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IMMUNOSUPPRESSION

Shrirang Bichu, Umesh Oza

 

Normal humans are blessed with an immune system. Sustenance of life would have been impossible without a strong immunity. The immune system guards oneself against invaders like viruses, bacteria, fungi and parasites. Anything
that is “not self” is recognised as foreign and attacked.

Unfortunately this incredible ability of our body works against oneself in organ transplantation. Our body fails to understand that the transplanted organ is infact life saving. Our immune system attacks it resulting in “rejection” of the organ.

Surgeons have mastered the techniques of kidney transplantation. However the success of transplantation lies in protecting the graft from the immune onslought. Over the years many immunosuppresants have been introduced and few have passed the test of time.

All immunosuppressants have serious side effects; susceptibility to infection and malignancies are the ones that cause more concern.

Hence immunosuppression is a double edged sword. A good transplant physician tailor-makes immunosuppression regimen for his patient. Combinations of drugs and dosages just enough to protect the graft but not more to avoid serious side effects is essential for successful transplantation.

The most commonly used regimen is a combination of these drugs namely, prednisolone, cyclosporin and azathioprin. Mycophenolate mofetil is now rapidly replacing azathioprin as it is much superior though more expensive. More recently sirolimus has been introduced in India. Although an excellent antirejection drug it has multiple
debilitating side effects and hence has to be used with extreme caution. Various antibodies are also used both for preventing and treating rejection. Fig. 1 shows sites of action of commonly used immunosuppressants.

Good HLA tissue matching of the donor and recipient decreases the chances of rejection and allows the use of less powerful and cheaper combination of drugs like prednisolone with azathioprin alone. Crossmatching of the serum of prospective recipient with the donor lymphocytes is absolutely necessary. A positive crossmatch is a contraindication for transplant as chances of hyperacute rejection are high. With the advent of newer immunosuppressant drugs the edge offered by a good tissue match is getting blunted and many centres have now given up tissue typing if these drugs are used. However crossmatching is a must.



A transplant patient has to take immunosuppressants life long. Stoppage leads to rejection even after years of normal graft function. "Tolerance", a state when immuosuppressant is not required and the graft is accepted by ones body is
a dream of all transplant physicians and scientists. Millions of dollars and hundreds of man hours are

 

CONVERTING PATIENTS TO INSULIN
Any patient with hyperglycaemic symptoms, particularly weight loss, on maximum tolerated doses of hypoglycaemic
agents should be considered for insulin.

In patients on the maximum tolerated doses of metformin and sulphonylureas the best option is to discontinue the sulphonylurea and commence id mixed insulin. Continuing metformin can help prevent weight gain and help minimise insulin doses. Those unable to take metformin, particularly the elderly on maximum sulphonylurea, often respond well to the addition of once-daily long-acting insulin to supplement the failing ß cells.

The Practitioner, 2003; 247 : 582

ORAL PREDNISONE AFTER EMERGENCY TREATMENT OF COPD
The optimal approach to the treatment of patients who are discharged from the emergency room after an exacerbation of
chronic obstructive pulmonary disease is not known. This study compared the patients' usual medications and antibiotics with those medications plus 10 days of prednisone at a dose of 40 mg per day. Patients receiving the corticosteroid had fewer relapses and better lung function than those receiving placebo.

Although these investigators found a benefit of corticosteroid treatment, the evidence favouring prednisone is not overwhelming. Physicians should consider prednisone as another treatment option rather than as mandatory therapy.

N Engl J Med, 2003; 348 : 2618.

ORDINARY ACTIVITY IS AS GOOD AS EXERCISES OR RELAXATION FOR NECK PAIN
Dynamic muscle training and relaxation training are no better for neck pain or neck related disability than ordinary physical activity. Viljanen and colleagues randomised 393 women of.ce workers with chronic neck pain to dynamic muscle training, relaxation training, or ordinary activity (controls). The range of motion for rotation and lateral .exion in the neck region improved slightly more in the training groups than in the control group, but no other differences in neck pain were found between the three groups at three, six, or twelve months. Neck pain is common, affecting an estimated two thirds of people during their adult lives.

BMJ, 2003; 327 : 475.

 

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