Basal cell carcinoma in a series of renal transplant recipients: epidemiology and clinicopathologic features.

BACKGROUND: Basal cell carcinoma (BCC) is the most common malignancy among Caucasians worldwide. The risk of BCC is 10-16 times higher among immunosuppressed transplant recipients compared with the general population. OBJECTIVE: To analyze the incidence, clinical presentation, histologic features, treatment and recurrence rate of BCC in a cohort of 69 renal transplant recipients (RTRs; 53 male). METHODS: Retrospective population-based cohort study of immunosuppressed RTRs. RESULTS: Ten of 69 patients (14.5%, five male) developed a total of 17 BCCs, mostly on the head. Mean age at first diagnosis of BCC was 65.5 +/- 8.5 years, and latency between kidney transplantation and diagnosis of the first BCC was 11.1 +/- 6.3 years (mean +/- SD). The risk of female RTRs to develop BCCs appeared to be three times higher than the risk of male RTRs, and female RTRs developed BCCs earlier after transplantation. Nodular BCC was the most common histologic subtype. Most BCCs in these RTRs were treated by complete surgical excision. Recurrence after surgical excision was observed in one of the 10 patients (10%). CONCLUSION: Our results suggest female RTRs to be at higher risk to develop cutaneous BCCs than male RTRs. There are no differences in localization and clinicopathologic presentation of BCCs developing in RTRs compared with immunocompetent patients. Therefore, BCCs in RTRs do not require different treatment than in other patient groups. As patients tend to develop a second BCC, close follow-up is mandatory.

Immune responses in healthy and allergic individuals are characterized by a fine balance between allergen-specific T regulatory 1 and T helper 2 cells.

The mechanisms by which immune responses to nonpathogenic environmental antigens lead to either allergy or nonharmful immunity are unknown. Single allergen-specific T cells constitute a very small fraction of the whole CD4+ T cell repertoire and can be isolated from the peripheral blood of humans according to their cytokine profile. Freshly purified interferon-gamma-, interleukin (IL)-4-, and IL-10-producing allergen-specific CD4+ T cells display characteristics of T helper cell (Th)1-, Th2-, and T regulatory (Tr)1-like cells, respectively. Tr1 cells consistently represent the dominant subset specific for common environmental allergens in healthy individuals; in contrast, there is a high frequency of allergen-specific IL-4-secreting T cells in allergic individuals. Tr1 cells use multiple suppressive mechanisms, IL-10 and TGF-beta as secreted cytokines, and cytotoxic T lymphocyte antigen 4 and programmed death 1 as surface molecules. Healthy and allergic individuals exhibit all three allergen-specific subsets in different proportions, indicating that a change in the dominant subset may lead to allergy development or recovery. Accordingly, blocking the suppressor activity of Tr1 cells or increasing Th2 cell frequency enhances allergen-specific Th2 cell activation ex vivo. These results indicate that the balance between allergen-specific Tr1 cells and Th2 cells may be decisive in the development of allergy.