Congenital Severe Neutropenia Presents With Different Clinical, Hematological Findings Than Noncongenital Neutropenia

Greater infection rate, higher white blood cell (WBC), monocyte, and absolute neutrophil counts (ANC) are more significantly associated with severe congenital neutropenia (SCN) than with patients with idiopathic and recovered neutropenia, according study results.

SCN is a primary immunodeficiency disease defined by persistent severe neutropenia and recurrent bacterial infections. In addition to SCN, other diseases characterized by severe neutropenia include autoimmune neutropenia and severe idiopathic neutropenia. Seeking to determine any hematological differences between SCN and these other noncongenital forms of neutropenia, researchers enrolled 39 Chinese children with severe neutropenia for longer than 6 months unrealted to virus infection or autoimmune diseases.

Patients who had a gene mutation were diagnosed as having SCN, otherwise they would be considered as having severe neutropenia with an unknown etiology. Any recovery of neutropenia to an ANC >1.0 x 10⁹ /L for greater than 3 months was considered recovered neutropenia.

Of the patients, 7 had detectable gene mutations and were characterized as SCN. Out of the gene mutations associated with SCN—ELANE, HAX-1, and G6PC3—6 patients carried mutations of ELANE, while 1 patient carried a mutation of G6PC3. After a mean follow-up period of 1.92 years, 13 patients were lost to follow-up, leaving only 26 patients for analysis.

One patient with noncongenital severe neutropenia died from severe sepsis. The median ANC was 0.7 x10⁹ /L, and 10 of the 19 patients (52.63%) with severe neutropenia of unknown etiology recovered from neutropenia. For patients who did not recover, the median duration of neutropenia 31.5 months. Patients who did recover required on average 14.5 months.

Regardless neutropenia type, all patients had at least 1 infection, with pneumonia being the most prevalent. The median number of infection types in the SCN group was 2, while the severe neutropenia of unknown etiology and recovered severe neutropenia groups had a median of 1 infection type. The SCN group also had more frequent infections, with a median of 5 times per year compared with a median of 4 times per year for both the severe neutropenia of unknown etiology and the recovered neutropenia groups.

Median ANCs were significantly higher in the SCN group (0.4 x 10⁹ /L) compared with the severe neutropenia of unknown etiology (0.2 x 10⁹ /L) and the recovered severe neutropenia group (0.21 x 10⁹ /L). Median monocyte counts and white blood cell (WBC) counts were also higher in the SCN group compared with the other 2 groups (monocyte count was 1.60 x 10⁹ /L, 0.57 x 10⁹ /L, and 0.55 x 10⁹ /L and WBC count was 5.34 x 10⁹ /L, 4.15 x 10⁹ /L, and 4.40 x 10⁹ /L for SCN, severe neutropenia of unknown etiology, recovered neutropenia, respectively).

Reflecting on the study results, the researchers wrote that higher ANC, WBC, and monocyte counts warrant gene testing as these patients are more likely to have SCN.

Reference:

Gong RL, Wu J, Chen TX, et al. Clinical, laboratory, and molecular characteristics and remission status in children with severe congenital and non-congenital neutropenia. Front Pediatr. 2018;6:305. doi: 10.3389/fped.2018.00305.