RESUMO
The aim of this work was to study T-lymphocyte function in relation to secondary hyperparathyroidism, oral one alpha-calcidol treatment and dialysis duration. Eighty chronic renal failure patients who were maintained on regular haemodialysis treatment for 6-144 months [CRF] and 20 normal control subjects [N] were studied. Cases known to have autoimmune diseases, other diseases, which would affect the immune system or receiving medications known to affect immunity were excluded. CRF cases were 45 males and 35 females and their age was 43.06 +/- 11.1 years, while N cases were 12 males and 8 females and their age was 35.6 +/- 9.79 years. A11 CRF cases were receiving 1-alpha-calcidol orally as 1 mug/day for at least 3 months before the study onset. CRF and N cases were clinically examined and were tested for serum urea and creatinine, serum calcium and phosphorus, serum level of intact parathormone [RIA] beside the in vitro assessment of lymphoblastoid transformation of peripheral blood lymphocytes with and without phytohaemagglutinin [PHA] stimulation. The serum level of intact parathormone varied significantly among CRF cases; it was < 40 pg/ml in 13 [CRF1], 40-80 in 14 [CRF2] and > 80 in 53 [CRF3]. Among these 3 subgroups, pre-activation of T-lymphocytes was significantly higher in CRF3 [28 +/- 3.94 vs. 33.7 +/- 5.44 vs. 37.36 +/- 3.58% in CRF1, 2, 3 respectively],while PHA induced T-cell proliferation was significantly higher in CRF1 [77.54 +/- 3.97 vs. 73.7 +/- 4.83 vs. 59.9 +/- 7.37% in CRF1, 2, 3, respectively]. Duration of dialysis [DX] was significantly shorter in CRF1 [15.6 +/- 5.94 vs. 33.57 +/- 11.9 vs. 79.7 +/- 30.2 months in CRF1, 2, 3, respectively]. There was no significant difference between the 3 subgroups in dose or duration of 1-alpha-calcidol treatment. CRF1 had significantly higher s-phosphorus and s-PTH, significantly lower PHA induced T-cell proliferation and insignificant difference in serum calcium and T-lymphocytes pre-activation when compared to N [5.32 +/- 0.41 vs. 3.39 +/- 0.64 mg%, 30.08 +/- 4.89 vs. 19 +/- 4.57 pg/ml, 77.54 +/- 3.97 vs. 84.8 +/- 2.8%, 9.73 +/- 1.07 vs. 9.92 +/- 0.48 mg% and 28 +/- 3.94 vs. 29.2 +/- 4.73%,respectively]. DX had a significantly +ve correlation with either PTH level or T-lymphocytes pre-activation and a significantly -ve correlation with PHA induced T-cell proliferation. PTH had a significantly +ve correlation with T-lymphocytes pre-activation and a significantly -ve correlation with PHA induced T-cell proliferation. The study concluded that increased DX duration is responsible for: Significant increase in s-PTH; increased resistance of parathyroid to suppression by 1-alpha-calcidol and progressive deterioration of T-cell function as proved by increased T-lymphocytes pre-activation and decreased PHA induced T-cell proliferation