Adalimumab therapy was associated with a significant decrease in sperm count in a 35-year-old man who had taken the biologic for 3 years as treatment for ankylosing spondylitis, according to a case report presented in the March issue of Annals of the Rheumatic Diseases.

Anti-tumor necrosis factor (anti-TNF) agents have been used in rheumatology for more than a decade, and few new side effects have been observed, wrote Dr. Lukas M. Wildi and Dr. Boulos Haraoui of the University of Montreal.

The patient was the father of a healthy 4-year-old, but after 3 years of adalimumab treatment he was tested for infertility. A sperm analysis showed a combination of decreased sperm motility and an unusually low sperm count (0.9 million/mL), which led to a diagnosis of oligoasthenozoospermia (Ann. Rheum. Dis. 2012;71:473-4).

No other cause of the problem was identified, and the patient discontinued adalimumab. After 3 months of no treatment, the patient’s sperm count increased to 6 million/mL, but only 1% of the sperm were normal. However, after 6 months, the sperm count increased to 12 million/mL and the sperm morphology reached the normal range (15%), but sperm motility remained below normal (motile concentration of 3.5 million/mL).

The patient’s symptoms of ankylosing spondylitis recurred, and he opted to resume adalimumab therapy after freezing some sperm, the researchers said.

Previous case series have shown similar reductions in sperm count and quality in men taking infliximab, the researchers said, but no impact on fertility was reported.

Additional studies have shown decreased sperm motility in ankylosing spondylitis patients on conventional treatment compared with those on TNF-alpha blockers, the researchers said. "However, in general, male patients also seem to remain fertile under anti-TNF alpha therapy," they said.

"Imbalances in TNF-alpha level, either too high or too low, seem to influence spermatogenesis and may sometimes lead to infertility," the researchers noted. "The present case demonstrates the reversibility of this adverse event after cessation of therapy and raises an issue not frequently discussed with male patients," they said.

The authors had no financial conflicts to disclose.