Li Q, et al. - The data on subjects with pulmonary hypertension (occurs in systemic lupus erythematosus {SLE} for several reasons, such as vasculopathy) and non-pulmonary hypertension lupus nephritis were retrospectively examined by the researchers in order to determine the clinical and pathological importance of complement alternative pathway activation with pulmonary hypertension in lupus nephritis subjects. Major plasma levels of complement components were assessed. The depositions of Bb, C3d, and C5b-9 in the lung specimens of pulmonary hypertension combined with SLE subjects were identified by immunofluorescence staining. Out of 352 lupus nephritis cases, 24 were diagnosed with pulmonary hypertension and 328 with non-pulmonary hypertension. Higher levels of Bb and lower levels of factor H were detected in the pulmonary hypertension group, in contrast with the negative group. As concluded by the log-rank and Cox test for survival analysis, pulmonary hypertension was observed to be a risk factor for renal outcome. In lung specimens of lupus nephritis subjects with pulmonary hypertension, C3d, C5b-9, and Bb were discovered as positive. Hence, there could be a possibility that activation of the complement alternative pathway could be included in the pathogenesis of pulmonary hypertension in lupus nephritis.