Interleukin-12p40 overexpression promotes interleukin-12p70 and interleukin-23 formation but does not affect bacille Calmette-Guérin and Mycobacterium tuberculosis clearance

Interleukin (IL)-12p40, a subunit of IL-12p70 and IL-23, has previously been shown to inhibit IL-12p70 activity and interferon-gamma (IFN-gamma) production. However, recent evidence has suggested that the role of IL-12p40 is more complex. To study the contribution of IL-12p40 to immune responses against mycobacterial infections, we have used transgenic (tg) mice overexpressing IL-12p40 under the control of a major histocompatibility complex-II promoter. The IL-12p40 transgene was expressed during steady state at concentrations of 129 +/- 25 ng/ml of serum and 75 +/- 13 ng per spleen, while endogenous IL-12p40 was hardly detectable in control littermates. Bacille Calmette-Guérin (BCG) infection strongly induced the expression of IL-12p40 transgene in infected organs, and IL-12p40 monomeric and dimeric forms were identified in spleen of IL-12p40 tg mice. Excessive production of IL-12p40 resulted in a 14-fold increase in IL-12p70 serum levels in tg mice versus non-transgenic mice. IL-23 was also strongly elevated in the serum and spleens of IL-12p40 tg mice through BCG infection. While IFN-gamma and tumour necrosis factor protein levels were similar in IL-12p40 tg and non-transgenic mice, Th2 type immune responses were reduced in IL-12p40 tg mice. The number of BCG granulomas and macrophage expressing inducible nitric oxide synthase were similar in IL-12p40 tg and non-transgenic mice. IL-12p40 tg mice were as resistant as non-transgenic mice to BCG and Mycobacterium tuberculosis infections as they could efficiently control bacillary growth. These data show that high amounts of IL-12p40 promotes IL-12p70 and IL-23 formation, but that does not affect T helper 1 type immune responses and granuloma function, thus leading to normal mycobacterial clearance in infected organs.     

Absent left common carotid artery in a right aortic arch: Separate origins of left internal and external carotid arteries from brachiocephalic artery

We present a case of cyanotic congenital heart disease with left common carotid artery agenesis in the setting of the right aortic arch highlighting the potential implications in management.     

Ruptured sinus of valsalva presenting late following repair of tetralogy of fallot

Rupture of sinus of valsalva following repair of tetralogy of fallot (TOF) is very rare. It should be suspected as a cause of recurrent or prolonged pleural effusion and congestive cardiac failure in patients who have undergone repair of TOF. We report one such patient.     

Congenital right coronary artery aneurysm with fistula to right ventricle associated with isolated pulmonary valvular stenosis

Congenital aneurysmal dilatation of coronary artery with coronary cameral fistula is rare in childhood. We report an even rarer association of congenital right coronary artery aneurysm and right coronary artery to right ventricle fistula with bicuspid pulmonary valve stenosis and an intact ventricular septum in a 3-year-old child.     

Incidental detection of calcified left coronary artery pseudoaneurysm years after surgery for TOF

We present images from computed tomography angiography in a 40-year-old female with a calcified pseudo-aneurysm in her left coronary artery, who had previously undergone repair of tetralogy of Fallot.     

A two-vessel aortic arch: Rare configuration with bilateral brachiocephalic arteries

We present a case of type B aortic dissection with a rare aortic arch branching variation whereby two separate brachiocephalic trunks arise from the arch. This case also highlights the potential implications of this variant in the management of thoracic aortic dissections and aneurysms.