Hydroxychloroquine is a good second-line treatment for adults with immune thrombocytopenia and positive antinuclear antibodies.

Treatment of patients with lupus-associated thrombocytopenia (SLE-ITP) is not standardized. We report data on efficacy and safety of hydroxychloroquine (HCQ) in this setting and in ITP patients with positive antinuclear antibodies (ANA) without definite SLE. Inclusion criteria were: definite diagnosis of ITP with a platelet count (PLT) <50 × 10(9) /L, ANA ≥ 1/160 on Hep2 cells with or without a definite diagnosis of SLE, and no sustained response to at least one previous treatment-line and treatment with HCQ. Response criteria were Complete Response (CR) for PLT ≥ 100 × 10(9) /L and Response (R) for PLT ≥30 × 10(9) /L and at least twice the initial value. Forty patients (32 females) with a mean age of 35 ± 17 years and PLT at ITP diagnosis of 14 ± 13 × 10(9) /L were analyzed. Twelve (30%) patients had a SLE-ITP, 28 patients had only positive ANA. All the patients failed to respond to oral prednisone with a median of two treatment-lines (1-5) before HCQ which was initially given in combination with another ITP treatment in 36 patients. Overall response rate was 60% (24/40) including 18 lasting CR and six lasting R maintained with a median follow-up of 64 months (6-146), in ¾ of cases with only HCQ and no concomitant ITP treatment. The response rate (CR+R) was higher in the SLE group vs ANA-positive group (83% vs 50%, P < 0.05). No patient stopped HCQ because of a side-effect. HCQ appears to be a safe and effective second line treatment for patients with SLE-ITP or ITP and high titer of ANA. This trial was registered at www.clinicaltrials.gov as # NCT01549184.