Methods (Differential Diagnosis, Investigations and Treatment):
A complete blood count (CBC) showed leukopenia at the expense of severe
neutropenia, mild normocytic anemia, and normal platelets.
Table 1 shows the initial lab results for the patient. (separate File)
Differential Diagnosis included infections, sarcoidosis, systemic lupus
erythematosus, and myeloproliferative syndromes. Further workup was
carried out to determine the cause of decreased neutrophil count. A
chemistry panel showed paraproteinemia, normal kidney function, and
normal liver enzymes. The infectious panel showed a negative rapid COVID
test, HIV negative, hepatitis C antibody test non-reactive, and
serologic testing for hepatitis B suggested passive immunity. She was
found to have a positive antinuclear antibody (ANA) test and a positive
rheumatoid factor. The anti-cyclic citrullinated peptide (anti-CCP) was
high >340. A peripheral flow cytometry was unremarkable.
The patient had a bone marrow biopsy, and aspiration showed a norm
cellular marrow with maturing trilineage hematopoiesis, a preserved
marrow reserve pool on the two occasions. In addition, there was no
morphologic evidence of overt or advanced myelodysplasia, acute
leukemia, metastatic neoplasm, plasma cell dyscrasia, or lymphoma.
An ultrasound of the abdomen showed a slightly enlarged liver due to
possible fatty infiltration, and the spleen measured 11.8 x 4.5 x 13.6
cm, which was mildly enlarged (Figure 1) (separate File)
Due to the positive RF factor, she was evaluated by rheumatology due to
features of Felty syndrome and diagnosed with rheumatoid arthritis. She
initially started Prednisone 10 mg daily and later transitioned to
Hydroxychloroquine 200 mg qd. Despite treatment, the patient reported
only mild improvement in her body aches, but her neutropenia and severe
fatigue persisted.
Due to her dropping neutrophil count and peak COVID infection, a joint
decision to treat her was made with a trial of prednisone 1 mg/kg daily
for two weeks, resulting in the normalization of the absolute neutrophil
count (ANC). This response was sustained for four months before
relapsing. After stopping steroids, the ANC level again dropped.
Rituximab was then considered as an alternative for long-term management
of autoimmune neutropenia in the setting of Felty syndrome.
Figure 2 and Figure 3 show the trend of absolute neutrophil count and
white blood cell count after treatment with steroids and Rituximab. (In
separate Files)