Depersonalization : (A phenomenological study in psychiatric patients).
Antirabies post-vaccinal complications using simple vaccine are considered rare. Figures vary from author to author (1: 4000 to 1:10,000). Of late, the neuroparalytic accidents appear to have increased. Varied clinical manifestations make it very difficult to determine whether it is actual rabies infection or it is due to iatrogenic accident (complication of anti-rabies vaccine injection). A total of eight neuroparalytic accidents with a history of dog bite and administration of anti-rabies vaccine (ARV) admitted to Kasturba Medical College Hospital from June, 1977 to March, 1980 were investigated. All these cases (test group) were diagnosed on the basis of LMI test using sheep brain extract as an antigen. The LMI test in these test group cases were compared with control I (infection other than rabies and no history of ARV injection for dog bite) and control II (cases having history of dog bite and administration of ARV injection).
Three groups of patients were investigated by leucocyte migration inhibition test using same antigen.
Control Croup I
This group included 21 patients who attended the Kasturba Hospital Manipal, with various clinical illnesses (encephalitis 15 cases, bacterial menignitis 4 cases, brain abscess 2 cases) other than, rabies infection. None of these patients had any history of dog bite or administration of antirabies vaccine.
Control Group II
This group consisted of 13 patients, in whom there was a history of dog bite and administration of full course of antirabies vaccine (2 ml/day for 10 days). Details of vaccines were not available. These patients were investigated within 5 to 7 days after a full course of ARV injections.
This group includes 8 patients (2 cases each from 2 families) who were clinically suspected to be cases of post-vaccinal encephalitis. All of them gave a history of taking antirabies vaccine (2 ml/day). Details of vaccine were not available. Three patients had 7 injections and 2 patients had 8 injections; the rest of them had just completed the course of antirabies vaccine. The clinical features and other details of the cases are given in [Table 1].
Twenty grams of sheep brain, were made into a homogeneous suspension with 10 ml of sterile distilled water by using Ten broke tissue grinder. Then the homogenate suspension was transferred to a 15 ml centrifuge tube and was centrifuged for 10 minutes at 1,500 r.p.m. The supernatant was taken and filtered through a Whatman's number: 1 filter paper and later through a Seitz filter. The clear fluid obtained after Seitz filtration was used as antigen for leucocyte migration inhibition tests.
Leucocyte migration test
The test was performed according to the technique employed by Federlin et al. The amount of sheep brain antigen used was 0.05 ml, 0.025 ml and 0.005 ml per chamber. The control and various concentrations of the antigen were placed in 16 Mackney's chambers (Vora Company, Bombay) which hold 0.35 ml each. Throughout the experiment TC-32 medium (Microlab, Bombay) was used. The chambers were incubated at 37°C for 18 hours in large petri dishes. The humidity was maintained in these petri dishes by inserting a piece of gauze soaked in water. The chambers containing the capillary tubes were then examined under scanner lens (x 40) and the area of migration was plotted on a graph paper by using Camera Lucida. The results were expressed as MI or migration or index.
MI =Mean area of spread of leucocytes in the presence of the antigen
Mean area of spread of leucocytes in the absence of the antigen.
In the absence of antigen, leucocyte migration did occur as expected; the inhibition of leucocyte migration was well marked when 0.05 ml of antigen was used in all 8 test group cases.
In all 8 test group cases, the LMI was well below 0.8 at 0.05 ml antigen, whereas in the control group at the corresponding antigen it varied between 0.9 and 1.2. Hence MI (Migration index) of 0.8 or below at 0.05 ml antigen appears to be a good criterion to differentiate between the control and the test groups. However, at lower concentrations of antigen no such inference could be drawn. The results of MI in test groups and control groups are given as maximum, minimum and mean ± standard deviation in [Table 2].
The results of LMI at various amounts of antigen in the control and test groups is given in [Table 3].
The efficacy of the nerve tissue vaccine (NTV) in man has not been evaluated by control studies. The vaccine of this type suffers from the serious disadvantage that the nervous tissue they contain may sensitise a small proportion (1 in 4000 to 1 in 10,000) of persons, being immunised who later may develop an encephalitis. Sheep brain vaccines are the most widely used vaccines and hence the sheep brain extract antigen was used for leucocyte migration inhibition tests in the present series.
The lymphokinase factor is responsible for inhibition of sensitised leucocytes/ macrophages and under the influence of this factor the macrophages become rounded and immobile. In our studies, it appears that the leucocyte migration inhibition test is useful in the diagnosis of antirabies vaccinal encephalitis.