Clinical Relevance of Cytogenetics Abnormalities in Adult Patients with Acquired Aplastic Anaemia.

The clinical relevance of cytogenetics abnormalities in aplastic anaemia (AA) patients at time of diagnosis is unclear. We evaluated the clinical course of 81 AA patients with successful cytogenetics at diagnosis and treated with immunosuppressive therapy (IST) from January 1993 to March 2004. A cytogenetic study was considered to be successful if there were a minimum of 15 evaluable metaphases in the absence of a clonal abnormality. Response to IST, survival and later clonal complications in patients with an abnormal karyotype (n=10) was compared to those with a normal karyotype (n=71).

The cytogenetic abnormalities at diagnosis consisted of trisomy 6 (n=2), trisomy 8 (n=2), trisomy 15 (n=2), monosomy 7 (n=1), add(10) (n=1), t(3;11) (n=1) and t(4;6) (n=1). Four out of five evaluable patients with a trisomy responded to a first or subsequent course of IST. One patient with monosomy 7 achieved a complete response and later developed haemolytic PNH but with no recurrence of the monosomy 7. None of the patients with a non-numerical karyotypic abnormality responded to IST. No significant differences in 4-year event-free survival (EFS) (54% vs. 30%, p=0.15), overall survival (OS) (84% vs. 80%, p=0.33) or later clonal disorders (PNH, MDS and AML) were observed between the patients with a normal karyotype and those with an abnormal karyotype. Advanced age (≥60 years) was the only independent poor prognostic factor for survival in a multivariate analysis.

Among the patients with a normal karyotype (n=71), 6 patients later developed a clonal cytogenetic abnormality with a cumulative risk of 10% at 4 years. These abnormalities were trisomy 15 (n=2), trisomy 6(n=1), monosomy 7 (n=2) and t(13;15) (n=1). None of the three patients who acquired trisomies developed any clinically significant problem, while acquisition of monosomy 7 was associated with a transformation to MDS/AML.

Our data show that AA patients with a trisomy cytogenetic clone at diagnosis show a similar response to IST, evolution to later clonal abnormalities and survival, compared to those AA patients with a normal karyotype.