[Clinical characteristics of Pneumocystis carinii pneumonia in children with systemic lupus erythematosus]. 
To identify the risk factors which will indicate the Pneumocystis carinii (Pc) infection in children with systemic lupus erythematosus (SLE) and investigate the clinical features and to elevate the level to find out the high-risk patients and make early diagnosis and treatment.  The characteristics, clinical features, laboratory examinations, treatment and prognosis of Pneumocystis carinii pneumonia (PCP) in children with SLE under 18 years of age treated in our hospital between January 2000 and January 2013 were prospectively reviewed.  A comparison was made with the 26 cases of SLE children without PCP who were matched for gender, age and course, and a literature review was made. ( 1) Five cases were enrolled, 3 were male and 2 female.  Their age range was 13-17 (14.0 ± 1.6) years.  All the children had kidney involvement.  The courses were from 3 months to 4.5 years.  All patients were receiving daily glucocorticoid therapy and immunosuppressive drugs before the diagnosis of PCP.Four patients were in the inactive phase of SLE (SLEDAI 2-4 points), and the fifth case was in active phase (SLEDAI 8, low complement 2 points, anti-dsDNA antibody positive 2 points, urine-protein 4 points). ( 2) Besides the clinical manifestations of SLE, most patients had progressive dyspnea, fever and dry cough at onset of PCP.  Two children accepted mechanical ventilation because of respiratory failure.  The mean duration of the symptoms to diagnosis was 10-30 (17.6 ± 7.8) days.  Lactose dehydrogenase (LDH) was elevated more or less, median was (700 ± 263) U/L. Lymphocyte count were (0.3-1.4)×10(9)/L (median 0.5×10(9)/L), and three children had CD4 T lymphocyte count <0.3×10(9)/L. Arterial blood gas analyses showed severe hypoxemia.  Chest radiographs showed in all cases diffuse interstitial infiltration.  Pc was positive in the sputum.  All patients were treated with trimethoprim-sulfamethoxazole and corticosteroids.  When SLE children are treated with corticosteroids and immunosuppressive drugs, low lymphocyte count is the risk factor for Pc infection. It is essential to monitor lymphocyte count. We should pay more attention to fever, dry cough and hypoxemia.  Chest radiologic examination may help diagnose the PCP in SLE children. It may be helpful for SLE children whose CD4T lymphocyte was below 0.3×10(9)/L to take trimethoprim-sulfamethoxazole for PCP prophylaxis.