Is lymphocytosis (an increase in lymphocytes, a type of white blood cell) associated with enteric fever (typhoid fever)?

From the Guidelines

No, enteric fever typically does not cause absolute lymphocytosis, but rather relative lymphocytosis with an overall decrease in white blood cell count. In the context of enteric fever, the total white blood cell count and differential may provide suggestions of a bacterial etiology, and a monocyte predominance may suggest the presence of an intracellular pathogen such as Salmonella 146. According to the 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea 1, the Widal test, a serologic test, should not be used for diagnosis of enteric fever due to poor performance characteristics.

The hematological pattern in enteric fever is characterized by leukopenia with a total white blood cell count between 2,000-4,000 cells/μL, and while the proportion of lymphocytes may increase relative to neutrophils (relative lymphocytosis), the absolute lymphocyte count is typically normal or decreased. This finding can be helpful diagnostically, as it distinguishes enteric fever from other bacterial infections that typically cause leukocytosis. Key points to consider include:

• Leukopenia is a characteristic feature of enteric fever
• Relative lymphocytosis may occur, but absolute lymphocytosis is not typical
• The Widal test is not recommended for diagnosis due to poor performance characteristics 1
• Monocyte predominance may suggest the presence of an intracellular pathogen such as Salmonella 1

From the Research

Lymphocytosis in Enteric Fever

• Lymphocytosis is not directly mentioned in the provided studies as a common feature of enteric fever 2, 3, 4, 5, 6.
• However, enteric fever can lead to complications such as hemophagocytic lymphohistiocytosis (HLH), which is characterized by an abnormal immune response and can affect lymphocyte counts 6.
• The studies primarily focus on the treatment and management of enteric fever, including the use of antimicrobials such as azithromycin, ceftriaxone, and fluoroquinolones 2, 3, 4, 5.
• There is no clear evidence to suggest that lymphocytosis is a typical presentation of enteric fever, but it may be associated with certain complications or immune responses 6.

Immune Response in Enteric Fever

• Enteric fever can trigger an immune response, which may lead to changes in lymphocyte counts 6.
• The use of antimicrobials such as azithromycin and ceftriaxone can affect the immune response and potentially influence lymphocyte counts 2, 3, 5.
• However, the relationship between enteric fever, antimicrobial treatment, and lymphocytosis is not well-established in the provided studies 2, 3, 4, 5, 6.

Complications of Enteric Fever

• Enteric fever can lead to complications such as HLH, which is associated with an abnormal immune response and can affect lymphocyte counts 6.
• Other complications of enteric fever include coagulopathy, encephalopathy, and high mortality rates 6.
• The management of enteric fever and its complications requires careful consideration of antimicrobial treatment and supportive care 2, 3, 4, 5, 6.