]. It can be found in a number of body fluids such as tears, perilymph, lymph, saliva, colostrum, breast milk, duodenal fluid, gallbladder bile, synovial fluid, cervical mucus, semen, and aminitic fluid [4],[5],[6],[7],[8],[9]. It plays an important role in both physiological and pathological conditions by inactivating enzymes activated by bacteria or other agents Alpha-1 antitrypsin has been shown to play a role in regulating the immune response by inhibiting the transformation and migration of lymphocytes [10].
The role of tear alpha-1 antitrypsin in corneal ulcer and other diseases have been studied [11],[12]. It has been suggested that it may have a protective function However, the studies available on alpha-1 antitrypsin level in tears in patients with conjunctival diseases [11],[13] are small and no definite conclusion could be drawn from them. The purpose of this study was to measure the tear alpha-1 antitrypsin in a large number of patients with different conjunctival diseases and evaluate the effect of therapy
on its level in these diseases. We have also measured serum albumin in tear fluids as it is an indicator of leakage of serum proteins into tears.
| Material and Methods | |  |
The study was carried out among 142 patients with conjunctival diseases chosen from the outpatient department of Guru Nanak Eye Centre, New Delhi, and 81 healthy subjects. The latter group served as a control and comprised subjects who had no evidence of any systemic or ocular diseases after complete physical and ophthalmological examinations.
The diagnosis of the conjunctival diseases was based on detailed clinical examination including slit lamp biomicroscopy and relevant bacteriological and other laboratory investigations. The patients did not have any other ocular or systemic disease.
In patients with acute bacterial conjunctivitis pathogens were identified on conjunctival smears and cultures [Table - 1]. The bacterial infection was mixed in majority of the patients The patients with chronic irritative conjunctivitis were factory workers whose eyes were exposed to noxious fumes for many months. Their chief complaints were watering, burning, stinging, foreign body sensation and an urge to rub their eyes. Hyperaemia of the conjunctiva was a Drominent feature and was particularly marked in the area of the palpebral aperture Patients with acute conjunctivitis were subgrouped as mild and severe according to the intensity of clinical features. None of the patients had received any medication before the tear fluid samples were collected. The patients were treated with appropriate therapy. Tear samples were again collected for the determination of alpha-1 antitrypsin and serum albumin levels from 81 patients with acute bacterial conjunctivitis, acute allergic conjunctivitis, vernal conjunctivitis, phlyctenular conjunctivitis and chronic irritative conjunctivitis during the stage of remission when there was no clinical evidence of the disease.
In males the levels of alpha-1 antitrypsin was 4.07 ± 2.39 µg/ml and that of serum albumin was 12.15 ± 5.97 µg/ml and in females the level of alpha-1 antitrypsin was 3.92 ± 2.29 µg/ml and that of serum albumin was 11.07 ± 6.40 µg/ml. There was no significant difference statistically between the two sexes in the levels of alpha Tear samples were collected by the method described earlier [14]sub and stored at -20 0sub C until assayed Alphaantitrypsin and serum albumin levels in tear fluid samples were quantified by electroimmunodiffusion technique [15]. Monospecific goat antihuman alpha-I antiserum and antihuman serum albumin sera and their respective reference standards were obtained from Meloy Laboratories, Virginia, U.SA The levels of the two proteins in tear fluids were calculated from the calibration curves constructed by incorporating three known concentrations of the respective reference standard for every set of determination. The results were statistically analysed by Student's 't' test
| Results | | |
The age and sex distributions of healthy subjects and patients are shown in [Table - 2]. Alpha-1 antitrypsin and serum albumin were found in all the tear samples in measurable quantity. Their levels in tear fluids in various age groups in healthy subjects are given in [Table - 3]. There was no statistically significant difference in the levels of alpha-1 antitrypsin and serum albumin in tears between the various age groups. The correlation coefficient(r) between age and alpha-1 antitrypsin was found to be 0.10 which is statistically not significant (P > 0.40). The correlation coefficient (r) between age and serum albumin in tear fluids was found to be 0.02 which is again not statistically significant (P > 0.80).
1 antitrypsin (P > 0.80) and serum albumin (P > 0.50)
[Table - 4] shows the level of alpha-1 antitrypsin and serum albumin in tears in the diseased groups. The tear alpha-1 antitrypsin level was significantly increased in all the diseases excepting epithelial xerosis.
[Table - 5] shows the alpha-1 antitrypsin and serum albumin levels in tear fluids in mild and severe stages of acute conjunctival diseases. Alpha-1 antitrypsin and serum albumin levels showed statistically significant increase even in the mild stages of the diseases as compared to the respective levels in healthy subjects verneal conjunctivitis (P < 0.001, P < 0.001), acute bacterial conjunctivitis (P < 0.001, P < 0.001), acute allergic conjunctivitis (P < 0.001, P < 0.001) and phlyctenular conjunctivitis (P < 0.001), P < 0.001). There was also statistically significant difference in the levels of both the proteins between the mild and severe stages of the diseases.
