Patients with
primary antibody deficiency (PAD) are being increasingly diagnosed in the developing world. However, care of these children continues to remain suboptimal due to financial and social constraints.
Immunoglobulin (Ig) trough level is an important predicting factor for
infections in children on replacement immunoglobulin therapy. There are no data on this aspect from the developing world. Therefore, we studied serial
immunoglobulin G (
IgG) trough levels in 14 children with
X-linked agammaglobulinemia (XLA) receiving replacement
intravenous immunoglobulin (
IVIG).
Infections during the course of enrolment were documented prospectively. Mean age at the time of diagnosis was 5.1 years (range 2-11 years). Mean time from onset of symptoms and initiation of
therapy was 3.3 years. Two children had established chronic
lung disease prior to enrolment. Total numbers of major and minor
infections were 7 and 40, respectively. At a mean dose of 414 mg/kg/month of
IVIG, mean trough
IgG level was 435 mg/dl. Median
IgG trough levels during the episodes of major and minor
infections were 244 and 335 mg/dl, respectively. An escalation in
IVIG dose of 100 mg/kg produced an increase in serum
IgG levels by 53.6 mg/dl. Median trough
IgG level of 354 mg/dl was found to be protective with 64% sensitivity and 75% specificity. A median dose of 397 mg/kg was required to keep children free of
infections. Despite financial constraints and several challenges in the context of a developing country, children with XLA have good outcome on replacement immunoglobulin therapy. Furthermore, mean biological trough
IgG levels are much lower than reported in for Western patients; however, studies involving larger number of subjects are required in future to draw firm conclusions.