Consider autosplenectomy in thrombocytosis with SLE

Italian researchers warn that the sudden appearance and persistence of thrombocytosis, or even the apparent reversal of thrombocytopenia in patients with systemic lupus erythematosus (SLE), should raise suspicion of autosplenectomy. To evaluate the prevalence of thrombocytosis in SLE and its relationship to functional asplenia Dr Gabriella Castellino (University of Ferrara, Italy) and colleagues evaluated 465 consecutive patients with SLE. Seventeen (3.6%) of the participants were diagnosed with thrombocytosis (defined as a platelet count >400 x 109/L in at least three blood samples). Examination of blood smears for these 17 patients showed Howell-Jolly bodies, spherocytes and target cells (n=3, 17.6%). For these three patients ultrasound and computed tomography failed to show the spleen, and liver-spleen scans showed absence of splenic uptake, suggesting functional autosplenectomy. One patient satisfied the criteria for antiphospholipid syndrome and the other two patients had positive IgG antiphospholipid antibodies at medium titre. Dr Castellino’s group suggest that multiple thrombotic events within the splenic microvasculature may explain these findings but note that three other patients had thrombocytosis and antiphospholipid antibodies, but not asplenia. "If Howell-Jolly bodies, pitted erythrocytes beyond 2%, acanthocytes and target cells are seen," the authors conclude, "a diagnosis of autosplenectomy should be strongly considered and immunization against encapsulated bacteria must be provided." Reference Castellino, G. Govoni, M. Prandini, N. et al. 2007. ‘Thrombocytosis in Systemic Lupus Erythematosus: A Possible Clue to Autosplenectomy?’. Journal of Rheumatology. vol. 34, pp. 1497-1501....