The role of immunosuppression and immune-activation in classic Kaposi's sarcoma

Immunodeficiency and elevated levels of cytokines have been associated with the development of Kaposi's sarcoma (KS) lesions in patients with AIDS and iatrogenic immunodeficiency. However, their role in classic KS (CKS) is unclear. We measured peripheral blood cell levels, including T-cell subsets, as well as neopterin and beta(2)-microglobulin in 91 HIV-negative Greek patients with histologically confirmed CKS and in 107 controls matched for age and sex. CKS cases had slightly lower leukocyte counts (p = 0.08) and lymphocyte counts (p = 0.02). Although the percentage of CD4 and CD8 T-lymphocytes were not significantly different from controls (p = 0.10 and p = 0.45, respectively), CD4 T-lymphocytes were lower in cases than controls (812 cells/microliter and 1,009 cells/microliter, respectively; p = 0.01); part of this difference resulted from the lower lymphocyte counts (p = 0.07 after adjusting for lymphocyte counts). However, neopterin and beta(2)-microglobulin were both considerably elevated [geometric mean (95% CI): 8.35 (7.27-9.73) nmol/L and 2,904 (2,479-3,401) microgram/L in cases and 5.86 (5.40-6. 35) nmol/L and 2,042 (1,880-2,218) microgram/L in controls, respectively]. We conclude that CKS patients are predominantly characterised by immune activation, although an element of minor immunosupression may also be present.