ObjectivesThrombocytopenia (TP) is a common adverse effect of linezolid (LZD). However, risk factors for LZD-associated TP have been reported in Western patients with relatively heavy body weight. The aim of this study was to determine the risk factors for LZD-associated TP in Asian population.Materials and methodsA retrospective cohort study was conducted among 101 consecutive patients who received LZD therapy (1,200 mg/day) between July 2003 and December 2013 at a tertiary referral hospital in Tokyo, Japan. The patients with obvious other causes for TP were excluded. The information of target infectious disease, patients’ age, gender, body weight, body mass index, baseline serum creatinine (SCr), baseline platelet count, and treatment duration was collected retrospectively. TP was defined as ≥50 % decrease in platelet count from baseline. Bi- and multi-variate analyses were performed.ResultsA total of 101 patients were included (mean age [SD] 64 [18]; male gender [%], 57 [56]). Median duration [range] of LZD therapy was 14 days [1–67]. LZD-associated TP was identified in 42 patients (42 %). For TP, adjusted odds ratio (OR) [95 % CI] of daily per kg dose (DPKD) and SCr was 1.14 [1.05–1.26] and 1.51 [1.01–2.50], respectively.ConclusionsHigher DPKD and elevated SCr are significantly associated with LZD-associated TP. These findings suggest that daily dose of LZD should be adjusted using body weight, as typically done in pediatrics, in adults as well. Renal function also should be considered for dose adjustment.

BackgroundAssociation of CTD is one of the poor prognostic factors for PAH patients. Although it remains unclear whether immunosuppressive therapy is effective for CTD-PAH, the efficacy of immunosuppressive agents for CTD-PAH has been reported recently. PAH patients with systemic lupus erythematosus (SLE) or mixed connective tissue disease (MCTD), especially in early stage, are suggested to be good responders to immunosuppressive therapy [1].ObjectivesTo evaluate the efficacy of immunosuppressive therapy for CTD-PAH (except SSc-PAH) patients by close monitoring with right heart catheterization (RHC).MethodsHere we report clinical courses of 6 CTD-PAH cases under management with immunosuppressive agents. In all cases, we started high-dose prednisolone (PSL) followed by intravenous cyclophosphamide (IVCY) without adding or modifying vasodilators and evaluated therapeutic efficacy on hemodynamics with RHC. Initial post-therapeutic RHC was performed within three months. Paired t-test was used for comparison of pre- and post-therapeutic hemodynamics: mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR). In one case, we analyzed her peripheral blood by Fluorescence Activated Cell Sorting (FACS) analysis before and after IVCY therapy.ResultsAll cases were Japanese females and mean age was 41.3±12.2 years old; one with SLE, one with SLE plus CREST syndrome, one with MCTD and three with Sjögren syndrome. Each hemodynamic was significantly improved. Mean mPAP was 41.0±9.5 mmHg and 27.0±8.5 mmHg (p<0.01), and mean PVR was 7.89±3.45 WU and 5.14±2.12 WU (p <0.05) in pre- and initial post-therapeutic RHC respectively. After first follow-up RHC, vasodilator therapy was modified if necessary. In four cases, the second RHC was performed within half a year after the first evaluation. Although mPAP got slightly worse (31.8±5.9 mmHg), PVR maintained improvement (5.28±1.34 WU). The analysis of B-cell count showed reduction from 241 /μL to 129 /μL.ConclusionsHigh-dose PSL and IVCY are effective to all cases, indicating the importance of the immune system in CTD-PAH etiology. RHC revealed that only high-dose PSL can remarkably reduce mPAP and PVR. The response to preceding PSL monotherapy could predict overall effectiveness of immunosuppressive therapy for CTD-PAH patients. In addition, B-cell reduction in PBMC was apparent after IVCY, suggesting that B-cell count may predict activity.ReferencesJais X et al. Arthritis Rheum. 2008;58:521-31.Disclosure of InterestNone declared