[Table - 6] shows that there was a statistically significant difference in the levels of alpha-1 antitrypsin and serum albumin in tear fluids between the acute and remission stages of the conjunctival diseases. However, there was no significant difference between the tear alpha-1 antitrypsin levels in healthy subjects and in remission stages of the diseases : acute bacterial conjunctivitis (P > 0.20), acute allergic conjunctivitis (P > 0.10), chronic irritative conjunctivitis (P > 0.80), phlyctenular conjunctivitis (P > 0.60) and vernal conjunctivitis (P > 0.20), Similarly there was no significant difference between the serum albumin levels in tear fluids in healthy subjects and in remission stages of the diseases : acute bacterial conjunctivitis (P > 0.20), acute allergic conjunctivitis (P > 0.60), chronic irritative conjunctivitis (P > 0.60), phlyctenular conjunctivitis (P > 0.50) and vernal conjunctivitis (P > 0.20).
| Discussion | | |
The tear alpha-1 antitrypsin level in healthy subjects in the present series is similar to that reported by others [11],[16] others However, several other workers have reported higher levels [6],[17]. This variation in the level maybe due to the difference in the techniques employed for collecting tear samples and also for measuring the protein.
Alpha-1 antitrypsin level in healthy subjects in the present series was found to be independent of age and sex This is in agreement with the findings of Prause [16]sub . It has also been established earlier that the levels of alpha1 antitrypsin in tear fluids in healthy subjects is not dependent on its concentration in the serum [6],[11] This leads us to believe that in healthy subjects alpha-1 antitrypsin in tears is due to local release or production.
Several proteolytic enzymes are liberated during the bacterial infections [18]. The action of these proteases is modulated by various inhibitors like alpha-1 antitrypsin, alpha- I antichymotrypsin, interalpha trypsin inhibitor, anti-thrombin-2, C-1 inactivator, and alpha-2 macroglobulin [19]
Alpha-1 antitrypsin level in tear fluids have been reported to be increased in patients with comeal ulcers [11],[12] We have measured its level in a large number of patients with conjunctival diseases without corneal ulcer in an attempt to determine the relationship if any between conjunctival inflammation per se and tear alpha-1 antitrypsin levels. It is clear from this study that tear alpha-1 antitrypsin level does rise in inflamed eyes in the absence of corneal ulceration.
Berman et al studied one patient with conjunctivitis and another with allergic conjunctivitis and reported several fold increase in alpha-1 antitrypsin level in tears in the patients with allergic conjunctivitis [11]. Zirm and Ritzinger reported high levels of alpha-1 antitrypsin in some other patients with bacterial conjunctival infections [13].
In a comprehensive study we found a remarkable elevation of alpha-1 antitrypsin and serum albumin in tear fluid samples bathing the inflamed conjunctiva. The concentrations of alpha-1 antitrypsin and serum albumin in tear fluids were found to be increased by about 15 times the level in healthy subjects. In acute bacterial conjunctivitis and acute allergic conjunctivitis and 2-3 times in vernal conjunctivitis, phlyctenular conjunctivitis and chronic irritative conjunctivitis. There is a general agreement between. the extent of conjunctival inflammation and the levels of alpha-1 antitrypsin and serum albumin in tear fluids [Table - 5]. This relationship is most evident while comparing mild and severe conjunctival inflammations. The levels of the two proteins returned to their respective levels in healthy subjects during the remission stage. This means that the high levels of alpha-1 antitrypsin and serum albumin in tear fluids in patients with acute bacterial conjunctivitis and other conjunctival diseases were due to inflammation and not inherent or pre-existent
The route(s) by which alpha-1 antitrypsin enters tears is not known. The present study indicates that serum proteins including antiproteases leak passively from the blood vessels into tear fluids in patients with inflamed eyes. Ratio of serum albumin to alpha-1 antitrypsin in tears is about 3 : 1. The albumin and alpha-1 antitrypsin ratio in blood is known to be 20: 1. This relative increase in alpha-1 antitrypsin level in tear fluids in conjunctival inflammatory diseases may be due to the smaller molecular weight (52000) of alpha-1 antitrypsin as compared to serum albumin (67000) which makes it easier for alpha 1 antitrypsin to leak out from inflammed conjunctival vessels. However, a small amount of local release or production of alpha-1 antitrypsin in inflamed eyes in addition to leakage from serum into tears cannot be ruled out.
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[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6]
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