Kartar Dawani ( Postgraduate Medical Institute, Lahore. )
Mohammad Tayyab ( Postgraduate Medical Institute, Lahore. )
Ventricular CSF glucose, total protein, protein electrophoresis, lgG, lgA, IgM and CSF cytology were determined in thirty seven patients with brain tumours. CSF glucose was unchanged and total protein was significantly high. Protein electrophoresis showed higher albumin and gamma globulin fractions. Mean IgG and IgA were significantly higher (Pc 0.001) in malignanttumours than in benign ones. IgM was detectable in 7 of 37 cases. The higher concentration of total protein, albumin and gamma globulin shows some degree of impairment of blood brain barrier. Increased concentration of lgG, IgA and IgM indicates humoral immune response of the brain against the tumours (JPMA42: 88, 1992).
The brain has long been regarded as an immunologically privileged site and this essentially is due to the blood brain barrier and absence of lymphatic channels1. Later experimental and human studies on gliomas showed some immunologic response and the term suggested was changed to “brain is a partially privileged site2,3. This study was carried out to see the humoral immune response of the brain against turnouts by CSF electrophoresis and immunochemical analysis.
PATIENTS AND METHODS
Thirty seven patients with brain tumours were selected from the department of neurosurgery, Lahore General Hospital, Lahore. There were 26 males and 11 females with ages ranging between 3 4 - 60 years. Selection was based on initial signs and symptoms of space occupying lesion in the brain and histological diagnosis after craniotomy. Cerebrospinal fluid was collected from patients in the operation theatre by inserting a brain cannula in the ventricles. CSF was kept in 2 aliquots and a smear was prepared for microscopic examination of malignant cells. From one aliquot glucose and total protein were measured on the same day while the other was frozen at -40°C.
Cerebrospinal fluid was concentrated for electrophoresis and immunoglobulin assay. As immunoglobulins were not detectable even in low level kits of RID supplied by Kallisted Laboratories USA. Concentration was done by freeze drying method in Consol 12, Vitris USA. Electrophoresis was done on cellulose acetate membrane in Elvi 70 tank and different protein fractions measured quantitatively by feeding level of total, protein in un concentrated sample on Elvi 165 densitometer. Student \\\'t\\\' test was used for comparison.
The mean ventricular CSF glucose was 77.85 ± 2.71 pg/dl and it ranged from 45.40 to 110 mg/dl. The total CSF proteins with the electrophoresis pattern and immunoglobulin assay are shown in Table I.
Immunoglobulin G (mean ± SEM was 784.5 ± 50.36 ug/dl. No significant difference was noted in the IgG levels of children and adults, males and females and among the different age groups. However, level of IgG in malignant tumours was significantly higher (Pc 0.00 1) than in benign tumours (Table II). IgA was detectable in 34 cases, the level ranged between 26 and 520 ug/dl. There was again no difference between the various groups. But it was significantly higher (Pc 0.05) in malignant tumours (Table II).
IgM was detectable in only 7 patients and values ranged between 171 and 212ug/dl (Table II). In all 37 patients with benign and malignant tumours CSF cytology showed no malignant cells.
Studies of general. immunocompetence in patinets with brain tumours are almost non existent, presumeably due to popular emphasis upon cell mediated mechanism of host response to neoplasia4. Mean ventricular CSP glucose is higher than lumber CSF glucose5, and in this study it is not affected by tumours. Mean total protein was significantly higher than normal values6. Whether this increase is transudate of serum of produced intrathecally, needs to be investigaed. In this study significant increase of almumin and gammaglobulin fraction than normal levels of other workers7, is compareable with the findings of Harter et al8, but Tventen9 described no change in his brain tumour patients. The increase of above factions suggests impair-ment of blood brain barrier as also emphasised by other workers10,12. Findings of increased IgG and IgA inmalignangt tumours than in benign tumours is compareable with results of many other workers.’1”2 It is presumed that the elevation of these immunoglobulins is related with humoral immune response of brain against tumours. Sensitivity of method is important as, lNerenberg et al., 13 using RIA technique detected raised IgM in 19 of 20 cases, while Monari et al., 14 was unable to detect IgM in any of his cases. It was detected in 7 cases of 37 in this dtudy. Although PID is much less sensitive method for lower levels, finding of IgM suggests some humoral immune response against brain tumours and warrants further investigations in this regard with more sensitive methods.
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