Primary immunodeficiency (PID) has not been well known in Indonesia. Most physicians considered that PID is difficult to diagnose because the laboratory equipment in Indonesia is not complete. However, using simple laboratory tests such as CBC, a lot of data can be retrieved and be used as a clue in diagnosing PID.
Case
A baby girl, 7 days old, was referred to neonatology unit from other hospital due to thrombocytopenia with mark increased in AST and ALT. She received IVIG for 3 days in previous hospital. Her laboratory tests showed the percentage of lymphocytes ranged between 35.6 % - 66 %. Retrospective calculation revealed total lymphocyte count ranged between 2760 – 3830/uL (normal value >3400/uL). Neutrophil count within normal limits. Levels of IgM and IgG antibodies to rubella increased, accompanied by increased levels of IgG antibodies to toxoplasma, CMV and HSV1. She received PRC and TC transfusions. She was diagnosed as having rubella infection, discharged in good condition after 24 days of treatment. She then had Hepatitis B and BCG vaccination in outpatient clinic.
At age 3 months, she experienced dyspnea, admitted to PICU for pneumonia that needed ventilator support. Her laboratory tests again showed lymphopenia. Further exploration found increased levels of IgM, with normal level of IgG, IgA and IgE, also decreased CD4 and C3 levels. HIV PCR was negative. IgM CMV was positive; she was treated with gancyclovir. She was died after 30 days of hospitalization.
Discussion
CBC test result does not automatically include the value of total lymphocytes; it included only the percentage of lymphocytes. Because the lymphocytes percentage were always within normal limits, the treating physicians were not concerned with the low value of total lymphocytes, reflecting the low levels of T and/or B lymphocytes. Unfortunately, the patient then underwent severe infection and further tests found low CD4 lymphocyte levels with increased levels of IgM. There should be an opportunity to explore PID, especially in this case the possibility of Severe Combined Immune Deficiency (SCID), in the first hospitalization during newborn period. If we were aware of PID, this patient could be treated and prevented for possible severe infections .
Conclusions
Simple tests such as CBC needs to be interpreted in more detailed of the presence of lymphopenia or neutropenia to be indicative of primary immunodeficiency.