Medscape is available in 5 Language Editions – Choose your Edition here.


Felty Syndrome Workup

  • Author: Richard M Keating, MD, FACR, FACP; Chief Editor: Herbert S Diamond, MD  more...
Updated: Feb 12, 2014

Laboratory and Imaging Studies

Laboratory tests

Obtain a white blood cell (WBC) count and differential, which are crucial when determining the degree of granulocytopenia. Studies show that the greatest risk for infection is a granulocyte count lower than 1000/µL. It must be kept in mind, however, that the level of neutropenia varies over time without medical intervention. Granulocyte dysfunction and an absolute decrease in the number of granulocytes may predispose to infection.

Anemia and thrombocytopenia may result from hypersplenism. Anemia of chronic disease may result from the underlying inflammatory disease.

Mild elevations of alkaline phosphatase and transaminase levels may occur.

Some 98% of patients with Felty syndrome (FS) have high titers of rheumatoid factor (RF). This is because extra-articular manifestations of rheumatoid arthritis (RA) are strongly associated with RF.

Antinuclear antibodies (ANAs), found in 67% of cases; antihistone antibodies; and even antineutrophil cytoplasmic antibodies (perinuclear pattern; p-ANCA), found in 77% of cases, commonly occur in patients with Felty syndrome. The significance of autoantibodies in Felty syndrome is unknown, and their contribution, if any, to the disease itself is uncertain.

Erythrocyte sedimentation rate (ESR) and serum immunoglobulin levels are invariably elevated in patients with FS. Cryoglobulins may be present.

Diagnostic imaging

Radionuclide studies, ultrasonography, or computed tomography (CT) may define the presence and extent of splenomegaly. The same modalities can also be used to assess patient response to therapy.


Histologic Findings

Bone marrow aspiration and biopsy are especially important to rule out large granular lymphocytosis (LGL). The bone marrow of patients with FS shows adequate megakaryocytes and myeloid hyperplasia with arrested development at the level of immature cell forms.

An unusual type of liver involvement known as nodular regenerative hyperplasia is associated with FS. This condition is characterized by mild portal fibrosis or lymphocyte and plasma cell infiltration but is not typical of cirrhosis. It may be complicated by portal venule occlusion and regenerative nodule formation.

Contributor Information and Disclosures

Richard M Keating, MD, FACR, FACP Program Director, Rheumatology Fellowship, Scripps Clinic

Richard M Keating, MD, FACR, FACP is a member of the following medical societies: American College of Physicians, American College of Rheumatology

Disclosure: Nothing to disclose.


Kavitta B Allem, MD Fellow in Rheumatology, Scripps Clinic

Disclosure: Nothing to disclose.

Dana A Copeland, MD Department of Rheumatology, Scripps Clinic

Disclosure: Nothing to disclose.

Chief Editor

Herbert S Diamond, MD Visiting Professor of Medicine, Division of Rheumatology, State University of New York Downstate Medical Center; Chairman Emeritus, Department of Internal Medicine, Western Pennsylvania Hospital

Herbert S Diamond, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American College of Rheumatology, American Medical Association, Phi Beta Kappa

Disclosure: Nothing to disclose.

  1. Felty AR. Chronic arthritis in the adult associated with splenomegaly and leukopenia. Bull Johns Hopkins Hosp. 1924. 35:16.

  2. Burks EJ, Loughran TP Jr. Pathogenesis of neutropenia in large granular lymphocyte leukemia and Felty syndrome. Blood Rev. 2006 Sep. 20(5):245-66. [Medline].

  3. Hellmich B, Csernok E, Schatz H, et al. Autoantibodies against granulocyte colony-stimulating factor in Felty's syndrome and neutropenic systemic lupus erythematosus. Arthritis Rheum. 2002 Sep. 46(9):2384-91. [Medline].

  4. Campion G, Maddison PJ, Goulding N, James I, Ahern MJ, Watt I, et al. The Felty syndrome: a case-matched study of clinical manifestations and outcome, serologic features, and immunogenetic associations. Medicine (Baltimore). 1990 Mar. 69(2):69-80. [Medline].

  5. Gridley G, Klippel JH, Hoover RN, et al. Incidence of cancer among men with the Felty syndrome. Ann Intern Med. 1994 Jan 1. 120(1):35-9. [Medline].

  6. Brücker R, Schlumpf U. [Felty syndrome: a therapy-resistant variant of chronic rheumatoid arthritis? 2 case reports and literature review]. Praxis (Bern 1994). 1996 Apr 16. 85(16):534-40. [Medline].

  7. Ghavami A, Genevay S, Fulpius T, et al. Etanercept in treatment of Felty's syndrome. Ann Rheum Dis. 2005 Jul. 64(7):1090-1. [Medline].

  8. Talip F, Walker N, Khan W, et al. Treatment of Felty's syndrome with leflunomide. J Rheumatol. 2001 Apr. 28(4):868-70. [Medline].

  9. Ishikawa K, Tsukada Y, Tamura S, et al. Salazosulfapyridine-induced remission of Felty's syndrome along with significant reduction in neutrophil-bound immunoglobulin G. J Rheumatol. 2003 Feb. 30(2):404-6. [Medline].

  10. Sordet C, Gottenberg JE, Hellmich B, et al. Lack of efficacy of rituximab in Felty's syndrome. Ann Rheum Dis. 2005 Feb. 64(2):332-3. [Medline].

  11. Chandra PA, Margulis Y, Schiff C. Rituximab is useful in the treatment of Felty's syndrome. Am J Ther. 2008 Jul-Aug. 15(4):321-2. [Medline].

  12. Weinreb N, Rabinowitz A, Dellaripa PF. Beneficial response to rituximab in refractory Felty Syndrome. J Clin Rheumatol. 2006 Feb. 12(1):48. [Medline].

  13. Tomi AL, Lioté F, Ea HK. One case of Felty's syndrome efficiently treated with rituximab. Joint Bone Spine. 2012 Mar 6. [Medline].

  14. Narváez J, Domingo-Domenech E, Gómez-Vaquero C, López-Vives L, Estrada P, Aparicio M, et al. Biological agents in the management of Felty's syndrome: a systematic review. Semin Arthritis Rheum. 2012 Apr. 41(5):658-68. [Medline].

All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.