Complement factor H mRNA in Epstein-Barr virus-transformed B lymphocytes of a factor H-deficient patient: detection by polymerase chain reaction.

A Spanish family with a hereditary deficiency of factor H was identified in previous studies. The deficiency was subtotal as low amounts of a dysmorphic molecule with partial identity to factor H were detected in her serum. The aim of this study was to obtain further characterisation of her deficiency employing her immortalised lymphocytes. After purification of mRNA from her Epstein-Barr virus (EBV)-transformed lymphocytes and from Raji cells, and cDNA synthesis we succeeded in amplifying cDNA which codes for factor H domains 13-15 from both cell lines, using specific oligonucleotides. The amplified fragments were indistinguishable from the one which was amplified from the control cloned cDNA template. The failure to amplify the 3' end of the patient's factor H mRNA suggests that the mRNA is truncated, which is consistent with the characteristics of the dysmorphic protein. Thus, factor H mRNA was detectable in Raji cells and the patient's EBV-transformed lymphocytes. We suggest that immortalised B lymphocytes can be used for the study of a range of inherited complement deficiencies.