SIR,-We would like to comment briefly on Dr. J. M. Sowa's letter (2 April, p. 858) dealing with the immunosuppressive therapy of systemic lupus erythematosus (S.L.E.).We published the results we obtained with 2,3,5 -tris -ethylenimino -p -benzoquinone (triaziquone) in three cases of S.L.E., and since then we treated another patient with the same cytostatic agent.Since in these cases the steroid therapy gave little advantage or serious side-effects, we tried the triaziquone therapy, which gave very good results: the sedimentation rate promptly fell to almost normal values, both the L.E. cell test and the L.E. factor test became negative, the electrophoretic pattern and the renal clearances and the urine analysis showed a marked improvement, the latter leaving only a residual slight albuminuria. The longest remission period was of two and a half years, and up to now a second cycle of treatment has not been necessary. The side-effects were negligible and promptly subsided on discontinuing the therapy.In our opinion the newer immunosuppressive drugs are of definite value in the treatment of S.L.E., provided that the following criteria are observed:(1) Their use should be limited to cases which either do not respond to doses of 50-60 mg. of prednisone daily or show some side-effect. In our experience doses of 100-120 mg. of prednisone daily almost always produce serious side-effects.(2) The dosage should be kept as low as possible (for triaziquone 2-3 mg. in all), and the therapy should be discontinued when the clinical condition and the laboratory tests show a marked improvement.(3) It is advisable that the cytostatic agents should be administered together with as little as 5-10 mg. of prednisone daily.Though more data, obtained possibly with a controlled study, are required, we strongly suggest the treatment of patients with S.L.E. who do not promptly respond to steroid therapy with triaziquone or other immunosuppressive drugs.-We are, etc., FRANCO PACINI. ANTONIO MORETTINI.