CD40 ligand - An anti-apoptotic molecule in Hodgkin's disease

The expression of CD40L was investigated in HD involved lymph nodes by flow cytometry (FCM) and reverse transcriptase polymerase chain reaction (RT-PC R). Also an investigation of the role of CD40L in upregulation of the anti- apoptotic gene BclxL in a Hodgkin's disease (HD) derived cell line was unde rtaken. HD patients (n = 18) had significantly higher numbers of activated CD4(+) and CD8(+) T cells in the tumor microenvironment as compared to cont rols (n = 8). HD patients also demonstrated higher numbers of CD4(+), CD8() and CD19(+) lymphocytes co-expressing CD40L as compared to controls. The CD40L signal was consistently and significantly upregulated in HD patients (n = 5) as compared to controls (n = 3) at the mRNA bevel. RT-PCR and FCM a nalysis revealed that soluble CD40L upregulated BclxL levels in the I;as-se nsitive HD cell line HDLM2. We conclude that CD40L can act as an important anti-apoptotic molecule by upregulating BclxL expression in Reed-Sternberg cells of HD and may be partly responsible for their survival 'in-vivo'.