Transforming growth factor beta-1 (TGF-beta 1) released by an Epstein-Barr virus (EBV) positive spontaneous lymphoblastoid cell line from a patient with Kostmann's congenital neutropenia inhibits the growth of normal committed haemopoietic progenitors in vitro.

This study reports the characterization of a spontaneous lymphoblastoid cell line (LCL) raised from the peripheral blood of a patient with Kostmann's congenital neutropenia. The LCL was composed of EBV-infected polyclonal B cells and displayed surface markers and pattern of growth in vitro typical of normal LCLs. The supernatant of the LCL contained a colony inhibiting activity (CIA) that decreased the cloning efficiency of normal committed haemopoietic progenitors and was identified as immunoreactive transforming growth factor beta 1 (TGF-beta 1) by neutralization experiments with a specific antiserum. Control studies with a panel of LCLs spontaneously derived from the peripheral blood of patients seropositive for Epstein-Barr virus (EBV) infections showed that 5/30 LCLs produced a CIA. This CIA was not identifiable as TGF-beta 1 but rather was due to the combined effects of tumour necrosis factor alpha (TNF alpha), tumour necrosis factor beta (TNF beta) and interferon alpha (IFN alpha), that were present in the LCL supernatants. The hypothesis that the B cells latently infected by EBV in vivo and possibly expanded as a consequence of the infection may have contributed to the inhibition of the patient granulopoiesis by releasing TGF-beta 1 will be discussed.