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Neutropenia and infections in Felty's syndrome
F C Breedveld1, W E Fibbe, A Cats
1Department of Rheumatology, University Hospital, Leiden, The Netherlands.
Abstract:
Fifteen patients with Felty's syndrome (FS) were studied prospectively during a 3-year period to determine the influence of multiple haematologic parameters on the incidence of infections. An increased risk of recurrent major and minor infections was primarily related to peripheral blood polymorphonuclear cell (PMN) counts of less than 0.1 x 10(9)/l. Bone marrow lymphocytosis, a decreased percentage of PMN in bone marrow differential counts and an impaired in vitro growth of colony-forming unit-PMN macrophage were also related to an increased incidence of infection but were predominantly present in patients with less than 0.1 x 10(9)/l circulating PMN. The maximal response in the number of circulating PMN measured after injection of epinephrine and hydrocortisone varied substantially within patients, but those with less than 0.1 x 10(9)/l PMN always had lower responses than those with greater than 0.1 x 10(9)/l PMN. These variables did not therefore contribute to the identification of FS patients at risk of infection.
Insights
Patients with Felty's syndrome (FS) and low polymorphonuclear cell (PMN) counts (<0.1 x 10(9)/l) face a higher risk of infections. Other factors like bone marrow changes were associated but not independent predictors of infection risk in FS.
Area of Science:
- Hematology
- Immunology
- Rheumatology
Background:
- Felty's syndrome (FS) is a triad of rheumatoid arthritis, splenomegaly, and neutropenia.
- Infections are a significant cause of morbidity and mortality in FS patients.
Purpose of the Study:
- To investigate the relationship between hematologic parameters and infection incidence in FS patients.
- To identify predictive markers for infection risk in Felty's syndrome.
Main Methods:
- Prospective study of 15 FS patients over 3 years.
- Analysis of peripheral blood polymorphonuclear cell (PMN) counts.
- Evaluation of bone marrow differential counts and in vitro colony-forming unit-PMN macrophage growth.
- Assessment of PMN response to epinephrine and hydrocortisone stimulation.
Main Results:
- Peripheral blood PMN counts <0.1 x 10(9)/l were strongly associated with recurrent infections.
- Bone marrow lymphocytosis, decreased bone marrow PMN percentage, and impaired in vitro PMN growth were linked to infection risk but secondary to low circulating PMN counts.
- Epinephrine and hydrocortisone stimulation showed lower PMN responses in patients with <0.1 x 10(9)/l PMN, but this did not aid in risk stratification.
Conclusions:
- Low peripheral blood polymorphonuclear cell (PMN) counts are the primary hematologic determinant of infection risk in Felty's syndrome.
- Other hematologic parameters studied do not independently predict infection risk in FS patients.
- Monitoring circulating PMN counts is crucial for assessing infection risk in FS.