Keratinocyte and lymphocyte apoptosis: relation to disease outcome in systemic lupus erythematosus patients with and without cutaneous manifestations

ABSTRACT

To investigate the relation of keratinocyte and lymphocyte apoptosis and macrophage function to disease activity and severity in SLE patients with and without cutaneous manifestations. Fifty SLE patients [25 with cutaneous manifestations [group I], 25 without cutaneous manifestations [group II]] and 20 normal controls [group III] were studied. SLEDAI score was used to assess lupus activity. Peripheral lymphocyte apoptosis by Annexin V, macrophage function by serum neopterin and immunohistochemical detection of apoptotic cells in the skin by p.53 were done. Renal biopsy was done in indicated cases. Mean SLEDAI score was significantly higher in group I than II [18.6 +/- 6, 8.8 +/- 2.7 respectively, p<0.001]. The mean percentage of peripheral apoptotic lymphocytes was significantly higher in group I compared to group II and III [55.3 +/- 21.4, 25.6 +/- 8. 7 and 19.4 +/- 3.2 respectively, p<0.001] and so was the serum neopterin level [27.5 +/- 7.3, 14.9 +/- 2.7, 9.4 +/- 1.1 respectively, p<0.001]. The mean number of P53+ve keratinocytes of group I was significantly higher than group II and III [20.6 +/- 5.4, 1.6+0.5, 1.7 +/- 0.4 respectively, p<0.001]. A higher percentage of class IV and V glomerulonephritis was found in group I [47%, 26%, respectively] compared to group II [11% both] [p<0.001]. The mean number of p53+ve keratinocyte showed a significant positive correlation to SLEDAI score, percentage of peripheral apoptotic lymphocytes and serum neopterin [p<0.001]. Accumulation of apoptotic keratinocytes and lymphocytes in SLE seems to be crucial in the pathogenesis of skin lesions and in triggering systemic disease activity and organ damage