Abstract
Purpose: :
To study the TPMT enzyme activity in patients who were treated with Azathioprine for severe sight threatening uveitis.
Methods: :
Retrospective review of 1000 patients revealed 136 who had received Azathioprine as immunosuppressive therapy in sight-threatening Uveitis. Each patient when started on Azathioprine therapy was tested for the TPMT enzyme level (genotype testing). The diagnosis for which Azathioprine was given was analysed. Adverse effects or intolerance to Azathioprine was also noted and a correlation with TPMT genotype in those patients was studied. TPMT enzyme assay was carried out in these patients as well.
Results: :
45% were males (n= 61), 55% were female (n = 75). Average age of the patients were 49.38 years for female and 36.59 years for Male. Uveitis was Anterior (14.7%), Intermediate (17.64%), posterior (48%) and Total (17%). 14% (n=20), developed intolerance or side-effects to Azathioprine and had to be changed to other immunosuppressive drugs. 20% (4/20) of these were found to have the genotype associated with low TPMT activity (*03A and *03B). TPMT assay tests (normal range 8-22 nmol/h/ml rbc) revealed that these patients had very low (< 5 nmol/h/ml rbc). These patients had severe myelosuppression which improved after changing them over to other immunosuppressive drugs.
Keywords: enzymes/enzyme inhibitors • uveitis-clinical/animal model • drug toxicity/drug effects