Complications
Large deletions in the region of the CYBB gene are known to delete adjacent genes, such as XK, the gene that controls the expression of the Kell blood group antigen.
Patients with chronic granulomatous disease (CGD) who have this gene deletion can become sensitized to Kell antigens after RBC transfusion, leading to hemolytic complications after subsequent transfusions.
For this reason, carefully examine the Kell-antigen status in patients with chronic granulomatous disease who require a blood transfusion.
Prognosis
The prognosis for patients with chronic granulomatous disease has improved over the last two decades. No formal studies of the natural history of this disease have been conducted, but as previously stated, a European study found the mean survival time for patients with X-linked chronic granulomatous disease (gp91phox deficient) to be 37.8 years, and for those with autosomal recessive chronic granulomatous disease, 49.6 years. [8] The highest mortality rate is in early childhood. The usual cause of death is infection. However, chronic granulomatous disease has significant clinical heterogeneity in the severity of disease in affected patients.
Although in general patients with the X-linked form of the disease have more severe disease and patients with the p47-deficient autosomal recessive form have milder disease, many patients are exceptions to this rule. Patients with identical genetic defects can have different clinical presentations, making definition of prognosis for individual patients difficult.
A French retrospective study showed no significant difference in the frequency or severity of infections in patients with either X-linked or autosomally inherited chronic granulomatous disease. [27] Of 11 patients in whom chronic granulomatous disease was diagnosed after adolescence, 8 had X-linked chronic granulomatous disease. However, all 8 patients had small but detectable quantities of cytochrome b 558.
A case report describes a previously healthy 67-year-old man with X-linked chronic granulomatous disease who developed P cepacia sepsis. He had a CYBB gene mutation consisting of a single base substitution that resulted in a quantitatively normal but dysfunctional cytochrome b. His neutrophils exhibited markedly deficient phox activity.
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Scanning electron micrograph of Aspergillus species.
