Summary
This study was designed to explore the prevalence and clinical significance of elevated
antiphospholipid antibodies (APA) titres in patients affected by acute myeloid leukemia
(AML) and highgrade non-Hodgkin’s lymphoma (NHL). We also analyzed possible correlations
with circulating levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha),
and the soluble form of the receptor for interleukin-2 (sIL-2r). Nineteen patients
with de novo AML and 14 patients with newly-diagnosed NHL were investigated. Tests
for APA included the measurement of anticardiolipin antibodies (ACA) with a solid-phase
immunoassay, and the detection of the lupus-like anticoagulant (LA) activity. Five
patients with AML (26.3%) and 5 patients with NHL (35.7%) presented elevated APA at
diagnosis, as compared to 3 of 174 persons of the control group (p <0.0001). APA titres became normal in all patients responding to treatment, whereas
nonresponders retained elevated levels. In addition, 6 patients (4 with AML and 2
with NHL), who had normal APA at diagnosis and were either refractory to treatment
or in relapse, subsequently developed LA and/or ACA positivity. At presentation, the
mean levels of IgG- and IgM-ACA in patients were not significantly different from
Controls, and concordance between ACA and LA results reached just 30%. With regard
to the clinical course, we were not able to detect any statistically significant difference
between patients with normal and elevated APA. Pretreatment concentrations of IL-6
and TNF-alpha in AML, and sIL-2r in NHL were found significantly elevated compared
to Controls (p = 0.003, p = 0.009 and p = 0.024 respectively). In addition, the levels of these cytokines correlated with
IgG-ACA at the different times of laboratory investigations. These results demonstrate
that APA may have a role as markers of disease activity and progression in some haematological
malignancies.
