In a nonreferral setting, the NIH-modified scoring system for lupus nephritis is only moderately reproducible and, if used to prognosticate renal outcome, may result in erroneous predictions of risk for renal failure and response to therapy.

The detection of rheumatoid factors (RFs) in synovial membranes and fluids of patients with rheumatoid arthritis (RA) has suggested that local production of these antiimmunoglobulin autoantibodies may have a role in the pathogenesis of synovitis. To quantitate RF synthesis in the rheumatoid synovial membrane, 12 synovial specimens were obtained from patients with seropositive RA, 5 from patients with seronegative RA, and 6 from patients with other arthritides. Single cell suspensions were cultured, and supernatants were analyzed for IgG, IgM, IgG‐RF, and IgM‐RF by solidphase radioimmunoassays. IgM‐RF was detected in all of the 12 seropositive culture supernatants, and IgG‐RF was detected in 8 of the 12. Addition of cycloheximide to the cultures resulted in a ⩾40% decrease in the amount of IgM‐RF. A similar decrease in IgG‐RF occurred in the 4 cultures in which the largest amounts of IgG‐RF were detected. IgM‐RF synthesis represented 7.3 ± 0.7% (mean ± SEM) of the total IgM produced, and IgG‐RF represented 2.6 ± 1.1% (mean ± SEM) of the IgG synthesized in those cultures with detectable IgG‐RF. Cultures of synovial membrane cells (SMC) from seronegative RA patients or patients with other arthritides did not contain detectable amounts of IgM‐RF or IgG‐RF. Selective synthesis of RF by seropositive synovium was suggested by the observation that the fractions of synthesized IgM with RF activity were greater in the SMC supernatants than in paired sera in all cases, and the fractions of IgG with RF activity were greater in the SMC supernatants of 3 of the 4 cases in which substantial amounts of IgG‐RF were produced. Comparison of the percentages of newly synthesized IgM with RF activity in paired cultures of SMC and peripheral blood mononuclear cells similarly indicated selective synthesis of IgM‐RF by the synovium. These results demonstrate active and selective synthesis of both IgG‐RF and IgM‐RF by seropositive SMC. However, RFs account for only a minor fraction of the total Ig produced.

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Central nervous system (CNS) toxicity from lowdose methotrexate (MTX) has been reported rarely, and reported symptoms consist primarily of dizziness and headache. We reviewed the records of 25 consecutive patients treated with low-dose MTX, and found 5 who had spontaneously reported unpleasant cranial sensations, mood alteration, or memory impairment. Rechallenge with MTX on 5 occasions in 3 patients led to recurrent CNS symptoms in all cases. CNS toxicity was the sole reason for discontinuation of MTX in 2 patients. These 5 patients differed from the 20 without CNS toxicity in age (mean 68 versus 50) and baseline serum creatinine level (1.3 mg/dl versus 0.9 mg/dl), but not in weekly dosage of MTX (12 mg versus 16 mg). These results suggest that CNS toxicity is more common than previously reported, particularly in older patients with mild renal insufficiency.Methotrexate (MTX) given in a low-dose weekly regimen is an effective agent in controlling both rheumatoid arthritis (RA) (1-1 1) and psoriatic arthritis (12,13). Indications for MTX must be weighed against the potential risk of severe liver, lung, or