In vitro correction of Fanconi's anemia chromosome instability

In five patients with Fanconi's anemia, type Estren-Damashek, the possibility has been tested to correct in vitro the chromosome instability. No significant difference in the rate of chromosome aberrations was observed between the patients' metaphases obtained by the standard technique and from lymphocytes grown in the presence of an identical proportion or a tenfold excess of normal lymphocytes. Conversely, the addition to the culture medium of a conditioned medium (CM) prepared by ultrafiltration from normal PHA lymphocytes supernatant resulted in a rather drastic decrease of the chromosome instability rate. The 'curing' effect of the CM appeared rather specific and, possibly, due to some non-dialyzable substance present in the supernatant of normal PHA cultured lymphocytes, was either dismissed during the cell growth in vitro or discharged from some unstimulated cell dying in vitro.