Antibodies to topoisomerase I (Scl-70)
Antibodies to Scl-70, proteins associated with the centromere (CEN-A, CEN-B), U3-ribonucleoprotein (U-3 RNP), and RNA polymerases I and III. These antibodies are highly specific for systemic sclerosis and are associated with a higher risk of interstitial lung disease. When present in high titers, they are associated with more extensive skin involvement and disease activity.
Antibodies to Ribo-P
The reported incidence of antiribosomal P protein antibodies among patients with SLE is variable. These antibodies were initially detected in 10–20% of patients with SLE; however, several authors (particularly those studying Asian populations and children) have reported higher incidence rates (40–50%). Some clinical data suggest that the presence of antiribosomal P protein antibodies among patients with lupus is associated with lupus cerebritis. The presence of antibodies to ribosomal P protein has an overall sensitivity and specificity for neuropsychiatric lupus of 26% and 80%, respectively. The test characteristics were similar for psychosis, mood disorder, or both (sensitivity 27%, specificity 80%). These antibodies may also be found among patients with lupus hepatitis and/or nephritis.
Antibodies to Jo-1
Antibodies to the Jo-1 antigen (histidyl-tRNA synthetase) are found in approximately 30% of adult patients with myositis (including polymyositis, dermatomyositis, and overlap syndromes) and are particularly common (approximately 60%) in patients with both myositis and interstitial lung disease (cryptogenic fibrosing alveolitis or pulmonary interstitial fibrosis). Jo-1 antibodies are most commonly found in patients with the antisynthetase syndrome, which is characterized by acute onset, steroidresponsive myositis with interstitial lung disease, fever, symmetrical arthritis, Raynaud phenomenon, and mechanic’s hands. The presence of Jo-1 antibodies in idiopathic polymyositis patients is usually accompanied by severe disease, tendency to relapse, and poor prognosis.
ANTIPSYCHOTICS*
Definition
Antipsychotics are neuroleptic drugs in the following groups: phenothiazines, thioxanthenes, dibenzoxazepines, dihydroindoles, butyrophenones, and diphenylbutylpiperidine and alkali metal. Typical antipsychotics: chlorpromazine (Thorazine), fluphenazine (Permitil), thioridazine (Mellaril), thioxanthene, haloperidol (Haldol), and loxapine (Loxitane). Atypical antipsychotics: clozapine (Clozaril), olanzapine (Zyprexa), quetiapine (Seroquel), and risperidone (Risperdal).
Other agent: lithium (Lithobid).
Normal range:
see Table 16.10.
TABLE 16–10. Normal Levels of Antipsychotics
Use
