Hypogammaglobulinemia in racing Alaskan sled dogs

Serum immunoglobulin dynamics have not been studied in racing sled dogs, despite hypoglobulinemia having been reported during racing events.

Hypoglobulinemia in racing sled dogs is associated with decreases in serum IgA, IgE, IgG, and IgM concentrations during prolonged exercise.

One hundred and fifty-seven Alaskan sled dogs that successfully completed a 1,000 mile race.

Serum was obtained from 118 sled dogs within 1 month before the race and within 12 hours after completing the race. Serum also was obtained after 4 months of rest from 51 dogs that successfully completed the race, including 12 previously sampled dogs. Serum total protein ([TP]), albumin, and globulin ([Gl]) were measured, and serum IgA, IgE, IgG, and IgM were quantified by ELISA.

The proportion of dogs with [Gl] < or = 2.2 g/dL was significantly greater immediately after racing (38 of 118 dogs, 32.2%) than before racing (21 of 118 dogs, 17.8%, P = .005). Four months after racing, [Gl] was < or = 2.2 g/dL in 23.5% (12 of 51) of dogs. [IgG] was significantly lower before (8.21 +/- 4.95 mg/mL) and immediately after (7.97 +/- 5.62) racing compared with 4 months after racing (18.88 +/- 5.76). Serum [IgM] and [IgE] were higher and [IgA] was lower before racing compared with immediately after racing.

Sled dogs participating in long-distance racing have substantial decreases in [IgG] in addition to decreases in [IgM] and [IgE]. The pronounced hypogammaglobulinemia observed in a large proportion of racing sled dogs might predispose them to infectious disease.